The Prevalence and Distribution of Human Onchocerciasis in Two Senatorial Districts in Ebonyi State, Nigeria

Abstract

Background: There has been a recent increase in the number of human Onchocerciasis cases in hospitals in Ebonyi Central. This study therefore sets out to determine the prevalence of the disease in Ebonyi North and Central Senatorial Zones of Ebonyi State as well as determine the age groups and sex most affected. Methods: This study was carried out in Ebonyi North and Central Senatorial Zones of Ebonyi State between January 2011 and April 2012, among subjects of 20-59 years. Diagnosis was by skin examination for onchocercal lesions, ocular examination for ocular lesion and parasitological examination for the presence of microfilariae of Onchocerca volvulus in skin biopsies and adult filariae in excised nodules. Results: Out of the 250 persons randomly examined in each zone, 82 (32.8%) persons in Ebonyi Central zone comprising of 60 (38.7%) males and 22 (23.1%) females were found positive for Onchocerca volvulus while 73 (29.2%) persons in Ebonyi North Zone comprising 48 (32.0%) males and 25 (25.0%) females. Chi-square test shows that male subjects had significantly higher diseases prevalence (p < 0.05) than their female counterparts in the two zones but combined prevalence among male and female do not differ significantly in the two zones. The age group most affected was 50-59 years with the prevalence of 40.0% in Ebonyi Central and 38.6% in Ebonyi North Zones. Out of the 155 (30.8%) persons infected in the two zones, 28 (5.6%) males and 14 (2.8%) females had Onchocercal skin lesions, 57 (11.4%) males and 22 (4.4%) females had low vision. Partial blindness was observed in 16 (3.2%) males and 8 (1.6%) females. However, 7 (1.4%) males and 3 (0.6%) females had complete blindness. Farmers were mostly affected than any other occupational group. Conclusion: The findings obtained from this work suggested that Ebonyi Central and North Senatorial Zones are Onchocerciasis hypo-endemic Zones having the prevalence rate of 32.8% and 29.2% respectively. Sex, age and occupation are related to Onchocerciasis infections in both Zones. Males are more infected than females. Massive distribution of insecticides to destroy the vector Simulium damnosum (black fly), provision of adequate antiflarial drugs-ivermectin and mass health education targeted on preventive measures are highly recommended.

Exploring Consumer Perceptions and Economic Burden of Onchocerciasis on Households in Enugu State, South-East Nigeria

“…A key limitation, of this study is the sole reliance on physical examination of symptoms by non-medical persons which may have lowered the precision of diagnosis. Future costing studies could combine physical examination and precise clinical methods, including biopsies and tests for visual acuity [ 36 ]. However, careful training and supervision of examiners used in this study may well have reduced this limitation to a barest minimum.…”

Onchocerciasis Fingerprints in the Geriatric Population: Does Host Immunity Play a Role?

“…In the preliminary stage, there is atrophy of germinal centers and sinus histiocytosis and, later, the replacement of lymphoid tissue by fibro-adipose tissue, which has a perivascular pattern in the later stages [113]. Lymphatic complications as a result of onchocerciasis are more distributed among the older population than the younger population [12,15,95,100,114] (see Table 2). Furthermore, some of the lymphatic complications predispose onchocerciasis elderly patients to other forms of lymphatic complications.…”

“…On the other hand, some patients have an intact and symptomatic immune response to O. volvulus antigens [82]. Moreover, contrary to most phenotypes of OSL [14,15,95,114,121], pruritus has been reported to be more prevalent in the younger age group [12,15,100]. This may be due to the fact that the first visible symptom of onchocerciasis is OSLs, which usually begin with intense itching, followed by irritating papular rashes [122].…”

Neglected infectious diseases in the geriatrics

“…36 Okoro et al also reported that the prevalence of blindness secondary to onchocerciasis was 28.5%. 37 A case series by Dozie et al reported six elderly patients with blindness secondary to onchocerciasis. 38 Most of the included studies in the literature included participants ≥50 years of age.…”