is hepatitis A?
Hepatitis A is an acute infectious disease of the liver,
caused by the hepatovirus hepatitis A virus
is hepatitis A usually found?
Hepatitis A is found around the world; it
is endemic in most developing countries, particularly is areas with hygiene and
water supply problems. It is also associated with seafood and food preparation
common is hepatitis A?
Hepatitis A occurs in at least 1.5 million people
per year, probably many times that figure, as under-reporting is common, and many
cases are undiagnosed. Most of these people live in developing countries, but
Hepatitis A also occurs in the developed world; at least 150,000 cases per year
in the USA, for example.
How is hepatitis A transmitted?
A is a food borne virus, most commonly spread by poor hygiene in food preparation,
with the virus passed on by an infected person - or someone who has had indirect
contact with an infected person, who excretes in the virus in faeces. But the
virus can survive on the skin or other surface for three to four hours, making
food preparation a very easy route: not only the food, but utensils used in preparing
or serving food. Contaminated shellfish is a common source of infection.
hepatitis A be spread from person-to-person?
Hepatitis A can be spread
by person-to-person contact, such as oral kissing or anal sex; and shared intraveneous
equipment is probably a convenient route.
Who is most
at risk from hepatitis A?
Those at risk include:
- Recent travellers
to endemic countries
- Young children who attend day care
of a person with hepatitis A
- Certain occupations
- Receipt of clotting
factor concentrates (in some countries)
- Men who have sex with men
Statistically, people from developed countries who
travel to developing countries are at highest risk of acquiring hepatitis A. The
risk is present even in urban areas of such countries, where the food supply chain
is not secure, and water may be contaminated.
are the symptoms of hepatitis A?
Hepatitis A is an acute but self-limiting
disease. there is an incubation period of about 30 days (but this can vary from
15 - 50 days). Early symptoms include fever, severe malaise, anorexia, vomiting,
abdominal discomfort, followed by a persistent fatigue, which can be disabling.
Hepaptitis A is associated with jaundice, which sets in as the initial
symptoms begin to subside. Jaundice is characterized by yellowing of the skin,
eyes and mucous membranes - caused by excretion being obstructed in the liver
and therefore released into the blood. Urine will also turnappear dark and concentrated
with bile, while faeces are typically clay-colored from lack of bile.
general, the acute illness lasts from about day to three weeks; then most patients
begin to feel better as the liver settles down and blood chemistry starts to get
back to normal. The severity of illness tends to increase with age.
are the long term effects of hepatitis A?
It is not unusual for blood chemistry
to remain abnormal for several months, delaying full recovery for up to a year.
Most patients, however, recover completely within 3 - 6 months of the onset of
Relapse can occur with Hepatitis A, usually within three months
of the initial illness - and it is more common in children than adults.
vast majority of people will fully recover from Hepatitis A, which does not lead
to chronic hepatitis.
What is the mortality rate
for hepatitis A?
The mortality rate is about 2 in 1000; usually people
weakened by co-existing illness, older people or the very young.
is hepatitis A diagnosed?
initailly, hepatitis is usually diagnosed by
the characteristic clinical picture; confirmation of the type will depend on laboratory
The presence of IgM anti-HAV in the blood confirms the diagnosis
of acute hepatitis A infection. Once infected and recovered, the antibodies to
the virus will provide protection from future re-infection. Following infection,
the HAV blood test will always be positive.
there a treatment for hepatitis A?
There is no specific treatment for hepatitis
A. Patients are treated symptomatically; for example, antihistamines for the unbearble
itching that may accompany jaundice. A small number of patients will go on to
acute liver failure, and need multisystem support - but this is rare.
there a way to prevent infection?
Hepatitis A risks can be reduced by lifestyle
choices, careful travelling and hygiene - especially with food and food preparation.
There is evidence that a key factor in limiting the duration of outbreaks
is rapid intervention, plus the need to reconise that communities where
significant numbers may return to visit their country of oriign will significantly
inmpact on control measures1.
is the hepatitis A vaccine?
There are four vaccines against HAV; all are
safe and effective, with long-lasting protection. None are licensed for children
less than one year of age.
What is the protocol
for hepatitis A vaccination?
A single dose of vaccine will provide short-term
protection, but manufacturers recommend two doses to ensure long-term protection.
After two or more doses of hepatitis A vaccine, 99%100% of recipients can
expect protection for at least 8 - 20 years; possibly for life.
should get vaccinated against hepatitis A?
In regions where the disease
is endemic at a low level, vaccination is indicated for individuals with increased
risk of contracting the infection, such as travellers to higher risk areas.
WHO currently does not recommend mass vaccination in countries where the disease
is endemic at a high level. In these countries, almost everyone is infected in
childhood with the virus, without symptoms, and this effectively prevent the disease
being a problem for adolescents and adults. In these countries, large-scale vaccination
programmes are not recommended.
In countries of intermediate endemicity,
where adult infection is an issue, and where hepatitis A is a significant public
health issue, childhood vaccination may be considered in parallel with health
education and improved sanitation.
Are there adverse
reactions to the hepatitis A vaccine?
The are well tolerated and no serious
adverse events have been statistically linked to their use, after many millions
Hepatitis A vaccine may be safely administered with many
Contraindications include a known allergy to vaccine components.
Can hepatitis A be controlled environmentally?
low-incidence areas, the most effective control is simple hygiene and common sense,
coupled with the appropriate use of vaccine. In higher-incidence areas, hygiene
must be combined with education and the development of safer water supplies and
food preparation systems; mass vaccination may be considered.
areas, where the vast majority of the population is infected in childhood, environmental
control is not a realistic target until basic poverty is better managed, and the
water and food supplies can be secured.
Is there legal
protection for workers and others?
There's plenty of precedent for legal
action against food services where people have contracted hepatitis A; civil action
for pain ansd suffering - and possibly loss of earnings involved, plus criminal
action relating to negligence, health and safety and / or food hygiene laws.
can be learned from history?
While infectious hepatitis is known to have
existed for many hundrds of years (if not forever!), it was not until the second
half of the 20th century that the disease has been recognised as having several
distinct for, courses and management needs.
Question asked about "infectious
types of hepatic jaundice" started to show results in 1963; and hepatitis
A virus (HAV) was eventually isolated by Purcell as recently as 1973.
and Further Information Sources
N., et al (2012) Factors Associated to Duration of Hepatitis A Outbreaks:
Implications for Control. PLoS One 7(2)
I regret I cannot assist with individual cases or essays and school projects,
but if it's something I've missed, I'll be happy to try and help.
Article written by Andrew Heenan BA (Hons), RGN, RMN