Epidemiological Study of Mycobacterium bovis Infection in Buffalo and Cattle in Amazonas, Brazil

Abstract

Bovine Tuberculosis (BTB) is an endemic disease in about one hundred countries, affecting the economy causing a decrease in productivity, condemnation of meat, and damaging the credibility on international trade. Additionally, Mycobacterium bovis the major causative agent for BTB can also infect humans causing a variety of clinical presentations. The aim of this study was to determine BTB prevalence and the main risk factors for the Mycobacterium bovis prevalence in cattle and buffalos in Amazonas State, Brazil. Tissue samples from 151 animals (45 buffalo and 106 cattle from five herds with buffalo only, 22 herds with cattle only, and 12 herds with buffalo and cattle) were obtained from slaughterhouses under State Veterinary Inspection. M. bovis were isolated on Stonebrink medium. The positive cultures were confirmed by polymerase chain reaction (PCR) testing. The apparent herd and animal prevalence rates were 56.4 and 5.40%, respectively. Regarding animal species, the apparent prevalence rates were 3% in cattle and 11.8% in buffalo. Generalized Linear Mixed Models (GLMM) with random effect were used to assess the association with risk factors on the prevalence. Species (buffalo), herds size (>100 animals) and the presence of both species (buffalo and cattle) in the herd were the major risk factors for the infection by Mycobacterium bovis in the region. The findings reveal an urgent need for evidence-based effective intervention to reduce BTB prevalence in cattle and buffalo and prevent its spread to the human population. Studies are needed to understand why buffalo are more likely to be infected by M. bovis than cattle in Amazon. Recommendations for zoning, use of data from the inspection services to generate information regarding BTB focus, adoption of epidemiological tools, and discouragement of practices that promote the mixing of cattle and buffalo, were made.

Prevalence, Risk Factors, and Diagnostic Efficacy of Bovine Tuberculosis in Slaughtered Animals at the Chiang Mai Municipal Abattoir, Thailand

“…The higher prevalence of bTB in buffaloes compared to beef cattle is consistent with previous reports ( 48 , 49 ). Accordingly, buffaloes posed a higher risk of bTB than beef cattle.…”

Genetic Diversity and Potential Paths of Transmission of Mycobacterium bovis in the Amazon: The Discovery of M. bovis Lineage Lb1 Circulating in South America

“…A total of 24 M. bovis isolates were selected, representing one herd of each municipality involved in two previous studies ( 6 , 20 ) that obtained a total of 63 M. bovis isolates from Amazonas State (12 from cattle and 45 from buffalo) and from Pará State (5 from cattle and 1 from buffalo). The selection of M. bovis isolates maintained the proportionality according to species (cattle and buffalo) and the local prevalence from the previous studies ( 6 , 20 ).…”

“…A total of 24 M. bovis isolates were selected, representing one herd of each municipality involved in two previous studies ( 6 , 20 ) that obtained a total of 63 M. bovis isolates from Amazonas State (12 from cattle and 45 from buffalo) and from Pará State (5 from cattle and 1 from buffalo). The selection of M. bovis isolates maintained the proportionality according to species (cattle and buffalo) and the local prevalence from the previous studies ( 6 , 20 ). Accordingly, these isolates were from tissue samples of 8 cattle and 16 buffalos collected at the slaughterhouse from herds with or without known tuberculin skin test (TST) status originating from 12 different municipalities: Alenquer ( n = 1), Apui ( n = 1), Autazes ( n = 1 ), Careiro da Varzea ( n = 1), Itacoatiara ( n = 2), Manacapuru ( n = 1), Novo Ceu ( n = 8), Parintins ( n = 3), Prainha ( n = 2), Presidente Figueiredo ( n = 1), and Urucara ( n = 3).…”

“… Geographic origin and host species of the Mycobacterium bovis isolates from municipalities of Lower Amazon River Basin, Brazil. Isolates were selected from 63 M. bovis strains previously isolated from cattle and buffalo ( 6 , 20 ). …”

“…However, the disease remains a major problem in developed countries with wildlife reservoirs that end up transmitting the pathogen to domestic livestock and vice-versa, and in developing countries where inefficient bTB control programs result in high disease endemicity and spread ( 1 , 2 ). In the Brazilian Amazon, few studies aiming to better understand bTB's epidemiology were performed ( 3 – 6 ). The prevalence within animals in the area ranged from 0.1% ( 4 ) to 5.4% ( 6 ) and the major risk factors associated with bTB were the introduction of new animals into the herds ( 4 ), the buffalo species, herds with more than 100 animals, and the presence of cattle and buffalo in the same farm ( 6 ).…”