The impact of climatic risk factors on the prevalence, distribution, and severity of acute and chronic trachoma

Summary

Trachoma – the leading cause of infectious blindness – is spread through contact with infected persons by hands and towels, and by ‘eye-seeking flies’. Trachoma prevalence is high in areas characterised by poverty, inadequate water supply and poor sanitation. Trachoma is controlled by the SAFE strategy: S = surgery to the upper eyelids; A = antibiotics for active infection; F = facial cleanliness; and E = environmental improvement.

In this study we reviewed the scientific literature to assess the extent to which climatic factors (e.g. rainfall, heat, dust, altitude) influence trachoma distribution. A systematic review of the literature found eight papers that measured an association between a climatic factor and trachoma in children or adults. Several studies reported that trachoma is less common at higher altitudes, indicating that temperature may play a role in trachoma transmission. Some studies also reported that trachoma is higher in areas with low rainfall, which is consistent with anecdotal evidence that trachoma is associated with dry environments.