Rabies in cattle is a viral disease with mandatory notification in Brazil, transmitted by Desmodus rotundus, which causes an invariably fatal acute encephalitis. To understand the dynamics of this disease in Tocantins state, Brazil, an analysis of the time series of rabies cases in cattle between 2006 and 2019 was carried out to describe the pattern of its occurrence, aiming to subsidise the Official Veterinary Service (OVS) with relevant information to enable the improvement of control actions provided for in the guidelines of the National Program for the Control of Rabies in Herbivores (NPCRH). The statistical analyses of the time series under study were performed using the R Studio software, version 1.1.463, in which the existence of trend, cyclicality and seasonality of rabies cases in cattle was assessed. These analyses showed that this disease is endemic in Tocantins state, with epidemic outbreaks that can occur every 3 or 4 years, without a seasonality pattern. The autoregressive integrated by moving average (ARIMA(4,1,4)) model predicted the approximate occurrence of 38 rabies cases in cattle in 2022 and all monthly records of this disease remained within the predicted confidence interval (95% CI) in 2020 and 2021, demonstrating it has a good predictive capacity and allowing OVS to intervene in the present processes to achieve better control of this disease.

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RESUMO De outubro a dezembro de 2007, 845 amostras de sangue foram coletadas de 836 vacas (98,9%) e nove touros (1,1%), em um matadouro com inspeção federal no Estado do Tocantins. Cento e quarenta e duas amostras [(16,8%) IC 95% 14,3-19,4] tiveram reação positiva ao teste do antígeno acidificado e tamponado de Brucella abortus. Um touro foi positivo ao teste. Quinhentos e sessenta e um bovinos (66,3%) procederam do Estado do Pará e 284 (33,7%) do Estado do Tocantins. A prevalência de soropositividade foi de 17,2% [IC (95%) 13,6 - 19,9] e de 16,6% [IC (95%) 13,0 - 22,2] para o gado do Pará e Tocantins, respectivamente. Estas prevalências não são significativamente diferentes (p > 0,05). Nenhuma das vacas tinha registro de vacinação contra brucelose. Os exames "ante e post-mortem" não detectaram qualquer sinal ou lesão sugestiva à brucelose, como descargas vaginais, orquites, artrites ou bursites [(0,00%) IC 95% 0,00-0,43] em todos os bovinos da amostra. Esta situação, associada às altas prevalências da doença e à falta de diagnóstico da brucelose nos rebanhos, aumenta o número de bovinos infectados abatidos sob condições sanitárias inadequadas, o risco de contaminação dos trabalhadores e a colocação no mercado, sem restrição, de carne de animais infectados.

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Bovine brucellosis is transmitted by Brucella abortus and causes considerable economic losses to agribusiness. To determine the seroconversion rate attributable to vaccination of heifers with B. abortus strain B-19, 330 blood serum samples from 110 heifers aged three to eight months from five properties in the municipality of Araguaína, Tocantins, Brazil, were analyzed. On day zero (D-0), blood samples were collected, and 55 heifers from the intervention group were vaccinated. The remaining blood samples were collected on days seven (D-7), 14 (D-14), and 21 (D-21). The serum samples were analyzed using the buffered acidified plate antigen (BAPA) test. The rate of seroconversion attributable to vaccination was calculated by subtracting from the seroconversion incidence rate in the intervention group the incidence rate of the control group. On D-0, 100% (110/110) of the heifers were negative in the BAPA test (95% CI [96.70 - 100%], p < 0.05). On D-7, the seroconversion rate was 94.55% (52/55) (95% CI [84.88 - 98.84%], p < 0.05) in the intervention group and 0% (0/55) (95% CI [0.00 - 6.49%], p < 0.05) in the control group. On D-14, the rate was 98.18% (54/55) (95% CI [90.28 - 99.95%], p < 0.05) in the intervention group and 0% in the control group. Therefore, seroconversion attributable to vaccination varied from 78.39% (84.88 - 6.49%) to 92.35% (98.86 - 6.49%) on D-7 and from 83.79% (90.28 - 6.49%) to 93.46% (99.95 - 6.49%) on D-14, respectively. On D-21, the seroconversion rate in the 55 heifers from the control group vaccinated on D-14 was 100% (55/55) (95% CI [93.51 - 100%], p < 0.05) but was not significantly different (p > 0.05) from that of heifers from the intervention group vaccinated on D-7. The results of this study allow making recommendations to the Official Veterinary Service on establishing a vaccination audit, with random collection of blood samples starting on day seven after vaccination in heifers considered vaccinated with B. abortus strain B-19 using the BAPA test as a diagnostic test and considering a minimum seroconversion rate of 75% to evaluate vaccination against brucellosis.