Gonococcal conjunctivitis in Central Australia

Non-pathogenic Neisseria: members of an abundant, multi-habitat, diverse genus

The genus Neisseria contains the important pathogens Neisseria meningitidis and Neisseria gonorrhoeae. These Gram-negative coccoid bacteria are generally thought to be restricted to humans and inhabit mucosal surfaces in the upper respiratory and genito-urinary tracts. While the meningococcus and gonococcus have been widely studied, far less attention has been paid to other Neisseria species. Here we review current knowledge of the distribution of commensal Neisseria in humans and other hosts. Analysis of the microbiome has revealed that Neisseria is an abundant member of the oropharyngeal flora, and we review its potential impact on health and disease. Neisseria also exhibit remarkable diversity, exhibiting both coccoid and rod-shaped morphologies, as well as environmental strains which are capable of degrading complex organic molecules.

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 Barkly 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 nonsexually 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.