Analysis of the associations between territorial, farm and climatic factors and the presence of brucellosis on buffalo and cattle farms in Campania (2015–2023)

Le résumé fourni par la source

Brucellosis remains one of the most important zoonotic diseases affecting cattle and buffalo populations, causing substantial economic losses and representing a major challenge for animal health and eradication programs. Although management-related risk factors have been widely investigated, the contribution of climatic and territorial determinants to disease occurrence has received less attention. This study aimed to evaluate the association between climatic, territorial and farm-level factors and the occurrence of brucellosis in cattle and buffalo farms in the Campania Region (Southern Italy) during the period 2015–2023. A retrospective longitudinal study was conducted including all officially registered cattle and buffalo farms under the regional eradication programme. Annual farm-level brucellosis status was obtained from the national veterinary information system. Climatic (Temperature–Humidity Index, THI), territorial (farm density, presence of outbreaks within a 2 km radius, province) and historical (previous farm positivity) variables were analysed. Annual comparisons between positive and negative farms were performed using Fisher’s exact and Wilcoxon rank-sum tests. Generalized linear mixed-effects models (GLMMs) were then developed separately for buffalo and cattle farms. In buffalo farms, the presence of outbreaks within a 2 km radius was the strongest predictor of disease occurrence (OR = 4.55; 95% CI: 3.57–5.80), while previous positivity also significantly increased the risk (OR = 1.44; 95% CI: 1.11–1.87). Farm density became an increasingly important risk factor from 2019 onwards. THI showed a significant association in the univariate analysis but a more limited contribution after adjustment for territorial variables. In cattle farms, THI emerged as a major predictor of disease occurrence (OR = 1.36; 95% CI: 1.28–1.44), while previous positivity (OR = 5.29; 95% CI: 3.77–7.42), nearby outbreaks (OR = 4.94; 95% CI: 4.02–6.08) and provincial location, particularly Salerno, were also independently associated with increased risk. These findings demonstrate distinct epidemiological patterns between buffalo and cattle farms. While disease persistence in buffaloes is primarily driven by local epidemiological pressure and farm density, climatic conditions appear to play a more prominent role in cattle. Integrating climatic, territorial and historical information into surveillance systems could improve risk-based prevention and contribute to more effective brucellosis control strategies in endemic areas.

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