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Biomedical subjects

A P Dash

Publications and source records attributed to A P Dash.

At least 19 recordsLinked to original sources
PubMed2006

Impact of single dose of diethylcarbamazine and other antifilarial drug combinations on bancroftian filarial infection variables: assessment after 2 years.

The impact of single dose mass drug administration of diethylcarbamazine (DEC), DEC with albendazole (ALB), and ivermectin (IVR) with albendazole, was examined on the human bancroftian filarial infections in village scale trials in south India, from a follow-up study after 2 years. The treatment arms administered with DEC alone and DEC+ALB demonstrated long-term benefits in reducing microfilaraemia significantly (P<0.05), while antigenaemia reduction was negligible. The arm with ALB+IVR did not show such reductions. Among the antigenaemic and microfilaraemic individuals, 87% became amicrofilaraemic in DEC+ALB arm, which were higher than that observed in the other 2 treatment arms. Among amicrofilaraemics (but Ag+), nearly 35% cleared of infection in DEC+ALB, while 26% and 6% in DEC alone and IVR+ALB arms, respectively. The drug combination DEC+ALB was observed to demonstrate a significant impact in reducing filarial infection even after 2 years post treatment.

Albendazole↗
PubMed2006

Malaria parasite burden and treatment seeking behavior in ethnic communities of Assam, Northeastern India.

OBJECTIVES: The objectives of the study were to define the infectious reservoir of malaria with particular reference to transmission dynamics of Plasmodium falciparum, and to ascertain the disease trends in view of the existing containment practices and treatment seeking behavior in malaria endemic communities of Assam, India. METHODS: Cross-sectional surveys were conducted in population groups of malaria endemic districts of the state to determine parasite prevalence, and data were analysed retrospectively for the years 1991-2003 to ascertain the disease trends. Structured questionnaire based surveys were conducted to study the treatment seeking behavior and practices of healthcare providers. RESULTS: P. falciparum and P. vivax were the only two parasite species encountered, the former being in the majority (>60%). Malaria transmission was persistent, and a seasonal peak of P. falciparum was consistently observed during the months of heavy rainfall (April to September). Among children (5-15 years) there was a significantly higher malaria parasite rate as compared to the <5 years age group and adults (>15 years). There was a decline in parasite rates for all age groups over the years of the study that could not be attributed to vector control intervention intensities and/or meteorological factors. CONCLUSIONS: The persistence of P. falciparum is attributed to the emergence of drug resistant varieties, inadequate interventions and treatment seeking patterns, and for its containment focused intervention measures are advocated in partnership with the communities.

Adolescent↗
PubMed2006

Community-based study to assess the efficacy of DEC plus ALB against DEC alone on bancroftian filarial infection in endemic areas in Tamil Nadu, south India.

As part of the Global Programme for Elimination of Lymphatic Filariasis (GPELF), India is implementing mass drug administration (MDA) with annual single dose of diethylcarbamazine (DEC) with and without albendazole (ALB). The impact of MDAs on filarial infections and soil-transmitted helminth (STH) infections was assessed during a 3-year period in two communities, one with DEC + ALB and the other with DEC alone. Prior to each MDA (during 2001, 2002 and 2003), filarial indices (microfilaraemia and antigenaemia) were assessed from blood samples of 450-650 persons aged 2-25 years and STH infections in stool samples (Kato-Katz method) from 325 to 500 children aged 9-10 years. Mosquitoes resting indoors were collected to determine the filarial infection status. The microfilaraemia prevalence decreased significantly (P < 0.05) in both arms, with the highest decline in the DEC + ALB arm (72%vs. 51%). Decline in micrefilaria intensity was also higher in the DEC + ALB arm (81.4%vs. 48.5%). In this arm alone, the antigenaemia prevalence was reduced significantly (62%; P < 0.001). The reduction in STH prevalence was lower in the DEC alone arm (6.5%; NS) than in the DEC + ALB arm (70.9%; P < 0.001). Also, the egg reduction in DEC alone arm was only half that of DEC + ALB arm (49%vs. 97%). Our community-based follow-up study showed higher and sustained benefits with regard to filarial and STH infections for the two-drug arm over the DEC alone arm. The trends suggest that at least 10 MDAs may be necessary to achieve the goal of elimination.

Adolescent↗
PubMed2006

Malaria control using indoor residual spraying and larvivorous fish: a case study in Betul, central India.

