Anopheline Mosquito Species Composition, Kdr Mutation Frequency, and Parasite Infectivity Status in Northern Tanzania

Abstract

The scaling-up of malaria control interventions in northern Tanzania has resulted in a decline in malaria prevalence and vector species composition. Despite this achievement, residual malaria transmission remains a concern in the area. The main aim of this study was to investigate malaria vector species composition, parasite infectivity rates, and the presence of insecticide knockdown resistance (kdr) mutations in three sites that have experienced a significant decline in malaria in northern Tanzania. Adult mosquitoes were sampled using light traps in houses and hand-aspirators in cowsheds, whereas the standard dipping method was used for sampling mosquito larvae. Adult mosquitoes identified as Anopheles gambiae s.l. and An. funestus s.l. and larval stages III and IV of An. gambiae s.l. were stored in absolute ethanol for further laboratory molecular identification. The identified species in the An. gambiae complex were An. gambiae s.s., An. merus, An. quadriannulatus, and An. arabiensis, whereas the An. funestus group comprised An. funestus s.s., An. rivulorum, and An. leesoni. For An. gambiae s.s. analyzed from Zeneth, 47.6% were kdr-East homozygous susceptible, 35.7% kdr-East heterozygous resistant, 9.6% kdr-East homozygous resistant, and 7.1% undefined, whereas specimens from Kwakibuyu were 45.5% kdr-East homozygous susceptible, 32.7% kdr-East heterozygous resistant, 16.3% kdr-East homozygous resistant, and 5.5% undefined. There were no kdr-West alleles identified from any specimen. The overall malaria parasite infectivity rate was 0.75%. No infections were found in Moshi. The findings indicate that populations of the major malaria vector mosquitoes are still present in the study area, with An. funestus taking a lead in malaria transmission.

Insecticidal Efficacy of Microbial-Mediated Synthesized Copper Nano-Pesticide against Insect Pests and Non-Target Organisms

“…Vector-borne diseases are considered to be major problems to public health worldwide [ 2 , 3 , 16 ]. Synthetic chemical insecticide was effective against agricultural and medical pests, but there were challenges faced such as insecticide resistance [ 17 ]. Continuous use of chemical insecticides has hampered the insect control programs and formed many insecticide resistance problems [ 28 ].…”

“…anisopliae has been used as microbial pesticides for controlling medical and agricultural pests. Their conidia produced remarkable mortality under laboratory and field conditions [ 3 , 17 ]. There are no toxicological or pathological symptoms observed in birds, fish, mice, rats, and guinea pigs following exposure to M .…”

Field evaluation of Veeralin, an alpha-cypermethrin + PBO long-lasting insecticidal net, against natural populations of Anopheles funestus in experimental huts in Muheza, Tanzania

“…arabiensis ( NʼGuessan et al., 2010 ; Koudou et al., 2011 ; Pennetier et al., 2013 ), this evaluation trial was conducted in an area dominated by An. funestus ( s.s. ) malaria vectors ( Derua et al., 2015 ; WHO, 2017 ; Kweka et al., 2018 , 2020 ). The assessment of the laboratory-based knockdown effect (using susceptible An.…”

“…arabiensis and An. gambiae ( s.s. ), perhaps related to differential effects of intervention tools among species ( Lwetoijera et al., 2014 ; Kweka et al., 2020 ).…”

The Impact of Insecticide Pre-Exposure on Longevity, Feeding Succession, and Egg Batch Size of Wild Anopheles gambiae s.l.

“…coluzzii , and An. funestus members are the main malaria vectors that are responsible for spread of the disease in SSA [ 9 – 15 ]. So far, vector control measures remain a main intervention strategy for the global malaria eradication programme [ 16 – 19 ].…”