1.1.1 Hepatitis A virus (HAV) is the causative agent.
1.1.2 Hepatitis A is a viral liver disease
that can cause mild to severe
1.2 Incubation period.
1.2.1 The incubation period is fifteen to fifty
days, with an average of 28–30 days.
1.3.1 Hepatitis A occurs
worldwide. In developing
countries most people
are infected during
1.3.2 It is highly endemic in some areas, particularly
Central and South America, Africa, the Middle East,
Asia, and the Western Pacific. There is no appreciable
seasonal variation in hepatitis A incidence. All non
immune people are susceptible to infection.
Immunity after infection is probably lifelong.
1.4 Period of communicability.
1.4.1 Viral shedding persists for 1 to 3
weeks. Infected persons are most
likely to transmit HAV 1 to 2 weeks
before the onset of illness, when
HAV concentration in stool is
highest. The risk then decreases
and is minimal the week after the
onset of jaundice.
1.5.1 A blood test indicating IgM anti-HAV antibodies
confirms recent infection. These antibodies are
present for two to four months after infection. IgG
antibodies alone are evidence of past infection.
2.1 Mode of Transmission.
2.1.1 Infection is transmitted by the faecal-oral route from
person to person or via fomites.
2.1.2 Infectious food handlers may
contaminate non-cooked foods such
2.1.3 Infection can occur through ingestion of
contaminated food or water.
2.2 Natural reservoirs.
2.2.1 Humans are the only natural reservoir of
the virus. There are no insect or animal
vectors. A chronic HAV case has not been
3.1 Signs and symptoms.
3.1.4 Appetite loss
3.1.5 Hyperbilirubinemia induced
jaundice - of the skin or sclera
3.1.6 Bile in urine - dark
3.1.7 Light, or clay-coloured faeces
3.2.1 Epidemics can be explosive and cause
significant economic loss.
3.2.2 Young children who are infected with hepatitis A typically
have a milder form of the disease, usually lasting from 1–3
weeks, whereas adults tend to experience a much more
severe form of the disease.
3.2.3 Hepatitis does not cause chronic infection and rarely causes
death: Hepatitis A has a mortality rate of less than one percent
(0.6) and over 70 percent of deaths occur in adults over the age
of 49 (usually fulminant hepatitis.)
3.2.4 Hepatitis A occurs
sporadically and in
epidemics worldwide, with a
tendency for cyclic
recurrences. Hepatitis A
viruses persist in the
environment and can
processes routinely used to
inactivate and/or control
4.1.1 Vaccination programmes - two types of vaccines: one containing
inactivated hepatitis A virus, and another containing a live but
attenuated virus. There are both pediatric formulations, approved for
persons 12 months through 18 years, and adult formulations approved
for persons 19 years and older.
184.108.40.206 More than 95% of adults will develop
protective antibody within 4 weeks of a single
dose of either vaccine, and nearly 100% will
seroconvert after receiving two doses. The
vaccine protects against HAV in more than
95% of cases for longer than 25 years.
4.1.2 Preventing faecal contamination and ensuring handwashing takes
place is essential to controlling outbreaks.
4.2 Preventative measures.
4.2.1 Groups at high risk of HAV infection as a
result of behaviour, lifestyle or occupation
should be the primary target of a hepatitis A
4.2.2 Improved sanitation and hygiene are the most effective
ways to combat the disease behind vaccination.
4.2.3 No specific treatment for hepatitis A is known. Sufferers are advised
to rest, avoid fatty foods and alcohol (these may be poorly tolerated
for some additional months during the recovery phase and cause
minor relapses), eat a well-balanced diet, and stay hydrated.
4.2.4 Controlling risk factors: poor sanitation; lack of safe water; injecting drugs;
living in a household with an infected person; being a sexual partner of
someone with acute hepatitis A infection; and travelling to areas of high
endemicity without being immunized.