Influenza 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 members of the Orthomyxoviridae family and the causative organisms of influenza, a highly contagious febrile respiratory disease. There are 3 primary influenza 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 (A, B, and C) and various subtypes, which are classified based on their virulent surface antigens, hemagglutinin Hemagglutinin Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc. Measles Virus ( HA HA Hemolytic anemia (HA) is the term given to a large group of anemias that are caused by the premature destruction/hemolysis of circulating red blood cells (RBCs). Hemolysis can occur within (intravascular hemolysis) or outside the blood vessels (extravascular hemolysis). Hemolytic Anemia) and neuraminidase Neuraminidase An enzyme that catalyzes the hydrolysis of alpha-2, 3, alpha-2, 6-, and alpha-2, 8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate. Antivirals for Influenza (NA). Influenza typically presents with a 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, myalgia Myalgia Painful sensation in the muscles. Ion Channel Myopathy, 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 symptoms of an upper respiratory infection Upper respiratory infection Rhinitis. Symptoms of gastroenteritis Gastroenteritis Gastroenteritis is inflammation of the stomach and intestines, commonly caused by infections from bacteria, viruses, or parasites. Transmission may be foodborne, fecal-oral, or through animal contact. Common clinical features include abdominal pain, diarrhea, vomiting, fever, and dehydration. Gastroenteritis may also commonly occur in children. Influenza is usually a self-limiting Self-Limiting Meningitis in Children condition, though viral or secondary bacterial pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia may complicate the disease. Management is generally supportive, although NA inhibitors can be helpful if initiated within 48 hours of infection. Prevention relies on the annual vaccination Vaccination Vaccination is the administration of a substance to induce the immune system to develop protection against a disease. Unlike passive immunization, which involves the administration of pre-performed antibodies, active immunization constitutes the administration of a vaccine to stimulate the body to produce its own antibodies. Vaccination of the public and practicing good hygiene.
Last updated: 9 May, 2022
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.
The influenza 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 member of the Orthomyxoviridae family.
A diagram of the structure of the Influenza 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 by Lecturio. License: CC BY-NC-SA 4.0Influenza
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 cause a febrile respiratory disease known as influenza.
There are 3 distinct clinically relevant species of 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:
Characteristics | Influenza A Influenza A Antivirals for Influenza | Influenza B | Influenza C |
---|---|---|---|
Natural hosts |
|
Humans only |
|
Epidemiology | Antigenic shift and drift | Antigenic drift only | Antigenic drift only |
Manifestations | Large epidemics and pandemics with significant mortality Mortality All deaths reported in a given population. Measures of Health Status | No pandemics; elderly and immunocompromised immunocompromised A human or animal whose immunologic mechanism is deficient because of an immunodeficiency disorder or other disease or as the result of the administration of immunosuppressive drugs or radiation. Gastroenteritis patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship | Mild disease without seasonality |
Antigenic shift:
Two or more different strains of a
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 combine to form a new subtype that is radically different.
Antigenic drift:
Mutations accumulate in the viral
genes
Genes
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.
DNA Types and Structure that code for viral surface
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 resulting in new antigenic sites. Changes are generally minor.
Influenza
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 replication:
1: A viral particle attaches its
hemagglutinin
Hemagglutinin
Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc.
Measles Virus (
HA
HA
Hemolytic anemia (HA) is the term given to a large group of anemias that are caused by the premature destruction/hemolysis of circulating red blood cells (RBCs). Hemolysis can occur within (intravascular hemolysis) or outside the blood vessels (extravascular hemolysis).
Hemolytic Anemia) spikes to
sialic acid
Sialic Acid
Antivirals for Influenza-containing
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 on the surface of respiratory epithelial cells.
2: The viral particle is internalized via
receptor
Receptor
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-mediated
endocytosis
Endocytosis
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. Endosomes play a central role in endocytosis.
The Cell: Cell Membrane.
3: Once inside the cell, the M2 protein acts as an ion channel, allowing an influx of hydrogen particles, which results in
uncoating
Uncoating
Intracellular step that follows virus internalization during which the viral nucleic acid and capsid are separated.
Virology of 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.
4: The viral
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 then moves into the
nucleus
Nucleus
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus.
The Cell: Organelles of the cell, where it is replicated and
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 is synthesized.
5: The
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 is then translated into new viral
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 using the cellular machinery.
6: Viral particles and newly replicated
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 are brought to the surface of the cell and assembled into virions.
7: As the new
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 buds off of the respiratory epithelial cells, the
hemagglutinin
Hemagglutinin
Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc.
Measles Virus again binds to the
sialic acid
Sialic Acid
Antivirals for Influenza-containing
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. The
neuraminidase
Neuraminidase
An enzyme that catalyzes the hydrolysis of alpha-2, 3, alpha-2, 6-, and alpha-2, 8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate.
Antivirals for Influenza (NA) then cleaves the new viral particle off of the respiratory epithelial cell so it can go infect nearby cells.
Influenza A Influenza A Antivirals for Influenza and B create the same disease patterns.
Adults:
Children:
The diagnosis of influenza infection is typically made clinically; however, rapid 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 may be useful if the results will influence management.
Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests showing right lower lobe bacterial pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia
Image: “Chest radiography” by Department of Critical Care Medicine, University Hospital Thessaly, Larissa, Greece. License: CC BY 2.0An AP supine radiograph on an intubated patient showing patchy consolidation Consolidation Pulmonary Function Tests in both lung fields, more prominent on the left due to hospital-acquired pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia
Image: “AP supine radiograph” by King Fahad Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia. License: CC BY 2.0Chest radiograph from a patient with viral pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia showing widespread bilateral interstitial infiltrates
Image: “Chest radiograph” by Department of Infectious Infectious Febrile Infant Diseases, Leicester Royal Infirmary, Level 6 Windsor Building, Leicester, LE1 5WW, UK. License: CC BY 2.0The majority of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship require only supportive care and recover without complications. Antiviral Antiviral Antivirals for Hepatitis B medications are used in hospitalized or high-risk patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship.