The influence of age on insecticide susceptibility of  Anopheles arabiensis  during dry and rainy seasons in rice irrigation schemes of Northern Tanzania

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Abstract

Background

Insecticide resistance is the major emerging challenge facing the malaria vector control programmes in Tanzania. Proper monitoring and detection is of paramount importance guiding the vector control programmes. This paper presents the effect of mosquito aging on insecticide resistance status in Anopheles arabiensis populations in dry and rainy seasons in northern Tanzania.

Methods

Anopheles gambiae s.l. larvae were sampled from rice fields in both dry and rainy seasons and reared in the insectary to adults. The emerged females in batches of 2, 3, 5, and 10 days old were exposed to six insecticides (deltamethrin, permethrin, lambda-cyhalothrin, DDT, bendiocarb and pirimiphos-methyl) to see the effects of age on insecticide resistance. Mosquitoes were exposed to insecticides using WHO standard susceptibility test kits. Knockdown was recorded during the 1-h exposure, while mortality and resistance ratio were recorded 24 h later. Mosquito specimens were identified to species level using the polymerase chain reaction (PCR) method.

Results

Among the 326 specimens processed by PCR, 323 (99.1%) were identified as Anopheles arabiensis. There was reduced mortality (ranging from 61 to 97.7%) when adults reared from larvae were exposed to all pyrethroids and bendiocarb in both dry and rainy seasons, while they were fully susceptible to DDT and pirimiphos-methyl. There was a significant increase in mortality rate with increase in mosquito’s age in both dry and rainy seasons following exposure to pyrethroids (DF = 1, P < 0.05). Mosquitoes showed significantly higher mortality rates in the rainy season than in the dry season after being exposed to pyrethroids (DF = 1, P < 0.05). Higher mortality rates (94.0–99.8%) were observed in all ages and seasons when mosquitoes were exposed to bendiocarb compared with pyrethroids. Pirimiphos-methyl was only tested in the rainy season so no comparison with dry season mosquitoes could be made.

Conclusions

Results showed that An. arabiensis were resistant to pyrethroids in both seasons and that the young age groups exhibited higher levels of resistance compared with the older age groups. Mosquitoes were full susceptible to DDT and pirimiphos-methyl irrespective of the season and age.

Related collections

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Author and article information

Contributors

Saada Mbepera: saadambepera@yahoo.com

Gamba Nkwengulila: gamba@udsm.ac.tz

Rose Peter: rose.peter@arysta.com

Emmanuel A. Mausa: mausaemmanuel@yahoo.com

Aneth M. Mahande: Anethmmahande@gmail.com

Maureen Coetzee: maureen.coetzee@wits.ac.za

Eliningaya J. Kweka:

ORCID: http://orcid.org/0000-0002-8891-758X

pat.kweka@gmail.com

Journal

Journal ID (nlm-ta): Malar J

Journal ID (iso-abbrev): Malar. J

Title: Malaria Journal

Publisher: BioMed Central (London )

ISSN (Electronic): 1475-2875

Publication date (Electronic): 11 September 2017

Publication date PMC-release: 11 September 2017

Publication date Collection: 2017

Volume: 16

Electronic Location Identifier: 364

Affiliations

[1 ]ISNI 0000 0004 0648 0244, GRID grid.8193.3, Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, , University of Dar-es-salaam, ; P.O.Box 35165, Dar-es-salaam, Tanzania

[2 ]Public Health Strategic Partnerships Associate, Arysta Life Science, 12 Denys Road, River Club, 2191 South Africa

[3 ]ISNI 0000 0001 2164 855X, GRID grid.463518.d, National Plant Genetic Resource Centre, , Tropical Pesticides Research Institute, ; P.O. Box 3024, Arusha, Tanzania

[4 ]ISNI 0000 0001 2164 855X, GRID grid.463518.d, Division of Livestock and Human Diseases Vector Control, , Tropical Pesticides Research Institute, ; Mabogini Field Station, Moshi, Tanzania

[5 ]ISNI 0000 0004 1937 1135, GRID grid.11951.3d, Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, , University of the Witwatersrand, ; Johannesburg, South Africa

[6 ]ISNI 0000 0004 0630 4574, GRID grid.416657.7, Centre for Emerging, Zoonotic & Parasitic Diseases, , National Institute for Communicable Diseases, ; Johannesburg, South Africa

[7 ]ISNI 0000 0001 2164 855X, GRID grid.463518.d, Division of Livestock and Human Diseases Vector Control, , Tropical Pesticides Research Institute, ; P.O.Box 3024, Arusha, Tanzania

[8 ]ISNI 0000 0004 0451 3858, GRID grid.411961.a, Department of Medical Parasitology and Entomology, School of Medicine, , Catholic University of Health and Allied Sciences, ; P.O. Box 1464, Mwanza, Tanzania

Author information

Eliningaya J. Kweka http://orcid.org/0000-0002-8891-758X

Article

Publisher ID: 2022

DOI: 10.1186/s12936-017-2022-6

PMC ID: 5594483

PubMed ID: 28893240

SO-VID: 95e6c43c-df5b-43f8-8102-8e0712782b56

License:

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.