Assessment of Brazil's Vesicular Syndrome Surveillance System: Profile of notifications and performance of the official veterinary service

Foot-and-mouth disease (FMD) is an ailment that causes serious damage to the productive chain, and its control through vaccination is of utmost importance for its eradication. Brazil initiated the National Foot-and-Mouth Disease Surveillance Program (PNEFA) with the aim of making the country FMD-free by 2026. As part of the program, notifications of vesicular lesions became mandatory for the Official Veterinary Service (OVS), which is responsible for verifying them. Due to its size, border areas with countries that do not have FMD-free status pose a risk to Brazil and require greater attention. This study described the profile of notifications of suspected outbreaks of vesicular syndrome in Brazil and analyzed the performance of the surveillance system. The results showed 7,134 registered notifications of suspected vesicular syndrome outbreaks from 2018 to 2022, with 2022 having the highest number (n = 2,343 or 32.85%). The species that generated the most notifications were swine (90.99%), cattle and buffaloes (7.54%), goats and sheep (1.44%), and others (0.03%). The sources of notification were "Veterinary medicine professionals" (61.82%), "Owners or employees" (13.66%), "Third parties" (8.90%), "OVS" (7.20%), and "others" (2.66%). 41.69% of notifications originated from non-border municipalities, and 58.32% from border areas. Only the state of Paraná account for 51.73% of the total notifications. This state also accounted for 66.70% of the 32.47% of notifications with a final diagnosis of "absence of clinically compatible signs or susceptible animals", indicating a certain lack of knowledge in the area, leading to unnecessary notifications and system overload. The performance of the OVS was evaluated based on the service response time from notification registration trough Logistic and Negative binomial regressions. A total of 27.83% of notifications did not meet the Brazilian legally specified time, and the zone related to the state of Parana needs improvements in performance. The presence and peaks of Senecavirus A cases may have influenced an increased number of swine notifications and led to a decrease in OVS response time. The results demonstrate better performance of surveillance in border areas. Given the vast territory of Brazil, it is not expected that 100% of responses occur within the legal timeframe, however, the performance of the surveillance system proved to be adequate, with 86% complied to the legislation. The performance indicators could be used as a monitoring tool, along with indicators to demonstrate system overload. Continued education actions are crucial for strengthening PNEFA.