Hepatitis A and E Flashcards
Hepatitis A virus
(a) Family
(b) Genus
(c) Genome type
(d) Number of serotypes, genotypes
(e) Enveloped/Non-enveloped?
(f) Transmission
(a) Family: Picornaviridae
(b) Genus: Hepatovirus
(c) Genome type: positive sense single-stranded RNA virus
(d) Number of serotypes, genotypes: 1, 6
(e) Enveloped/Non-enveloped? Non-enveloped
(f) Transmission: feco-oral [may also be transmitted sexually]
What are some risk factors that may increase the probability of HAV infection?
🩺 Close personal contact with HAV-infected persons
🩺 Institutionalization (e.g., prisoners, day care)
🩺 Occupation (daycare, prison guards, lab techs)
🩺 Male homosexuality
🩺 PWIDS (People who inject drugs)
Briefly discuss the pathogenesis of Hepatitis A.
🛸 HAV is primarily transmitted through ingestion of contaminated food or water, or through direct contact with an infected person’s faeces.
🛸 After entering the body, HAV is believed to replicate in the mucosal cells of the intestines.
🛸 The virus attaches to liver cells (hepatocytes) using a receptor called HAVCR (Hepatitis A Virus Cellular Receptor) and replicates within these cells.
🛸 HAV does not directly destroy liver cells. Instead, it replicates within them without causing immediate cell death.
🛸 The liver damage seen in Hepatitis A is primarily due to the body’s immune response. Cytotoxic T-cells attack the infected hepatocytes, leading to inflammation and liver damage.
🛸 The virus is released into the bloodstream (viremia) and bile. It is then excreted in the feces, which can contaminate food and water, continuing the cycle of transmission.
Briefly discuss the clinical presentation of HAV infection.
🩺 Incubation period: 2-4 weeks
🩺 Asymptomatic phase: HAV infection may be asymptomatic, and especially in children
🩺 Prodrome phase: non-specific symptoms e.g. fever, nausea, anorexia, fatigue, headache, and general malaise
🩺 Icteric phase: jaundice, pain in the upper right quadrant of the abdomen, dark-colored urine, pruritus [itching due to bile salts deposited in the skin]
Although rare, Hepatitis A infection can cause fulminant hepatitis. What is fulminant hepatitis?
Fulminant hepatitis is a severe and rapid form of liver failure that develops within days or weeks. Early symptoms include fatigue, nausea, and stomach discomfort. Advanced symptoms include jaundice, confusion of encephalophathy [due to build up of toxins which the liver normally clears], sleepiness, personality changes and easy bruising.
What are primary tests in the diagnosis of HAV infection?
(1) HAV IgM Antibodies (ELISA) [a positive result indicates a recent or current HAV infection]
(2) HAV RNA (RT-PCR)
Why isn’t the presence of IgG antibodies taken as evidence for a current or recent HAV infection?
IgM antibodies are produced first and indicate a recent or current infection. They appear early in the course of the infection and are the primary marker for actute Hepatitis A.
IgG antibodies develop later and remain in the body for life, indicating past infection or immunity (from previous infection or vaccination).
treatment of Hepatitis A
treatment is supportive
List prevention measures against Hepatitis A.
(a) Adequate, safe drinking water
(b) Proper disposal and treatment of waste
(c) Personal hygiene
(d) Vaccination
Hepatitis E virus
(a) Family
(b) Genome type
(c) Number of serotypes, genotypes
(c) Enveloped/Non enveloped?
(d) Transmission
(a) Family: Hepeviridae
(b) Genome type: positive-sense, single-stranded RNA genome
(c) Number of serotypes, genotypes: 1, 8
(c) Enveloped/Non enveloped? Non-enveloped
(d) Transmission: fecal-oral route
HEV pathogenesis
🛸 HEV enters the body through the fecal-oral route, typically via contaminated water or food. It initially replicates in the gut mucosa.
🛸 The virus then spreads to the liver where it attaches to hepatocytes using specific receptors.
🛸 HEV replicates within hepatocytes. Unlike some viruses, HEV is non-cytolytic.
🛸 The liver damage seen in HEV infection is primarily due to the immune response. Cytotoxic T-cells attack the infected hepatocytes, leading to inflammation and liver damage.
🛸 The virus is released into the bloodstream and bile, eventually being excreted into the faeces.
[Symptoms are similar to HAV.]
Hepatitis A and E have similar transmission routes, except for one key difference…
HEV can be acquired via zoonotic transmission.
Compare HAV and HEV in terms of severity and chronicity.
HAV: Typically causes acute, self-limiting hepatitis and does not lead to chronic infection.
HEV: Can cause acute hepatitis, but in some cases, especially in immunocompromised individuals, it can lead to chronic infection.
Discuss complications that may arise from HEV infection during pregnancy.
🩺 Liver Failure: Pregnant women with HEV are at a higher risk of developing acute liver failure.
🩺 Fetal Loss or Death: The infection can lead to fetal loss or even maternal death.
🩺 Up to 30% of pregnant women who contract HEV in the third trimester may die from the infection.
What are primary tests in the diagnosis of HEV infection?
(1) HEV IgM Antibodies (ELISA) [a positive result indicates a recent or current HAV infection]
(2) HEV RNA (RT-PCR)
