Molecular epidemiology of animal and human brucellosis in Mongolia

In Mongolia, human brucellosis became an issue in the 1960s. During the 1980s, thanks to livestock vaccination, human incidence was reduced to less than 1 case per 100,000 populations. In the 1990s, human brucellosis re-emerged due to the breakdown of government run disease surveillance and control programs and the lack of resources in the veterinary and medical sectors. Since 2000, the government of Mongolia has been implementing a mass brucellosis vaccination which extended until 2021. The brucellosis mass vaccination was not able to interrupt transmission from livestock to humans. This requires trace-back investigation of brucellosis using molecular epidemiological methods for medical and veterinary sectors in Mongolia. There is still a lack of understanding of the most important livestock-human brucellosis transmission, and no molecular epidemiological data is available for analysis of the current situation.
The principal objective of this PhD thesis was to provide the national brucellosis control program with evidence-based decision making to enhance its effectiveness. The evidences were provided through employing different research methods implemented in the selected areas of the study.
A simultaneous assessment of humans and livestock was conducted to help better understand the disease situation and understand access of the rural people to brucellosis diagnosis and treatment. Another study was carried out sampling of infected livestock and brucellosis patients from a hospital to identify the main Brucella spp. using bacteriological and molecular methods. Brucella melitensis turns out to be the main strain dominantly circulating in the country. The main reservoir host for B. melitensis is the sheep from which the strains spill over to goats and humans. A vaccine cool chain assessment of the national livestock vaccination checked the quality of brucellosis vaccines. Overall these assessments strive to improve the quality of the national brucellosis control program.