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Echinococcus/Echinococcosis

Echinococcosis is a parasitic disease caused by Echinococcus tapeworms. Infection most often occurs from the ingestion of Echinococcus eggs in food or water contaminated with dog feces. Signs and symptoms are caused by hydatid cyst development in visceral organs and depend on the species. E. granulosus causes cystic Cystic Fibrocystic Change echinococcosis, which can involve any organ. The most notable presentations involve the 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 or lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy, resulting in RUQ abdominal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, hepatomegaly, cough, or dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea. E. multilocularis causes alveolar echinococcosis, which typically involves the 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. Serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus and imaging may be used for the diagnosis, the latter of which can show characteristic findings of hydatid cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change. Management depends on the size and complexity of the cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change but can involve observation, anthelmintic therapy Anthelmintic therapy Agents that kill parasitic worms. They are used therapeutically in the treatment of helminthiasis in man and animal. Toxocariasis, percutaneous drainage, or surgery.

Last updated: Sep 19, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

General Characteristics and Epidemiology

General features of Echinococcosis

Echinococcosis is a parasitic disease caused by Echinococcus tapeworms. Features include:

Eggs:

  • Small
  • Round
  • Thick-shelled
  • Contain a 6-hooked (hexacanth) embryo Embryo The entity of a developing mammal, generally from the cleavage of a zygote to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the fetus. Fertilization and First Week

Adults:

  • Small (1.2–7 mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma long, depending on the species)
  • Ribbon-like body shape:
  • Can reproduce by self-fertilization Self-fertilization The fusion of a male gamete with a female gamete from the same individual animal or plant. Mycology
  • Absorb nutrients:
    • No mouth or anus
    • No digestive system

Clinically relevant species

  • Cystic Cystic Fibrocystic Change echinococcosis: E. granulosus (most common)
  • Alveolar echinococcosis: E. multilocularis
  • Polycystic echinococcosis:
    • E. vogeli
    • E. oligarthrus

Epidemiology

E. granulosus:

  • Geographic distribution:
    • South America
    • Middle East
    • Eastern Mediterranean
    • Sub-Saharan Africa
    • Western China
    • Australia and New Zealand
  • Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency: 2%–6% in endemic regions
  • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: Approximately 50 cases per 100,000 persons per year in endemic regions
  • Average age: 30–40 years

E. multilocularis:

  • Geographic distribution:
  • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 1–20 cases per 100,000 persons per year in endemic regions
  • Average age: > 50 years

E. vogeli and E. oligarthrus:

  • Geographic distribution: Central and South America
  • Rare

Pathogenesis

Hosts

E. granulosus:

  • Definitive hosts: dogs
  • Intermediate hosts:
    • Sheep
    • Horses
    • Goats
    • Deer
    • Camels
  • Humans are incidental hosts.

E. multilocularis:

  • Definitive hosts: 
    • Dogs
    • Foxes
    • Coyotes
  • Intermediate hosts: rodents
  • Humans are incidental hosts.

Transmission

Transmission occurs through ingestion of eggs, usually from food or water contaminated with animal feces.

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

E. granulosus:

  • Adult tapeworm dwells in the definitive host’s small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy → releases eggs → passed in feces
  • Ingested by an intermediate host → eggs hatch in the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy
  • Oncospheres Oncospheres Taenia/Taeniasis penetrate the intestinal wall → bloodstream → reach visceral organs
  • Development of hydatid cyst → produces protoscolices and daughter cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
  • Definitive host ingests infected organs.
  • Protoscolices leave cyst → attach to the intestine → develop into adult worms → cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation continues
Echinococcosis

The life cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation for Echinococcus granulosus

Image by Lecturio.

E. multilocularis:

  • Adult tapeworm dwells in the definitive host’s small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy → releases eggs → passed in feces
  • Ingested by an intermediate host → eggs hatch in the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy
  • Oncospheres Oncospheres Taenia/Taeniasis penetrate the intestinal wall → bloodstream → reach visceral organs
  • Development of multilocular, thin-walled (alveolar) hydatid cyst → proliferation by outward budding Budding Mycology → production of protoscolices
  • Definitive host ingests infected organs. 
  • Protoscolices leave cyst → attach to the intestine → develop into adult worms → cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation continues
Echinococcus

The life cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation for Echinococcus multilocularis

Image by Lecturio.

