ABSTRACT

A cross-sectional study was carried out in four farming communities in Aniocha North Local Government Area of Delta State of Nigeria, Idumuogo, Ogodor, Anioma and Ubulubu – between November 2008 and March 2009.

The study was carried out to determine the current status of Onchocerciasis in the communities, through the study of the clinical manifestations of the disease and socio-economic effects on the sufferers, and to connect on the ongoing control measures with ivermectin in the area.

A total of 450 subjects were selected for examination for clinical manifestation of Onchocerciasis. 140 (31.1%) males, and 104 (23.1%) females were found to be infected with one or two clinical manifestations. Although infections were found in all age groups, it occurred mostly in older groups. Various rates of clinical manifestation were recorded thus: leopard skin 106 (24%), Onchocercal nodules 32 (7.1%), Onchodermatitis 51 (11.3%), itching 50 (11.1%) and impaired vision 18 (4.0%) with Idumuogo and Ubulubu, having the highest infections rates of 114 (25.3%) and 76 (16.9%) respectively. Males were significantly more infected than females (X2 = 176.4, df = 24, P<0.01). From the result of the study, the communities surveyed can be said to be hypoendermic for Onchocerciasis with a nodular rate of 32 (7.1%).

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CHAPTER ONE

INTRODUCTION

Onchocerciasis, also known as “river blindness” is a disease caused by a nematode filarial worm. Onchocerca volvulus, and is transmitted through the bites of an infected female blackfly (Similium species). The manifestations of onchocerciasis are predominantly

dermal, lymphatic and ocular in character. Dermal, manifestation include pruritis, lesions (papules, macules, urticaria, oedema, excoriatia

pustules, crusts, scaling ulceration, lichenification, pachydermia, Atrophy, pigmentary change leopard skin and others) Nodules, lymphatic

manifestations are in form of lymphadenopathy, lyphoedema and Hanging groin.

Ocular damages affect the conjunctiva, cornea, lens in form of cataract, Retina in form of pigment epithelial atrophy, cotton wool spots and Haemorrhages choroid and optic nerves in form of optic neuritis and optic atrophy (WHO, 1995).

Worldwide onchocerciasis is second to trachoma as a leading cause of blindness of infectious origin (Thylefors et al 1995). More than 100 million people worldwide are at risk of infection, 18 million people are infected, 800,000 people are visually impaired, 270,000 people are

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already blind, 3.3 million of the people reside in Nigeria, where it is still regarded as a public health problem (WHO, 1995). Blindness which is the ultimate consequence of onchocerciasis renders the productive

segment of the community unproductive, and dependent on others. Also most fertile lands have been abandoned because of this disease, (Okolo et al, 2004).

Onchocerciasis in Nigeria is transmitted solely by members of the

Similium damnosum complex. They are widespread in the savanna forest, savanna mosaic and rainforest areas of Nigeria. S. damnosum, which breeds in large streams and rivers in the woody and open country

side, has been known to be common in the rocky sections of the river Niger and its tributaries (Eneanya and Nwaorgu, 2001). Maikaje et al

(2008) also found S. damnosum breeding along River Muvur and Uba, to habour infective Onchocerca volvulus microfilarae. In Mubi North and Hong Local Government Areas of Adamawa State. Okonkwo et al (1991)

found

S. damonsum breeding along the Oji River of Enugu State. Nwoke et al (1998) also carried out epidemiological studies of human onchocerciasis in rivers of Katsina Ala (tributary of Benue) Anambra and Oji Rivers (tributaries of River Niger), the Cross River and Imo River, the costal

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areas of Rivers, Akwa-Ibom and Cross River States. The exposure of those rocks in the beds or side margins of these fast flowing rivers as well as numerous trailing vegetation create favourable breeding sites for

Similium damnosum complex. All these reports indicate that fast flowing river, rivulets and streams, favours the breeding of blackfly.

A Rapid Epidemiological Mapping of Onchocerciasis carried out in nine sentinel villages in Edo/Delta (Okhoromi, Ugbokogbe, Oke, Ovao, Ekilor, Eko-Ibadan, Idumuogo, Agbor Alidinma and Igbogili) recorded a

prevalence of 40.4% of microfilaria infection, 18.9% of nodules and 7.7% of leopard skin, led to choosing Delta State as an endemic state with

sufficiently important public health problem to warrant community wide ivermectin treatment, where the prevalence of microfilaria is greater than

40%, (WHO, 1991). Offor et al (1998) trapped blackflies exposed on human legs between 0600 hours and 18 hours local time in Okpanam (River Awai) and Ogwashuku (River Mgbiligba) of Delta State and

blackflies were likely forest S. yahense.

The aim of the present study is to determine the current status of onchocerciasis in selected communities in Aniocha North Local Government Area of Delta State.