Amebiasis (Amebic Dysentery)

Amebiasis (Amebic Dysentery) Causal agent: Entamoeba histolytica is well recognized as a pathogenic amoeba. Geographic Distribution: Worldwide, with higher incidence of amebiasis in developing countries.  In industrialized countries, risk groups include travelers , recent immigrants, and institutionalized populations. History: Loosh was first described in 1875

Epidemiology Prevalence of amebic infection varies with level of sanitation and generally higher in tropics and subtropics than in tempearate climates. *Worldwide prevalence is about 10% to 50% *Cyst passers are important source of infection The true estimated prevalence of E. histolytica is close to 1% worldwide. Entamoeba histolytica is the second leading cause of mortality due to parasitic disease in humans. (The first being malaria). Amebiasis is the cause of an estimated 50,000-100,000 deaths each year.

Transmission 1-driect contact of person to person( fecal-oral) 2- Food or drink contaminated with feces containing the E.his. cyst 3- Use of human feces (night soil) for soil fertilizer 4- contamination of foodstuffs by flies, and possibly cockroaches

CLINICAL PRESENTATION The incubation period of intestinal amoebiasis is highly variable and may be as short as a few days or as long as several months. Most patients have a gradual illness onset days or weeks after infection. Symptoms include cramps, watery or bloody diarrhea, and weight loss and may last several weeks. Occasionally, the parasite may spread to other organs (extraintestinal amebiasis), most commonly the liver. Amebic liver abscesses may be asymptomatic, but most patients present with fever and right upper quadrant abdominal pain, usually in the absence of diarrhea.

Diagnosis clinical Diagnosis: Sigmoidoscopic examination: precence of a grossly normal mucosa between the ulcers serves to differentiate amebic from bacillary dysentery,( the entire mucosa being involvoed in bacillary dysentery). Hepatomegally C.B.C. : leukocytosis in Amebic dys. rises above 12000 per microliter, but counts may reach 16000 to 20000 per microliter.

Treatment Intestinal Amebiasis: *Asymptomatic amebiasis(cyst passer): Diloxanide furoate ( furamide) 500 mg 3 times daily / 10 days *Symptomatic amebiasis ( troph. & cyst): - Iodoquinol , 650 mg 3 times daily/ 20 days or Metronidazole (Flagyl) , 750 mg 3 times daily/ 10 days *Amebic colitis: Chloroquine, 250 mg 2 times daily * Acute amebic dysentery: Emetine hydrochloride, 1mg/kg daily IM or SC

Treatment *Amebic liver abscess, ameboma: Extraintestinal Amebiasis: Metronidazole, as above plus dehydroemetine / 10 days or Metronidazole or dehydroemetine as above plus Chloroquine , 500 mg 2 times daily / 2 days,…..

prevention Amoebiasis is difficult to eradicate because of the substantial human reservoir of infection. The only progress will be through improved standards of hygiene and better access to clean water. Cysts are destroyed by boiling, but chlorine and iodine sterilizing tablets are not always effective.

Control/Prevention improve personal hygiene especially institutions treat asymptomatic carriers eg, family members health education hand-washing sanitation food handling protect water supply treat water if questionable boiling iodine not chlorine