Pathophysiology

  • Human ingestion of eggs → 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 oncospheres Oncospheres Taenia/Taeniasis in the intestine
  • Migration to visceral organs → hydatid cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
  • Cyst rupture → protoscolices are released → secondary cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change can develop in other sites

Clinical Presentation

Both cystic Cystic Fibrocystic Change and alveolar echinococcosis are characterized by asymptomatic incubation Incubation The amount time between exposure to an infectious agent and becoming symptomatic. Rabies Virus periods (months to years).

Cystic Cystic Fibrocystic Change echinococcosis

Symptoms depend on:

  • Parasite load
  • Site of cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change (any organ can be infected)
  • Size of cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change (can cause complications from mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast effect and obstruction)
  • Note: Rupture of cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change can cause anaphylactic shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock.

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 (75% of cases):

  • General signs and symptoms:
    • Often asymptomatic
    • Abdominal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways 
    • 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 vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
    • Hepatomegaly
    • Abdominal mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast
    • Jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice
    • 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
  • Complications of cyst rupture into the biliary tree Biliary tree The bile ducts and the gallbladder. Gallbladder and Biliary Tract: Anatomy:
    • Biliary colic
    • Obstructive jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice
    • Cholangitis
    • Pancreatitis Pancreatitis Inflammation of the pancreas. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of chronic pancreatitis. The two most common forms of acute pancreatitis are alcoholic pancreatitis and gallstone pancreatitis. Acute Pancreatitis
  • Complications of mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast effect on bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy ducts or veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology:
    • Cholestasis
    • Portal hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • Budd–Chiari syndrome

Lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy (5%–15% of cases):

  • General signs and symptoms:
    • Chronic cough 
    • Dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea 
    • Chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain
    • Hemoptysis Hemoptysis Hemoptysis is defined as the expectoration of blood originating in the lower respiratory tract. Hemoptysis is a consequence of another disease process and can be classified as either life threatening or non-life threatening. Hemoptysis can result in significant morbidity and mortality due to both drowning (reduced gas exchange as the lungs fill with blood) and hemorrhagic shock. Hemoptysis
  • Complications of cyst rupture:
    • Pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax
    • Pleural effusion Pleural Effusion Pleural effusion refers to the accumulation of fluid between the layers of the parietal and visceral pleura. Common causes of this condition include infection, malignancy, autoimmune disorders, or volume overload. Clinical manifestations include chest pain, cough, and dyspnea. Pleural Effusion
    • Secondary bacterial infection

Central nervous system Central nervous system The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges. Nervous System: Anatomy, Structure, and Classification

  • Brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification:
    • 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
    • Dizziness Dizziness An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness. Lateral Medullary Syndrome (Wallenberg Syndrome) 
    • Decreased level of consciousness
    • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
  • Spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy:
    • Paresthesia
    • Weakness

Other organ systems:

  • Heart: pericardial tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis
  • Kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy: hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma
  • Bones: pathologic fractures
  • Eyes: ocular cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change

Alveolar echinococcosis

  • Malaise Malaise Tick-borne Encephalitis Virus
  • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery
  • RUQ pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Hepatomegaly
  • Jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice
  • Cholangitis
  • Portal hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • Budd–Chiari syndrome

Diagnosis

Imaging

Imaging of hydatid cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change is the mainstay of diagnosis.

Ultrasonography: 

  • 90%–95% sensitivity
  • Findings for cystic Cystic Fibrocystic Change echinococcosis:
    • Round, anechoic Anechoic A structure that produces no echo at all (looks completely black) Ultrasound (Sonography), smooth cyst
    • Internal septations → daughter cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
    • Fine, echogenic contents (“hydatid sand”) → protoscolices
    • “Eggshell calcifications” → cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change with calcified rim
  • Findings for alveolar echinococcosis:
    • Irregular cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change without well-defined walls
    • Central necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage
    • Irregular wall calcifications

CT:

  • Best for determining the number, size, and location of cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
  • Better than ultrasound in:
    • Detecting extrahepatic cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
    • Assessing for complications (e.g., rupture)

MRI:

  • Not usually required
  • No major advantage over CT

Serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus

Serologic tests are used for diagnosing echinococcosis and for monitoring after treatment.

