Displaying publications 1 - 20 of 83 in total

Abstract:
Sort:
  1. Dy FJ
    Bull World Health Organ, 1954;11(4-5):725-63.
    PMID: 13209318
    The author summarizes the information given by 13 governments-Afghanistan, Burma, Ceylon, China, India, Indonesia, Malaya, Netherlands New Guinea, Philippines, Portuguese India, Sarawak, Thailand, and Viet Nam-on their existing and proposed malaria-control programmes in response to a questionnaire prepared by WHO for discussion at the First Asian Malaria Conference, which was held in Bangkok in September 1953.Although in late 1953 nearly 46.5 million of the 271 million people living in malarious regions were protected against the disease, more than 224 million others were still unprotected.It is noted that residual-insecticide spraying-the basis of most campaigns-has significantly reduced spleen- and parasite-rates; that the minor opposition to spraying initially encountered in some places quickly disappeared as the benefits became apparent; that malaria control has resulted in general improvements in public health and has promoted socio-economic development; that anopheline resistance to the insecticides used has not been observed; that ten governments voiced the need for indoctrination of public officials concerning malaria control; and that there is a trend among governments to make financial provision for long-term malaria-control schemes.
  2. Wells CW
    Bull World Health Organ, 1954;10(5):731-42.
    PMID: 13182594
    A fulminating extension of rabies-which has been enzootic in northern Malaya since 1924-occurred in Kuala Lumpur in April 1952. The outbreak was suppressed by the compulsory mass vaccination of dogs, stringent legislation, and intensive stray-dog destruction. Similar measures are being employed in the current campaign, the aim of which is the complete eradication of the disease.From an average annual incidence of 112 confirmed canine cases prior to 1952-when a total of 198 cases was reported-the incidence fell to 15 cases (all in unvaccinated dogs) for the period January-November 1953, during the last 5(1/2) months of which no case in either animals or man was reported. It is considered that the extensive publicity campaign and strict enforcement of the control measures have contributed measurably to the present improved position.Statistics relating to confirmed cases in dogs previously vaccinated with (a) phenolized 20% brain-tissue suspension vaccine (buffalo origin) and (b) chicken-embryo vaccine (Flury strain) are quoted and their probable significance in favour of the latter under Malayan conditions is discussed. The hypothesis that the development of rabies may, in many instances, have been blocked by the vaccine is advanced.The plan for a pan-Federation compulsory vaccination campaign in 1954, to consolidate the 1952-3 improvements, is outlined.
  3. Reid JA
    Bull World Health Organ, 1955;12(5):705-10.
    PMID: 14379006
    After two years' use of hexachlorocyclohexane (BHC) as a larvicide in Georgetown, on Penang Island, control of Culex fatigans breeding became unsatisfactory. Two laboratory colonies of fatigans were established, one from Georgetown, and one from Kuala Lumpur where no insecticides had been used; tests were then made to determine the median lethal concentrations (MLC) of BHC, dieldrin, and DDT for the larvae of the two strains. The Georgetown strain was found to have acquired a tenfold resistance to BHC, and also to dieldrin to which it had not been exposed, but it showed no significant increase of resistance to DDT, to which it had also not been exposed. A year later, when both strains had passed through some ten generations in the laboratory without exposure to insecticides, the Georgetown strain was found to have lost much of its resistance to BHC, although the MLC was still twice that of the non-resistant Kuala Lumpur strain.
  4. De Zulueta J, Lachance F
    Bull World Health Organ, 1956;15(3-5):673-93.
