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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fenitrothion was evaluated for residual spraying in antimalaria programmes in a large-scale field trial near Kisumu, Kenya from 1972 to 1976. The insecticide was applied in a hyper/holoendemic malarious area of 200 km(2) inhabited by about 50 000 people. All houses and animal shelters were sprayed at a target dosage rate of 2 g/m(2) at 3-month intervals for a total of 8 consecutive spray rounds in 2 years. The malaria vectors Anopheles gambiae species A and B and A. funestus were reduced to negligible densities indoors and outdoors immediately after initiation of spraying and for 10 months after the last spray round. However, A. gambiae reappeared during the main wet season at densities high enough to reestablish low-level transmission for short periods. Spraying produced a marked and rapid decrease in both the incidence and prevalence of malaria. The daily probability of acquiring malaria infection was reduced from 0.009 before spraying to 0.0003 under spray protection, a reduction of 96%. Data collected on a longitudinal basis indicated that sustained spray protection would reduce malaria prevalence to an asymptotic limit of 6.9% under the assumption that the inoculation and recovery rates remain stable. However, to attain malaria eradication in this type of epidemiological situation, complementary measures such as mass drug administration appear to be necessary.
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PMID:Evaluation of fenitrothion for the control of malaria. 30 9

A large-scale prospective study was designed to test the effects of aerial ultralow volume (ULV) application of malathion on epidemic Plasmodium falciparum malaria. The study was conducted during 1972 to 1973, in the Miragoane Valley of Haiti, an area having annual anticipated outbreaks of malaria, which allowed prospective assessment. Spraying of malathion at a dosage of 4.5 fluid ounces per acre reduced populations of adult Anopheles albimanus to less than 1% of prespray levels and interrupted epidemic transmission of P. falciparum malaria. No change was measured in susceptibility of the vector mosquito to malathion after six applications of spray during a period of 50 days. Ecologic study revealed no significant impact on nontarget vertebrates. Factors that contributed to the success of this method in Haiti were: 1) a susceptible population of mosquitoes; 2) suitable topography and climate conditions for spraying; and 3) treatment of an area sufficiently large to minimize the influence of immigration of mosquitoes from unsprayed areas.
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PMID:A prospective study of the effects of ultralow volume (ULV) aerial application of malathion on epidemic Plasmodium falciparum malaria. I. Study design and perspective. 109 Nov 67

A field study to evaluate the impact of deltamethrin spraying on DDT and HCH resistant A. culicifacies population was carried out in Razapur primary health centre (PHC), Distt. Ghaziabad (U.P.) India. The PHC comprising of about 0.14 million population was divided into 3 sections of equal size and sprayed with (i) 3 rounds at 12.5 mg/sq m at 6 weeks interval, and (ii) 2 rounds each at 20 mg/sq m and 25 mg/sq m at 8 weeks interval. One section in Dadri PHC located at a distance of about 22 kms was held as control. In this area 3 rounds of HCH were sprayed by the NMEP as was done to control malaria in this district. Deltamethrin spraying was carried out for 3 years. Results revealed that spraying at 12.5, 20 and 25 mg/sq m resulted in drastic reduction of DDT and HCH resistant A. culicifacies population and in the interruption of malaria transmission. In control area high vector densities and malaria transmission was encountered throughout the period of study. Spraying of deltamethrin resulted in build-up of Culex quinquefasciatus population due to resistance.
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PMID:Field evaluation of deltamethrin against resistant Anopheles culicifacies in Distt. Ghaziabad (U.P.) India. 238 82

An epidemic of tertian malaria in some coastal areas of The Netherlands resulted in the setting up of official measures in 1920. A scientific and a propaganda commission were charged with control. Efforts were made to reduce mosquito populations by adult and larval spraying. After the discovery that infected mosquitoes were to be found only inside houses, control operations were focussed against adult mosquitoes. Some later discoveries resulted in a more effective control. a) Spraying ditches with Paris green did not prevent adult mosquitoes from entering the control area. b) Anopheles maculipennis turned out to be a complex of species, with A. atroparvus as the vector. The latter preferred brackish water and did not go into full hibernation. The closing of the Zuyder Sea and the expected desalinization gave hope for less suitable conditions for the vector. c) Plasmodium vivax normally had an incubation period of 8 months. d) Pyrethrum was an effective but short-lasting insecticide. e) Healthy parasite carriers could infect mosquitoes. This knowledge was applied through an extensive system of investigation, including spleen examination of schoolchildren. Suspected houses were sprayed bimonthly from August to November, during which period infected mosquitoes were likely to be present. This system worked extremely well, and during the next epidemic from 1943 to 1947 the thus treated towns remained virtually free of malaria! DDT became available and was either sprayed in suspected houses as before, or through wide-spread coverage of all houses. The epidemic subsided whatever method employed and not only due to the use of DDT. The number of cases even went down to the point of no return and the last case of Dutch malaria was recorded in 1959. The wealth of experience on house-spray control, parasite and mosquito biology and experimental malaria of the Dutch malariologists has had its impact on the international bodies engaged in the battle against malaria.
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PMID:The Dutch school of malaria research. 333 84

