Indian journal of malariology最新文献

Spray impact of Spherix (Bacillus sphaericus B-101, Serotype H5a, 5b) was assessed against larval and adult populations of mosquito species in rural areas of Farrukhabad district, Uttar Pradesh. High mortality (> 95%) was observed against anopheline and culicine larvae within 48 h of spray @ 1 g/sq m. But the biolarvicidal effect declined within a week which indicated nonrecycling capacity and weekly reapplications were required. The encouraging results obtained through weekly sprays were short-lived because of decline in efficacy in some perennial intradomestic Culex breedings after 15 rounds of spray. The two year intensive field trials, however, had no appreciable impact on adult densities of both malaria vector An. culicifacies and bancroftian filariasis vector Culex quinquefasciatus. Environmental disturbances and manmade problems also affected the efficacy of the biolarvicide.

Bacillus sphaericus has a potential of use as a larvicide in water storage practices but no such study has been done against Anopheles stephensi. Baseline susceptibility status of eleven wild and three mutant strains of An. stephensi to Spherix, a formulation of B. sphaericus, strain B-101 (serotype H5a, 5b) was determined to find the variations in the degree of their response to B. sphaericus toxins and to study the possibility of development of resistance. The LC50 and LC90 values of different strains of An. stephensi to B. sphaericus formulation varied from 0.088 to 1.42 mg/l and 0.314 to 10.98 mg/l, respectively. Among all the strains tested, Sarojini Nagar, Delhi strain of An. stephensi (a wild type strain) was least susceptible. Laboratory selection of Sarojini Nagar strain of An. stephensi with B. sphaericus at a concentration of 4 mg/l resulted in the development of a high degree of resistance (LC50 > 1600 mg/l) to B. sphaericus within four generations.

A method to infect mosquitoes with Japanese encephalitis virus (JEV) and to demonstrate virus transmission after an extrinsic incubation period is described. Using per oral feeding method infection rate as high as 90% could be achieved. Demonstration of transmission of the virus was achieved by allowing the infected mosquitoes to probe a suitable serum medium and testing the probed serum for virus. Both infection and transmission were demonstrated by using insect-bioassay.

Ninety-one mosquito species in 15 genera were collected from 22 habitat types of Upper Brahmaputra valley in Assam and bordering areas of Arunachal Pradesh. Nineteen species have been recorded for the first time in Assam including seven first records from the northeast region and three first country records. Jaccard's coefficient was used to quantify the similarity between 13 different geographical localities surveyed on the basis of their mosquito fauna. Group average sorting (UPGMA) cluster analysis was used to find out relationship between Jonai, Dhemaji, Dibrugarh, Tinsukia and north Lakhimpur (study zones) on the basis of their mosquito community. Immatures of three malaria vectors incriminated from the northeast India, viz. Anopheles dirus, An. minimus and An. philippinensis were collected exclusively from forest areas. Fourteen potential vectors of Japanese encephalitis incriminated from elsewhere in India were collected during the study.

Efficacy of Plasmodium falciparum histidine-rich protein (HRP-II) based diagnostic test ParaSight-F, was evaluated for diagnosis of P. falciparum malaria at the Malaria Clinic in Malaria Research Centre (Field Station), Chennai, Tamil Nadu. A total of 93 febrile patients were screened in parallel by microscopy and by ParaSight-F. The sensitivity and specificity of the test were 100% for the detection of P. falciparum infection.

Falciparum malaria in pregnancy is a significant health problem in India. Pregnant women constitute an important high risk group for malaria infection which may cause abortion, still births, intra uterine growth retardation (IUGR), and pre-mature labour. Two hundred eighty-eight admitted female patients of falciparum malaria were included in the study out of which 45 were pregnant. The mortality rate was highly significant in pregnant females (37.77%) in comparison to non-pregnant females (14.81%); (p < 0.001). The incidence of various pernicious syndromes including cerebral malaria, severe anaemia (Hb < 5 g%) hepatic and renal failure were more in pregnant females in comparison to non-pregnant females. The incidence of infection was higher among primigravida and second gravida 30/45 (66.66%) as compared to multigravida 15/45 (33.33%) and the greater incidence of infection was seen during 14-28 wk of gestation 23/45 (51.11%). Pregnancy related complications in the form of preterm live birth (20%). Intra uterine death (IUD 31.11%), still births (13.33%) and abortions (11.11%) were more pronounced in primiparous women as compared to multiparous. Weight of placenta in majority of patients ranged between 200-400 g (22/31; 70.96%). Normal pregnancy continued in only 11 out of 45 pregnant females, out of which seven had low birth weight body (63.63%). As the pregnancy is associated with increased incidence and adverse outcome of falciparum malaria infection, chemoprophylaxis should be made an integral part of antenatal care along with antianaemic therapy to reduce the risk of serious maternal and fetal complications.

In an entomological study in South Tripura district of Tripura state during June 1998, a total of 31 species of mosquitoes belonging to eight genera were recorded. Among the known malaria vectors in India, Anopheles annularis, An. jeyporiensis, An. minimus, An. philippinensis/nivipes and An. varuna were collected but none of them could be incriminated. During the survey, Aedes pallidostriatus and Malaya genurostris were recorded for the first time in the north-eastern region and Tripura state respectively. Presence of host seeking An. minimus in light-trap collections indoors and its absence during morning indoor resting collections indicated the probability of some degree of exophilic behaviour of An. minimus population in Tripura.

Fifteen species of larvivorous fishes, viz. Aplocheilus blockii, Aplocheilus lineatus, Rasbora daniconius, Puntius vittatus, Puntius melanampyx pradhani, Puntius amphibius, Macropodus cupanus, Danio aequipinnatus. Oreochromis mossambicus, Heteropneustes sp, Therapon jarbua, Etroplus suratensis, Mugil cephalus. Osteochilichthys nashii and Hypselobarbus dobsoni were collected from different parts of Goa. Their habitat wise distribution was studied and density was recorded. Daily average consumption of mosquito larvae varied between 62.5 and 736 per fish. On the basis of their larvivoracity and extensive distribution, Aplocheilus blockii and Rasbora daniconius are recommended for use in malaria control operations in Goa.

Antibody levels of Pf RESA derived peptide R1 (EENVEHDA-C) from individuals living in malaria endemic areas correlated well with levels of endemicity. Serological and parasitological investigations were done in 32 adults (> 20 yrs) and 35 children (2-5 yrs) for three years; i.e. from 1992-95 periodically in village Piyawoli, U.P. Antibody levels against R1 peptide was estimated by ELISA, and blood smear for P. falciparum and P. vivax were screened using Jaswant Singh-Bhattacharya (JSB) staining. It appeared from our investigations that anti-R1 antibodies had a short span of life, i.e. 6-9 months. The longevity of these antibodies do not differ much in adults and children. The studies do not indicate any protective role for these antibodies. However, the levels of anti-R1 antibodies in a population living under malariogenic condition are related to Pf malaria endemicity.