  • More sensitive for E. multilocularis than for E. granulosus
  • Options:
    • Indirect hemagglutination 
    • ELISA ELISA An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed. St. Louis Encephalitis Virus 
    • Indirect immunofluorescence 
    • Immunoblot
    • Latex agglutination

Management and Prevention

Management

There are 4 management strategies: observation, medical therapy, percutaneous drainage, and surgery.

Observation is appropriate:

  • With inactive 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 cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
  • In the absence of complications

Medical therapy:

  • Definitive therapy for small, single-compartment cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
  • Often used as adjunctive therapy with percutaneous drainage and surgery
  • Options:
    • Albendazole Albendazole A benzimidazole broad-spectrum anthelmintic structurally related to mebendazole that is effective against many diseases. Anthelmintic Drugs (preferred)
    • Mebendazole Mebendazole A benzimidazole that acts by interfering with carbohydrate metabolism and inhibiting polymerization of microtubules. Anthelmintic Drugs
    • Praziquantel Praziquantel An anthelmintic used in most schistosome and many cestode infestations. Anthelmintic Drugs

Percutaneous drainage:

  • Involves drainage of fluid and injection of hypertonic Hypertonic Solutions that have a greater osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid. Renal Sodium and Water Regulation saline (scolicidal) into the cyst cavity
  • Risk of anaphylaxis Anaphylaxis An acute hypersensitivity reaction due to exposure to a previously encountered antigen. The reaction may include rapidly progressing urticaria, respiratory distress, vascular collapse, systemic shock, and death. Type I Hypersensitivity Reaction

Surgery:

  • Treatment of choice for complicated cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
  • Goal is to remove the whole cyst.
  • Hypertonic Hypertonic Solutions that have a greater osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid. Renal Sodium and Water Regulation saline is injected into the cyst before attempting surgical excision.

Prevention

  • Do not allow dogs to feed on livestock or rodents.
  • Control stray dog populations.
  • Avoid contact with foxes, coyotes, and stray dogs.
  • Wash hands after contact with dogs.
  • Improve water sanitation Sanitation The development and establishment of environmental conditions favorable to the health of the public. Hepatitis E Virus.
  • Avoid consumption of contaminated food.

Comparison of Tapeworm Species

Table: Characteristics and diseases of different tapeworm species
Organism Diphyllobothrium Diphyllobothrium Diphyllobothriasis represents an intestinal parasitic infection caused by the cestode Diphyllobothrium. Diphyllobothriasis is acquired by ingestion of late larvae in undercooked or raw fish. The clinical presentation of diphyllobothriasis varies from asymptomatic, nonspecific symptoms to intestinal obstruction, and/or vitamin B12 deficiency. Diphyllobothrium/Diphyllobothriasis latum Taenia Taenia Taenia belong to the Cestoda class of helminths. Humans are infected with these tapeworms by eating undercooked beef (T. saginata) or pork (T. solium and T. asiatica). Taeniasis is often asymptomatic, but the ingestion of larvae can cause abdominal discomfort, nausea, and constipation or diarrhea. Taenia/Taeniasis saginata Echinococcus granulosus
Characteristics
  • 2–7 mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma long
  • Hooks present
  • 3–6 proglottids Proglottids Taenia/Taeniasis
Transmission Eating raw infected fish FISH A type of in situ hybridization in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei. Chromosome Testing Eating raw infected beef Fecal–oral (ingestion of contaminated food or water)
Disease Diphyllobothriasis Diphyllobothriasis Diphyllobothriasis represents an intestinal parasitic infection caused by the cestode Diphyllobothrium. Diphyllobothriasis is acquired by ingestion of late larvae in undercooked or raw fish. The clinical presentation of diphyllobothriasis varies from asymptomatic, nonspecific symptoms to intestinal obstruction, and/or vitamin B12 deficiency. Diphyllobothrium/Diphyllobothriasis Taeniasis Taeniasis Taenia belong to the Cestoda class of helminths. Humans are infected with these tapeworms by eating undercooked beef (T. saginata) or pork (T. solium and T. asiatica). Taeniasis is often asymptomatic, but the ingestion of larvae can cause abdominal discomfort, nausea, and constipation or diarrhea. Taenia/Taeniasis Cystic Cystic Fibrocystic Change echinococcosis
Clinical
  • Usually asymptomatic
  • Mild GI symptoms
Depends on location and size of hydatid cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
Diagnosis Eggs or proglottids Proglottids Taenia/Taeniasis in stool Eggs or proglottids Proglottids Taenia/Taeniasis in stool
Management
  • Albendazole Albendazole A benzimidazole broad-spectrum anthelmintic structurally related to mebendazole that is effective against many diseases. Anthelmintic Drugs
  • Percutaneous drainage
  • Surgical excision
Prevention
  • Freeze fish FISH A type of in situ hybridization in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei. Chromosome Testing.
  • Thoroughly cook fish FISH A type of in situ hybridization in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei. Chromosome Testing.
  • Water sanitation Sanitation The development and establishment of environmental conditions favorable to the health of the public. Hepatitis E Virus measures
Beef should be cooked thoroughly.
  • Personal hygiene
  • Avoid contact with stray dogs.
  • Avoid potentially contaminated food.
  • Improve water sanitation Sanitation The development and establishment of environmental conditions favorable to the health of the public. Hepatitis E Virus.

