Hepatitis A-E viruses Flashcards
(39 cards)
What is the source of the hepatitis A, route of transmission, chronic infections? and prevent?
Faeces
faecal-oral
no chronic infection
prevented with pre/post exposure immunization
What is the source of the hepatitis B, route of transmission, chronic infections? and prevent?
blood / blood-derived body fluids
percutaneous permucosal
can cause chronic infection
prevented with pre/post exposure immunization
What is the source of the hepatitis C, route of transmission, chronic infections? and prevent?
blood/blood-derived body fluids
percutanoues permucosal
can cause chronic infection
prevented by blood donor screening, risk behavior modification
What is the source of the hepatitis D, route of transmission, chronic infections? and prevent?
blood/blood-derived body fluids
percutaneous/permucosal
can cause chronic infection
prevented by pre/post exposure immunization and risk behavior modification
What is the source of the hepatitis E, route of transmission, chronic infections? and prevent?
faces
faecal oral route
sometimes causes chronic infection
ensure sage drinking water
How is hepatitis A transmitted?
close personal contact (sex, household, child day care centers)
contaminated food, water (infected food handlers, raw shellfish)
blood exposure (rare)
What age groups is hep a highest?
late childhood/young adults
What are the clinical features of hepatitis A ?
incubation period: avg 30 days, range 15-50
jaundice by age group
- <6 = <10%
- 6-14 = 40-50%
- >14 70-80%
complications: fulminant hepatitis, cholestatic hepatitis, relapsing hepatitis
How is hep A diagnosed?
diagnosed by detection of HAV-IgM in serum by EIA
Which age group have the highest attack rates of hep A in and why?
5-14 year olds
- children serve as reservoir of infection
Which people are at greater risk of developing hep a?
travelers
homosexual men
injecting drug users
How can hepatitis A be prevented from spreading?
pre-exposure - vaccination
post-exposure (within 14 days)
- vaccinate household and other intimate contacts
- also vaccinate institutions such a child care centers and look at common sources of exposure (food)
How many serotypes and genotypes are there of hep E?
one serotype and 4 genotypes
1,2,4 = endemic areas
3= non-endemic areas
What are most hep E outbreaks associated with ?
facially contaminated drinking water
- most outbreaks in indian subcontinent, mexico, china, africa
What is thought to be a food source of infection with hep E?
swine meat uncooked or partially cooked
What are the clinical features of hepatitis E?
incubation period = avg 40 days, range 15-60
case-fatality rate = 1-3% but in pregnancy women 15-25%
illness severity = increased with age
chronic hepatitis occurs in immunocompromised patients
What prevention and control measures should be undertaken by travelers to prevent getting hep E?
avoid drinking water (ice) of unknown purity, uncooked shellfish and uncooked fruit/veg not peeled or prepared by traveler
IG prepared from donors in western countries doe not prevent infection
recombinant vaccine in china
ribavirin is tx for chronic infections in immunocompromised
How is hep B transmitted?
sex - sex workers and homosexuals are at particular risk
parenteral - iVDA, health workers at increased risk
perinatal - mothers who are HBeAg positive are much more likely to transmit to their offspring than those who are not - main mode of transmission in high prevalence populations
Which body fluids is hep b most concentrated?
high in blood, serum and wound exudates
moderate in semen, vaginal fluid and saliva
low/not detectable in urine, faces, sweat, tears, breast milk
What are the clinical features of hep b ?
incubation period = avg 60-90 days, range 45-180 clinical illness (jaundice) - <5 = <10% - 5 yrs = 30-50% acute case facility rate = 0.5-1% chronic infection <5 yrs = 30-90% 5 yrs = 2-10% premature mortality = 15-25%
What are the spectrum of conditions that can arise from hep B infection?
1) chronic persistent hepatitis = asymptomatic
2) chronic active hepatitis symptomatic exacerbations of hepatitis
3) cirrhosis of liver
4) hepaticellular carcinoma
What % of cases of acute hep B resolve / become fulminant hepatitis?
90% resolution
1% fulminant hepatitis
9% HBsAg+ for >6 months
What are the diagnostic markers of HBV?
HBsAg - if present for >6 months defines persistent infection
HBeAg - determines relative infectivity
Anti-HBe - seroconversion from HBeAg to anti-hie indicates progression towards resolution
Anti-HBc IgM - differentiates acute/recent infection from persistent infection or resolved HBV infection
Anti-HBc - always present in acute and persistent infection and in recovered infection
HBV DNA - marker of infectivity
Why is HBV DNA useful?
diagnosis
assessing patients for treatment
assessing response to HBV antiviral therapy
assessing infected health workers for FTP
