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Rani A, Gupta A, Nagpal BN, Gupta SK, Anushrita, Prasad P, Singh H. Impact of urbanization on the abundance and distribution of Anophelines population in Ghaziabad district, Uttar Pradesh, India. J Vector Borne Dis 2024; 61:29-42. [PMID: 38648404 DOI: 10.4103/0972-9062.383639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 06/26/2023] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND OBJECTIVES In urban areas, upsurge in population has resulted in more breeding sites for malaria vectors, and hence this scenario potentially undermine malaria elimination and control programs. The change in land use due to urbanization may result in the presence and distribution of malaria vectors. Understanding potential malaria vectors is essential for current and future malaria transmission control strategies. This study investigated the effects of rapid urbanization on malaria vectors An. culicifacies s.l. and An. stephensi L. in Ghaziabad district. METHODS Ghaziabad district which presents several levels of urbanization was selected for this study. Entomological investigations were conducted seasonally from 2014-2016 in the rural, urban, and peri-urban regions. Vector incrimination study was done using ELISA (confirmation by PCR) on suspected Anopheles vectors viz. An. culicifacies, An. stephensi, An. annularis and An. subpictus. RESULTS An. culicifacies showed alteration in distribution influenced by rural and agricultural land whereas An. stephensi was found to be influenced by artificial habitats and population growth. INTERPRETATION CONCLUSION The study also confirms the association between the abundance of malaria vectors and land use change.
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Affiliation(s)
- Alka Rani
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Abhishek Gupta
- Department of Zoology, Ch. Charan Singh University, Meerut, Uttar Pradesh, India
| | - B N Nagpal
- World Health Organization, SEARO, Delhi, India
| | | | - Anushrita
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Pooja Prasad
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Himmat Singh
- ICMR-National Institute of Malaria Research, New Delhi, India
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Bubun N, Anetul E, Koinari M, Freeman TW, Karl S. Coating formulation change leads to inferior performance of long-lasting insecticidal nets in Papua New Guinea. Malar J 2022; 21:349. [PMID: 36424604 PMCID: PMC9685832 DOI: 10.1186/s12936-022-04392-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) play a key role in reducing malaria transmission in endemic countries. In a previous study, the authors demonstrated a substantial decrease in the bioefficacy of LLINs for malaria prevention delivered to Papua New Guinea (PNG) between 2013 and 2019. This coincided with a rise in malaria cases in the country. The present study was aimed at determining the underlying cause of the reduced bioefficacy observed in these LLINs. The main hypothesis was that a change in the coating formulation of the respective LLIN product was responsible, and had led to significantly altered product properties and performance. METHODS A set of PermaNet® 2.0 LLIN samples (n = 12) manufactured between 2007 and 2019 was subjected to combustion ion chromatography in order to understand the chemistry of the LLIN polymer coating formulation. In addition, World Health Organization (WHO) LLIN standard wash tests and cone bioassays were conducted to further characterize the change in product performance that occurred between 2012 and 2013. RESULTS High polymer fluorine content (average 3.2 g/kg) was measured in PermaNet® 2.0 manufactured up to 2012, whereas nets which were manufactured after 2012 contained very little polymer fluorine (average 0.04 g/kg) indicating a coating formulation change from a fluorocarbon (FC)-based to a non-FC-based formulation. The coating formulation change as part of the manufacturing process thus resulted in a significant reduction in bioefficacy. In addition, the manufacturing change affected wash resistance leading to a faster reduction in 24 h mosquito mortality in the non-FC-coated product with consecutive washes. CONCLUSION A change in coating formulation of PermaNet® 2.0 resulted in reduced product performance in PNG. Post-2012 PermaNet® 2.0 LLINs should not be considered to be the same product as PermaNet® 2.0 LLINs produced prior to and in 2012. Coating formulation changes should be validated to not impact LLIN product performance.
