Molecular Epidemiology of Mycobacterium bovis in Humans and Cattle

Abstract

Bovine tuberculosis (bTB), caused by Mycobacterium bovis (M. bovis), is a serious re-emerging disease in both animals and humans. The evolution of the Multi- and Extensively drug-resistant M. bovis strains (MDR-TB and XDR-TB) represents a global threat to public health. Worldwide, the disease is responsible for great economic losses in the veterinary field, serious threat to the ecosystem, and about 3.1% of human TB cases, up to 16% in Tanzania. Only thorough investigation to understand the pathogen's epidemiology can help in controlling the disease and minimizing its threat. For this purpose, various tools have been developed for use in advanced molecular epidemiological studies of bTB, either alone or in combination with standard conventional epidemiological approaches. These techniques enable the analysis of the intra- and inter-species transmission dynamics of bTB. The delivered data can reveal detailed insights into the source of infection, correlations among human and bovine isolates, strain diversity and evolution, spread, geographical localization, host preference, tracing of certain virulence factors such as antibiotic resistance genes, and finally the risk factors for the maintenance and spread of M. bovis. They also allow for the determination of epidemic and endemic strains. This, in turn, has a significant diagnostic impact and helps in vaccine development for bTB eradication programs. The present review discusses many topics including the aetiology, epidemiology and importance of M. bovis, the prevalence of bTB in humans and animals in various countries, the molecular epidemiology of M. bovis, and finally applied molecular epidemiological techniques.

Isolation and identification of Mycobacterium bovis in milk from cows in northeastern Brazil

“…While most cases of tuberculosis in humans are caused by M. tuberculosis, it is estimated that about 3.1% of the cases of human tuberculosis in the world are caused by M. bovis (EL-SAYED et al, 2016). However, infection in humans is generally not confirmed by isolation and identification of the agent, making it impossible to identify the possible source of infection.…”

Genetic diversity of Mycobacterium bovis in Jalisco, Mexico: Tracing back sources of infection

“…bTB causes direct and indirect economic losses to the livestock industry, infected animals have poor production performance, die or are culled prematurely. Free trade of animals and animal products in affected areas is prohibited, especially for exportation (Bawinek and Taylor, 2014;El-Sayed et al, 2016).…”

Effect of a low dose of BCG-Phipps vaccine on the development of reactivity to tuberculin skin test in neonatal calves and adult cows

“…Incidence of this disease represents a significant problem to livestock production, because of a fast dissemination of the disease. Due to multiple factors, such as defective management, poor feeding, new infected animals in the herd, and mainly lack of adequate biosafety measures, bTB represents a risk of disease for humans (Thoen et al, 2006;Schiller et al, 2010;El-Sayed et al, 2016).…”