Biting behavior of malaria vectors and malaria elimination efforts in Tak province, Thailand
A study to investigate behavior of malaria vectors, susceptibility to insecticides and durability of field used Long Lasting Insecticide Treated Nets (LLINs) was conducted on Thai-Myanmar Border at Village No. 12, Ban Huay Pla Kong, Khaneijue Sub-district, Mae Ramat District, Tak Province for 11 months between December 2014 and October 2015. Thirteen species of Anopheles were collected with three malaria vectors and found all year round (i.e. Anopheles minimus, An. maculatus group and An. dirus). An. minimus was found in high density from February to June with highest peak in April. It preferred to bite outdoors than indoors and it was highly zoophilic but there was no statistically significant difference (p=0.079). An. maculatus group showed significant preference to bite humans outdoors than indoors (p=0.030). It was found with high density from April to October with highest peak in June and it was highly zoophilic. Density of An. dirus was insufficient for statistical analysis. These findings indicated that both vector species prefer to bite humans outdoors rather than indoors. Moreover, they were highly zoophilic. This outdoor biting behavior suggested that it may reduce the effective of LLIN and indoor residual spray, which aPre the main vector control measures for malaria elimination. Both An. minimus and An. maculatus group were highly susceptible to deltamethrin, permethrin and bifenthrin. Furthermore, it was found that durability of LLINs manufactured from deltemethrin (55 mg a.i./m2)-coated polyester net could last longer than 5 years and permethrin (2.0% a.i. w/w)-impregnated polyethylene net lasting longer than 4 years, after distribution into this village. These findings provided evidence that durability of LLINs is much longer than the recommendation made by the manufacturers and the World Health Organization (WHO). Findings from the western Thai province of Tak with regard to outdoor biting behavior of malaria vectors and long durability of LLINs may not be conclusive since this was only one study. Further studies in other parts of Thailand should also be conducted to draw more conclusive findings. Data from additional studies will be very useful for policymakers to further review and improve existing vector control measures to advance the country’s malaria elimination program. Findings from this study has also suggested to include adult survey and animal bait collection to determine occurrence of malaria vector for stratification of areas for assignment of malaria elimination and vector control measures.
2. Bureau of Vector Borne Diseases. A guideline for partnership for containment of artemisinin resistance and moving towards the elimination of plasmodium in Thailand. Bangkok: The Agricultural Co-operation Federation of Thailand, Ltd.; 2014. (in Thai)
3. Bureau of Vector Borne Diseases. Thailand Malaria Elimination Program [Internet]. 2018 [cited 2018 Sep 30]. Available from: https://220.127.116.11/malariaR10/index_newversion.php (in Thai)
4. Bureau of Vector Borne Diseases. Guidelines on malaria elimination for local administrative organizations and health networks. Bangkok: Aksorn Graphic and Design Publication; 2018. (in Thai)
5. World Health Organization. Guidelines for laboratory and field testing of long-lasting insecticidal mosquito nets. Geneva: World Health Organization; 2005.
6. Bureau of Vector Borne Diseases. National Malaria Elimination Strategy, Thailand 2017-2026 and Operational Plan, Thailand 2017-2021. Bangkok: Aksorn Graphic and Design Publication; 2016. (in Thai)
7. World Health Organization. Test procedures for insecticide resistance monitoring in malaria vector mosquitoes. Geneva: World Health Organization; 2013.
8. World Health Organization. Guidelines for laboratory and field testing of long-lasting insecticidal nets. Geneva: World Health Organization; 2013.
9. Tainchum K, Ritthison W, Chuaycharoensuk T, Bangs MJ, Manguin S, Chareonviriyaphap T. Diversity of Anopheles species and trophic behavior of putative malaria vectors in two malaria endemic areas of northwestern Thailand. J Vector Ecol 2014;39:424-36.
10. Rosenberg R, Andre RG, Somchit L. Highly efficient dry season transmission of malaria in Thailand. Trans R Soc Trop Med Hyg 1990;84:22-28.
11. Obsomer V, Defourny P, Coosemans M. The Anopheles dirus complex: spatial distribution and environmental drivers. Malar J 2007;6:26.
12. Sinka ME, Bangs MJ, Manguin S, Chareonviriyaphap T, Patil AP, Temperley WH, et al. The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis. Parasit Vectors 2011;4:89.