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Affiliation(s)
- Nakei Bubun
- grid.417153.50000 0001 2288 2831Vector-Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Evodia Anetul
- grid.417153.50000 0001 2288 2831Vector-Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Melanie Koinari
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD Australia
| | - Timothy W. Freeman
- Rotarians Against Malaria Papua New Guinea, Port Moresby, National Capital District, Papua New Guinea
| | - Stephan Karl
- grid.417153.50000 0001 2288 2831Vector-Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province Papua New Guinea ,grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD Australia
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Villalta EL, Soto Bravo AM, Vizcaino L, Dzuris N, Delgado M, Green M, Smith SC, Lenhart A, Macedo de Oliveira A. Evaluation of the durability and use of long-lasting insecticidal nets in Nicaragua. Malar J 2021; 20:106. [PMID: 33608024 PMCID: PMC7893764 DOI: 10.1186/s12936-021-03604-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/22/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vector control for malaria prevention relies most often on the use of insecticide-treated bed net (ITNs) and indoor residual spraying. Little is known about the longevity of long-lasting insecticidal nets (LLINs) in the Americas. The physical integrity and insecticide retention of LLINs over time were monitored after a bed net distribution campaign to assess community practices around LLIN care and use in Waspam, northeastern Nicaragua. METHODS At least 30 nets were collected at 6, 12, 24, and 36 months post distribution. Physical integrity was measured by counting holes and classifying nets into categories (good, damaged, and too torn) depending on a proportionate hole index (pHI). Insecticide bioefficacy was assessed using cone bioassays, and insecticide content measured using a cyanopyrethroid field test (CFT). RESULTS At 6 months, 87.3 % of LLINs were in good physical condition, while by 36 months this decreased to 20.6 %, with 38.2 % considered 'too torn.' The median pHI increased from 7 at the 6-month time point to 480.5 by 36 months. After 36 months of use, median mortality in cone bioassays was 2 % (range: 0-6 %) compared to 16 % (range: 2-70 %) at 6 months. There was a decrease in the level of deltamethrin detected on the surface of the LLINs with 100 % of tested LLINs tested at 12 months and 24 months crossing the threshold for being considered a failed net by CFT. CONCLUSIONS This first comprehensive analysis of LLIN durability in Central America revealed rapid loss of chemical bioefficacy and progressive physical damage over a 36-month period. Use of these findings to guide future LLIN interventions in malaria elimination settings in Nicaragua, and potentially elsewhere in the Americas, could help optimize the successful implementation of vector control strategies.
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Affiliation(s)
| | | | - Lucrecia Vizcaino
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Nicole Dzuris
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Marco Delgado
- Entomología Médica, Ministerio de Salud, Managua, Nicaragua
| | - Michael Green
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Stephen C Smith
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Audrey Lenhart
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Alexandre Macedo de Oliveira
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA.
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Kayedi MH, Khamisabadi K, Haghdoost AA, Kayedi Z, Fallahi S, Abdali N. Short and long term evaluation of the efficiency of PermaNet® 2.0 bed net against environmental factors and washing using bioassay tests. Rev Inst Med Trop Sao Paulo 2017; 59:e18. [PMID: 28423093 PMCID: PMC5398190 DOI: 10.1590/s1678-9946201759018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 02/16/2017] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to examine the resistance of PermaNet® 2.0 bed nets against repeated washing and environmental factors by using bioassay tests. After 5, 15 and 21 washings with detergents and by using bioassay tests, the resistance of 40 PermaNet® 2.0 bed nets was compared with that of 40 bed nets conventionally treated with one K-O tablet. To examine the long-term resistance, 31 PermaNet® 2.0 bed nets were also distributed among villagers, and were re-collected to perform bioassay tests after 1, 2 and 5 years. In the first phase of this study, the insecticidal effect of the conventionally-treated nets significantly decreased due to repeated washings (P < 0.001); however, it was not significant regarding PermaNet® 2.0 bed nets (P = 0.92 in continuous exposure and P = 0.12 in mortality tests). In the long-term phase of this study, the time required for knockdown of PermaNet® 2.0 increased over the first 2 years and then decreased. In addition, the mortality rate decreased over the first 2 years and then increased. In conclusion, it seems that the technique used by the manufacturer for impregnation of PermaNet® 2.0 bed nets has an acceptable efficiency in comparison with conventional techniques.
