Resum
The African Programme for Onchocerciasis Control (APOC) sponsored a baseline study in Nigeria between 1998 and 1999 on the prevalence and distribution of Onchocerciasis. The randomly selected 1,064 subjects in the baseline study underwent detailed eye exam ination in Cross River (rain forest), Taraba (savanna) and Kogi (forest-savanna) States. This paper compares and contrasts the public health significance of ocular onchocerciasis in these ecological zones. A blindness prevalence of 2.4% was recorded in the study, onchocerciasis being responsible for 30.2% of the bilaterally blind subjects. Onchocerciasis –induced blindness prevalence was relatively high in the rain forest and forest savanna zones of Cross River and Kogi States, Cross River having the highest site-specific prevalence (50.0%), followed by Kogi (41.7%). Taraba recorded only 27.3%. Other conditions identified included glaucoma, optic nerve disease and cataract rates of which were also found to be high among the population (6.9%, 6.5 % and 8.9% respectively). Anterior segment onchocercal lesions, punctate and sclerosing keratitis were the predominant features of the infection in the savanna zone (14.1% and 6.3% respectively), while posterior segment lesions were much more common in the forest zone. The need to sustain the present efforts to control onchocerciasis through mass ivermectin treatment is recommended.
Keywords: Onchocerciasis, Onchocercal blindness, Ivermectin distribution, ecological zones.
Résumé
Le programme Africain pour le control de l’onchocercose(PACO) a sponsorise une étude de base au Nigeria entre 1998 - 1999 sur la prévalence et la distribution de l’onchocercose. 1064 sujets sélectionnés au hasard au cours de cette étude ont suivis des examens détaillés dans les États de Cross river (foret),de Taraba (en savane) et de Kogi (foret-savane). Cette étude compare en sante la significative de l’onchocercose oculaire dans ces zones ecologiques.une prévalence de cécité de 2.4% était reporte pendant l’étude, l’onchocercose était responsable de 30.2% de cécité bilatérale. Le taux d’aveuglée induit par onchocercose était relativement élevé dans les zone de foret pluvieuse et foret savane des États de Crossriver et de Kogi, Cross river avait un site de prévalence plus élevée (50.0%), suivis de Kogi (41.7%), Taraba reportait seulement 27.3%. d’autres conditions identifiées incluaient glaucome, le mal de nerf optique et le taux de cataracte qui étaient élevé dans la population (6.9%, 65% et 89% respectivement). Le segment antérieur de la lésion onchocercose et sclérose kératite étaient lescaractéristiques prédominants de l’infection en zone de savane (14.1% et 63% respectivement), alors que les segments postérieur des lésions était bien plus fréquent en zone de foret. La nécessité de soutenir les efforts actuels à Contrôler l’onchocercose a travers un traitement de masse est recommandée.
Correspondence: Dr. A.O. Mahmoud, Department of Ophthalmology, University of Ilorin, Ilorin, Nigeria. E-mail: mahmoud_ao@yahoo.com
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