Page 71 - VHSA - Onderstepoort 100 Years - Part 3

ONDERSTEPOORT 100
Another scientific breakthrough which occurred at this time under Neitz’s direction was the discovery by Pols that bovine besnoitiosis was transmissible from acutely infected natural cases by sub-inoculation of blood to susceptible cattle and to rabbits. The discovery of a susceptible laboratory animal paved the way for later studies on the epidemiology and control of the disease, the rabbit proving to be an excellent model for further research on the disease (see below). Pols took over the Ambulatory Clinic at the Faculty in the mid-1950s and thereafter left the profession for the more lucrative building trade, in which he had been involved before studying veterinary science.
“Another scientific breakthrough which occurred at this time under Neitz’s direction was the discovery by Pols that bovine besnoitiosis was transmissible from acutely infected natural cases by sub-inoculation of blood to susceptible cattle and to rabbits.”
Neitz worked very closely with Col. R.M. (Bob) McCully who initially visited Onderstepoort as a member of the Armed Forces Institute of Pathology, Washington DC and later returned to South Africa when he retired from the US Air Force. McCully was an excellent pathologist and although they did not publish much together, he assisted Neitz with many of his necropsies and performed some of the histopathological investigations.
Research on besnoitiosis was assigned to Bigalke by Neitz when Pols left. He succeeded in transmitting bovine besnoitiosis from chronically infected cattle by inoculation of suspensions prepared from their cyst- bearing skin to rabbits and cattle, thus
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Two African buffalo calves being enticed towards the tick-free stables, with inquisitive cows looking on
A typical chronic case of elephant skin disease (besnoitiosis) in an Afrikaner bull
proving that the chronically infected beast was a potential source of infection in the field. With T.W. Naudé, he also showed that the cysts which were visible to the naked eye in the scleral conjunctiva of chronically infected cattle – by far the majority were subclinically affected, i.e. cysts were present in the scleral conjunctiva in the absence of the typical skin lesions – could be used to carry out surveys on the incidence of the disease. Bigalke followed this up with epidemiologi- cally-orientated research in which he inter alia demonstrated that the disease could be transmitted mechanically by a number of bloodsucking insects, such as tabanids, tsetse flies, stable flies (Stomoxys calcitrans) and even mosquitoes, from chronically infected to susceptible cattle and rabbits. These investigations formed the subject matter of his thesis for a DVSc degree, which was awarded in 1969. Bigalke also succeeded in growing Besnoitia besnoiti in cell culture in 1962
Protozoology
1908-2008
Years