Differential Diagnosis

  • Ascariasis Ascariasis Ascariasis is most often caused by A. lumbricoides. If symptomatic, characteristics typically follow 2 phases, which correlate with the migration of the parasite through the body. The early phase may include cough, dyspnea, and wheezing. The late phase typically includes abdominal discomfort, bloating, nausea, and intermittent diarrhea. Ascaris/Ascariasis: infection caused by the parasitic roundworm Ascaris Ascaris Ascaris is a genus of parasitic nematodes. The infection, ascariasis, is most often caused by A. lumbricoides. Transmission occurs primarily via ingestion of water or food contaminated with Ascaris eggs. Most patients with ascariasis are asymptomatic. Ascaris/Ascariasis lumbricoides. Transmission occurs from ingestion of water or food that is contaminated with Ascaris Ascaris Ascaris is a genus of parasitic nematodes. The infection, ascariasis, is most often caused by A. lumbricoides. Transmission occurs primarily via ingestion of water or food contaminated with Ascaris eggs. Most patients with ascariasis are asymptomatic. Ascaris/Ascariasis eggs. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may be asymptomatic or may experience cough and hemoptysis Hemoptysis Hemoptysis is defined as the expectoration of blood originating in the lower respiratory tract. Hemoptysis is a consequence of another disease process and can be classified as either life threatening or non-life threatening. Hemoptysis can result in significant morbidity and mortality due to both drowning (reduced gas exchange as the lungs fill with blood) and hemorrhagic shock. Hemoptysis. A large worm burden can cause intestinal obstruction Intestinal obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis and impair growth in children. Examination of the stool may show the presence of worms or eggs.  Management is with anthelmintic therapy Anthelmintic therapy Agents that kill parasitic worms. They are used therapeutically in the treatment of helminthiasis in man and animal. Toxocariasis.
  • Hepatocellular carcinoma Hepatocellular carcinoma Hepatocellular carcinoma (HCC) typically arises in a chronically diseased or cirrhotic liver and is the most common primary liver cancer. Diagnosis may include ultrasound, CT, MRI, biopsy (if inconclusive imaging), and/or biomarkers. Hepatocellular Carcinoma (HCC) and Liver Metastases: the most common primary 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 cancer. Usually arises in a chronically diseased or cirrhotic 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. Constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis are rare and RUQ pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways does not often occur. Imaging will show a well-defined mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast with enhancement during the arterial phase and washout during the venous phase. The mainstay of treatment is 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 resection.
  • Pyogenic 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 abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease: polymicrobial infection that arises from contiguous or hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases spread. 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 a triad of 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, malaise Malaise Tick-borne Encephalitis Virus, and RUQ pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. Imaging will reveal solitary or multiple lesions on ultrasonography or CT scan. These lesions are generally well-defined and rim enhancing on contrast imaging.  Diagnosis requires aspiration with Gram stain Gram stain Klebsiella and culture. A combination of drainage and IV antibiotic therapy is the primary method of treatment.
  • Cirrhosis Cirrhosis Cirrhosis is a late stage of hepatic parenchymal necrosis and scarring (fibrosis) most commonly due to hepatitis C infection and alcoholic liver disease. Patients may present with jaundice, ascites, and hepatosplenomegaly. Cirrhosis can also cause complications such as hepatic encephalopathy, portal hypertension, portal vein thrombosis, and hepatorenal syndrome. Cirrhosis: late stage of hepatic necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage and scarring Scarring Inflammation. Etiology varies from infectious (hepatitis 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) to toxin-induced (alcohol). Symptoms of cirrhosis Cirrhosis Cirrhosis is a late stage of hepatic parenchymal necrosis and scarring (fibrosis) most commonly due to hepatitis C infection and alcoholic liver disease. Patients may present with jaundice, ascites, and hepatosplenomegaly. Cirrhosis can also cause complications such as hepatic