The impact of livestock on the abundance, resting behaviour and sporozoite rate of malaria vectors in southern Tanzania

Malaria Journal

Research

Heather M Ferguson¹  Gamba Nkwengulila²  Issa N Lyimo³  Hassan Ngonyani³  Hassan Mtambala³  Valeriana S Mayagaya³  Japheti Kihonda³  Tanya L Russell⁴ 

[1] Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, G12 8QQ, Glasgow, UK;Department of Zoology and Wildlife Conservation, University of Dar es Salaam, PO Box 35065, Dar es Salaam, Tanzania;Environmental Health and Ecological Sciences, Ifakara Health Institute, PO Box 53, Ifakara, Tanzania;Faculty of Medicine, Health and Molecular Sciences, James Cook University, PO Box 6811, 4870, Cairns, Queensland, Australia;

关键词: Malaria transmission;    Environmental management;    Vector behaviour;    Ecology;    Zooprophylaxis;    Kilombero Valley;   

DOI  :  10.1186/s12936-014-0536-8

 received in 2014-09-24, accepted in 2014-12-27,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundIncreases in the coverage of long-lasting insecticidal nets (LLINs) have significantly reduced the abundance of Anopheles gambiae sensu stricto in several African settings, leaving its more zoophagic sibling species Anopheles arabiensis as the primary vector. This study investigated the impact of livestock ownership at the household level on the ecology and malaria infection rate of vectors in an area of Tanzania where An. arabiensis accounts for most malaria transmission.MethodsMosquito vectors were collected resting inside houses, animal sheds and in outdoor resting boxes at households with and without livestock over three years in ten villages of the Kilombero Valley, Tanzania. Additionally, the abundance and sporozoite rate of vectors attempting to bite indoors at these households was assessed as an index of malaria exposure.ResultsThe mean abundance of An. gambiae s.l. biting indoors was similar at houses with and without livestock. In all years but one, the relative proportion of An. arabiensis within the An. gambiae s.l. species complex was higher at households with livestock. Livestock presence had a significant impact on malaria vector feeding and resting behaviour. Anopheles arabiensis were generally found resting in cattle sheds where livestock were present, and inside houses when absent. Correspondingly, the human blood index of An. arabiensis and An. funestus s.l. was significant reduced at households with livestock, whereas that of An. gambiae s.s. was unaffected.Whilst there was some evidence that sporozoite rates within the indoor-biting An. gambiae s.l population was significantly reduced at households with livestock, the significance of this effect varied depending on how background spatial variation was accounted for.ConclusionsThese results confirm that the presence of cattle at the household level can significantly alter the local species composition, feeding and resting behaviour of malaria vectors. However, the net impact of this livestock-associated variation in mosquito ecology on malaria exposure risk was unclear. Further investigation is required to distinguish whether the apparently lower sporozoite rates observed in An. gambiae s.l. at households with livestock is really a direct effect of cattle presence, or an indirect consequence of reduced risk within areas where livestock keepers choose to live.

【 授权许可】

CC BY   
© Mayagaya et al.; licensee Biomed Central. 2015