Spatial and temporal trend analysis of bovine brucellosis in Brazil, 2014 to 2018

Bovine brucellosis, a zoonotic disease endemic to Brazil, is a serious public health problem. It is a notifiable disease that, like tuberculosis, is regulated through a national control and eradication program. The epidemiological status of bovine brucellosis must be characterized in order to direct measures aimed at controlling the disease. This study focused on analyzing the spatial and temporal distribution of bovine brucellosis in Brazil. An ecological and time series study was conducted based on secondary data reported by the National Animal Health Information System for cases of bovine brucellosis diagnosed in Brazil (2014 - 2018). The gross and average incidence rate of brucellosis was estimated per state. Joinpoint regression was applied to calculate the annual percentage change (APC) in incidence and to identify states with significant trend changes. Spatial analysis of animals with brucellosis was performed using Kernel density estimation. A total of 19,631 animals with bovine brucellosis were confirmed, and the average incidence rate varied from 0.03 to 33.93/100,000 cattle in Brazil. The highest density of positive animals was found in the states of Santa Catarina and Parana, which can be considered areas of greater transmission of Brucella abortus. Reductions in gross incidence rates were observed in Parana (APC: -13.2; 95% confidence interval [CI]: -20.3 - -5.4; p=0.01), Rondonia (APC: -44.7; 95%CI: -62.0 - -19.4; p=0.01), Mato Grosso do Sul (APC: -59.0; 95%CI: -77.7 - -24.5; p=0.01). Acre (APC: -40.0; 95%CI: -50.0 - -28.0; p=0.00), and Ceara (APC: -37.9; 95%CI: -50.9 - -21.4; p=0.00). The incidence rate significantly increased in Tocantins (APC: 122.1; 95%CI: 4.5 - 372.2; p=0.04). The findings of this study will be helpful in guiding surveillance and prevention measures aimed at reducing the incidence of bovine brucellosis in Brazil.