Suspected Sources of Infection and Transmission Factors Associated With Campylobacteriosis in Northern Portugal

Campylobacteriosis is considered the most common bacterial cause of human gastroenteritis worldwide, with food being one of the main sources of infection. The occurrence of human campylobacteriosis, however, may differ between geographical areas and other factors. Our study aims to identify possible sources of Campylobacter infection in the Northern region of Portugal.

A cross-sectional study was conducted, including all laboratory-confirmed campylobacteriosis cases notified through the Portuguese epidemiological surveillance system (SINAVE) between 2015 and 2017. We analysed socio-demographic and exposure variables, including contact with other ill individuals, contact with animals, consumption of suspect food items, consumption of non-controlled water and travelling.

A total of 683 confirmed campylobacteriosis cases were reported between 2015 and 2017 in the Northern region of Portugal, corresponding to a notification rate of 6.3 per 100,000 population. The median age was 2 years old (IQR 0.96-4.6); 58.3% were male. Close contact with animals was the most common exposure (50.2%), followed by consumption of non-controlled water (26.1%), suspect food consumption (13.8%) and contact with ill individuals (8.8%). Campylobacteriosis cases from the Tâmega e Sousa subregion were more frequently exposed to non-controlled water (46.0% vs. 26.1%) than in the rest of the Northern region.

Contact with animals and exposure to non-controlled water were the main suspected sources of the campylobacteriosis cases notified in Northern Portugal in 2015-2017. Exposure to non-controlled water was predominant in the Tâmega e Sousa subregion, a socio-economically deprived area with lower access to public supply water per capita. Prevention and control interventions to reduce the burden of human campylobacteriosis should be implemented following a One Health approach with local stakeholders.