Page 54 - VHSA - Onderstepoort 100 Years - Part 1

OND
ERSTEPOORT 100
disciplines. Genome libraries were constructed for a number of viruses and haemoparasites, and genes identified which could be used as diagnostic probes or in PCR tests. An outstanding example was the development by Anita Michel of diagnostic probes for the differential diagnosis of wildebeest- and sheep-
introduction into the country transmitted mainly by dogs. The latter strain has become the main source of infection in humans, especially in KwaZulu-Natal.
A world first was the isolation of equine arteritis virus from donkeys by J.T. (Janus) Paweska. The widespread occurrence of a sub-clinical infection in donkeys caused quite a stir amongst
derived malignant catarrhal fever in cattle – Genes for bacterial toxins were cloned and expressed, assisting in the production and evaluation of vaccines, and immunogenic proteins identified in various organisms as a first step in the development of recom- binant vaccines. A number of recombi- nants were in fact constructed, such as BTV/ baculovirus, AHSV/baculovirus, fowlpox/ Newcastle disease virus and recombinants between lumpy skin disease virus and AHSV, bovine ephemeral fever virus and Rift Valley fever virus. The majority of these are as effective or more effective than existing vaccines but for various reasons, including cost and production problems, they have not yet reached the market.
a first worldwide.
A major accomplishment was the elu-
cidation by D.F. (Denis) York of the com-
plete genome sequence of the jaagsiekte
retrovirus in 1992 in collaboration with
French researchers. It was the first full genome sequence determined by a South African scientist and led to the discovery of an endogenous non-oncogenic form of the virus in normal sheep, thus complicating the diagnosis of the disease.
Important contributions in virology include the discovery by G.R. Thomson and co-workers, by means of nucleotide 54 sequence analysis, that two different biotypes of the rabies virus exist in South Africa. One is the indigenous type primarily transmitted by mongooses, and the other a relatively recent
economic losses to sheep farmers along the banks of some of our rivers because of the intense irritation caused by their bites. In this case researchers from Onderstepoort, led by E.M. (Errol) Nevill, developed a procedure involving the application of two larvicides to the river that was successful in controlling the pest.
More details of these and other studies and of the people involved can be found in the chapters (Part 3) dealing with individual scientific disciplines.
“A world first was the isolation of equine arteritis virus from donkeys by
J. T. (Janus) Paweska. The widespread occurrence of a sub-clinical infection in donkeys caused quite a stir amongst horse breeders but fortunately the virus was found not to spread from donkeys to horses.”
horse breeders but fortunately the virus was found not to spread from donkeys to horses. A somewhat similar result was the demonstration by B.J. (Banie) Barnard that zebras can act as passive carriers of the African horsesickness virus, solving the old problem of how the virus survives during winter.
Following an outbreak of bluetongue in southern Europe, a collaborative five- nations programme funded by the Euro- pean Union was launched to study the bio- systematics, distribution and vector com- petence of Culicoides midges. An additio- nal vector of this disease was discovered by R. (Rudi) Meiswinkel, as well as almost a hundred new species of these midges. A separate study concerned blackflies or Simulium midges which do not transmit diseases locally but can cause considerable
PART 1
Onderstepoort Veterinary Institute: General History
1908-2008
Years