Page 110 - VHSA - Onderstepoort 100 Years - Part 3

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amongst them several researchers from abroad (particularly in the serotyping of AHS and BT viruses by plaque reduction neutralization tests). Sadly, like his colleague Boshoff, he also suffered from poor health. Despite his ailments he exuded great enthusiasm and possessed acute powers of observation. Not unexpectedly, he died in 1994 at the relatively young age of 52 years. Despite his early demise he left a great legacy at Onderstepoort.
Other technologists who made major contributions to the activities of the Virology Section are: Roelf Greyling (1973-1985; 1996-date); Katie Roos (neé Potgieter) (1981-date) and Charlie de Koker (1970-1997). The details for many technologists are not available but mention is made of their names: Frans Erasmus, David Saayman, Riekie Labuschagne, Johan Malan, Monica Griessel, Stefaans Voges, Pieckie Combrink, Maria Kostal, Daleen Potgieter, Aubrey Kümm, Rhona Rambach, Susan Boshoff and Karen Kruger.
Milestones
The intention of this contribution is not to attempt a detailed chronological description of all the work performed in the Section of Virology since its inception but merely to dwell on certain momentous milestones or highlights achieved during the past century. It is acknowledged with apology that this approach will not give due recognition to the work of many diligent researchers which, although extremely valuable, may not meet the criterion of a major milestone
African horsesickness imposes a severe restriction on the movement and export of horses, affecting especially the race horse industry
Alexander succeeded in propagating the virus in the brains of mice, following the technique employed by Max Theiler (Arnold Theiler’s youngest son) in New York in his pioneering work on yellow fever. Adaptation of various virus strains to mouse brains led to the development of the intracerebral neutralization test in mice which proved to be an economical and reliable method for the immunological differentiation of strains and hence confirmation of Theiler’s concept of antigenic multiplicity amongst AHS viruses. By analogy to the work of Max
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or could not be fitted into the limited space available for this contribution.
• African horsesickness
Even before 1908 Theiler conducted a great deal of work on establishing the cause of the disease but more particularly on finding prophylactic measures for it. Most of his early work concerned the simultaneous or successive inoculation of AHS infective blood and hyperimmune horse antiserum to equines as a method of vaccination. Although very crude by today’s standards, some degree of success was achieved, particularly in mules. The first real breakthrough in the study of AHS came in 1932 when
“Of major significance was the discovery by R. du Toit that orbiviruses are transmitted by Culicoides biting midges. This discovery confirmed the observation by farmers that animals can be protected against infection with these diseases by keeping them indoors during the hours when insects are most active.”
Culicoides
biting midges transmit African horsesickness virus to equines and bluetongue virus to sheep
Theiler on yellow fever, for which he received the Nobel Prize, Alexander proved that serial passage of AHS virus in the brains of adult mice led to attenuation of the virus. This resulted in the development of the first live attenuated AHS vaccine in 1934, a most significant milestone in veterinary science.
Of major significance was also the discovery by R. du Toit that orbiviruses (i.e. AHS and BT virus) are transmitted by Culicoides biting midges. This discovery confirmed the observation by farmers that animals can be protected against infection with these diseases by keeping them indoors during the hours when insects are most active. It also explained many
PART 3
History of Individual Disciplines
1908-2008
Years