Onchocerciasis in Gilgel Ghibe River Valley southwest Ethiopia.
OBJECTIVE
To determine the prevalence of onchocerciasis and the entomological transmission indices such as the parous rate and annual transmission potential (ATP).


METHODS
Gilgel Ghibe village, Gilgel Ghibe River Valley Southwest Ethiopia between April 1994 and March 1995.


METHODS
Two hundred twenty eight subjects of the total 400 population in Gilgel Ghibe village were subjected to parasitological and clinical examinations.


METHODS
Two skin snips per person were taken and examined for microfilariae of Onchocerca volvulus. Fly collections were done from dawn to dusk from human baits seated in pairs at four representative sites at the river bank and away from the river bank. Flies were dissected for parity and infections with O. volvulus larvae.


RESULTS
Among the 228 people examined, the prevalence of the disease was low (17%), being higher in males (19%) than in females (14%). The geometric mean of microfilarial density was 11.1 (range, 1-132) mf per skin snip. Itching followed by pigmentary changes were the most common clinical signs and symptoms. The predominant anthropophilic blackfly species was Simulium (Edwardsellum) damnosum s.l. The annual parous rate and ATP were 74.7% and 1669.5, respectively, being higher at the river bank than at sites further away suggesting a greater risk of infection by the river side.


CONCLUSIONS
The low prevalence of onchocerciasis in Gilgel Ghibe area vis-a-vis the high ATP level could be due to the possible presence of bovine onchocerciasis in the area. Further studies employing molecular techniques are thus required to identify O. volvulus from other filariae in flies.
Taye
A
A
Department of Biology, Addis Ababa University, Ethiopia.
Gebre-Michael
T
T
Taticheff
S
S
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000818:Animals; D002648:Child; D002675:Child, Preschool; D019353:Endemic Diseases / Q000706:statistics & numerical data*; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D005618:Fresh Water / Q000469:parasitology*; D006801:Humans; D007223:Infant; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009855:Onchocerciasis / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission; D011159:Population Surveillance; D015995:Prevalence; D012307:Risk Factors; D017678:Sex Distribution; D012843:Simuliidae / Q000469:parasitology / Q000502:physiology