3719632
Hepatitis A
- ORIGIN
- The causative organism
- Hepatitis A virus (HAV) is the causative agent.
- Hepatitis A is a viral liver disease
that can cause mild to severe
illness.
- Hepatitis A virus (HAV) is the causative agent.
- Incubation period.
- The incubation period is fifteen to fifty
days, with an average of 28–30 days.
- The incubation period is fifteen to fifty
days, with an average of 28–30 days.
- Occurrence.
- Hepatitis A occurs
worldwide. In developing
countries most people
are infected during
childhood.
- 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.
- Hepatitis A occurs
worldwide. In developing
countries most people
are infected during
childhood.
- Period of communicability.
- 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.
- 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.
- Identification
- 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.
- 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.
- The causative organism
- MODE
- Mode of Transmission.
- Infection is transmitted by the faecal-oral route from
person to person or via fomites.
- Infectious food handlers may
contaminate non-cooked foods such
as salads.
- Infection can occur through ingestion of
contaminated food or water.
- Infection is transmitted by the faecal-oral route from
person to person or via fomites.
- Natural reservoirs.
- Humans are the only natural reservoir of
the virus. There are no insect or animal
vectors. A chronic HAV case has not been
reported.
- Humans are the only natural reservoir of
the virus. There are no insect or animal
vectors. A chronic HAV case has not been
reported.
- Mode of Transmission.
- EFFECT
- Signs and symptoms.
- Fatigue
- Fever
- Nausea
- Appetite loss
- Hyperbilirubinemia induced
jaundice - of the skin or sclera
(eye whites.)
- Bile in urine - dark
amber colour
- Light, or clay-coloured faeces
- Fatigue
- Mortality/Morbitiy
- Epidemics can be explosive and cause
significant economic loss.
- 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.
- 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.)
- Hepatitis A occurs
sporadically and in
epidemics worldwide, with a
tendency for cyclic
recurrences. Hepatitis A
viruses persist in the
environment and can
withstand food-production
processes routinely used to
inactivate and/or control
bacterial pathogens.
- Epidemics can be explosive and cause
significant economic loss.
- Signs and symptoms.
- CONTROL
- Methods.
- 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.
- 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.
- 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.
- Preventing faecal contamination and ensuring handwashing takes
place is essential to controlling outbreaks.
- 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.
- Preventative measures.
- Groups at high risk of HAV infection as a
result of behaviour, lifestyle or occupation
should be the primary target of a hepatitis A
vaccination programme.
- Improved sanitation and hygiene are the most effective
ways to combat the disease behind vaccination.
- 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.
- 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.
- Groups at high risk of HAV infection as a
result of behaviour, lifestyle or occupation
should be the primary target of a hepatitis A
vaccination programme.
- Methods.
Medienanhänge
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