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Affiliation(s)
- Mohammad Hassan Kayedi
- Lorestan University of Medical Sciences, School of Medicine, Department of Parasitology and Mycology, Khorramabad, Iran
| | - Kiumars Khamisabadi
- Tehran University of Medical Sciences, School of Public Health, Kazeroun Field Station, Tehran, Iran.,Iran National Institute of Health Research, Tehran, Iran
| | - Ali Akbar Haghdoost
- Kerman University of Medical Sciences, Institute for Futures Studies in Health, Modeling in Health Research Center, Kerman, Iran
| | - Zohreh Kayedi
- Shiraz University of Medical Sciences, School of Pharmacy, Student Research Committee, Shiraz, Iran
| | - Shirzad Fallahi
- Lorestan University of Medical Sciences, School of Medicine, Department of Parasitology and Mycology, Khorramabad, Iran
| | - Nargess Abdali
- Lorestan University of Medical Sciences, Razi Herbal Medicines Research Center, Student Research Committee, Khorramabad, Iran.,Pasteur Institute of Iran, North Research Center, Amol, Iran
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Abstract
Malaria epidemiology is complex due to multiplicity of disease vectors, sibling species complex and variations in bionomical characteristics, vast varied terrain, various ecological determinants. There are six major mosquito vector taxa in India, viz. Anopheles culicifacies, An. fluviatilis, An. stephensi, An. minimus, An. dirus and An. sundaicus. Among these, An. culicifacies is widely distributed and considered the most important vector throughout the plains and forests of India for generating bulk of malaria cases (>60% annually). Major malaria epidemics are caused by An. culicifaices. It is also the vector of tribal malaria except parts of Odisha and Northeastern States of India. An. culicifacies has been the cause of perennial malaria transmission in forests, and over the years penetrated the deforested areas of Northeast. An. culicifacies participates in malaria transmission either alone or along with An. stephensi or An. fluviatilis. The National Vector Borne Disease Control Programme (NVBDCP) spends about 80 per cent malaria control budget annually in the control of An. culicifacies, yet it remains one of the most formidable challenges in India. With recent advances in molecular biology there has been a significant added knowledge in understanding the biology, ecology, genetics and response to interventions, requiring stratification for cost-effective and sustainable malaria control. Research leading to newer interventions that are evidence-based, community oriented and sustainable would be useful in tackling the emerging challenges in malaria control. Current priority areas of research should include in-depth vector biology and control in problem pockets, preparation of malaria-risk maps for focused and selective interventions, monitoring insecticide resistance, cross-border initiative and data sharing, and coordinated control efforts for achieving transmission reduction, and control of drug-resistant malaria. The present review on An. culicifacies provides updated information on vector biology and control outlining thrust areas of research.
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Affiliation(s)
- V P Sharma
- Centre for Rural Development & Technology, Indian Institute of Technology, New Delhi, India
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Badolo A, Guelbéogo WM, Tiono AB, Traoré A, Sagnon N, Sirima SB. Laboratory evaluation of Fendona 6SC treated bednets and Interceptor long-lasting nets against Anopheles gambiae s.l. in Burkina Faso. Parasitol Res 2014; 113:1069-75. [PMID: 24425451 DOI: 10.1007/s00436-013-3742-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 12/26/2013] [Indexed: 10/25/2022]
Abstract
Insecticide-treated bednets play a cornerstone role in the efforts to control malaria. Bednets entomological efficacy is the determinant factor of their use to control malaria. In this study, we compared under laboratory conditions, the efficacy of two long-lasting nets (PermaNet versus Interceptor) and two treatments kits K-O TAB (deltamethrin) versus Fendona 6SC (alpha-cypermethrin) against Anopheles gambiae s.l. malaria vectors. The efficacy of washed and unwashed bednets was assessed by contact bioassays using World Health Organization (WHO) cones. Three to five-days-old mosquitoes were exposed to the netting for 3 min; the median and 95% knockdown time, the after 24 h mortality was recorded for each type of bednet. The mortality after 24 h was equivalent for the Fendona 6SC treated bednets and the K-O TAB treated bednets [79.4% confidence limits (CL) (73.9-84.6) and 74% CL (68.3-80.0), respectively]. However, the Fendona 6SC treated bednets were superior in 50% knockdown time to the K-O TAB treated bednets [7.8 min, CL (6.5-9.0) and 15. 2 min, CL (14.0-16.4), respectively]. Washed Interceptor and PermaNet bednets showed similar efficacy in terms of 50% knockdown times. Mortality after 24 h was similar from the fifth to the twentieth wash, but PermaNet performed better than Interceptor for the first four washes and for unwashed bednets. This study showed that Fendona 6SC kit and the Interceptor bednets have exhibited consistent comparable efficacy in the laboratory compared to the well known and in use K-O TAB kit and PermaNet bednets.
