Indian journal of malariology最新文献

Insecticide susceptibility tests were conducted on the adults of four anopheline species namely. Anopheles annularis, An. culicifacies, An. stephensi and An. subpictus against the diagnostic doses of six insecticides, viz. DDT (4.0%), dieldrin (0.4%), malathion (5.0%). fenitrothion (1.0%), propoxur (0.1%) and permethrin (0.25%) in District Bikaner (Rajasthan). A time dependent effect has been observed with each insecticide. All the four species were found resistant to DDT and dieldrin and susceptible to fenitrothion and permethrin. An culicifacies and An. subpictus showed susceptibility to malathion, while further verification for the other two species was required. However, with propoxur An. annularis showed resistance, whereas for other three species further studies are required. DDT and dieldrin, the two organochlorines, were found least effective as compared to organophosphates and carbamates.

Twenty-two cases (nineteen Plasmodium falciparum and three P. vivax) of severe malaria among 200 pregnant women from District Jabalpur, M.P. were studied for malaria parasite density. Almost all of them were found anaemic. The patients were treated with quinine/chloroquine intravenously but seventeen Pf cases died within 96 h of admission in hospital. Out of twenty-two, thirteen were primigravidae.

Concentrations of HCH and DDT in soil, water and whole blood were determined in two areas under malaria control. These were, (i) bioenvironmental control of malaria at BHEL, and (ii) residual spraying of insecticides in rural and urban area of Bahadrabad PHC of Hardwar district. Mean concentrations of HCH in soil and whole blood samples from BHEL was 2.26 micrograms/kg and 1.20 micrograms/l and from Bahadrabad 61.12 micrograms/kg and 24.3 micrograms/l respectively. Similarly, the mean concentration of DDT in soil and whole blood from BHEL was 3.68 micrograms/kg and 4.71 micrograms/l, while in Bahadrabad 270.51 micrograms/kg and 38.13 micrograms/l respectively. HCH and DDT were never detected in any water samples from BHEL area, while the mean concentration of these compounds in water of Bahadrabad area was 0.18 and 0.07 microgram/l respectively. Residual level of HCH and DDT were 27 and 73.5 times higher in soil and 20.2 and 8.1 times higher in whole blood samples from Bahadrabad as compared to their corresponding values from BHEL respectively.

A hut-scale trial of pyraclofos 50% EC applied as an indoor residual spray at 1 gm/sq m was carried out against malaria vectors. Anopheles fluviatilis and An. culicifacies in Kandhaguda village of Malkangiri district, Orissa. Bandhaguda village was kept as control. Pyraclofos was effective in reducing the vector density by 80-96% after 24 h of spray, but the density increased within three weeks. Parity rates were reduced only for three weeks as measured by diurnal indoor resting collection. Contact bioassays on mud wall showed pyraclofos has a residual life of only three weeks. No adverse effect was noticed among villagers or spraymen. Cockroaches were found to be very sensitive to this compound.

Malaria survey in Tarajulie tea estate (TE) and its adjoining hamlets revealed that Pf was the predominant parasite species (79%) and morbidity was alarming. Malaria positive cases were recorded in all age groups including infants. However, morbidity was much pronounced in the hamlets than among garden dwellers. Mostly Anopheles minimus were recorded in the day resting collections from human dwellings (indoor) and in overnight man biting catches in the hamlets. From these collections. An. minimus was incriminated and the sporozoite infection rate was found to be 4.23 per cent. An. minimus were not recorded in the garden premises. Thus morbidity in the garden population was attributed to the movement of labourers to and fro between hamlets and the garden premises. The hamlets served as reservoirs for malaria infection.

A systematic survey has been carried out during 1993-94 to study the occurrence and distribution of anopheline mosquitoes in Siliguri-Naxalbari block of Darjeeling district. The anopheline fauna of this region consists of 13 species, namely, An. vagus, An. culicifacies, An. annularis, An. barbirostris, An. subpictus, An. maculatus, An. tessellatus, An. jamesii, An. aconitus, An. "hyrcanus" group, An. karwari, An. fluviatilis and An. jeyporiensis among which the first five species forms the major bulk (92%). All the species showed preference to cattlesheds than human-habitation for resting. The ratio between morning and evening collection was 1:0.87.

Investigations were carried out in the villages of Buhari PHC, Surat district, Gujarat to determine factors responsible for high prevalence of P. falciparum. The area is well-known for sugarcane cultivation, industrialization and frequent movement of labourers. The slide positivity rate (44.24%) and P. falciparum infections (95.37%) were significantly high. The children of 5-9 yrs of age group suffered maximum from malaria. The infection in children was found associated with splenomegaly also. High falciparum infection (82.35%) was found in labourers camping near villages out of which 90% afebrile cases were reported which were silent carriers and source of transmission. Chloroquine was effective in 75% cases despite of existence of resistant falciparum strain. Among seven anopheline species encountered, An. culicifacies was predominant and found breeding in most of the breeding sites. The status of the insecticide spray and its receptivity among the community were poor. The investigation led to the conclusion that adequate measures are required to deal with migratory labourers, improper insecticide coverage, poor surveillance and mass ignorance.

A serological investigation was conducted in north India to determine malaria endemicity based on the antibody levels against a nonapeptide RI (EENVEHDA-Cys) from the P. falciparum antigen Pf 155/RESA. P. falciparum sonicated crude antigen was also used in the study. Subjects of all age groups from various strata of malaria endemicity were included in this study. A total of 4273 finger prick blood samples from 49 villages of five districts were collected during January to March 1991 which is a non-transmission season and the antibody levels were estimated by ELISA. Although a good correlation was found between the antibody titre to the RI peptide and that to the crude antigen, the most consistent results were obtained with the RI peptide. When compared with the annual parasite index (API) values, an established method for defining malaria endemicity, mean anti-RI antibody titres obtained from several villages within a single zone correlated (r = 0.94, p = 0.023) with mean API value of the area. Thus, our results suggest that by using the RI peptide as antigen in seroepidemiology, it is possible to stratify malaria endemicity. We didn't distinguish between endemicity of Pv and Pf since each area experiences cycle of transmission of P. vivax followed by P. falciparum and our sera were from individuals having no fever.

Breeding behaviour and seasonal prevalence of vector anopheline in different habitats associated with rice land agroecosystem of terai and bhabar area of District Naini Tal was studied from July 1992 to June 1994. Adult prevalence in both the areas shows two distinct An. fluviatilis peaks in the months of March and October and the breeding places for the species were pokhars in bhabar and stream and irrigation drains in terai. Prevalence of adult An. culicifacies was observed during July to August in bhabar and April and August in terai. In bhabar high immature density of An. culicifacies was noted mainly in tanks, pokhars and paddy fields (early transplantation period). In terai high immature density of An. culicifacies was noted in stream, while low in paddy fields. Higher prevalence of immatures and adult anopheline vectors coincide with peak malaria incidence in both the areas. In bhabar in the months of August and September large number of malaria cases were contributed by An. culicifacies and in November by An. fluviatilis. In terai, malaria cases in April and from June to September were contributed by An. culicifacies, whereas An. fluviatilis might be responsible for transmission in October.