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Lymphocytic Choriomeningitis Virus

Lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology (LCMV) is a single-stranded RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology transmitted to humans via rodents, the primary reservoir Reservoir Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers. Escherichia coli. Viral infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease can occur through direct contact (such as through a break in the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions) with rodent urine, saliva Saliva The clear, viscous fluid secreted by the salivary glands and mucous glands of the mouth. It contains mucins, water, organic salts, and ptyalin. Salivary Glands: Anatomy, or droppings or via inhalation of aerosolized virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology. Vertical transmission Vertical transmission The transmission of infectious disease or pathogens from one generation to another. It includes transmission in utero or intrapartum by exposure to blood and secretions, and postpartum exposure via breastfeeding. Congenital TORCH Infections and, rarely, organ transplantation Organ Transplantation Transplantation is a procedure that involves the removal of an organ or living tissue and placing it into a different part of the body or into a different person. Organ transplantations have become the therapeutic option of choice for many individuals with end-stage organ failure. Organ Transplantation also lead to infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease. The disease typically results in a self-limited, febrile, biphasic disease. In severe cases, patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship can present with encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis, aseptic meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis, or meningoencephalitis Meningoencephalitis Encephalitis. Lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease of pregnant women have also been recognized as a significant teratogen resulting in fetal death or congenital Congenital Chorioretinitis defects. Diagnosis is by serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus or RT-PCR RT-PCR A variation of the pcr technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard pcr protocols. Polymerase Chain Reaction (PCR). Management is supportive.

Last updated: Jul 7, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Classification

Rna viruses flowchart classification

RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology identification Identification Defense Mechanisms:
Viruses can be classified in many ways. Most viruses, however, will have a genome formed by either DNA or RNA. RNA genome viruses can be further characterized by either a single- or double-stranded RNA. “Enveloped” viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology are covered by a thin coat of cell membrane Cell Membrane A cell membrane (also known as the plasma membrane or plasmalemma) is a biological membrane that separates the cell contents from the outside environment. A cell membrane is composed of a phospholipid bilayer and proteins that function to protect cellular DNA and mediate the exchange of ions and molecules. The Cell: Cell Membrane (usually taken from the host cell). If the coat is absent, the viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology are called “naked” viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology. Viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology with single-stranded genomes are “positive-sense” viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology if the genome Genome The complete genetic complement contained in the DNA of a set of chromosomes in a human. The length of the human genome is about 3 billion base pairs. Basic Terms of Genetics is directly employed as messenger RNA Messenger RNA RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm. RNA Types and Structure ( mRNA mRNA RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm. RNA Types and Structure), which is translated into proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis. “Negative-sense,” single-stranded viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology employ RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure dependent RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure polymerase, a viral enzyme, to transcribe their genome Genome The complete genetic complement contained in the DNA of a set of chromosomes in a human. The length of the human genome is about 3 billion base pairs. Basic Terms of Genetics into messenger RNA Messenger RNA RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm. RNA Types and Structure.

Image by Lecturio. License: CC BY-NC-SA 4.0

General Characteristics

Basic features of lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology (LCMV)

  • Enveloped
  • Spherical
  • Midsize (diameter between 60 and 300 nm)
  • 2 viral surface glycoproteins Glycoproteins Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins. Basics of Carbohydrates on envelope Envelope Bilayer lipid membrane acquired by viral particles during viral morphogenesis. Although the lipids of the viral envelope are host derived, various virus-encoded integral membrane proteins, i.e. Viral envelope proteins are incorporated there. Virology: G1 and G2
  • Virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology genome Genome The complete genetic complement contained in the DNA of a set of chromosomes in a human. The length of the human genome is about 3 billion base pairs. Basic Terms of Genetics:
    • Encapsulated Encapsulated Klebsiella by a helical Helical Computed tomography where there is continuous x-ray exposure to the patient while being transported in a spiral or helical pattern through the beam of irradiation. This provides improved three-dimensional contrast and spatial resolution compared to conventional computed tomography, where data is obtained and computed from individual sequential exposures. Computed Tomography (CT) nucleocapsid
    • Segmented with:
      • A large (L) single-stranded, negative-sense RNA Negative-sense RNA RNA viruses that have their genetic material encoded in the form of single-stranded, negative-sense RNA. Unlike retroviruses they do not employ DNA intermediates in their life-cycle. Respiratory Syncytial Virus  
      • A small (S) ambisense RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure
    • Carries RNA-dependent RNA polymerase RNA-dependent RNA polymerase An enzyme that catalyses rna-template-directed extension of the 3′- end of an RNA strand by one nucleotide at a time, and can initiate a chain de novo. Virology (RDRP)

