Onchocerciasis: the burden of disease.

The greatest burdens related to human onchocerciasis are the result of the eye and skin lesions and severe itching produced by the microfilariae. Although the major manifestations of the disease do show geographical variation (e.g. onchocercal blindness is not a common complication in all endemic countries), they are often sufficiently severe to prevent human use of the often very fertile land close to the rivers in which the vectors breed. Though for many years thought to be of relatively minor importance compared with onchocercal eye disease, the skin lesions of onchocerciasis have recently been shown to be a major socio-economic burden, in terms of disability-adjusted life-years. The demonstration of an excellent correlation between the prevalence of palpable nodules in a community and the community microfilarial load has led to the development of rapid, safe and non-invasive methods to assess and map the levels of endemicity across whole countries. This has enabled mass treatment with Mectizan (ivermectin, MSD) to be targeted first at hyperendemic communities. Estimates of the burden of onchocerciasis will continue to change as better means of measurement become available. It seems possible, however, that use of Mectizan will eliminate the disease before its true burden can be estimated accurately.

Socioeconomic consequences of blinding onchocerciasis in west Africa.

Onchocerciasis or river blindness, a major cause of irreversible blindness among adults, has been the focus of international disease control efforts for over 20 years in West Africa. This paper employs the international classification of impairment, disability and handicap (ICIDH) to interpret results from a field study to assess the socioeconomic consequences of onchocerciasis in Guinea in 1987. In a sample of 136 blind, 94 visually impaired and 89 well-sighted persons, decreasing visual acuity is strongly associated with mobility, occupational and marital handicaps. Individual, household and disease correlates were explored. The implications of these findings for the ICIDH concept of handicap are discussed with particular emphasis on the need to extend analysis beyond the individual when assessing the socioeconomic consequences of disabling disease.

PIP: The author assesses the impact of decreased visual acuity, including irreversible blindness, on 319 individuals in northeast Guinea, an area in which onchocerciasis (river blindness) is highly endemic. 136 of the individuals in the 1987 study were blind, 94 visually impaired, and 89 well-sighted. Subjects' visual statuses were classified based upon the international classification of impairment, disability, and handicap (ICIDH). Analysis found individuals' decreasing visual acuity to be strongly associated with mobility, occupational, and marital handicaps. Individual, household, and disease correlates were explored. The implications of these findings for the ICIDH concept of handicap are discussed with particular emphasis upon the need to extend analysis beyond the individual when assessing the socioeconomic consequences of disabling disease.

The socio-economic aspects of human onchocerciasis in Africa: present appraisal.

The pattern of socio-economic liability that has emerged due to human onchocerciasis in Africa has been particularly damaging. Due to debilitation and blindness, the sufferer is unable to maintain for long any type of productive activity. As a cause of permanent disability through blindness or serious visual impairment, it withdraws the affected individuals' potential supply of labour years of activity requiring vision. The desertation of many river valleys in the savannah zone that are agriculturally fertile have been attributed mainly to the effects of this disease. This has by definition, meant that emigrants impose demands upon other territories that are often agriculturally less fertile consequently resulting to constant population maladjustment. As a cause of death, infection removes individual's supply of labour years in the future. The social life obtainable in these areas is better imagined than seen. It is a common trend seeing chains of blind adults being led to markets or within cities by children with good vision-constituting destitutes. The distressing skin features give patients prematurely aged appearance and together with dreadful malformation due to sclerosing lymphadenitid, infected individuals show shyness towards free social interactions; even sexual life is greatly affected if not completely hindered. The present economic benefit analysis of control projects, limitations and needs for future studies are disoussed.