EPIDEMIC GONOCOCCAL CONJUNCTIVITIS IN CENTRAL AUSTRALIA

Objectives: To describe an epidemic of gonococcal conjunctivitis in central Australian Aboriginal children, the responsible phenotypes of Neisseria gonorrhoeae, factors facilitating spread and treatment efficacy. Design: Prospective study of patients with laboratory confirmed or clinical gonococcal conjunctivitis diagnosed from January to July 1991. Setting: The Alice Springs and Barkty Tablelands Health Districts of the Northern Territory, the Anangu Pitjantjatjara Lands of South Australia and the Ngaanyatjarra Homelands of Western Australia. Methods: Cases were identified from surveillance data and laboratory notifications, and by active case finding. A community survey explored risk factors. Main outcome measures: Age-specific attack rates, auxotype/ serovar characterisation of isolates, and clinical response to single dose treatment. Results: We identified 432 cases. The highest attack rate was in the 0-4 year age group (86 per 1000), and the risk of conjunctivitis decreased with age. The odds ratio of secondary infection in household compared with community contacts was 14.5 (P < 0.002; 95% CI, 1.8-120.0). Disease was less common in children with clean faces and hands. The outbreak occurred after unseasonable rains and large community gatherings. Isolates were predominantly IA serovars, less common among central Australian serovars. Conclusions: The trigger for non-sexually transmitted gonococcal conjunctivitis epidemics remains obscure. Age is a significant risk factor and social and ecological factors may also contribute. Active case finding within affected households and treatment with a suitable penicillin is effective in stopping transmission.