Taxonomy:

  • Family Arenaviridae Arenaviridae A family of RNA viruses naturally infecting rodents and consisting of one genus (arenavirus) with two groups: old world arenaviruses and new world arenaviruses. Infection in rodents is persistent and silent. Vertical transmission is through milk-, saliva-, or urine-borne routes. Horizontal transmission to humans, monkeys, and other animals is important. Lassa Virus
  • Genus Mammarenavirus Mammarenavirus Lassa Virus
  • Viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology contain host ribosomes Ribosomes Multicomponent ribonucleoprotein structures found in the cytoplasm of all cells, and in mitochondria, and plastids. They function in protein biosynthesis via genetic translation. The Cell: Organelles, giving the virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology a granular appearance (arenosus is Latin for “sandy”)
  • Other arenaviruses include:
    • Lassa virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology (Lassa fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
    • Junin virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology (Argentine hemorrhagic fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
    • Machupo virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology (Bolivian hemorrhagic fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
    • Guanarito virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology (Venezuelan hemorrhagic fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
    • Sabia (Brazilian hemorrhagic fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
    • Chapare (Chapare hemorrhagic fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
    • Lujo (Lujo hemorrhagic fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
Electron micrograph of lymphocytic choriomeningitis virus

Electron micrograph of lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology

Image: “Negative stain electron micrograph of an arenavirus from a mouse that tested positive for LCM” by CDC. License: Public Domain

Epidemiology

Pathogenesis

Reservoir Reservoir Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers. Escherichia coli

Arenaviruses: cause chronic infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease in rodents (house mouse, Mus musculus)

Transmission

  • Direct contact with material contaminated by feces/urine/ saliva Saliva The clear, viscous fluid secreted by the salivary glands and mucous glands of the mouth. It contains mucins, water, organic salts, and ptyalin. Salivary Glands: Anatomy of infected rodents (through the eye, nose Nose The nose is the human body’s primary organ of smell and functions as part of the upper respiratory system. The nose may be best known for inhaling oxygen and exhaling carbon dioxide, but it also contributes to other important functions, such as tasting. The anatomy of the nose can be divided into the external nose and the nasal cavity. Nose and Nasal Cavity: Anatomy, mouth, a break in the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions, or animal bite) 
  • Inhalation of aerosolized virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology 
  • Vertical transmission Vertical transmission The transmission of infectious disease or pathogens from one generation to another. It includes transmission in utero or intrapartum by exposure to blood and secretions, and postpartum exposure via breastfeeding. Congenital TORCH Infections from mother to fetus
  • Organ transplantation Organ Transplantation Transplantation is a procedure that involves the removal of an organ or living tissue and placing it into a different part of the body or into a different person. Organ transplantations have become the therapeutic option of choice for many individuals with end-stage organ failure. Organ Transplantation (recipient of infected donor tissue)

