Hepatitis A Epidemiology Flashcards
Hepatitis A Epidemiology
Seropositivty varies from country to country
- In endemic, developing countries, seropositivty often ..%
Treatment. Immune …… ……… given in the early …………. period can prevent symptoms
vaccine available for travellers
Seropositivity varies from country to country.
In endemic, developing countries, seropositivity often 90%
Treatment. Immune serum globulin given in the early incubation period can prevent symptoms.
Vaccine available for travellers
Hepatitis viruses
Hepatitis A and B best known, but several NANBH recognised
- Now C, D and E
All affect liver, causing …… and release of ….. enzymes
- Viral ……
Course nature and serology differs for each type
all ……..
Hepatitis A and B best known, but several NANBH recognised
Now C, D and E.
All affect liver, causing jaundice and release of liver enzymes.
Viral hepatitis
Course nature and serology differs for each type.
All contagious.
Hepatitis A
Infectious hepatitis
Caused by a picornavirus
- single stranded …… sense ……….
- ……….. virus
Only one serotype
Interacts specifically with receptor on l….. cells and few other types
Infectious hepatitis
Caused by a picornavirus
- single stranded …… sense ……….
- ……….. virus
Only one serotype
Interacts specifically with receptor on l….. cells and few other types
Hepatitis A Pathogenesis
Ingested and enters bloodstream via oropharynx or ………… ……… of intestine and reaches parenchymal cells of the ….
- Incubation period 4 weeks (2-6 weeks)
Virus reproduces, excreted in …. and passed out in s……
Virus shed 10 days before onset of symptoms
Ingested and enters bloodstream via oropharynx or epithelial lining of intestine and reaches parenchymal cells of the liver.
Incubation period 4 weeks (2-6 weeks).
Virus reproduces, excreted in bile and passed out in stool.
Virus shed 10 days before onset of symptoms.
Hepatitis A Pathogenesis
Replicates slowly in liver,
- Jaundice occurs when immune system …… and damages ….. cells ]
Symptoms ..-..dys after infection
Fever …….., nau….. and abdominal pain
Viral ………. stops before symptoms disappear.
No chronic infection and no association with liver cancer
- …….. …………
Replicates slowly in liver,
Jaundice occurs when immune system active and damages liver cells.
Symptoms 15-50dys.after infection.
Fever malaise, nausea and abdominal pain.
Viral shedding stops before symptoms disappear.
No chronic infection and no association with liver cancer.
Lifelong immunity.
Hepatitis A Epidemiology
Causes 40% causes of acute hepatitis
Virus released in large quantities in ……
Large percentage of people have inapparent infection but very contagious in ……..
-
-
HAV is resistant to acid at pH .., solv…. and det…….., drying and salt water
Causes 40% cases of acute hepatitis.
Virus released in large quantities in stools.
Large percentage of people have inapparent infection but very contagious.
Spread by food, water, dirty hands.
HAV is resistant to acid at pH 1, solvents and detergents,drying and salt water.
Hepatitis A Epidemiology
Survives range of temperature
Inactivated by …., f….. and UV ……..
Outbreaks from common source
Related also to poor ….. and ………
In endemic countries, children have ………….. infection and life long immunity
Survives range of temperature.
Inactivated by chlorine, formalin and UV radiation.
Outbreaks from common source.
Related also to poor hygiene and overcrowding.
In endemic countries, children have asymptomatic infection and life long immunity
Hepatitis E
Small single stranded RNA virus,
- Probably a calici……
Spread by ……. oral route and excreted in ……
Waterbourne infection, particularly in India.
May be cause of ….. of ….. hepatitis in developing countries
Small single stranded RNA virus,
Probably a calicivirus.
Spread by faecal oral route and excreted in faeces.
Waterborne infection, particularly in India,
May be cause of 50% sporadic hepatitis in developing countries
Hepatitis E
Incubation period …..-….. weeks
mild disease except in pregnant women
High mortality ,
- Disseminated i…………… c …………. during third ………….
No carriers
- Virus eliminated
Incubation period 6-8 weeks. Mild disease except in pregnant women. High mortality, Disseminated intravascular coagulation during third trimester. No carriers, Virus eliminated
Hepatitis B
Serum hepatitis
- Caused by hepadnavirus
Enveloped, partially double stranded circular DNA genome. Has reverse transcriptase
Limited tissue specificity specificity
- Liver, kidney and pancreas of humans and chimpanzees
Virion called …… ………….
Serum’ hepatitis.
Caused by hepadnavirus.
Enveloped, partially double stranded circular DNA genome. Has reverse transcriptase.
Limited tissue specificity
Liver, kidney and pancreas of humans and chimpanzees.
Virion called Dane particle.
Hepatitis B
Virion surrounded by core antigen HbcAg
Envelope containing glycoprotein surface antigen Hb..Ag
Also has Hb..Ag e and c share most of their …….. sequence
Hb..Ag particles released into serum and outnumber virions
- Immunogenic
Virion surrounded by core antigen HbcAg.
Envelope containing glycoprotein surface antigen HbsAg.
Also has HbeAg e and c share most of their protein sequence.
HbsAg particles released into serum and outnumber virions.
Immunogenic.
Hepatitis B
3 forms of HbsAg proteins.
Transcription of DNA in nucleus
Replication : attachment via HbsAg proteins
Replication of genome in cytoplasm
HBV and surface antigen released into serum
3 forms of HbsAg all found in virion.
Replication : attachment via HbsAg proteins.
Transcription of DNA in nucleus.
Replication of genome in cytoplasm.
