1.
INTRODUCTION
Amoebiasis
is also known as entamoebiasis. It is an infection caused by any of the amoeba
of the Entamoeba group. But the
symptoms are most common on infection of Entamoeba
histolytica. Amoebiasis can be present with no, mild or severe symptom.
Symptoms may include abdominal pain, mild diarrhoea, bloody diarrhoea or severe
colitis[1] with tissue death and perforations.
2.
HISTORY
The most
dramatic incident was Chicago World’s Fair Outbreak in 1933 in USA
In 1998
there was an outbreak of amoebiasis in the republic of Georgia
3.
CAUSATIVE
AGENT
In humans
for species of Genus Entamoeba have
been reported to cause amoebiasis – E.
gingivalis, E. coli, E. hartmanni, E. histolytica.
E. histolytica has world wide distribution. It parasitizes various primates and rodents. It inhabits the lumen and mucosa of large intestine, predominantly colon. It is capable of invading virtually any tissue and organ of the body. The most predominantly infected organ other than colon is liver. The cystic stage is formed in the lumen of gut and occurs in the stool of chronic dysenteric patients and carriers.
4.
SOURCE OF
INFECTION AND TRANSMISSION
It is
usually transmitted by the fecal-oral route, but it can also be transmitted
indirectly through contact with dirty h ands or objects. Infection is spread
through ingestion of the cyst form of the parasite[2]. Any non-encysted amoeba, or trophozoites[3]
, die quickly after leaving the body but may also be present in stool – these
are rarely the source of new infection. Members of both sexes of human are
infected by this parasite. There is, however, a higher prevalence of amoebiasis
in adult males in the agricultural occupation who have increased risk of
exposure.
5.
SYMPTOMS
Most
infected people (about 90%) are asymptomatic, but this disease has the
potential to make sufferer dangerously ill. It is estimated that about 40,000
to 100,000 people die annually worldwide due to amoebiasis[i].
Infection can sometimes last for years. Symptoms can develop after days or few
weeks of infection. But usually it is about two to four weeks. Symptoms can
range from mild diarrhoea to severe dysentery with blood and mucus. The blood
comes from lesions formed by the amoeba invading the lining of large intestine.
In about 10% infection the amoeba enters the bloodstream and may travel to
other organs in the body. Most commonly liver is infected[ii].
In asymptomatic infection the amoeba lives by eating and digesting bacteria and
food particles in the gut[4].
It does not usually come in contact with the intestine. Disease occurs when
amoeba comes in contact with the intestinal lining. Amoeba secrets the same
enzyme and destroys the mucosa and ingests the destroyed cells. Theoretically
the ingestion of one viable cyst can cause amoebiasis.
6.
PREVENTION/PROPHYLAXIS
Wash
hands thoroughly with soap and hot running water for at least 10 seconds after
before handling food.
Clean
bathrooms and toilets often, pay particular attention to toiled seats and taps.
Avoid
sharing towels or face washers.
Avoid raw
vegetables when in endemic areas, as they may have be fertilized using human
faeces.
Boil
water or treat with iodine tablets.
Avoid
eating street foods, especially in public areas where others are sharing sauces
in one container.
7.
TREATMENT
E. histolytica infection
occurs in both the intestine and tissues of intestine or liver. So two
different classes of drugs are needed. One for each location. Thus there are
two major components of treatment.
* Elimination
of tissue invading organisms
* Elimination
of organisms from the lumen of intestine
The drugs
commonly used are:
Iodoquinol
Metronidazol
Emetine
[1]
Inflammation of colon
[2]
A semi dormant and hardy
structure found in faeces.
[3]
a
growing stage in the life cycle of some sporozoan parasites, when they are
absorbing nutrients from the host