encephalopathy, portal hypertension, portal vein thrombosis, and hepatorenal syndrome. Cirrhosis are often nonspecific (e.g., fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia, anorexia Anorexia The lack or loss of appetite accompanied by an aversion to food and the inability to eat. It is the defining characteristic of the disorder anorexia nervosa. Anorexia Nervosa, weight loss Weight loss Decrease in existing body weight. Bariatric Surgery). Decompensation occurs late in the disease, with manifestations including jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice, ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites, portal hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, and 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 failure. Unlike in echinococcosis, ultrasonography will show nodularity of the 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. Diagnosis often requires 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 biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma. Management is mostly supportive, with 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 transplantation being the only curative treatment.
  • Lung cancer Lung cancer Lung cancer is the malignant transformation of lung tissue and the leading cause of cancer-related deaths. The majority of cases are associated with long-term smoking. The disease is generally classified histologically as either small cell lung cancer or non-small cell lung cancer. Symptoms include cough, dyspnea, weight loss, and chest discomfort. Lung Cancer: malignant transformation Transformation Change brought about to an organism’s genetic composition by unidirectional transfer (transfection; transduction, genetic; conjugation, genetic, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell’s genome. Bacteriology of lung tissue. Symptoms include cough, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, weight loss Weight loss Decrease in existing body weight. Bariatric Surgery, and chest discomfort. Regional and metastatic spread cause additional symptoms and complications depending on the location and organs affected. Definitive diagnosis and staging Staging Methods which attempt to express in replicable terms the extent of the neoplasm in the patient. Grading, Staging, and Metastasis are made by biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma, genetic mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations with biomarker testing, and imaging. Management is guided by the cancer stage and associated molecular profile.
  • Tuberculosis Tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis: disease caused by Mycobacterium Mycobacterium Mycobacterium is a genus of the family Mycobacteriaceae in the phylum Actinobacteria. Mycobacteria comprise more than 150 species of facultative intracellular bacilli that are mostly obligate aerobes. Mycobacteria are responsible for multiple human infections including serious diseases, such as tuberculosis (M. tuberculosis), leprosy (M. leprae), and M. avium complex infections. Mycobacterium tuberculosis Tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis. 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, productive cough, night sweats Night sweats Tuberculosis, and weight loss Weight loss Decrease in existing body weight. Bariatric Surgery. Cavitary lung lesions, which could resemble a hydatid cyst, may be seen on imaging. Diagnosis is made with identification Identification Defense Mechanisms of acid-fast bacilli Bacilli Shigella on sputum culture. Multiple antimicrobial medications are required for management, including isoniazid Isoniazid Antibacterial agent used primarily as a tuberculostatic. It remains the treatment of choice for tuberculosis. Antimycobacterial Drugs, rifampin Rifampin A semisynthetic antibiotic produced from streptomyces mediterranei. It has a broad antibacterial spectrum, including activity against several forms of Mycobacterium. In susceptible organisms it inhibits dna-dependent RNA polymerase activity by forming a stable complex with the enzyme. It thus suppresses the initiation of RNA synthesis. Rifampin is bactericidal, and acts on both intracellular and extracellular organisms. Epiglottitis, pyrazinamide Pyrazinamide A pyrazine that is used therapeutically as an antitubercular agent. Antimycobacterial Drugs, and ethambutol Ethambutol An antitubercular agent that inhibits the transfer of mycolic acids into the cell wall of the tubercle Bacillus. It may also inhibit the synthesis of spermidine in mycobacteria. The action is usually bactericidal, and the drug can penetrate human cell membranes to exert its lethal effect. Antimycobacterial Drugs.

References

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