OBJECTIVES: To assess the impact of intensified malaria control interventions in an ethnic minority community in Betul using existing tools. METHODS: Two rounds of indoor residual spraying with synthetic pyrethroid insecticide were applied and larvivorous fish introduced, followed by intensive surveillance for early detection of Plasmodium falciparum with rapid diagnostic tests and prompt treatment with sulphadoxine pyrimethamine. RESULTS: Pre-intervention surveys revealed a very high fever rate in the community in all age groups with a slide positivity rate of >50% with >90%P. falciparum. The post-intervention phase showed a sharp steady decline in number of malaria cases (beta 0.972; P < 0.0001, 95% CI 0.35-0.47). Monitoring of entomological results revealed a significant decline in both Anopheles species and An. culicifacies (P < 0.0001). CONCLUSION: A combination of indoor residual spraying and early detection and prompt treatment complemented by rapid diagnostic tests and larvivorous fishes successfully brought malaria under control. These approaches could be applied in other regions of different endemicity to control malaria in India.

Animals↗
PubMed2006

Wash resistance and bioefficacy of Olyset net--a long-lasting insecticide-treated mosquito net against malaria vectors and nontarget household pests.

During recent years, long-lasting insecticide-treated nets (LLINs) have been developed to overcome the problems of low retreatment rates, washing, and erratic dose of the insecticide resulting in the dilution of efficacy of the conventional insecticide-treated mosquito nets. These nets are treated at factory level with insecticide either incorporated into or coated around fibers. Olyset net, a polyethylene net with 2% permethrin incorporated within fibers, is one type of LLIN. Therefore, these nets were evaluated for their wash resistance and bioefficacy against malaria vectors Anopheles culicifacies Giles and Anopheles fluviatilis James (Diptera: Culicidae) and other nontarget species. Cone bioassay tests produced 100% mortality in these two vector species with 3-min exposure. Results of the bioassays on washed nets showed 100% mortality in An. fluviatilis even after 20 washings, whereas in An. culicifacies 100% mortality up to 11 washings and 80% mortality up to 20 washings were observed. Cone bioassay tests also were performed on nontarget mosquito species Culex quinquefasciatus Say; house fly, Musca domestica L.; American cockroach, Periplaneta americana (L.); head louse, Pediculus humanus capitis De Geer; and bed bug, Cimex lectularius L. with 30-min exposure. Except for bed bugs, 100% mortality was observed in these nontarget species after 24-h recovery period. In bed bugs, only 25% mortality was observed. The density of An. culicifacies and An. fluviatilis was significantly reduced in houses with Olyset nets compared with those with untreated nets or no nets. Thus, it may be concluded that Olyset nets are highly effective against malaria vectors and moderately against other nontarget household insects.

Animals↗
PubMed2006

Effectiveness of mosquito nets treated with a tablet formulation of deltamethrin for malaria control in a hyperendemic tribal area of Sundargarh District, Orissa, India.

A village-scale trial on the efficacy of mosquito nets treated with a tablet formulation of deltamethrin (K-OTAB) against malaria in comparison to untreated nets or no net was conducted in Sundargarh District of Orissa, India, which is characterized by perennial transmission with Plasmodium falciparum accounting for more than 80% of malaria cases. Three villages with similar topographical and epidemiological situations were selected and randomly assigned to 3 arms of the study: treated net, untreated net, and no net. Distribution of nets, based on a sleeping pattern survey, was carried out to cover 100% of the population in treated-net and untreated-net villages. Longitudinal and cross-sectional surveys were conducted to measure malaria incidence, prevalence, and splenomegaly. Malaria incidence was reduced by 64.3% in the village with treated nets, 45.2% in the village with plain nets, and 21.4% in the control village without nets. Comparison of malaria incidence data after 1 year of intervention showed significant difference between villages with treated net vs. untreated net (P < 0.05) and treated net vs. no net (P < 0.005). The incidence of clinical attack rate due to P. falciparum was significantly lower in the population using treated nets than in those using untreated nets and no nets. However, no age-specific protective efficacy of treated nets or untreated nets was observed. A significant reduction occurred in spleen rate and parasite rate in children aged 2-9 years using treated nets or untreated nets. An overall significant reduction was found in parasite rate in the total population using treated and untreated nets as compared to nonusers.

Adolescent↗
PubMed2006

Larvicidal activity of Hibiscus abelmoschus Linn. (Malvaceae) against mosquitoes.

The larvicidal activity of roots of Hibiscus abelmoschus was evaluated against the larvae of mosquitoes in the genera Anopheles and Culex. Mean median lethal concentration values of the aqueous extract from the roots of H. abelmoschus against the larvae of Anopheles culicifacies, An. stephensi, and Culex quinquefasciatus were 52.3, 52.6, and 43.8 ppm, respectively. Efficacy of fraction code HAM-4 decreased with an increase in water depth when sprayed at a dose calculated by surface area. Fraction code HAM-4 at the rate of 82 ppm showed 91.1% reduction of larval An. stephensi in a tank, whereas 87.4% reduction of larval Cx. quinquefaisciatus occurred in a blocked drain 24 h after application of HAM-4 under field conditions.

