COULD REACH N.Z.

Nelson Evening Mail, Volume 78, 28 June 1943, Page 3

COULD REACH N.Z.

MALARIA-CARRYING MOSQUITOES DANGER DISCUSSED BY DR MILLER PHILOSOPHICAL SOCIETY LECTURE The opinion that there was no shadow of doubt that mosquitoes capable of carrying malaria could reach New Zealand<»live on board ships and aeroplanes, was expressed by Dr Miller, of the Cawthron Institute, in an illustrated address to the Nelson Philosophical Society on the subject of mosquitoes and malaria. Dr Miller pointed out that the Health Department was alive to the possibility of the introduction of malaria to New Zealand under war conditions and that preventive measures were being taken. The lecturer gave details of the structure, habits and control of mosquitoes, and the means by which the malaria-carrying species can be distinguished from those that do not transmit that disease. This was followed by an account of the micro-or-ganisms that cause malaria and an explanation of the development oi the parasites in the blood of man and in the body of the mosquito. During the course of his address the speaker “It is common knowledge that some mosquitoes transmit the causative agents of certain diseases such as malaria, yellow fever, dengue fever and elephantiasis, while other species of mosquitoes do not. In the absence of disease, however, mosquitoes remain an important influence upon public health through the discomfort they cause, while by hampering the development of many localities they are responsible for a decided economic loss. This has been the case in New Zealand up to the present, but there is no need for it as mosquitoes are easily controlled by organised effort. One sometimes feels it a pity that some disease-car-rying mosquitoes do nqt exist in this country to stimulate an effective mosquito control campaign. “Why no mosquitoes capable of carrying human malaria occur naturally here we do not know; but that they can reach New Zealand alive on board ships from malarial regions is beyond a shadow of doubt, while under present war conditions of rapid and frequent air transport the danger becomes acute. I noted a statement reported in the Press a few weeks ago to the effect that mosquitoes could not survive air transport above some 6000 feet; this is utter nonsense and dangerously misleading. There are ample records to the contrary; indeed a journey at 12,000 feet does not incommode them. DANGER CANNOT BE IGNORED : “The urgent question is, that in view of the numbers of malaria pa- ; tients now recuperating in New Zealand is there any danger of the ma- ; larial mosquitoes that reach our : shores on planes and ships becoming . established here and spreading malaria amongst the civil population? The answer is that we dare not ignore the danger as it is by no means outside the bounds of possibility for one or more species of malarial mosquitoes to establish in New Zealand, at least under favourable localised conditions, and cause epidemics. “A consideration of some of the facts supports this view. Malaria is ■ not confined to the tropics, and in ; human malaria there are three types; - quartan, tertian, and subtertian or \ malignant tertian. It is doubtful if the last could develop under New Zealand conditions as it is virtually a . tropical disease. However there is a possibility that both the mosquitocarriers and the parasites of quartan and tertian malaria could establish in parts of the Dominion. Apart from : hurrtidity, which has an important influence, the distribution of these ; two fevers is limited in the Northern , and Southern Hemispheres by the 60deg. F. summer isotherm and ap- ; proximately the northern half of New Zealand lies within this zone. Further, when it is considered that i epidemic malaria in Europe is a feature of such countries as Holland and sometimes the south of England (which also lie within the isotherm mentioned), one naturally becomes alive to the possibilities in New Zealand ; PREVENTIVE MEASURES IN N.Z. | “The influence of atmospheric temS perature upon the malarial parasite in the blood of man is negligible, but it has a direct bearing upon the parasite undergoing its cycle in the mosquito, the body temperature of which varies with that of the atmosphere. For example, the quartan parasite in the mosquito can complete its cycle at temperatures under 59deg. F., that of tertian malaria between 59 to 86 deg. F., even overwintering within the insect to cause infection in man when the mosquito attacks him in spring, while the subtertian parasite requires much higher temperatures. Further, it has been found that the larvae of one of the principal carriers of tertian malaria are active in water where they breed at temperatures ranging between approximately y 43 deg. F., and 63 deg. F. and even higher. Thus for the survival of certain malarial mosquitoes, their larvae and malarial parasites of some types, New Zealand cannot, with any assurance, be ruled out of danger. “The subject has not been neglected. Serious consideration has been given it, and Dr. M. Watt, Director General of Health, has inaugurated a campaign for the elimination of breeding grounds where alien mosquitoes are most likely to become established.” HAPPINESS CLUB FLAG 500 EVENING The members and friends of the Happiness Club held another successful “Flag 500” evening in the Civic Tea Rooms. After 33 games had been played the winners proved to be Mrs Blair, Mrs Allcock, Mr and Mrs Moore with 23£ flags. The second prize was won by Mrs Linton. Mrs Froggatt, Mrs McArtney and Mr Symes with 21 £ flags. The travelling prizes went to Mrs Monk and Mr Ward, the special table prizes to Miss Southorn, Miss Purvis, Mr Andrews, snr., and Mr Andrews jnr. The special prize was won by Mrs Benjamin. After the cards a dainty supper was served and Mrs A. Clements, president, thanked all present for making the evening so enjoyable and invited all present to the next evening.