    PMID: 13404443
    A first experiment on malaria control in the interior of Borneo by spraying with residual insecticides is described. The work was carried out in the isolated, sparsely populated valleys of the Baram River and its tributary, the Tinjar, in northern Sarawak. The experimental area was divided into three parts: a DDT test area, where a 75% suspension of wettable powder was applied at the rate of 2 g of DDT per m(2) of surface; a BHC test area, where a 50% suspension of wettable powder was applied at the rate of 0.10 g of gamma isomer per m(2); and a check area.Entomological investigations made before the spraying operations were started showed that Anopheles leucosphyrus Dönitz, 1901 was the main malaria vector in both the test and the check areas. Out of a total of 7568 A. leucosphyrus dissected, 30 gland infections were detected-a sporozoite-rate of 0.40%. A. barbirostris was found to be a secondary vector throughout the experimental area.THE RESULTS OF INSECTICIDE SPRAYING WERE SATISFACTORY: in the DDT test area, the spleen-rate fell from 51.8% to 25.1%, and the parasite-rate from 35.6% to 1.6%, in 21 months, and a similar reduction in the rates was observed in the BHC test area. In the check area, the spleen- and parasite-rates rose during the period of observations. It is considered that if such a degree of control can be obtained in 21 months, complete eradication can be expected in the near future.Although BHC spraying proved effective, the fact that it has to be repeated every three months makes it impracticable in the interior of Sarawak, where communications are very poor and difficulties of transport very great. DDT spraying, which need only be done twice a year, is therefore to be preferred. The cost of the DDT operations-US$ 0.45 per person protected per year-is comparatively high, owing to the difficulty of communications and to the necessity for spraying not only the village "longhouses", but also the temporary shelters which the semi-nomadic people in the interior of Sarawak build each year in the rice-fields.
  5. De Zulueta J
    Bull World Health Organ, 1956;15(3-5):651-71.
    PMID: 13404442
    A general malaria survey of Sarawak and Brunei, two of the territories of British Borneo, is described. Contrary to what was expected in view of the climate and the general conditions, the prevalence of malaria in Sarawak and Brunei proved, on the average, to be low. The coastal areas were found to be practically free from the disease, although epidemics have occurred there in recent years. Malaria was found to be endemic in the hilly and mountainous interior. In fact, topography proved to be an important factor in malaria prevalence, the spleen- and parasite-rates, generally speaking, being higher the more abrupt the country. Differences were also observed in the prevalence among the various racial groups, but these were considered to be due to different habits and customs rather than to race itself.Entomological studies showed that Anopheles leucosphyrus Dönitz was the main malaria vector in the interior of Sarawak, A. barbirostris playing a secondary role. A. leucosphyrus balabacensis had already been recognized as the malaria vector in Brunei.The favourable results of a first field trial of residual insecticides are mentioned and plans for a nation-wide malaria-control programme are briefly outlined.
  6. Busvine JR, Coker WZ
    Bull World Health Organ, 1958;18(4):651-6.
    PMID: 13536807
    Colonies of three strains of Aëdes aegypti resistant to DDT were obtained from Trinidad, Haiti and Malaya and reared beside a normal colony. From their relative resistance to a series of compounds analogous to DDT, characteristic resistance "spectra" were obtained. The two colonies from the West Indies showed a similar type of resistance, rather different from the (smaller) resistance of the Malay strain. No resistance to methoxychlor or dieldrin was found.
  7. Wharton RH
    Bull World Health Organ, 1958;18(4):657-65.
    PMID: 13536808
    Resistance to insecticides in Culex pipiens fatigans has already been reported from two areas in Malaya. In Penang two years' use of BHC as a larvicide resulted in the development of a strain which was found to have acquired a tenfold resistance to BHC, and also to dieldrin to which it had not been exposed. In Singapore, when larval control became unsatisfactory after 6 months' use of a dieldrin emulsion, laboratory experiments confirmed that active resistance to dieldrin had developed. The present observations report the finding of two further dieldrin-BHC resistant strains of C. p. fatigans in Malaya, but differ from the previous reports in that resistance, in one strain at least, was developed as a result of house-spraying with dieldrin against adult mosquitos. In this strain resistance to dieldrin was about 100 times in both adults and larvae, resistance to gamma-BHC in larvae was about 20 times, while resistance to DDT was slight.
  8. Gordon Smith CE, Turner LH, Harrison JL, Broom JC
    Bull World Health Organ, 1961;24(6):807-16.
