Insights Into Resting Behavior of Malaria Vector Mosquitoes in Mutare and Mutasa Districts of Manicaland Province, Zimbabwe.

A study was conducted to investigate the current resting behavior of malaria vectors in Mutare and Mutasa districts, Zimbabwe. Mosquitoes were captured using pyrethrum spray collection, prokopac aspirator, pit shelter, and exit trap methods. Mosquitoes were sorted and identified using morphological key and polymerase chain reaction (PCR) techniques. The Anopheles funestus group constituted 97%, whereas Anopheles gambiae complex mosquitoes were few (3%). Endophilic collections in both species were five times greater than exophilic catches. The endophilic trait was further demonstrated by gravid to fed index (gravid/fed) of constantly more than 1. Nearly 90% endophilic An. funestus populations were collected on sprayable and 10% collected on unsprayable surfaces. Of the sprayable surfaces, 56% were collected on the roofs, with 44% on the walls. Of those on the walls, 44, 22, and 34% were caught on wall heights >1, 1.0-1.5, <1.5 m from the ground, respectively. Of the gravid An. funestus caught, nearly two-thirds were collected exiting pyrethroid-treated structures, with a 24-h mortality of less than 10%. The PCR analysis of 120 specimens taken randomly from the An. funestus group was all An. funestus s.s. The present work indicates that for effective malaria control in Mutare and Mutasa districts using indoor residual spraying, both walls and roofs must be sprayed.