13. Tisgratog P, Tananchai C, Juntarajumnong W, Tuntakom S, Bangs M J, Corbel V, et al. Host feeding patterns and preference of Anopheles minimus (Diptera: Culicidae) in a malaria endemic area of western Thailand: baseline site description. Parasit Vectors 2012;5:114.
14. Muenworn V, Sungvornyothin S, Kongmee M, Polsomboon S, Bangs M J, Akrathanakul P, et al. Biting activity and host preference of the malaria vectors Anopheles maculatus and Anopheles sawadwongporni (Diptera: Culicidae) in Thailand. J Vector Ecol 2009;34:62-9.
15. Tananchai C, Tisgratog R, Juntarajumnong W, Grieco J P, Manguin S, Prabaripai A , et al. Species diversity and biting activity of Anopheles dirus and Anopheles baimaii (Diptera: Culicidae) in a malaria prone area of western Thailand. Parasit Vectors 2012;5:211.
16. Bhumiratana A, Sorosjinda-Nunthawarasilp P, Kaewwaen W, Maneekan P, Pimnon S. Malaria-associated rubber plantations in Thailand. Travel Med Infect Dis 2013;11:37-50.
17. Paing M, Sebastian A, Tun-Lin W. Anopheline mosquitoes of Myanmar. I. Anopheles (Cellia) dirus Peyton and Harrison, 1979. Myanmar Health Sci Res J 1989;1:122-9.
18. Kitthawee S, Edman JD, Upatham ES. Mosquito larvae and associated macroorganisms occurring in gem pits in southern Tha Mai District, Chanthaburi Province, Thailand. Southeast Asian J Trop Med Public Health 1993;24:143-51.
19. Oo TT, Storch V, Becker N. Studies on the bionomics of Anopheles dirus (Culicidae: Diptera) in Mudon, Mon State, Myanmar. J Vector Ecol 2002;27:44-54.
20. Aung H, Minn S, Thaung S, Mya MM, Than SM, Hlaing T, et al. Well-breeding Anopheles dirus and their role in malaria transmission in Myanmar. Southeast Asian J Trop Med Public Health. 1999;30:447-53.
21. Kengluecha A, Singhasivanon P, Tiensuwan M, Jones JW, Sithiprasasna R. Water quality and breeding habitats of anopheline mosquito in northwestern Thailand. Southeast Asian J Trop Med Public Health 2005;36:46-53.
22. World Health Organization. Global plan for insecticide resistance management in malaria vectors. Geneva: World Health Organization; 2012.
23. Adriana Tami, Godfrey M, Alison T, Hassan M, Stéphane D, Christian L. Evaluation of Olyset™ insecticide-treated nets distributed seven years previously in Tanzania. Malar J 2004;3:19.
24. World Health Organization. Guidelines for monitoring the durability of long-lasting insecticidal mosquito nets under operational conditions. Geneva: World Health Organization; 2011.
25. World Health Organization. Indoor residual spraying: an operational manual for indoor residual spraying (IRS) for malaria transmission control and elimination. 2nd ed. Geneva: World Health Organization; 2015.
26. World Health Organization. Factors that affect the success and failure of Insecticide Treated Net Programs for malaria control in SE Asia and the Western Pacific [internet]. 2019 [cited 2019 Jan 2]. Available from: https://www.who.int/malaria/publications/atoz/itn_r62.pdf?ua=1
27. World Health Organization. Vector control and personal protection of migrant and mobile populations in the GMS: A matrix guidance on the best option and methodologies, New Delhi: World Health Organization; 2015.
28. Networks Project Vector Control Assessment Report in the GMS. Review of malaria prevention: strategies, tools, stakeholders, target group segmentation, behavioral issues and private sector development options [internet]. 2019 [cited 2019 Jan 2]. Available from: https://www.malariaconsortium.org/media-downloads/295/Networks%20project %20vector%20control%20assessment%20in%20Greater%20sub-Mekong%20Region
29. Aumaung B, Sevana J, Sinakom B, Yongchaitrakol S, Muernrat Y. Study on using long lasting insecticidal nano net jacket (ILLINJ) for malaria vector control. Dis Control J 2018;44:448-58. (in Thai)
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