Molecular epidemiology of Mycobacterium bovis and Mycobacterium caprae. Spanish database
Sabrina Rodríguez Campos defended this presentation at the Faculty of Veterinary Medicine of the Complutense University of Madrid in order to obtain the Master of Research
June 26th, 2008
Micobacteria are classified into three groups according to their pathogenic characteristics and the clinical picture they produce. Mycobacterium bovis and Mycobacterium caprae belong to the M. tuberculosis complex, along with M. tuberculosis (human bacillus), M. africanum (heterogeneous group primarily found in equatorial Africa), M. bovis BCG (vaccine strain derived from M. bovis), M. microti (rodent bacillus), M. canettii (African strain) y M. pinnipedii (seal bacillus). These pathogens cause tuberculosis, a zoonosis which presents an important problem in domestic animals, wildlife, and public health. In Spain, M. bovis and M. caprae are the most important micobacterial species involved in animal infection.
M. bovis is the main causative agent of tuberculosis in domestic animals (cattle, goat, sheep, swine, cat and dog) and in wildlife (red deer, fallow deer, feral pig, chamois, lynx and fox), and has been isolated from all over the country. Tuberculosis in humans caused by M. bovis is often associated with the veterinarian and agricultural profession. However, infections with unpasteurized dairy products can occur.
M. caprae primarily affects goats, but has recently been reported in cattle, swine, red deer and feral pig, as well as in Siberian tiger, camel, dromedary and bison, and has also been isolated from humans. At present, no official data regarding the prevalence of tuberculosis in goats in Spain are available because these animals are not included in the compulsory national eradication campaign.
Tuberculosis in livestock produces important economic losses due to the costs of eradication programs, disease compensations to farmers, decrease of production and the restrictions for animal movement and animal products.
Wildlife has an important role in maintaining tuberculosis because the animals represent a reservoir for the bacillus. Furthermore, the infection increases morbidity and mortality in protected and endangered species, and presents a public health problem.
DVR-spoligotyping is widely used for molecular characterization to establish epidemiological links between outbreaks in different geographical areas by identifying identical spoligotypes. The finding of identical spoligotypes can be due to the movement of anergic animals (false-negative reactors to intradermal tuberculin testing), illegal movement of infected animals or simply to the fact that some spoligotypes are more frequent than others and can be found in different regions.
Molecular typing is indispensable for epidemiological studies and therefore, together with the Spanish Ministry of the Environment, and Rural and Marine Affairs, a national database has been designed which comprises the geographical and molecular data regarding M. bovis and M. caprae infection in animals in Spain since 1996 until today.