Life cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation

  1. Virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology attaches to host receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors through envelope Envelope Bilayer lipid membrane acquired by viral particles during viral morphogenesis. Although the lipids of the viral envelope are host derived, various virus-encoded integral membrane proteins, i.e. Viral envelope proteins are incorporated there. Virology glycoproteins Glycoproteins Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins. Basics of Carbohydrates
  2. Virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology is subsequently endocytosed, thus gaining entry into the cell. 
  3. Viral fusion with an endosome Endosome Cytoplasmic vesicles formed when coated vesicles shed their clathrin coat. Endosomes internalize macromolecules bound by receptors on the cell surface. Hepatitis C Virus follows. 
  4. The virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology merges with the endosome Endosome Cytoplasmic vesicles formed when coated vesicles shed their clathrin coat. Endosomes internalize macromolecules bound by receptors on the cell surface. Hepatitis C Virus membrane, allowing the release Release Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane. Virology of the viral ribonucleocapsid into the cytoplasm. 
  5. The RDRP mediates the viral gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics replication and transcription Transcription Transcription of genetic information is the first step in gene expression. Transcription is the process by which DNA is used as a template to make mRNA. This process is divided into 3 stages: initiation, elongation, and termination. Stages of Transcription in the cytoplasm of the host. 
  6. New virions are assembled and budding Budding Mycology occurs, releasing the virion to infect other cells. 
Lassa virus

The life cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation of lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology:
1. Virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology attaches to host receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors through envelope Envelope Bilayer lipid membrane acquired by viral particles during viral morphogenesis. Although the lipids of the viral envelope are host derived, various virus-encoded integral membrane proteins, i.e. Viral envelope proteins are incorporated there. Virology glycoproteins Glycoproteins Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins. Basics of Carbohydrates.
2. Virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology is subsequently endocytosed, thus gaining cell entry.
3. Viral fusion with an endosome Endosome Cytoplasmic vesicles formed when coated vesicles shed their clathrin coat. Endosomes internalize macromolecules bound by receptors on the cell surface. Hepatitis C Virus follows.
4. The virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology fuses with the endosome Endosome Cytoplasmic vesicles formed when coated vesicles shed their clathrin coat. Endosomes internalize macromolecules bound by receptors on the cell surface. Hepatitis C Virus membrane, allowing release Release Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane. Virology of the viral ribonucleocapsid into the cytoplasm.
5. The RNA-dependent RNA polymerase RNA-dependent RNA polymerase An enzyme that catalyses rna-template-directed extension of the 3′- end of an RNA strand by one nucleotide at a time, and can initiate a chain de novo. Virology (RdRP) mediates the viral gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics replication and transcription Transcription Transcription of genetic information is the first step in gene expression. Transcription is the process by which DNA is used as a template to make mRNA. This process is divided into 3 stages: initiation, elongation, and termination. Stages of Transcription in the host cytoplasm.
6. New virions are assembled and budding Budding Mycology occurs, releasing the virion to infect other cells.
vRNP: viral ribonucleoprotein

Image by Lecturio.

Host risk factors

  • Owners of pet PET An imaging technique that combines a positron-emission tomography (PET) scanner and a ct X ray scanner. This establishes a precise anatomic localization in the same session. Nuclear Imaging mice or hamsters
  • Laboratory workers

Disease process

LCMV is not cytotoxic Cytotoxic Parvovirus B19, but while the host immune response tries to eliminate the virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology, this may also trigger Trigger The type of signal that initiates the inspiratory phase by the ventilator Invasive Mechanical Ventilation immune-mediated disease. The immune response produces the different manifestations of the disease.

  • Incubation Incubation The amount time between exposure to an infectious agent and becoming symptomatic. Rabies Virus period: up to 13 days
  • Primary viremia Primary viremia Mumps Virus/Mumps ensues → dissemination to other organs
  • The virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology reaches the CNS ( meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy, choroid plexus Choroid plexus A villous structure of tangled masses of blood vessels contained within the third, lateral, and fourth ventricles of the brain. It regulates part of the production and composition of cerebrospinal fluid. Ventricular System: Anatomy, and ventricular ependymal lining), leading to infiltration of inflammatory cells.

Clinical Presentation

Acquired lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology infection

Infection with LCMV results in a biphasic illness.

Symptom onset:

  • Occurs 8–13 days after exposure
  • 1st symptoms may last 5–7 days.
  • 33% are asymptomatic.
  • 50% have febrile illness without neurologic involvement.