HBV and surface antigen released into serum.
Hepatitis B pathogenesis
Capable of causing acu…, chr…, sym………… or asy………… disease
Determined by patient immune response to the infection
Presence of .. and surface antigen in serum indicates active infection
Surface antigen released until ….. of disease
Capable of causing acute, chronic, symptomatic or asymptomatic disease.
Determined by patient immune response to the infection.
Presence of e and surface antigen in serum indicates active infection.
Surface antigen released until resolution of disease.
Hepatitis B pathogenesis
Source of infection:
- Blo.., s.., mi….., va…….., and menstrual secretions and am……. fluid
IV injection very…….. Also spread by SI and birth
Low infective dose and high …….
Replicates……. acquisition, but no symptoms for … days or longer
Capable of causing acute, chronic, symptomatic or asymptomatic disease.
Determined by patient immune response to the infection.
Presence of e and surface antigen in serum indicates active infection.
Surface antigen released until resolution of disease.
Hepatitis B pathogenesis
Depends on infectious dose, route of infection and host immune system.
copies of virus genome …….. and become ……..
Cell mediated immunity responsible for outcome of disease.
Immune complexes can cause ……………. reactions.
- Milder symptoms in ………..
Depends on infectious dose, route of infection and host immune system.
Copies of virus genome integrate and become latent.
Cell mediated immunity responsible for outcome of disease.
Immune complexes can cause hypersensitivity reactions.
Milder symptoms in children.
Hepatitis B ….. infected at birth become chronic carriers
During acute phase, ….. damage and ……. cell infiltration
Problems in long term, especially if co-infection with ……. …….
Can lead to … and hepatic …….
90% children infected at birth become chronic carriers.
During acute phase, liver damage and inflammatory cell infiltration.
Problems in long term, especially if co-infection with delta virus.
Can lead to cirrhosis and hepatic carcinoma.
Hepatitis B Epidemiology
High rates of ……. in many countries
- Up to … infected during birth or ……
In parts of Africa and Asia, seropositivity is up to ….
- High levels of Hepatic carcinoma. 80% attributed to chronic ……
Chronic infection in ..-..% of those infected
High rates of seropositivity in many countries.
Up to 15% infected during birth or childhood.
In parts of Africa and Asia, seropositivity is up to 50%.
High levels of Hepatic carcinoma. 80% attributed to chronic HBV
Chronic infection in 5-10% of those infected
Hepatitis delta
15 million infected with Hepatitis delta
Uses HBV and ……. ……..
proteins to r……. and produce its one protein
Viral ……
Similar transmission to HBV,
- Makes … more severe
15 million infected with Hepatitis delta.
Uses HBV and target cell proteins to replicate and produce its one protein.
Viral parasite.
Similar transmission to HBV,
Makes HBV more severe.
Hepatitis C
90% of non A non B hepatitis C
- ……virus
Spread ………….. and sexually
- .. ….. abusers, transfusion and organ recipients and ………….
chronic asymptomatic infections leading to ….. in 20% of cases
90% of non A non B hepatitis is caused by Hepatitis C.
Flavirus.
Spread parenterally and sexually.
IV drug abusers, transfusion and organ recipients and haemophiliacs.
Chronic asymptomatic infections leading to cirrhosis in20% of acute cases.
Hepatitis C
Viraemia …-…. weeks post transfusion, lasting 4-6 …..
- up to 10 years
Causes chronic persistent …… and …… failure
Cell mediated pathology causes …… damage
Treatment, recombinant ………. alpha
Viraemia 1 - 3 weeks post transfusion, lasting 4-6 months.
Up to 10 years.
Causes chronic persistent hepatitis and liver failure.
Cell mediated pathology causes liver damage.
Treatment, recombinant interferon alpha.
Viral Gastroenteritis
Significant cause of infant gastroenteritis
causes death infant and young children in . ……… countries
- 5-10 million a year in asia africa and latin america
……….. transmission.
1972 virus particles seem on …. examination of faeces
Significant cause of infant gastroenteritis.
Causes death in infants and young children in developing countries
5-10 million/year in Asia, Africa and Latin America.
Faecal -oral transmission.
1972 virus particles seen on EM examination of faeces.
Rotavirus
Characterstic viruses
- 65nm particles
Cubic …….., ………. coat arranged like the spokes of a wheel
At least 2 humans serotypes
- Also found in kittens puppies, calves foals and piglets
Epidemics in young children espeically the …….. months
Characteristic viruses.
65nm particles.
Cubic symmetry, capsid coat arranged like the spokes of a wheel.
At least 2 human serotypes.
Also found in kittens puppies, calves foals and piglets.
Epidemics in young children, especially in the winter months.
Rotavirus - Pathogenesis
Very low infective dose:
-10 particles
Incubation period ……..
Viral replication in ….. …….. cellls leads to acute onset of vomitting and diarrhoea
1000 million/gram virus particles ……..
Respiratory symptoms also common
Very low infective dose:
10 particles.
Incubation period 1-4 days.
Viral replication in intestinal epithelial cells leads to acute onset of vomiting and diarrhoea.
1000 million/gram virus particles excreted.
Respiratory symptoms also common
Rotavirus-Treatment and Prevention
Rehydration
No treatment available
Other viral GIT infections caused by:
Calic,,,,
astro. ..
aden. ….
small round ……
parovi…..
Coro……..
Rehydration. No treatment available. Other viral GIT infections caused by: Caliciviruses (Norwalk), Astroviruses, Adenoviruses , Small round structured viruses, Parvoviruses Coronaviruse
