Development of reactive onchocercal skin lesions during a placebo-controlled trial with ivermectin among persons without lesions at baseline.

Clinical trials of the effects of ivermectin on onchocercal skin disease have documented reduction in itching, but a less than clear benefit on reactive skin lesions. It has been suggested that one of the positive effects might be the prevention of new lesions. A study among a rural adult farming population in southwestern Nigeria provided ivermectin in three treatment groups and a placebo to community members who were examined and treated at 3-monthly intervals over a 15-month period. Among the 1206 people recruited for the study, 627 (52%) had no lesions at baseline examination. Atotal of 291 participants without baseline lesions attended all five follow-up examinations, and only their results were analysed. Members of all four groups developed new lesions, but those receiving ivermectin had a consistently lower proportion of lesions than the placebo group. This difference reached statistical significance at the 5% level in three of the five periods and was below the 10% level at the other two periods. These findings are suggestive of an inhibiting effect of ivermectin among those without lesions at the beginning of a community treatment programme, and justify community treatment as a way of limiting morbidity and social stigma associated with these lesions.

Stigma associated with onchocercal skin disease among those affected near the Ofiki and Oyan Rivers in western Nigeria.

Skin diseases have been a major source of social stigma, whether they be infectious or not. The potential stigamtizing effect of skin disease associated with onchocerciasis is currently receiving attention because half of the 17 million victims of onchocerciasis in Africa live where the non-blinding form of the disease is prevalent. Some reports are available that onchocercal skin disease (OSD) is associated with social stigma including problems in finding a marriage partner. Previous studies have also implied positive effects of ivermectin treatment on OSD. Therefore a multi-country trial of ivermectin is underway to test the hypothesis that ivermectin treatment might affect perceptions of stigma associated with OSD. This paper presents the baseline stigma findings from the study site located in southwestern Nigeria. A total of 1032 persons living in villages near the Ofiki and Oyan Rivers were screened and interviewed and 500 (48%) were found to have an onchocercal skin lesion. A 13-item, 39-point stigma scale was used in interviews with affected persons. A mean score of 16.8 was obtained. No personal characteristics or disease factors were found to be associated with stigma score. The highest ranking items focused on issues of self-esteem such as feeling embarrassed, feelings of being pitied, thinking less of oneself, feeling that scratching annoys others, feeling that others thought less of the person and feeling that others had avoided the person. During the interviews it was discovered that only about half of those clinically diagnosed as having OSD labeled their own condition as onchocerciasis. Those who said their lesion was OSD had a lower stigma score than those who did not, conforming with previous studies wherein affected persons perceived less stigma from OSD than those without the disease. A broader community perspective on OSD was obtained through 50 interviews using paired comparisons of five skin-related local illnesses. Onchocerciasis placed midway in aversive responses between the higher end represented by leprosy and chicken pox and lower scoring papular rashes known locally as eela and ring worm. In-depth village based interviews yielded several case studies of how onchocerciasis had a negative social impact on its victims. While study on the cultural perceptions of OSD is recommended, the results indicate that with a fairly high prevalence of OSD, the community level effects of social stigma should be regarded as serious.

The effects of ivermectin on onchocercal skin disease and severe itching: results of a multicentre trial.

OBJECTIVE: To determine the effects of ivermectin in annual, 3-monthly and 6-monthly doses on onchocercal skin p6isease (OSD) and severe itching. METHOD: A multicentre, double-blind placebo controlled trial was conducted among 4072 residents of rural communities in Ghana, Nigeria and Uganda. Baseline clinical examination categorized reactive skin lesions as acute papular onchodermatitis, chronic papular onchodermatitis and lichenified onchodermatitis. Presence and severity of itching was determined by open-ended and probing questions. Clinical examination and interview took place at baseline and each of 5 subsequent 3-monthly follow-up visits. RESULTS: While prevalence and severity of reactive lesions decreased for all 4 arms, those receiving ivermectin maintained a greater decrease in prevalence and severity over time. The difference between ivermectin and placebo groups was significant for prevalence at 9 months and for severity at 3 months. Differences between placebo and ivermectin groups were much more pronounced for itching. From 6 months onward, the prevalence of severe itching was reduced by 40-50% among those receiving ivermectin compared to the trend in the placebo group. CONCLUSION: This is an important effect on disease burden as severe itching is for the affected people the most troubling complication of onchocerciasis. The difference among regimens was not significant, and the recommended regimen of annual treatment for the control of ocular onchocerciasis appears also the most appropriate for onchocerciasis control in areas where the skin manifestations predominate. The final determination of the effect on skin lesions requires a longer period of study.

Gender and ethnic differences in onchocercal skin disease in Oyo State, Nigeria.

During preparation for a study on the effects of ivermectin treatment on onchocercal skin disease in the Ifeloju Local Government Area of Oyo State, Nigeria, 1032 adults aged 20 years and older were examined for skin lesions and palpable nodules. It was found that for 4 types of skin lesions, acute papular onchodermatitis (APOD), chronic papular onchodermatitis (CPOD), lichenified onchodermatitis (LOD) and depigmentation (leopard skin), as well as for subcutaneous nodules, females had a significantly higher prevalence than males. Although the area is inhabited primarily by the Yoruba people, the study also included some of the cattle-herding Fulani ethnic group. The reactive skin lesions, APOD, CPOD and LOD, were found to be more common among the Fulani, although there were no significant differences in leopard skin and nodules between both groups. While there is need for further research on both immunological and behavioural factors that may lead to these differences in disease. The need to achieve equity in health programming by ensuring that women and ethnic minorities receive full disease control services is of more immediate concern.