    PMID: 20604093
    In previous papers it has been demonstrated that ground-dwelling rats are the principal reservoir of leptospirosis in Malaya. The present paper considers the distribution of infection by sex and weight in the ten principal rat species. There appears to be a general tendency for females to be infected more frequently than males, but significant differences were demonstrated only in R. sabanus (more than three times as many females as males infected) and R. whiteheadi. In Malaya, where seasonal changes are minimal, weights can be used as a good index of age in rats. In rat species with a low incidence of infection the incidence appeared to rise steadily with age. In species with a medium incidence the infection rate rose at first with age, fell in the 6-8-month age-group, and then rose again. In high-incidence species the rate rose rapidly from the second month.There appear to be three types of enzootic infection; (1) intensive transmission of a single serogroup in a crowded population of rats of a single species (transmission probably being through urinary contamination of damp soil); (2) low-intensity transmission of several serogroups among ground-rats frequenting wet places (probably with urinary transmission); and (3) low-intensity transmission of several serogroups among ground-rats in dry places (the transmission may be venereal).
  9. Smith CE, Turner LH, Harrison JL, Broom JC
    Bull World Health Organ, 1961;24(1):5-21.
    PMID: 20604085
    In recent years leptospirosis has been shown to be an important cause of human febrile illness in Malaya. Studies were therefore undertaken to determine its animal reservoirs and the factors influencing spread of infection from them to man and domestic animals. This paper presents the board picture obtained. A wide range of animal species were trapped in forest localities, ricefield areas, areas of scrub and cultivation and in several towns and villages. The maintenance hosts of leptospirosis in Malaya appear to be mainly or entirely rats, although evidence of infection has been found throughout the animal kingdom. Some rat species have characteristics which suggest that they are better maintenance hosts than others. Evidence was found of practically every serogroup of leptospires infecting animals in Malaya. Altogether 104 strains were isolated and identified, and 155 animals were found to have serological evidence of infection. Of 1763 rodents examined, 194 had evidence of infection, and 41 of 1083 other animals. A serum survey of domestic animals showed the highest incidence of antibodies to be in goats and the lowest in oxen.
  10. Smith CE, Turner LH
    Bull World Health Organ, 1961;24(1):35-43.
    PMID: 20604084
    One of the factors on which the incidence of leptospirosis is dependent is the survival time of shed leptospires in surface water or soil water, and this time is in turn affected by the acidity or alkalinity of the water. The authors have therefore studied the survival of four leptospiral serotypes in buffered distilled water at pH's ranging from 5.3 to 8.0. All survived longer in alkaline than in acid water, and significant differences between the serotypes were found in response to pH. Survival at pH's under 7.0 ranged from 10 to 117 days and at pH's over 7.0 from 21 to 152 days. Survival was also studied in aqueous extracts of soil samples from different areas in Malaya; no correlation was found between pH and survival time.It was also noted that in a group of Malayan ricefields a low incidence of leptospirosis in man was accompanied by a high infection rate among rodents, and when it was found that this phenomenon could not be explained by pH or salinity, attention was turned to the soil. Bentonite clay, similar to the montmorrillonite clay of the ricefields, was found to adsorb about half the leptospires in suspension. The authors recommend that field study of this laboratory observation be undertaken.
  11. Smith CE, Turner LH, Harrison JL, Broom JC
    Bull World Health Organ, 1961;24(1):23-34.
    PMID: 20604083
    In a previous paper the authors reported on the methods and zoogeographical background of a survey of animal leptospirosis in Malaya, giving a broad analysis of results. In the present paper the localities studied in towns and villages, in ricefields, in secondary forest and scrub and in primary forest are compared in detail. In towns and villages infection rates in rats were low, except in a seaport town where the invading R. norvegicus was heavily infected. In ricefields infection is maintained in R. argentiventer, alone or in association with R. exulans. In secondary forest and scrub there is overlap with forest species and the main hosts of leptospires appear to be R. exulans and R. jalorensis. In primary forest giant rats and, to a lesser degree, spiny rats are the main hosts.Ground-living rats appear to be better maintenance hosts than those scrambling on vegetation or arboreal rats. With some exceptions the incidence of infection of a rat species in an area was found to be in direct relation to the proportion that species formed of the total rat population. The critical number of rats for maintenance of leptospirosis in an area is estimated to be about two rats of the maintenance species per hectare.
