Testing of olive baboons and vervet monkeys for bovine tuberculosis infection in Masai Mara.
Bovine tuberculosis is a chronic bacterial disease of domestic animals, wildlife species and humans caused by Mycobacterium bovis. In a large number of countries bovine tuberculosis is a major infectious disease among cattle, other domesticated animals, and certain wildlife populations. Transmission to humans constitutes a public health problem. In 1985 an outbreak of tuberculosis in wild olive baboons (Papio cynocephalus anubis) was reported in Masai Mara, Kenya. Since then no other report has been made on bovine tuberculosis in the Mara ecosystem even though it is believed that there could be low grade infection in certain susceptible wildlife species. The detection of infection in a wildlife population requires bacteriological investigation or the use of valid testing methods for the species involved together with epidemiological analysis of information.
As part of the ongoing bovine tuberculosis investigation and surveillance, we tested 24 wild olive baboons using tuberculin and Stat-Pak (Rapid lateral flow) tests. None of the tested baboons was positive. A further confirmative test referred to as Quantiferone (Gamma interferone test) will also be performed on the samples from these baboons to confirm freedom of the disease in Mara baboons.
Capture and chemical restrain of baboons in Mara
Baboon troops were identified in different parts of the reserve (Simba, Keekorok, Sarova, KWS Research Camp and Fig Tree areas) then a few individuals were trapped using specially designed cage-traps and baits. The captured baboons were then anaesthetized using between 30 90mgs of ketamine depending on the age, sex and body size. They were then removed from inside and placed on top of the cage on dorsal recumbency for sampling and tuberculin testing. Blood samples were drawn from the superficial inguinal veins in plain tubes, EDTA-coated tubes and heparinized tubes.
An insulin needle was used to inject 0.05ml of bovine PPD intradermally on the right eye-lid and 0.05ml of avian PPD injected intradermally on the left eye-lid. The tuberculin needle was inserted obliquely into the skin and injection of tuberculin-PPDs was intradermal. A pea-like swelling was observed immediately after tuberculin injection confirming that the procedure was done correctly. Each of the tested baboon was given an identification mark either by shaving a particular site or coloured spray. The tested baboons were then held in closed cages under the roof for 3 days (72 hours) to read the tuberculin test. They were provided with adequate feeds and water ad-libitum and observed everyday to ensure their safety and comfort. After the test was read, the baboons were taken back and released to join the rest of the troops in the wild. None of the 24 tested baboons was positive on tuberculin test.
TBStat-Pak tests of baboons and vervet monkeys of Mara.
Blood samples from 24 baboons and 3 vervet monkeys were also tested using a rapid-lateral-flow serological test (Primate Stat-Pak). None of the tested baboons and vervet monkeys was found positive on Stat-Pak tests. Processed blood samples have been collected for a further confirmative test referred to as Quantiferone (Gamma interferone test) will also be performed on the samples from these baboons to confirm freedom of the disease in Mara baboons.
We acknowledge the support of the David Sheldrick Wildlife Trust (DSWT) towards research, wildlife disease investigations and clinical interventions. We also appreciate German Foundation of Research (DFG) who supported Bovine tuberculosis research in wildlife under the German-African Tuberculosis project through KWS and Friederich Loeffler Institute (FLI) of Animal Health.
Report by: Dr. Domnic Mijele