1st-phase symptoms:

  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
  • Lack of appetite
  • Headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess
  • Muscle aches
  • Malaise Malaise Tick-borne Encephalitis Virus
  • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics and/or vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
  • Lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy
  • Maculopapular Maculopapular Dermatologic Examination rash Rash Rocky Mountain Spotted Fever

2nd-phase symptoms:

Following a few days of recovery, 2nd-phase symptoms may start, which include neurologic symptoms (typical of meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis and/or encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis).

  • Increased headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess, photophobia Photophobia Abnormal sensitivity to light. This may occur as a manifestation of eye diseases; migraine; subarachnoid hemorrhage; meningitis; and other disorders. Photophobia may also occur in association with depression and other mental disorders. Migraine Headache
  • Nuchal rigidity Nuchal Rigidity Meningitis
  • Change in mental status ( lethargy Lethargy A general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction. Hyponatremia, coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma)

Other less frequent findings:

  • Orchitis Orchitis Inflammation of a testis. It has many features of epididymitis, such as swollen scrotum; pain; pyuria; and fever. It is usually related to infections in the urinary tract, which likely spread to the epididymis and then the testis through either the vas deferens or the lymphatics of the spermatic cord. Epididymitis and Orchitis
  • Myocarditis Myocarditis Myocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. Myocarditis
  • Arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis
  • Parotitis Parotitis Inflammation of the parotid gland. Mumps Virus/Mumps
  • Pneumonitis Pneumonitis Human Herpesvirus 6 and 7

Congenital Congenital Chorioretinitis lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology infection

Women who become infected with LCMV during pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care can pass the infection to the fetus.

  • Infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease occurring during the 1st trimester may result in fetal death or spontaneous abortion Spontaneous abortion Spontaneous abortion, also known as miscarriage, is the loss of a pregnancy before 20 weeks’ gestation. However, the layperson use of the term “abortion” is often intended to refer to induced termination of a pregnancy, whereas “miscarriage” is preferred for spontaneous loss. Spontaneous Abortion.
  • Infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease in the 2nd and 3rd trimesters can result in birth defects, including:
    • Blindness Blindness The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of eye diseases; optic nerve diseases; optic chiasm diseases; or brain diseases affecting the visual pathways or occipital lobe. Retinopathy of Prematurity: Chorioretinitis Chorioretinitis Chorioretinitis is the inflammation of the posterior segment of the eye, including the choroid and the retina. The condition is usually caused by infections, the most common of which is toxoplasmosis. Some of these infections can affect the fetus in utero and present as congenital abnormalities. Chorioretinitis is a common finding in children.
    • Developmental delay
    • Hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage 
    • Epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy

Organ transplant lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology infection

Significant immunosuppression in transplant recipients play a role in the development of disease:

  • Encephalopathy Encephalopathy Hyper-IgM Syndrome
  • Respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure
  • Renal/hepatic impairment
  • Graft Graft A piece of living tissue that is surgically transplanted Organ Transplantation dysfunction
  • Coagulopathy
  • Thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever

Diagnosis

Diagnostic tests Diagnostic tests Diagnostic tests are important aspects in making a diagnosis. Some of the most important epidemiological values of diagnostic tests include sensitivity and specificity, false positives and false negatives, positive and negative predictive values, likelihood ratios, and pre-test and post-test probabilities. Epidemiological Values of Diagnostic Tests

  • Confirmatory tests for the LCMV include:
    • Detecting IgM IgM A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin. Immunoglobulins: Types and Functions and IgG IgG The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b. Hypersensitivity Pneumonitis antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions in the CSF and serum
    • RT-PCR RT-PCR A variation of the pcr technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard pcr protocols. Polymerase Chain Reaction (PCR)
    • CSF viral culture Viral culture West Nile Virus
  • For congenital Congenital Chorioretinitis LCMV infection, babies may not have the virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology anymore, so IgM IgM A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin. Immunoglobulins: Types and Functions and IgG IgG The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b. Hypersensitivity Pneumonitis levels are used.
  • Common findings in the CSF include:
    • Increase in protein levels
    • Lymphocytic pleocytosis Pleocytosis Tick-borne Encephalitis Virus
    • Decrease in the glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance levels

