Environmental risk factors of human Q fever in Spain

Q fever is a zoonotic disease caused by Coxiella burnetii, primarily transmitted to humans via airborne from livestock such as cattle, sheep and goats, though the pathogen is also found in other domestic and wild species. There is limited information on how environmental factors, including climate or livestock-related influence transmission risk in endemic areas. This study aims to assess the impact of these factors in Spain, the European country with the highest annual Q fever notifications.

An ecological epidemiological study was conducted to evaluate Q fever risk in Spanish municipalities and its association with environmental factors. Spatial and spatio-temporal regression models were used to estimate relative risk and assess the effects of mean temperature, wind speed, precipitation and caprine, ovine, and bovine density (heads/km²).

The spatial model identified three high-risk areas: the Canary Islands, the north-central Iberian Peninsula and western Andalusia. Mean temperature and caprine density were significant, with a 14 % increase in spatial relative risk for every 10 additional goat heads/km². The spatio-temporal model did not confirm the effect of temperature but found a positive association with mean wind speed, alongside a similar impact of caprine density.

Caprine density appears to be a key determinant of municipal Q fever risk, with potential contributions from temperatures and wind speed. These findings highlight the need for targeted preventive measures, particularly regarding caprine livestock management and industry planning.