EFFECTS OF LONG-TERM COMMUNITY TREATMENT WITH IVERMECTIN ON ONCHOCERCA VOLVULUS INFECTIONS IN HUMANS AND THE SIMULIUM DAMNOSUM VECTOR IN PARTS OF KADUNA STATE

Abstract
This study assessed the impact of long-term treatment with ivermectin in Kagarko, Lere and Kauru onchocerciasis foci of Kaduna State by parasitological, entomological and economic evaluation of the onchocerciasis control programme including its cost effectiveness. Epidemiological evaluation of infection status was done by parasitological examination of skin snips of individuals in 10 communities in Kagarko LGA of Kaduna State, where there was an 80.6% administrative coverage after 4 – 10 rounds of ivermectin treatment. Of the 973 (56% of total population) people examined only 3 (0.31%) were positive for microfilariae and none had ocular microfilaria. A total of 24,937 Simulium damnosum were caught in two rivers, Rivers Galma and Gurara in Lere and Kagarko foci respectively. No breeding site was identified in Kauru focus. The flies were analyzed for the presence of O. volvulus DNA using the O-150 PCR assay which detected 23 positive pools out of the 250 pools (100 flies/pool). The prevalence was calculated using the Poolscreen 2.0. The prevalence of infective flies (L3 in the head) was 0 – 1.5/1,000 flies in R. Galma and 0.38 – 0.83/1,000 flies in R. Gurara while prevalence of infected flies (L1 and L2 in the body) was 1 – 1.9/1,000 flies in R. Galma and 0.4 – 0.5/1,000 in R. Gurara (p=0·0095%, 95% CI of 0.58-3.76 in head and body pools). The prevalence of infective flies was higher than 0.05% prevalence rate used as a standard to determine suppression of transmission. The economic evaluation indicated that the programme was cost effective and the control of the disease resulted in improved economic productivity. This study provides further evidence to strengthen the potential for elimination of onchocerciasis and in the development of guidelines for elimination of the disease in Nigeria and elsewhere.
Description
A DISSERTATION SUBMITTED TO THE POSTGRADUATE SCHOOL, AHMADU BELLO UNIVERSITY ZARIA NIGERIA IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF DOCTOR OF PHILOSOPHY IN ZOOLOGY DEPARTMENT OF BIOLOGICAL SCIENCES FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY, ZARIA NIGERIA JULY 2014
Keywords
EFFECTS,, LONG-TERM,, COMMUNITY,, TREATMENT,, IVERMECTIN,, ONCHOCERCA VOLVULUS,, INFECTIONS,, HUMANS,, SIMULIUM DAMNOSUM,, VECTOR,, PARTS,, KADUNA STATE.
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