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Affiliation(s)
- Athanase Badolo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), BP 2208, Ouagadougou 01, Burkina Faso,
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Schleier JJ, Peterson RKD. The joint toxicity of type I, II, and nonester pyrethroid insecticides. JOURNAL OF ECONOMIC ENTOMOLOGY 2012; 105:85-91. [PMID: 22420259 DOI: 10.1603/ec11267] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Evidence suggests that there are separate binding domains for type I and II pyrethroid insecticides on the voltage gated sodium channel of the nerve cell axon, but there are no studies that have examined the mixture toxicity of nonester pyrethroids and type I and II pyrethroids. Therefore, we examined the effect of nonester pyrethroid (etofenprox), type I (permethrin), and type II (cypermethrin) pyrethroid insecticides alone and in all combinations to Drosophila melanogaster Meigen. The combination of permethrin + etofenprox and permethrin + cypermethrin demonstrated antagonistic toxicity, while the combination of cypermethrin + etofenprox demonstrated synergistic toxicity. The mixture ofpermethrin + cypermethrin + etofenprox demonstrated additive toxicity. The toxicity of permethrin + cypermethrin was significantly lower than the toxicity of cypermethrin alone, but the combination was not significantly different from permethrin alone. The toxicity of permethrin + cypermethrin + etofenprox was significantly greater than the toxicity of both permethrin and etofenprox alone, but it was significantly lower than cypermethrin alone. The mixture of permethrin and etofenprox was significantly less toxic than permethrin. The explanation for the decreased toxicity observed is most likely because of the competitive binding at the voltage-gated sodium channel, which is supported by physiological and biochemical studies of pyrethroids. Our results demonstrate that the assumption that the mixture toxicity of pyrethroids would be additive is not adequate for modeling the mixture toxicity of pyrethroids to insects.
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Affiliation(s)
- Jerome J Schleier
- Department of Land Resources and Environmental Sciences, Montana State University, 334 Leon Johnson Hall, Bozeman, MT 59717, USA.
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Kweka EJ, Himeidan YE, Mahande AM, Mwang'onde BJ, Msangi S, Mahande MJ, Mazigo HD, Nyindo M. Durability associated efficacy of long-lasting insecticidal nets after five years of household use. Parasit Vectors 2011; 4:156. [PMID: 21819578 PMCID: PMC3174122 DOI: 10.1186/1756-3305-4-156] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 08/05/2011] [Indexed: 11/13/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) have been strongly advocated for use to prevent malaria in sub-Saharan Africa and have significantly reduced human-vector contact. PermaNet® 2.0 is among the five LLINs brands which have been given full approval by the WHO Pesticide Evaluation Scheme (WHOPES). The LLINs are expected to protect the malaria endemic communities, but a number of factors within the community can affect their durability and efficacy. This study evaluated the durability, efficacy and retention of PermaNet® 2.0 after five years of use in a Tanzanian community. Method Two to three day- old non blood-fed female mosquitoes from an insectary susceptible colony (An. gambiae s.s, this colony was established at TPRI from Kisumu, Kenya in 1992) and wild mosquito populations (An. arabiensis and Culex quinquefasciatus) were used in cone bioassay tests to assess the efficacy of mosquito nets. Findings The knockdown effect was recorded after three minutes of exposure, and mortality was recorded after 24 hours post-exposure. Mortality of An. gambiae s.s from insectary colony was 100% while An. arabiensis and Cx.quinquefasciatus wild populations had reduced mortality. Insecticide content of the new (the bed net of the same brand but never used before) and used PermaNet® 2.0 was determined using High Performance Liquid Chromatography (HPLC). Conclusion The results of this study suggest that, in order to achieve maximum protection against malaria, public health education focusing on bed net use and maintenance should be incorporated into the mass distribution of nets in communities.
