The penetration of the Lowveld by settlement was for many years stifled by two natural barriers - Malaria and Nagana; the first, crippling
and often fatal to human beings; the second inevitably fatal to cattle, horses, and dogs. Malaria and Nagana are both insect-borne diseases -
Malaria by mosquitoes and Ngana by the Tsetse-fly. Only once the two had been defeated was it possible for mass-scale immigration into the
area.
In 1896 the rinderpest swept through the country killing almost all the cattle. However this would turn out to be a blessing in disguise in that it also rid the country of the tsetse-fly. The link between the
disappearance of the rinderpest and the fly is not known. It was only after the the Anglo-Boer War, when cattle first re-entered the
Lowveld, that the disappearance of the fly was discovered.
Near the end of the 19th century, Sir Patrick Manson and a number of other researches formulated the hypothesis that malarial fever was
transmitted by mosquito. Major Roland Ross, at the Liverpool School of Tropical Medicine, went on to prove this link. This discovery allowed
researchers to establish four so-called 'laws' of Malaria: first, that it is caused by numbers of
micro-scopical parasites which live and
propagate themselves in the blood of human beings and other mammals;
secondly, that in one phase of the cycle of existence of these parasites
pass with the blood of infected persons into the bodies of the blood-sucking females of the anopheles mosquito; thirdly, that in another
phase of that cycle, they are again introduced into the blood of human beings and other susceptible animals by the bite of the infected
mosquito; and fourthly, that the anopheline mosquito breeds principally in shallow terrestrial waters.
This discovery opened the way to combat malaria, both in defense and attack; in
defense by preventing the mosquito from biting the person; in
attack, by destruction of the mosquito and/or the destruction of the parasites in the blood of the infected person.
In the 1930’s the Government of the day decided that the time had come to fight an all-out battle against Malaria. Before planning a campaign they consulted some of the world leading authorities on malaria and the mosquitoes that were responsible for spreading the infection. As a result of the scientific advice they received, they extended an invitation to a dutch scientist, Professor N.H. Swellengrebel, to visit South Africa and to report on the incidence of the disease. Professor Swellengrebel had won renown for his successful campaign against malaria in the Netherlands East Indies. He made Tzaneen his headquarters while he was in the Transvaal and produced a 25000-word report that horrified the Union Department of Health. He found that among 20 different types of anopheles mosquitoes in South Africa there were only two which in his opinion were responsible for the transmission of malaria. They were anopheles costalis (gambiae) and anopheles funestus. He found that costalis was a puddle-breeder. All it demanded for producing its young was a small indentation in the ground – a hoof print would do – that was filled with rainwater and in sunlight. The species funestus, on the other hand, was a stream-breeder and liked the verges of swiftly running streams.
Once the two had been identified it became a fairly straightforward task to spray oil on all possible breeding places. However, the campaign against the carriers had to be mounted on a vast scale to be effective.
The Government accepted Professor Swellengrebel’s recommendations in toto and, in 1931, established the Tzaneen Malaria Research and Control Station. To head the campaign against the disease they chose Dr. Siegfried Annecke. The campaign began with the establishment of some 600 “malaria depots” at which quinine could be obtained free of charge and from which educational campaigns were conducted. Some 20-million litres of larvacidal oil was sprayed on potential breeding places and more than half a million huts were treated.
The results of this all-out attack on the disease were little short of miraculous and when, at a later date,
D.D.T. became available, the victory was won. In the comparatively short space of 8 years
malaria cases admitted to hospitals dropped from some 2000 per annum to 200.
See also: The eradication of East Coast
Fever
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