Animals↗
PubMed2006

Serological and entomological investigations of an outbreak of dengue fever in certain rural areas of Kanyakumari district, Tamil Nadu.

BACKGROUND AND OBJECTIVES: During the first week of July 2003, suspected cases of dengue fever were reported from three villages in Kanyakumari district in Tamil Nadu. Since the fever outbreak occurred for the first time in these villages, serological, virological and entomological investigations were carried out to confirm the aetiology of outbreak. METHODS: A total of 76 plasma samples were collected from suspected cases of dengue fever and screened for the presence of IgM antibodies by Pan Bio ELISA kit. Toxo-IFA system was used for the isolation of dengue virus from the plasma samples. Vector survey employing ovitraps and adult landing collection were carried out in the study villages. Pooled samples of Aedes mosquito were screened for dengue virus antigen by an in-house antigen capture ELISA test employing dengue virus specific monoclonal antibodies. RESULTS: Of the 76 samples tested, 15 (20%) were found positive for dengue virus specific IgM antibodies. Dengue virus serotype-3 was detected from a plasma sample by Toxo-IFA test using virus specific monoclonal antibodies. Entomological survey revealed the abundance of Aedes albopictus (Skuse) mosquitoes in the study area. One pool consisting of 12 Ae. albopictus males were found positive for dengue virus infection. INTERPRETATION AND CONCLUSION: Based on the IgM antibody capture ELISA results, it was evident that the current infection was caused by dengue virus in the affected areas. All the age groups were affected during this outbreak. Detection of dengue virus serotype-3 in plasma samples further confirmed the aetiology of this outbreak. The high prevalence of the mosquito vector Ae. albopictus (Skuse) was observed. Detection of dengue virus antigen in the male mosquitoes confirms that the virus is maintained in wild populations of Ae. albopictus in these areas.

Adolescent↗
PubMed2006

Epidemiology of malaria in an area of low transmission in central India.

A longitudinal study on malaria was carried out from 2003 to 2005 in an area of unstable malaria in the Panna district in central India. Both Plasmodium vivax and P. falciparum were prevalent; however, the risk of P. falciparum malaria was 31.6% (95% confidence interval [CI] = 29.6-33.6%), which is four times higher compared with that of P. vivax malaria (7.8%, 95% CI = 6.7-9%). An increasing trend was recorded in malaria prevalence from 30.2% in 2003 to 46.6% in 2004 (odds ratio [OR] = 2.0, 95% CI = 1.6-2.5) that increased to 58.6% in 2005 (OR = 1.6, 95% CI = 1.2-2.1). This increase was statistically significant (chi(2) = 120.5, degrees of freedom = 2, P < 0.0001). Anopheles culicifacies was the dominant vector of malaria and showed partial (< 50%) resistance to DDT, which indicated that DDT can still be used. Improved access to treatment facilities, combination therapy, and vector control appears to be the most promising method for controlling malaria in this region.

Animals↗
PubMed2005

An efficient PCR--SSCP-based method for detection of a chloroquine resistance marker in the PfCRT gene of Plasmodium falciparum.

The spread of chloroquine resistance throughout the world poses a major problem in combating malaria. In the present study, an efficient polymerase chain reaction-single strand conformational polymorphism (PCR--SSCP)-based assay detected the PfCRT K76T point mutation, which is a marker for chloroquine resistance. For the first time, we have used a PCR--SSCP-based technique to identify the mutation in a single-step labelling reaction during PCR and SSCP gel electrophoresis. This assay is 100% efficient, giving no false-positive or -negative results, and can be carried out within a short bench time. We have successfully analysed 120 natural isolates using the PCR-SSCP method for detection of the chloroquine resistance marker and found 91 of the 120 samples to show the PfCRT T76 mutation, and 71% (65 of the 91 samples) showed a positive correlation with chloroquine resistance from the clinical data of the patients. The PCR-SSCP technique can also be applied for the detection of new haplotypes of the PfCRT gene and surveillance of chloroquine-resistant malaria in malaria-endemic localities around the world.

Animals↗
PubMed2005

Combined detection of Brugia malayi and Wuchereria bancrofti using single PCR.

A single step PCR method has been developed for the combined detection of the human filarial parasites, Brugia malayi and Wuchereria bancrofti. Parasites' DNA were isolated from filaria positive blood samples that were collected from endemic areas. The primers used were Hha1 and Ssp I, which amplified the DNA fragments of 322 bp and 188 bp specific to B. malayi and W. bancrofti, respectively. The sensitivity of the assay was tested with blood and mosquito samples having one W. bancrofti in a pool of 10 B. malayi. The assay was further evaluated on field collected blood and mosquito samples. Use of this assay as a diagnostic tool for the detection of filariasis being the most promising aspect of this study, offers scope for detection of both the parasites even at low levels of infection.

