Is there blinding Onchocerciasis in northern Uganda?

Abstract

Background: Onchocerciasis is a filarial nematode Onchocerca volvulus transmitted by female black flies which breeds in fast flowing rivers.
Clinical manifestations is ocular or skin lesions. The long-term armed conflict in northern Uganda deprived research on onchocerciasis
and no attempts have been made to establish the clinical manifestation of the disease in the region.
Objective: To establish whether Simulium damnosum transmitted onchocerciasis in this region was blinding.
Participants: Persons from thirteen endemic parishes in Pader district in northern Uganda were examined for clinical, parasitological and
ocular manifestations of onchocerciasis.
Results: A total of 675 persons were examined and microfilaria prevalence in skin snips was 28%, while nodules and onchodermatitis
were 30% and 29% respectively. The commonest skin lesion was Chronic Papular Onchodermatitis (17.5%). However, the prevalence of
both microfilaria in the anterior chamber of the eye and reversible ocular lesions was 4%. The reversible ocular lesions of onchocerciasis
observed were punctate keratitis stage B (0.1%), punctate keratitis stage D (0.1%) and punctate keratitis stage E (3.7%). While 16.1%
of the respondents had irreversible ocular lesions attributed mainly to Optic atrophy (6.4%) and sclerosing keratitis (5.2%). There was
significant association between irreversible onchocerciasis lesions and visual loss (p< 0.0001).
Conclusion: This study confirmed the occurrence of blinding onchocerciasis in Pader district, the first ever reported in indigenous
populations in Uganda.