ETIOLOGY OF UVEITIS IN SIERRA-LEONE, WEST-AFRICA

Background - In 1992, non-onchocercal uveitis caused 9% of blindness, 8% of visual impairment, and 11% of uniocular blindness among patients visiting an eye hospital in Sierra Leone, west Africa. The aim of thi s study was to determine the aetiology of uveitis in this population. Methods - General and ophthalmic examination complemented by serum and aqueous humour analyses for various infectious agents was performed f or 93 uveitis patients and compared with serum (n=100) and aqueous hum our (n=9) analysis of endemic controls. Results - At the initial exami nation, 45 patients (48%) proved to be severely visually handicapped. After clinical and laboratory analyses, an aetiological diagnosis was established for 49 patients (52%). Toxoplasma gondii was the most impo rtant cause of uveitis (40/93; 43%). Anti-toxoplasma IgM antibodies we re detected in serum samples of seven of 93 patients (8%) compared wit h one of 100 controls (1%, p<0.05). At least six patients (15%) with o cular toxoplasmosis had acquired the disease postnatally. Antibodies a gainst Treponema pallidum were detected in 18 of 92 patients (20%) and in 21 controls (21%). Other causes of uveitis were varicella tester v irus (one patient), herpes simplex virus (two patients), and HLA-B27 p ositive acute anterior uveitis with ankylosing spondylitis (one patien t), while one patient had presumed HTLV-I uveitis. Conclusions - In a hospital population in Sierra Leone, west Africa, uveitis was associat ed with severe visual handicap and infectious diseases. Toxoplasmosis proved to be the most important cause of the uveitis. Although the dis tribution of congenital versus acquired toxoplasmosis in this populati on could not be determined, the results indicate an important role of postnatally acquired disease. The results further suggested minor role s for HIV tuberculosis, toxocariasis, and sarcoidosis as causes of uve itis in this population.