  12. Thoms V
    Bull World Health Organ, 1962;27:595-601.
    PMID: 13981115
    The levels of susceptibility of C. p. fatigans larvae from four different localities in Malaya to DDT, dieldrin, malathion, fenthion, diazinon and Sevin have been studied; their toxicity was: diazinon > fenthion > malathion > dieldrin > DDT > Sevin.Larvae from different localities showed a wide range of susceptibility to the chlorinated hydrocarbon insecticides, dieldrin (40x) and DDT (10x), but the organophosphorus compounds and the carbamate compound, Sevin, gave consistent results from all localities. One strain from a rural area (Lamir) was the most susceptible to all insecticides and has been used as a reference strain for related studies on the development of resistance.
  13. Hawking F
    Bull World Health Organ, 1962;27:555-68.
    PMID: 13953210
    There has been little change since 1955 in the laboratory techniques for seeking new antifilarial compounds, although one valuable addition to laboratory study has been the experimental infection of cats with Brugia malayi.The chief drug for the treatment and control of filariasis-whether caused by Wuchereria bancrofti or by B. malayi-continues to be diethylcarbamazine, and the author reviews the reports recently published on its use. In India and China large-scale campaigns involving the use of this drug have been undertaken; and in Tahiti filariasis has been suppressed and almost eliminated. Campaigns on a smaller scale and pilot projects considered in this survey include those conducted in Pacific islands, Malaya, Ceylon, Brazil, Surinam and East and West Africa.It is generally agreed that the administration of diethylcarbamazine produces a great diminution in the microfilarial counts of those taking it, and in many persons both microfilariae and adult worms are eradicated. The difficulties which arise are due to toxic effects which occur in some recipients and which may adversely affect the acceptability of treatment.
  14. Gordon Smith CE, Turner LH, Armitage P
    Bull World Health Organ, 1962;27:717-27.
    PMID: 13993152
    Because of the risk of introduction of yellow fever to South-East Asia, comparative studies were made of yellow fever vaccination in Malayans who had a high prevalence of antibody to related viruses and in volunteers without related antibody. The proportions of positive neutralizing antibody responses to subcutaneous vaccination with 17D vaccine were not significantly different between volunteers with and without heterologous antibody but the degree of antibody response was greater in those without. The ID(50) of 17D in both groups was about 5 mouse intracerebral LD(50). Multiple puncture vaccination with 17D gave a much lower response rate than subcutaneous vaccination in volunteers with heterologous antibody. In both groups subcutaneous doses of about 50 mouse intracerebral LD(50) gave larger antibody responses than higher doses. The neutralizing indices and analysis of results were calculated by a method based on the survival time of the mice. This method, which has advantages over that of Reed & Muench, is fully described in an annex to this paper.
  15. Edeson JFB
    Bull World Health Organ, 1962;27(4-5):529-41.
    PMID: 20604131
    The author reviews the distribution, epidemiology, and treatment of filarial infection due to Brugia malayi, with special reference to Malaya. B. malayi infection in man is confined to the Far East between longitudes 75 degrees E and 140 degrees E and is essentially rural. The chief vectors are Mansonia spp., Anopheles hyrcanus group, A. barbirostris group, and Aëdes togoi. The epidemiological picture is complicated by the fact that B. malayi and other closely related species have now been found in several species of animals. The existence of an animal reservoir of infection might have important implications for filariasis control. As to the treatment of B. malayi infection, diethylcarbamazine has been found to reduce the microfilaria count and to kill the adult worms; the severe febrile reactions of microfilaria carriers to the initial doses of this drug may be reduced by administration of the steroid prednisolone.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links