Showing papers by "P. K. Das published in 1992"
TL;DR: The results suggest that 3 years is too short a period to relate the changes in entomological parameters to those in the microfilaraemia status of the population.
Abstract: An Integrated Vector Management (IVM) strategy was implemented from 1981 to 1985 in one part of Pondicherry, South India, for the control of the bancroftian filariasis vector Culex quinquefasciatus (the IVM area). The rest of the town (the comparison area) received the conventional larvicidal input. After 1985 both the areas were managed conventionally. The switch to conventional strategy resulted in an increase of vector density in both areas. The microfilaraemia prevalence in humans showed a general decline (P less than 0.05) from 1986 to 1989 only in the IVM area whereas its intensity did not change significantly in either area. While the age-specific rate of gain of infection was generally unchanged in the IVM area, an increase in all age classes was observed after 1985 in the comparison area, where the Annual Transmission Index was high during the previous years. In both areas the rate of loss of infection increased during 1986-9 compared to 1981-6. The results suggest that 3 years is too short a period to relate the changes in entomological parameters to those in the microfilaraemia status of the population.
32 citations
Journal Article•
TL;DR: The results suggest that maintenance of vector density at reduced levels for prolonged periods, is necessary to control infectious diseases like filariasis, which is difficult in the present day urban situations in developing countries.
Abstract: An Integrated Vector Management strategy, implemented as an alternative to the conventional control operations that include mainly chemical control in Pondicherry, South India, reduced very substantially the population density of Culex quinquefasciatus. This resulted in drastic decrease in the intensity of transmission of bancroftian filariasis transmitted by Culex quinquefasciatus and consequently the incidence of new infections in children of 0-5 age group was minimized. When the IVM strategy was withdrawn after five years of implementation and conventional control measures were re-adopted, resilience of Culex quinquefasciatus population was observed and human exposure to the risk of infection increased. The results suggest that maintenance of vector density at reduced levels for prolonged periods, is necessary to control infectious diseases like filariasis, which is difficult in the present day urban situations in developing countries. Hence the emphasis should be on chemotherapy to achieve control of lymphatic filariasis.
17 citations
Journal Article•
TL;DR: Clinical examination and analysis of different biochemical parameters in blood and serum samples showed in spite of the minimal absorption of the insecticide, there was no immediate adverse effect.
Abstract: A preliminary evaluation was undertaken on the safety aspects in mosquito net impregnation with lambdacyhalothrin, on the operators and users of the treated nets. The detection by HPLC of one of the principal metabolites of lambdacyhalothrin, 3-phenoxy benzoic acid (3-PBA) in blood samples of the users and operators in very small quantities (0.01 to 0.02 ng/microliters) showed that absorption of the insecticide was minimum. Clinical examination and analysis of different biochemical parameters in blood and serum samples showed in spite of the minimal absorption of the insecticide, there was no immediate adverse effect.
8 citations
Journal Article•
TL;DR: Only device "B" was found to give appreciable mortality in all three vector mosquito species compared to other devices which may be attributed to the uniform release rate (2 mg/hour) of bioallethrin.
Abstract: Different Electric-Mat-Device (EMD) vaporizers and bioallethrin impregnated mats were evaluated for the knockdown and mortality in the adults of Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti. Percentage knockdown of 80-100 was recorded throughout the test period of 11 hours. However, the percentage mortality observed was not appreciable in all types of EMD vaporizers. Device "A" was found to be effective only against Ae. aegypti. Devices "e" and "D" showed moderate effects against An. stephensi and Ae. aegypti. Only device "8" was found to give appreciable mortality in all three vector mosquito species compared to other devices which may be attributed to the uniform release rate (2 mglhour) of bioallethrin.
7 citations
Journal Article•
TL;DR: Laboratory reared larvae of Toxorhynchites splendens, which were previously starved for 24 hours, cannibalized eggs of their own kind or preyed upon the eggs of other species present on the surface of water in small containers.
Abstract: Laboratory reared larvae of Toxorhynchites splendens, which were previously starved for 24 hours, cannibalized eggs of their own kind or preyed upon the eggs of other species (Aedes aegypti and Anopheles stephensi) present on the surface of water in small containers. Second and third instars consumed eggs faster than first and fourth instars. The first instar consumed larvae of its own kind faster than the other instars, in the absence of other prey. However, when prey larvae were provided, there was a significant fall in the rate of cannibalism.
2 citations