Additional findings

During the 1st phase of the disease, the most common laboratory abnormalities are

  • CBC:
    • Leukopenia
    • Thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia
  • Elevated liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes

Management

  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with aseptic meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis, encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis, or meningoencephalitis Meningoencephalitis Encephalitis require: 
    • Hospitalization Hospitalization The confinement of a patient in a hospital. Delirium
    • Supportive treatment based on severity
  • Recovery generally takes up to 3 weeks.
  • Mortality Mortality All deaths reported in a given population. Measures of Health Status rate:
    • Acquired LCMV infection: approximately 1%
    • Congenital Congenital Chorioretinitis LCMV infection: can reach 35% depending on the associated disorders

Comparison of Species

Arenaviruses can cause neurologic disease (LCMV) and/or hemorrhagic fevers, for which one of the major etiologies is the Lassa virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology.

Table: Comparison of lymphocytic choriomeningitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology (LCMV) and Lassa virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
Organism LCMV Lassa virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
Family Arenaviridae Arenaviridae A family of RNA viruses naturally infecting rodents and consisting of one genus (arenavirus) with two groups: old world arenaviruses and new world arenaviruses. Infection in rodents is persistent and silent. Vertical transmission is through milk-, saliva-, or urine-borne routes. Horizontal transmission to humans, monkeys, and other animals is important. Lassa Virus
Genus Mammarenavirus Mammarenavirus Lassa Virus
Characteristics
  • Enveloped
  • Midsize
  • Spherical
  • Segmented genome Genome The complete genetic complement contained in the DNA of a set of chromosomes in a human. The length of the human genome is about 3 billion base pairs. Basic Terms of Genetics
  • Single-stranded RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure (ssRNA)
  • Enveloped
  • Midsize
  • Spherical
  • Segmented genome Genome The complete genetic complement contained in the DNA of a set of chromosomes in a human. The length of the human genome is about 3 billion base pairs. Basic Terms of Genetics
  • ssRNA
Reservoir Reservoir Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers. Escherichia coli Rodents
Transmission
  • Aerosols Aerosols Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents. Coxiella/Q Fever
  • Direct contact
  • Vertical transmission Vertical transmission The transmission of infectious disease or pathogens from one generation to another. It includes transmission in utero or intrapartum by exposure to blood and secretions, and postpartum exposure via breastfeeding. Congenital TORCH Infections
  • Organ transplantation Organ Transplantation Transplantation is a procedure that involves the removal of an organ or living tissue and placing it into a different part of the body or into a different person. Organ transplantations have become the therapeutic option of choice for many individuals with end-stage organ failure. Organ Transplantation
  • Aerosols Aerosols Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents. Coxiella/Q Fever
  • Direct contact
  • Ingestion
  • Person to person (through exposure to blood, secretions, tissue of infected individual)
Clinical course Biphasic:
  • Flu-like illness
  • Meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis, encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis
  • Majority of cases asymptomatic or only mild symptoms
  • Hemorrhagic manifestations
  • Deafness is common.
Diagnosis
Management Supportive
  • Supportive
  • Ribavirin Ribavirin A nucleoside antimetabolite antiviral agent that blocks nucleic acid synthesis and is used against both RNA and DNA viruses. Antivirals for Hepatitis C
Prevention Avoid contact with rodents and their body fluids.
  • Avoid contact with rodents and their body fluids.
  • Personal protective equipment Personal protective equipment Specialized clothing or equipment worn for protection against health hazards. Personal protective equipment may include masks; respiratory protective devices; head protective devices; eye protective devices; ear protective devices; protective clothing; and protective footwear. Leptospira/Leptospirosis

Differential Diagnosis

The following selected RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology can also lead to CNS infection. 

