DOMINION WITHIN MALARIA RANGE

Bay of Plenty Beacon, Volume 7, Issue 14, 12 October 1943, Page 3

DOMINION WITHIN MALARIA RANGE

AMPLE BREEDING GROUNDS

"No one can state with any degree of confidence that New Zealand lies outside the range of. malaria mosquitoes. Any statements to the contrary arc dangerously misleading," stated the Assistant Director and Chief Entomologist of the Cawthron Institute, Nelson (Dr. D. Miller), a noted authority on mosquitoes and malaria, in an address in Whangarei. Dr. Miller's address Avas given under the auspices of the Health Department.

Air transport brought New Zealand. within a few hours' journey from malaria infested areas of the South-west Pacific. New Zealanders had shown a quiet complacency in regard to the danger of a malaria cpidemic being brought about by the introduction of malarial mosquitoes and subsequent breeding in New Zealand.

"it is a great pity that malarial mosquitoes arc not found in New Zealand," said Dr. Miller, "for if they Avere, I am quite sure that the Avliole problem of mosquito control AA'ould be tackled more energetically."

There Avere. ample breeding grounds for mosquitoes in Ncav Zealand, lie said. Any aggregation of stagnant Avater Avas a paradise for breeding. Horse troughs, ditches, cellars, lift-Avells. and even air-raid shelters were suitable for breeding.

"We have to be prepared, to find malarial mosquitoes in New Zealand," declared Dr. Miller. At. a NeAv Zealand port a malarial-carry-ing mosquito had been found aboard an overseas vessel and tropical culicine mosquitoes had. been brought to the Dominion by aeroplane from a malarial region. En temperate regions, he said, Avas necessary to ensure that possible breeding grounds for a distance of three miles around airfields should be eliminated.

Survival of malaria mosquitoes after transport by ship ancl plane over long distances under varying conditions had been proved beyond all doubt, said Dr. Miller. Elevation of more than 12,000 feet did not. incommode them. They had even been known to reach their destination in a frozen state and yet retain their powers of causing malarial infection when submitted to warm temperatures. The development of air transport had, greatly aggravated, the danger of malarial mosquitoes extending their range.

The process by which the microorganisms of malaria were conveyed to humans by mosquitoes, together with their life c3 r cle, was described by Dr. Miller. He also referred to the way mosquitoes became infected through biting humans or animals. There were 200 known species of mosquitoes, and of these 44 had been proved to carry malarial infections. Some of the species preferred the blood of animals to that of humans. Mosquitoes at present found in New Zealand, he said, were a species known as culicine, a type which did not carry malarial infections. Adaptable to Surroundings Anopheline mosquitoes. which were malaria-carrying, had the knack of producing races or strains peculiarly adapted in new and unexpected surroundings,, and the same applied to the micro-organisms of malaria. There was no doubt that these mosquitoes and malaria had not yet reached the limit of distribution. Reunion, Mauritius and the Barbadoes Islands were no longer free of malaria, as they had been formerly. An island in the Solomons group had been invaded between 1933 and 1942, but the most outstanding case was the. establishment in Braz'il, in 1931 of an African species of anopheline transported by fast surface ship or aeroplane during a survey of the air route between Dakar, in Africa, and Natal, in Brazil. This affected the. large native population which had aci quired an immunity to the local variety of. jnalaria.

Of the many diseases inhabiting human progress, malaria had farreaching influence, he said, lln India it was estimated, that of the 100,,000,000 people, suffering annually from the disease, 1,000,000 perished from it. The disease lowered the vitality to such an extent that the inroads of other diseases accounted for a further 1,000,000' deaths. It was in times of war, however, that malaria became spectacular., owing to its power of immobilising armies. During the Macedonian campaign, the French, in 191(>, put no more than 20,000 troops in the field out of a force of at least 120,000, while in the. same year, the

British had about 30,000 men down with the dreaded disease,, and 70,000 in 1917. The Germans were no better off in the face of the common and powerful foe of malaria. lit was not far from the truth to say that in both peace and war, the direct and indirect influences of malaria placed it at the head of all other human disorders.