Concept map of Hepatitis A outbreak by:NURNADHRAH BT ZULKIFLI

Globally, symptomatic HAV infections are believed to occur in around 1.5 million people a year

Hepatitis A is much more common in countries with underdeveloped sanitation systems and, thus, is a risk in most of the world

HAV is a common infection in developing nations of Africa, Asia, and Central and South America

1) MOOD OF Transmission

Close personal contact

contaminated food or water

Blood exposure

2) HAV invade into human body by mouth and cause viremia

3) After one week, the HAV reach liver cells replicate within

4) Then enter intestine with bile and appear in feces.

5) After HAV replicating and discharging, liver cells damage begin

6) Affects liver functions- hyperbilirubinaemia-jaundice

7) Inflammation of liver-hepatomegaly-pressure effects on other organs

INCUBATION PERIOD

• 10-50 days( usually 14-28 days)

Pre-icteric stage

Sudden onset of fever

chills

fatigue, malaise

Within a day or two, develops gastro intestinal symptoms

diarrhea

nausea n vomittng

High coloured urine, light coloured stools lasting for about of 3 to 5 days

Icteric stage

Sclera looks yellow and skin looks lemon tinged

High coloured urine continues for several days

Stage lasts for 4 to 6 weeks

complication

fulminant hepatitis/severe liver function impairment

relapsing hepatitis

CAUSES

drugs

toxins

alcohol

virall infection (A,B,C,D)

other infections (parasites, bacteria)

physical damage

TYPES OF HEPATITIS

Control of reservoir

Complete bed rest

Disinfection of faeces and fomite

Control of transmission

Promote simple measures of personal and community hygiene

Hand washing before and after toilet

Sanitary disposal of excretion

Purification of community water supply

Control of susceptible population

IMMUNIZATION

Hepatitis A vaccination is recommended for all children starting at age 1 year, travellers to certain countries, and others at risk

A full course containing two intramuscular injections of the vaccine

Vaccination Strategies Epidemiologic Considerations

WHO SHOULD BE VACCINATED?

All children at age 1 year (i.e., 12–23 months)

Children and adolescents ages 2–18 who live in states or communities where routine Hepatitis A vaccination has been implemented because of high disease incidence

Persons traveling to or working in countries that have high or intermediate rates of Hepatitis A

Homo sexuals

Persons who have occupational risk for infection

Persons who have chronic liver disease

Acute infection is diagnosed by the detection of HAV-IgM in serum by EIA/ELISA

Past Infection i.e. immunity is determined by the detection of HAV-IgG by EIA/ELISA

Cell culture – difficult and take up to 4 weeks, not routinely performed

Direct Detection – EM(electorn microscopy), RT-PCR of faeces. Can detect illness earlier than serology but rarely performed.