The resurgence of malaria in India began in 1966 and the states of Karnataka and Tamil Nadu were no exception to this phenomenon. In both states the peak occurrence came in 1976. Malaria was largely confined to highly vulnerable and receptive areas. The problem of increased incidence was particularly associated with the development of several irrigation and hydro-electric schemes. Improperly maintained irrigation systems and reservoirs provided ideal breeding grounds. The present paper examines the scope and limitations of a major anti-malaria activity, namely residual insecticide spraying as adopted and practised in rural vector control programmes in irrigation development project areas. Past experiences (as during the National Malaria Eradication programme, 1958-1965) and current practices are reviewed on the basis of selected examples. Eradication programme, 1958-1965) and current practices are reviewed on the basis of selected examples. In view of the current re-emergence of the disease, the states are faced with new obstacles to residual insecticide spraying such as (a) the development of resistance of malaria vectors to DDT and other alternative compounds like BHC (benzene hexachloride), changing vector behaviour with avoidance of contact with indoor insecticide deposits on walls, (c) environmental contamination (risks of chemicals), (d) extensive use of insecticides and pesticides for crop protection under an expanding green revolution agricultural technology, particularly in irrigated areas and (e) the existence of outdoor resting populations of the major vector Anopheles culicifacies and their role in extra-domiciliary transmission, making residual insecticide spray less effective. Spraying operations are also hindered by the persistence of certain social and cultural factors. The custom of mud plastering, white-washing and rethatching rural houses, for example, results in the loss of insecticide-treated surfaces. Other outdoor rural activities persist as obstacles in attempts to break the transmission cycle; washing, bathing and sleeping outdoors; illegal fishing and woodcutting at night; poorly constructed make-shift structures;housing project labourers near water sources; cattle grazing in nearby forests and human population movements related to seasonal migrants. The chain and extent of the transmission is dependent upon the malaria parasite carriers in the community (both indigenous and imported types) and the degree of contact of the community with those sites where people carry on the above activities, and on the effectiveness of surveillance operations.
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PMID:The scope and limitations of insecticide spraying in rural vector control programmes in the states of Karnataka and Tamil Nadu in India. 620 95

Activities used to control malaria transmission in the pilot station of Vanh Canh in the Binh Dinh Province of central Vietnam from 1976 to 1991 have been evaluated. These activities were: spraying DDT in and around the houses in the villages and the settlements in the fields; spraying lambdacyalothrin in the houses; and use of bed-nets impregnated with permethrin. Their efficacy was measured by the number of fever episodes due to malaria infections among the population. The spraying of DDT in the houses was followed by a reduction of malaria infection by more than 90%. However, spraying of the settlements was not advantageous. The termination of DDT spraying was not followed by an increase of malaria infections. Spraying with lambdacyalothrin was slightly more effective than with pyrimiphos and DDT. The use of pesticide-impregnated bed-nets was efficient, especially in the villages far away from the forest. Thus, these activities can contribute to the control of the malaria endemic in central Vietnam.
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PMID:[Evaluation of malaria vector control measures in central Vietnam (1976-1991)]. 870 36

Since the 17th century, Europeans travelling in Madagascar described the contrast between the fever-free Plateau and the fever-ridden coasts. The former were inhabited by people of Asiatic origins and the latter by African migrants. At the end of the 18th century, "Merina" kings developed land irrigation and rice cultivation, using manpower from the coasts. Since then, rice has become a monoculture covering most of the arable lands of the Highlands. The first malaria epidemic occurred in the Tananarive area in 1878, and rapidly spread throughout the Plateau. The mortality rate was high. A second epidemic in 1895 may have been a resurgence of the previous one. Subsequently, malaria became meso-epidemic despite control measures, mainly consisting of larvivorous fishes, quinine treatment and prophylaxis. In 1949, an eradication program was launched based on DDT house-spraying and chloroquine prophylaxis in children. It was very successful on the Highlands where malaria disappeared, in 1962. Spraying was cancelled and only three small foci remained under surveillance. In 1987 and 1988, a malaria outbreak devastated the plateau. Subsequently, intensive spraying operations brought the situation under control by 1993. The main malaria vector on the Madagascar Highlands is An. funestus. More than 95% of its breeding sites are in the rice fields just before the harvest and afterwards in the fallow lands. The vector peak and the corresponding peak of malaria cases occur between February and May, depending on the farming calender. The second but less important vector, An. arabiensis, breeds in the rice fields just after seeding when the surface water is sunlit. Although rice fields remain the main source of this vector, it also breeds in rainwater pods and borow-pits. Malaria vectors on the plateau are products of human activities of rice cultivation, which is the basis of the economy. The epidemiological importance of rice fields varies greatly from one country to another. In Southeast Asia, the rice fields harbor several anopheline species most of which are only vectors of P. vivax. In West Africa where malaria is holoendemic, they produce large populations of An. gambiae; however, the malaria pattern is unaltered and remains at peak levels. In the dry areas of southern Madagascar, the vector An. funestus and meso-hyperendemic malaria are restricted to areas of cultivated rice. In West and Central Africa, An. funestus is never found in rice fields even though it is common in marshes. In Madagascar, this vector breeds in irrigated rice fields. Because it is practically impossible to control anophelines in rice fields by chemical, biological and ecological methods on the Highlands of Madagascar, house-spraying remains the best method for mass malaria control. Bed-nets impregnated with pesticides may offer an alternative, but their use is resisted by the local population.
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PMID:[Rice: source of life and death on the plateaux of Madagascar]. 870 34

