Prevalence of bovine tuberculosis and attention zones for Mycobaterium bovis in the state of São Paulo (SP), Brazil, based on data from sanitary inspections at slaughterhouses

Abstract

Bovine tuberculosis is a disease of importance for animal and public health, as it causes chronic infection in both animals and humans, leads to reduced milk and meat productivity, and may generate embargoes on the trade of products from affected herds. The Brazilian National Program for the Control and Eradication of Brucellosis and Tuberculosis (in Portuguese, PNCEBT) classifies the Brazilian states according to the level of risk for bovine brucellosis and tuberculosis determined by the prevalence of outbreaks of these diseases. The present study aimed to: determine the prevalence of outbreaks and cattle with tuberculosis in the State of São Paulo; locate the origin of animals microbiologically and molecularly positive for Mycobacterium bovis; establish microbiological differential diagnoses of inflammatory lesions found in slaughtered animals; and map areas of attention for the occurrence of M. bovis. The territory analyzed was divided into 15 administrative regions, and samples of tissues and organs were collected from 301 bovines from slaughterhouses registered at the São Paulo State Inspection Service (in Portuguese, SISP). Samples were subjected to microbiological culture in selective Stonebrink-Leslie medium, and conventional blood agar and MacConkey media. Colonies isolated in conventional media were analyzed by Matrix Assisted Laser Desorption Ionization (MALDI-TOF), and colonies isolated in Stonebrink-Leslie were subjected to Polymerase Chain Reaction (PCR) with primers from region of difference 4 (RD4) for confirmation of M. bovis. Data on cattle movement into and out of tuberculosis foci were geoprocessed in the QGIS software, version 3.28.1, to map the cities that could be involved. Samples from eight bovines (2.65%; CI 95% = 1,15% - 5,17%) showed mycobacteria in Stonebrink-Leslie medium and were confirmed as M. bovis. The prevalence rates of tuberculosis in cattle and in foci in rural properties were 2.65% and 5.94%, respectively. Mass spectrometry identified the most frequent bacteria in the samples analyzed: Trueperella pyogenes (10/301 = 3.32%), Macrococcus caseolyticus (9/301 = 2.99%), Escherichia coli (8/301 = 2.65%), Macrococcus canis (5/301 = 1.66%), Moraxella osloensis (4/301 = 1.32%), Lactococcus garvieae (3/301 = 0.99%), and Proteus hauseri (3/301 = 0.99%). The animal transportation forms (in Portuguese, GTAs) of animals positive for M. bovis indicated six rural properties with outbreaks. Geoprocessing showed 28 municipalities considered attention zones. The identification of M. bovis and other microorganisms in cattle reinforces the importance of slaughterhouses as sites for surveillance and traceability of infectious diseases, and emphasizes their role in ensuring the safety of animal products intended for human consumption.

Keywords: Bacterial etiology of bovine lymphadenitis; Epidemiology; Mass spectrometry; PCR (RD4); Traceability; Tuberculosis.