Page 77 - VHSA - Onderstepoort 100 Years - Part 3

assistance of Antoinette Josemans, most of the important Babesia spp. of cattle, horses and dogs, including the erythrocytic stages of Theileria equi, have been successfully cultured. Zweygarth’s tissue culture exper- tise enabled co-workers to sequence the whole genome of Ehrlichia ruminantium, in pursuit of nucleic acid-based vaccine de- velopment. He also managed to attenuate a virulent isolate of E. ruminantium, which has been shown to have potential use as a vaccine against heartwater.
Laura Lopez Rebollar qualified as a veterinarian in 1987 at the National Uni- versity of Mexico. She joined the Proto- zoology Section in 1990 as an assistant veterinary researcher, working mainly on the tick vectors of Babesia spp., where she was involved until 2003. She participated in the projects on the vectors of B. trautmanni in pigs, referred to above, and collaborated with Faculty researchers in their studies on B. felis.
Babesia canis and
ONDERSTEPOORT 100
aspects of cattle ownership and the low priority given to the commercial value of the animals.
Stoltsz left the Institute to take up a teaching position at the Onderstepoort Faculty of Veterinary Science in 1997. Shortly afterwards the Helminthology and Protozoology Sections merged, to become Parasitology headed by De Waal until he resigned in February 2002 to take on a teaching position at the University College, Dublin, in Ireland.
Mike Combrink, at the time chief vete- rinary technologist responsible for the blood vaccine production, was appointed Head of Parasitology in an acting capacity, until the new Programme manager, A.A.I. Latif, was appointed in 2004. He developed a real-time PCR diagnostic test, in close colla- boration with the Faculty of Veterinary Science, that is more sensitive and faster
than previous tests. An interesting result obtained thus far is that isolates of T. parva from cattle are genetically homoge- neous whereas isolates from buffaloes show considerable genetic variation.
Potgieter returned to Parasitology to continue his stu-
dies on the epidemiology of theileriosis in buffaloes and
cattle in 2004. Conventional tick pick-up and transmission experiments have already shown that some highly sensitive molecular diagnostic tests lack specificity as they cannot distinguish between some of the Theileria spp. encountered
in buffaloes. These tests therefore require further develop-
ment and validation. At least four T. parva isolates of buffalo 167 origin have been successfully established in culture and their molecular genetic relationships can now be studied.
A research project conducted on environmentally sus- tainable control of ticks and tick-borne diseases of cattle under tribal conditions in KwaZulu-Natal, where the State is involved in tick control practices, provided very interesting results. A surprisingly high prevalence of exposure to tick-borne diseases was revealed despite the perceived high dipping frequency. However, instability for redwater (babesiosis), gallsickness (anaplasmosis) and heartwater (ehrlichiosis) occurred in all but one of the districts studied.
167 Therefore deaths from these four (two types of redwater are involved) tick-borne diseases must occur fairly frequent- ly. Illuminative information was also obtained on cultural
In conclusion, it is fair to state that the scientific activities relating to protozoan diseases at the laboratory established by Theiler at Onderstepoort have made a very significant contribution to the Institute’s national and international fame for the 100 years of its existence. Research on micro-organisms has, however, become increasingly multidisciplinary, especially with the growing application of molecular techniques. The research programme of the Institute has slowly but surely shifted in emphasis from the classical research foundations laid by Pasteur and Koch to embrace the exciting opportunities offered by the crackers of the genetic code, Watson and Crick.
However, in protozoology there are still many research challenges that will not be solved by the application of molecular technology alone. In principle the technique of vaccine production against babesiosis of cattle has hardly changed for more than a century. The final host still has to be used
as source of infected blood. A similar situation exists in the case of the heartwater vaccine. There is a theoretical possibility of the development of new generation vaccines, but the progress has been slow. The future of the classical protozoologist at the Institute therefore still seems assured.
Protozoology
1908-2008
Years