Faculty of Veterinary Science
Department of Veterinary Tropical Diseases
Selected Highlights from Research Findings
Mycobacterium bovis is the causative agent of bovine tuberculosis (BTB), which is a major problem in the cattle industry worldwide. BTB was first diagnosed in African buffaloes in the Kruger National Park (KNP) in 1990, and M. bovis has subsequently been found also to infect lions, kudus and baboons.
Researchers at the Faculty’s Veterinary Tropical Diseases section launched a project entitled: Developing an ELISA for the detection of Interferon-gamma (IFN-g) in wildlife species as a diagnostic tool for Mycobacterium bovis and Mycobacterium tuberculosis infection, to help them find a solution to this problem.
Retrospective investigation suggests that BTB had entered the KNP in the 1960s. The lack of sensitive diagnostic tests capable of detecting infected wildlife before they become infectious to other animals has proven to be a major impediment, especially in breeding and reallocation projects.
Traditionally the detection of BTB relied on the use of tuberculin skin tests to measure cell-mediated immunity against M. bovis infection. A capture ELISA specific for bovine IFN-g and its use in the detection of cell-mediated immunity to M. bovis antigens in cultures of whole blood for cattle infected with BTB was first described in Australia in 1990 and is now in use worldwide.
In collaboration with the Faculty of Veterinary Medicine, Utrecht University, the Netherlands, the ARC-Onderstepoort Veterinary Institute, and SAN Parks, researchers have developed a robust and rapid capture IFN-g ELISA that can be used for the detection of BTB in various wildlife species.
Results indicate that native IFN-g from a number of wildlife species like elephant, rhinoceros, lion, tiger, buffalo, roan and sable antelope, can be detected using this capture ELISA.
This ELISA will be used to test animals in the field and thus allow researchers to identify infected individuals and infected populations. It will prove to be a valuable tool to use in reallocation and breeding strategies and ultimately may have potential in eradicating M. bovis from wildlife populations.
Ms D Morar
Veterinary Tropical Diseases
+27 (0) 12 529 8266
darshana.morar@up.ac.za
Theileria parva is a tick-borne pathogen, which, in South Africa, causes corridor disease in cattle. The African buffalo is the natural reservoir host of the parasite and infected buffalo cannot be translocated to disease-free areas of South Africa.
There is a demand for buffalo from game farmers in such areas since they are one of the “Big Five”, and disease-free buffalo command a much higher selling price than infected animals. There is therefore a need for a sensitive and specific diagnostic test to reliably certify buffalo free of the infection.
This research project involved the development and evaluation of a sensitive and specific real- time Polymerase Chain Reaction (PCR) test for the detection of T. parva in carrier animals.
The real-time PCR test was compared to existing molecular tests and was found to be significantly more sensitive. The technology will be implemented by the OVI and will result in more reliable testing of buffalo and cattle.
This research was part of BioPAD Project BP040 (Development of a molecular diagnostic test kit for tick-borne pathogens). The other members of the consortium were Utrecht University, Isogen Lifescience (the Netherlands) and the ARC-OVI.
Dr Nicola E. Collins
Veterinary Tropical Diseases
+27 (0) 12 529 8022
nicola.collins@up.ac.za
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