The first factor is the malaria parasite, for which the species P. falciparum and P. vivax are important. Secondly, the transmission determines the disease stability and challenges the host's immunity. The third factor is the human host, consisting of people of both African and Asiatic origin, the latter of whom are more susceptible to P. vivax. Human activities such as cultivating rice fields are of paramount importance for the proliferation of the vectors. The vectors A. gambiae, A. arabiensis and A. funestus are very similar to those of the African continent. These vectors are not endemic on Madagascar, suggesting that they were recently introduced to the island where 95% of the fauna species are endemic. On the Plateau and in the South, the rice fields provide most of the breeding places for A. gambiae s.l. and A. funestus. Five epidemiological belts are found in Madagascar which are very similar to their analogs on continental Africa (fig. 1). These facies include the equatorial belt on the east coast and the tropical belt on the west coast north of Morondava, the Plateau belt analogous to the southern African continent, the southern Madagascar belt which is similar to the Sahelian areas, and finally the zones above 1,500m, which are essentially free of malaria. The first two facies have a stable type of malaria, and in the following two, malaria is unstable. These areas include the Plateau, the area of the severe epidemics which occurred between 1985 and 1988 with more than 50,00 deaths. Malaria control is based on a variety of strategies to respond to the epidemiological heterogeneity of the disease. Spraying within the homes with DDT, used on the Plateau after 1988, was and still is very successful.
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PMID:[Particularities and stratification of malaria in Madagascar]. 878 45

Kala-azar has re-emerged from near eradication. The annual estimate for the incidence and prevalence of kala-azar cases worldwide is 0.5 million and 2.5 million, respectively. Of these, 90% of the confirmed cases occur in India, Nepal, Bangladesh and Sudan. In India, it is a serious problem in Bihar, West Bengal and eastern Uttar Pradesh where there is under-reporting of kala-azar and post kala-azar dermal leishmaniasis in women and children 0-9 years of age. Untreated cases of kala-azar are associated with up to 90% mortality, which with treatment reduces to 15% and is 3.4% even in specialized hospitals. It is also associated with up to 20% subclinical infection. Spraying of DDT helped control kala-azar; however, there are reports of the vector Phlebotomus argentipes developing resistance. Also lymphadenopathy, a major presenting feature in India raises the possibility of a new vector or a variant of the disease. The widespread co-existence of malaria and kala-azar in Bihar may lead to a difficulty in diagnosis and inappropriate treatment. In addition, reports of the organism developing resistance to sodium antimony gluconate--the main drug for treatment--would make its eradication difficult. Clinical trials in India have reported encouraging results with amphotericin B (recommended as a third-line drug by the National Malaria Eradication Programme). Phase III Trials with a first-generation vaccine (killed Leishmania organism mixed with a low concentration of BCG as an adjuvant) have also yielded promising results. Preliminary studies using autoclaved Leishmania major mixed with BCG have been successful in preventing infection with Leishmania donovani. Until a safe and effective vaccine is developed, a combination of sandfly control, detection and treatment of patients and prevention of drug resistance is the best approach for controlling kala-azar.
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PMID:Epidemiology of visceral leishmaniasis in India. 1041 21

The cost-effectiveness of lambdacyhalothrin-treated nets in comparison with conventional DDT spraying for malaria control among migrant populations was evaluated in a malaria hyperendemic area along the Thai-Myanmar border. Ten hamlets of 243 houses with 948 inhabitants were given only treated nets. Twelve hamlets of 294 houses and 1,315 population were in the DDT area, and another 6 hamlets with 171 houses and 695 inhabitants were in the non-DDT-treated area. The impregnated net program was most cost-effective (US$1.54 per 1 case of prevented malaria). Spraying with DDT was more cost-effective than malaria surveillance alone ($1.87 versus $2.50 per 1 case of prevented malaria). These data suggest that personal protection measures with insecticide-impregnated mosquito net are justified in their use to control malaria in highly malaria-endemic areas in western Thailand.
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PMID:Cost-effectiveness and sustainability of lambdacyhalothrin-treated mosquito nets in comparison to DDT spraying for malaria control in western Thailand. 1169 69


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