  • Tick-borne encephalitis Tick-borne encephalitis Encephalitis caused by neurotropic viruses that are transmitted via the bite of ticks. In europe, the diseases are caused by encephalitis viruses, tick-borne, which give rise to russian spring-summer encephalitis, central european encephalitis, louping ill encephalitis, and related disorders. Powassan encephalitis occurs in north america and russia and is caused by the powassan virus. Aseptic meningitis and rarely encephalitis may complicate colorado tick fever which is endemic to mountainous regions of the Western United States. Tick-borne Encephalitis Virus virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: due to a single-stranded RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology of the genus Flavivirus Flavivirus A genus of flaviviridae containing several subgroups and many species. Most are arboviruses transmitted by mosquitoes or ticks. The type species is yellow fever virus. Tick-borne Encephalitis Virus. Transmission primarily occurs via Ixodes ticks Ticks Blood-sucking acarid parasites of the order ixodida comprising two families: the softbacked ticks (argasidae) and hardbacked ticks (ixodidae). Ticks are larger than their relatives, the mites. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many tick-borne diseases, including the transmission of rocky mountain spotted fever; tularemia; babesiosis; african swine fever; and relapsing fever. Coxiella/Q Fever found in Europe, Russia, and Asia ASIA Spinal Cord Injuries. Most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are asymptomatic, but symptomatic individuals may experience a biphasic illness. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship can develop neurologic manifestations, such as meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis, encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis, or meningoencephalitis Meningoencephalitis Encephalitis. Serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus or PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) can confirm the diagnosis. There is no effective antiviral Antiviral Antivirals for Hepatitis B therapy for tick-borne encephalitis Tick-borne encephalitis Encephalitis caused by neurotropic viruses that are transmitted via the bite of ticks. In europe, the diseases are caused by encephalitis viruses, tick-borne, which give rise to russian spring-summer encephalitis, central european encephalitis, louping ill encephalitis, and related disorders. Powassan encephalitis occurs in north america and russia and is caused by the powassan virus. Aseptic meningitis and rarely encephalitis may complicate colorado tick fever which is endemic to mountainous regions of the Western United States. Tick-borne Encephalitis Virus virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, so management is supportive
  • Equine encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology: mosquito-borne arboviruses Arboviruses Arthropod-borne viruses. A non-taxonomic designation for viruses that can replicate in both vertebrate hosts and arthropod vectors. Included are some members of the following families: arenaviridae; bunyaviridae; reoviridae; togaviridae; and flaviviridae. Encephalitis (belonging to Togaviridae Togaviridae A family of RNA viruses, mainly arboviruses, consisting of two genera: alphavirus (group A arboviruses), and rubivirus. Virions are spherical, 60-70 nm in diameter, with a lipoprotein envelope tightly applied to the icosahedral nucleocapsid. Rubella Virus, genus Alphavirus Alphavirus A genus of togaviridae, also known as group a arboviruses, serologically related to each other but not to other togaviridae. The viruses are transmitted by mosquitoes. The type species is the sindbis virus. Equine Encephalitis Viruses) that can cause minor viral illness and, in severe cases, encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis in humans. The virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology is a positive-sense, single-stranded RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure. The eastern equine encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology is the most clinically relevant in the United States. The virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology is maintained in a cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation between mosquito and often avian hosts but spreads to humans via bridge vectors. Symptoms include fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess, and vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia, with the majority of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship recovering. The illness can progress to severe encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis. Diagnosis is by CSF studies, with serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus and virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology antigen Antigen Substances that are recognized by the immune system and induce an immune reaction. Vaccination or genomic sequence detection. There is no specific treatment, and therapy is largely supportive.
  • West Nile Virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: can cause neuroinvasive disease Neuroinvasive disease West Nile Virus, including meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis, encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis, and acute flaccid paralysis Acute flaccid paralysis West Nile Virus. The virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology is an enveloped, positive-sense, single-stranded RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology of the genus Flavivirus Flavivirus A genus of flaviviridae containing several subgroups and many species. Most are arboviruses transmitted by mosquitoes or ticks. The type species is yellow fever virus. Tick-borne Encephalitis Virus. The primary hosts are birds, and the disease is most often transmitted by Culex mosquitoes. Most people infected with the virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology are asymptomatic. Some patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship will have a self-limited febrile illness, termed West Nile fever West Nile fever A mosquito-borne viral illness caused by the West nile virus, a flavivirus and endemic to regions of africa, Asia, and europe. Common clinical features include headache; fever; maculopapular rash; gastrointestinal symptoms; and lymphadenopathy. Meningitis; encephalitis; and myelitis may also occur. The disease may occasionally be fatal or leave survivors with residual neurologic deficits. West Nile Virus. The diagnosis is confirmed with serum or CSF serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus or RT-PCR RT-PCR A variation of the pcr technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard pcr protocols. Polymerase Chain Reaction (PCR). Management is generally supportive. Prevention is aimed at local mosquito control and protection from mosquito bites. 
  • Saint Louis encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: enveloped, positive-sense, single-stranded RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology belonging to the genus Flavivirus Flavivirus A genus of flaviviridae containing several subgroups and many species. Most are arboviruses transmitted by mosquitoes or ticks. The type species is yellow fever virus. Tick-borne Encephalitis Virus and causing St. Louis encephalitis St. Louis Encephalitis A viral encephalitis caused by the St. Louis encephalitis virus, a flavivirus. It is transmitted to humans and other vertebrates primarily by mosquitoes of the genus culex. The primary animal vectors are wild birds and the disorder is endemic to the midWestern and southeastern United States. Infections may be limited to an influenza-like illness or present as an aseptic meningitis or encephalitis. Clinical manifestations of the encephalitic presentation may include seizures, lethargy, myoclonus, focal neurologic signs, coma, and death. St. Louis Encephalitis Virus. Transmission is by Culex mosquito species. Most infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease are asymptomatic. Symptomatic individuals may have flu-like symptoms Flu-Like Symptoms Babesia/Babesiosis, aseptic meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis, encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis, or meningoencephalitis Meningoencephalitis Encephalitis. The diagnosis is confirmed with serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus. There is no effective antiviral Antiviral Antivirals for Hepatitis B treatment, so management is supportive. Prevention is aimed at local mosquito control and personal protection with insect repellent Insect repellent Substances causing insects to turn away from them or reject them as food. St. Louis Encephalitis Virus and protective clothing. 