Animals↗
PubMed2005

Village-scale evaluation of mosquito nets treated with a tablet formulation of deltamethrin against malaria vectors.

A field trial was carried out in the Sundargarh district of Orissa, India on the efficacy of mosquito nets treated with a tablet formulation of deltamethrin (K-O TAB) against malaria vectors. Treated nets were used in one village, and in the two control villages, one used untreated nets and the other used indoor spraying with DDT, without nets. In this area the primary malaria vectors are Anopheles culicifacies Giles sensu lato (Diptera: Culicidae) and An. fluviatilis James s.l., which are both endophagic and endophilic, and fully susceptible to deltamethrin. Treatment of a 10-m(2) mosquito net with one of the tablets gave a deltamethrin deposit of 25 mg/m(2). Bioassays repeated on domestically used nets over 7 months showed persistence of almost 100% mortality of An. fluviatilis, whereas An. culicifacies showed a decline from 100% to 71% mortality over this period, after which the nets were re-treated and bioassays were not continued. The sum of collections of mosquitoes resting in village houses and those in exit traps and dead on floor sheets showed a reduction in the numbers of the two vector species due to the treated nets, compared with untreated or no nets, but no reduction in other anophelines or Culex species. Large proportions of the collections of the vector and non-vector anophelines were dead on the floor sheets, but among Culex, mortality was delayed. Treated and untreated nets reduced the proportion of anophelines that had blood-fed; the treated nets did so more effectively than the untreated in the case of An. culicifacies and of Culex mosquitoes. In rooms with treated nets a larger proportion of the total collections [dead + live] were in the exit traps, which can be attributed to the excito-repellent effect of deltamethrin. It is easier to pack and handle tablets of insecticide than liquid concentrate and the use of one tablet per net may be preferable to making up a large volume of diluted insecticide and dipping many nets at a time.

Animals↗
PubMed2005

Short Communication: detection of dengue virus antigens in desiccated mosquitoes: an improved tool for surveillance.

We developed a surveillance tool to monitor dengue virus (DENV) infection in vector mosquitoes using a dengue antigen-capture enzyme immunoassay (EIA) on desiccated specimens stored at room temperature (RT). We tested the effect of storage on the stability of DEN1, DEN2, DEN3 and DEN4 antigens. Although desiccated infected Aedes aegypti mosquitoes stored between 31 and 34 degrees C (RT) showed greater reactivity in the EIA than those stored at -80 degrees C, a significant difference between the two was observed only with DEN2. Storage between 31 and 34 degrees C for up to 4 weeks (the longest period tested) did not affect the reactivity in the EIA, indicating the stability of DENV antigens.

Aedes↗
PubMed2005

Efficacy of thermal fog application of deltacide, a synergized mixture of pyrethroids, against Aedes aegypti, the vector of dengue.

We evaluated the efficacy of indoor and peridomestic thermal fog applications of deltacide, a synergized mixture of pyrethroids (S-bioallethrin 0.7% w/v, deltamethrin 0.5% w/v and piperonyl butoxide 8.9% w/v) against adult populations of Aedes aegypti in Chennai, Tamil Nadu, India. We bioassayed adult caged mosquitoes, counted indoor resting and human landing adult mosquitoes and assessed the percentage of potential breeding sites with Aedes larvae. The bioassay mortalities indicated that the knockdown and killing effect was greater when fogging was applied inside houses rather than around them. Peridomestic thermal fogging reduced the resting and biting populations by 76% and 40%, respectively for the 3 days after treatment, whereas indoor fogging suppressed adult populations for 5 days.

Aedes↗
PubMed2005

A simple, artificial-membrane feeding method for the radio-isotope labelling of Aedes aegypti polypeptides in vivo.

An artificial feeding unit has been designed and constructed to feed laboratory-bred Aedes aegypti with a radio-isotope (35S), so that the mosquitoes' polypeptides can be labelled in vivo. In the unit, a piece of Parafilm M barrier film is stretched over the bottom, outer surface of a polystyrene Petri dish, to create a small gap in which the mixture of blood and radio-isotope is placed. Warm water is placed in the dish, to keep the blood at about 37 degrees C. When such units were placed on net-covered rearing cages, almost all (80%-90%) of the female mosquitoes in the cages took bloodmeals from them. When checked by polyacrylamide-gel electrophoresis and autoradiography 1 h after feeding had begun, the blood-fed mosquitoes were found to have radio-labelled polypeptides. The unit is simple, easy to handle, disposable and can be used to offer small blood samples (>or=50 microl) to Ae. aegypti and, presumably, other mosquito species.

Aedes↗