Page 27 - VHSA - Onderstepoort 100 Years - Part 1

ONDERSTEPOORT 100
attention of the new Minister of Agriculture who appointed a committee to advise the Civil Service Commission on the improvement of service conditions. It also recommended bursaries coupled to contracts to encourage employment of veterinarians by his department. As a result of these actions the students resumed their classes on the 22 March.
breeding areas supported the viability of an eradication campaign: only some 700 square km had to be treated in order to eradicate the flies in an area of about 18 000 square km historically susceptible to outbreaks of the disease.
Aerial spraying of tsetse flies in Zululand with DDT
Despite all these changes and difficul-
ties the research programme of the In-
stitute continued to yield outstanding
results. During the post-war years the
scene was dominated by the successful
tsetse fly eradication campaign in Natal
under the guidance of R.M. du Toit. It
was triggered by a devastating epidemic
of nagana in 1945 which killed more than
60 000 cattle. Nagana is the collective
term for the disease caused by one or
more of four trypanosome species found
in South Africa and is transmitted by the
three local Glossina (tsetse fly) species. The
development during the war of a new class
of highly effective chlorocarbon insecticides
led to the first limited laboratory study at
Onderstepoort in 1945 on the toxicity of
DDT for tsetse flies. At the same time field
studies were conducted to determine the distribution and breeding sites of the various Glossina species by means of Harris traps and sentinel animals. It was found that limited
In 1946 and 1947 an intense aerial DDT/BHC spraying programme was carried out with the assistance of the Defence Force who supplied the necessary aircraft and pilots. In addition to the aerial programme a corridor of land 3 km in width surrounding the Mkuze and Hluhluwe game reserves was cleared of bush and game and DDT dipping of cattle in adjoining areas was introduced. By 1948 Glossina pallidipes, the main vector of nagana in Natal had practically disappeared and the spraying programme could be terminated. In 1950 Natal was declared free from G. pallidipes. The fact that G. austeni and G. brevipalpis were still present in the game reserves did not pose a problem since they were shade- loving and thereby restricted to dense forest or heavy bush and did not spread beyond the borders of the reserves. Almost half a century passed before nagana re-emerged as a problem, mainly because of increased contact between wildlife and cattle. The total cost of the
campaign was estimated at £1,3 million.
Also of considerable importance was the first diagnosis
27
“During the post-war years the scene was dominated by the successful tsetse fly eradication campaign in Natal under the guidance of R.M. du Toit. It was triggered by a devastating epidemic of nagana in 1945 which killed more than 60 000 cattle.”
Growth and expansion (1927-1948)
1908-2008
Years