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Affiliation(s)
- Eliningaya J Kweka
- Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Mosquito Section, Arusha, Tanzania.
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Dev V, Phookan S, Padhan K, Tewari G, Khound K. Laboratory wash-resistance and field evaluation of deltamethrin incorporated long-lasting polyethylene netting (Netprotect(®)) against malaria transmission in Assam, north-east India. Acta Trop 2011; 119:172-7. [PMID: 21679681 DOI: 10.1016/j.actatropica.2011.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 05/20/2011] [Accepted: 05/29/2011] [Indexed: 11/26/2022]
Abstract
North-east India is co-endemic for Plasmodium falciparum and P. vivax malaria, and disease transmission is perennial and persistent. This study reports the results of a field-based village scale trial of deltamethrin incorporated long-lasting polyethylene netting (Netprotect(®)) conducted in P. falciparum predominant pocket of Assam, north-east India to assess operational feasibility, acceptability and sustainability against disease vectors and malaria transmission. The study monitored the residual efficacy of the long-lasting net in relation to serial washings in the laboratory and malaria prevalence in experimental villages for the first year of investigations from September 2008 to June 2009. The mosquito vector populations of Anopheles minimus were observed to be highly susceptible to deltamethrin (0.05%), and follow up investigations revealed that the vector mosquito had virtually disappeared in Netprotect(®) intervention villages. Concurrently, there was consistent decline in malaria cases in Netprotect(®) villages and transmission reduction was statistically significant compared to untreated net (net without insecticide) and no-net control villages for the corresponding study period. The contact cone-bioassay investigations against malaria transmitting mosquito species revealed that the bioavailability of the insecticide on the net fiber was persistent up to 20th serial wash resulting in ≥80% mortality. Community compliance and acceptance were high, and users reported decreased nuisance due to biting mosquitoes. It was concluded that deltamethrin incorporated polyethylene long-lasting netting was safe, wash-resistant, and assessed to be an operationally feasible, community-based intervention for sustainable management of disease vectors to prevent malaria transmission.
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Sreehari U, Raghavendra K, Rizvi MMA, Dash AP. Wash resistance and efficacy of three long-lasting insecticidal nets assessed from bioassays on Anopheles culicifacies and Anopheles stephensi. Trop Med Int Health 2009; 14:597-602. [PMID: 19228347 DOI: 10.1111/j.1365-3156.2009.02252.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To test the wash resistance and efficacy of long-lasting insecticidal nets (LLINs), namely Olyset Net and PermaNet 2.0; and a long-lasting treatment kit, K-O Tab 1-2-3, on Anopheles culicifacies and An. stephensi, major malaria vectors in India, by bioassays. Conventionally treated deltamethrin net (CTDN with K-O Tab) was used for comparison. METHOD Mortality and median time for knockdown (MTKD) of mosquitoes were determined using contact bioassays and ball frame bioassays respectively. Hand washing and machine washing were used. RESULTS LLINs showed good bio-efficacy against An. culicifacies and An. stephensi. The mortality of mosquitoes remained >80% after up to 20 hand washes and up to 15 machine washes on all LLINs tested. No significant differences were observed in mortalities between the An. culicifacies and An. stephensi in cone bioassays (P > 0.05). MTKD increased progressively with successive washes and there was a significant difference in median time for knockdown of test mosquitoes and between hand-washed and machine-washed nets (P < 0.05). CONCLUSION LLINs are more efficacious and last longer when washed by hand than by machine.
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Affiliation(s)
- U Sreehari
- National Institute of Malaria Research, Delhi, India
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