References:

  1. Bonthius D.J. (2012). Lymphocytic choriomeningitis virus: an underrecognized cause of neurologic disease in the fetus, child, and adult. Seminars in Pediatric Neurology 19:89–95. https://doi.org/10.1016/j.spen.2012.02.002
  2. Centers for Disease Control and Prevention. (2013). Viral hemorrhagic fevers. Retrieved May 20, 2021, from https://www.cdc.gov/vhf/virus-families/arenaviridae.html
  3. Centers for Disease Control and Prevention (2008). Brief report: Lymphocytic choriomeningitis virus transmitted through solid organ transplantation. MMWR Morb Mortal Wkly Rep 57:799–801.
  4. Centers for Disease Control and Prevention. (2014). Lassa fever. https://www.cdc.gov/vhf/lassa/symptoms/index.html
  5. Emonet, S., Retornaz, K., Gonzalez, J.P., de Lamballerie, X., Charrel, R.N. (2007). Mouse-to-human transmission of variant lymphocytic choriomeningitis virus. Emerg Infect Dis 13:472–475. https://doi.org/10.3201/eid1303.061141
  6. McDonald, P., Chandrasekar, P. (2017). Lymphocytic choriomeningitis virus (LCMV) infection. Medscape. Retrieved May 20, 2021, from https://emedicine.medscape.com/article/220796-overview
  7. Ryan K.J. (2017). Arthropod-borne and other zoonotic viruses. Chapter 16 of Sherris Medical Microbiology, 7th ed. https://accessmedicine.mhmedical.com/content.aspx?bookid=2268&sectionid=176083946
  8. Shao, J., Liang, Y., Ly, H. (2015). Human hemorrhagic fever causing arenaviruses: molecular mechanisms contributing to virus virulence and disease pathogenesis. Pathogens 4:283–306. https://doi.org/10.3390/pathogens4020283

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