Background Vector control is the main intervention used to control arboviral diseases transmitted by Aedes mosquitoes because there are no effective vaccines or treatments for most of them. Control of Aedes mosquitoes relies heavily on the use of insecticides, the effectiveness of which may be impacted by resistance. In addition, rational insecticide application requires detailed knowledge of vector distribution, dynamics, resting, and feeding behaviours, which are poorly understood for Aedes mosquitoes in Africa. This study investigated the spatiotemporal distribution and insecticide resistance status of Aedes aegypti across ecological extremes of Ghana. Methods Immature mosquitoes were sampled from containers in and around human dwellings at seven study sites in urban, suburban, and rural areas of Ghana. Adult Aedes mosquitoes were sampled indoors and outdoors using Biogents BG-Sentinel 2 mosquito traps, human landing catches, and Prokopack aspiration. Distributions of immature and adult Aedes mosquitoes were determined indoors and outdoors during dry and rainy seasons at all sites. The phenotypic resistance status of Aedes mosquitoes to insecticides was determined using World Health Organization susceptibility bioassays. The host blood meal source was determined by polymerase chain reaction. Results A total of 16,711 immature Aedes were sampled, with over 70% found in car tyres. Significantly more breeding containers had Aedes immatures during the rainy season (11,856; 70.95%) compared to the dry season (4855; 29.05%). A total of 1895 adult Aedes mosquitos were collected, including Aedes aegypti (97.8%), Aedes africanus (2.1%) and Aedesluteocephalus (0.1%). Indoor sampling of adult Aedes yielded a total of 381 (20.1%) and outdoor sampling a total of 1514 (79.9%) mosquitoes (z = − 5.427, P = 0.0000) over the entire sampling period. Aedes aegypti populations were resistant to dichlorodiphenyltrichloroethane at all study sites. Vectors showed suspected resistance to bendiocarb (96–97%), permethrin (90–96%) and deltamethrin (91–96%), and were susceptible to the organophosphate for all study sites. Blood meal analysis showed that the Aedes mosquitoes were mostly anthropophilic, with a human blood index of 0.9 (i.e. humans, 90%; human and dog, 5%; dog and cow, 5%). Conclusions Aedes mosquitoes were found at high densities in all ecological zones of Ghana. Resistance of Aedes spp. to pyrethroids and carbamates may limit the efficacy of vector control programmes and thus requires careful monitoring. Graphical abstract

Background Outbreaks of Aedes-borne arboviral diseases are becoming rampant in Africa. In Ghana, there is no organized arboviral control programme with interventions restricted to mitigate outbreaks. Insecticide application is a crucial part of outbreak responses and future preventative control measures. Thus, knowledge of the resistance status and underlying mechanisms of Aedes populations is required to ensure optimal insecticide choices. The present study assessed the insecticide resistance status of Aedes aegypti populations from southern Ghana (Accra, Tema and Ada Foah) and northern Ghana (Navrongo) respectively. Methods Phenotypic resistance was determined with WHO susceptibility tests using Ae. aegypti collected as larvae and reared into adults. Knockdown resistance (kdr) mutations were detected using allele-specific PCR. Synergist assays were performed with piperonyl butoxide (PBO) to investigate the possible involvement of metabolic mechanisms in resistance phenotypes. Results Resistance to DDT was moderate to high across sites (11.3 to 75.8%) and, for the pyrethroids deltamethrin and permethrin, moderate resistance was detected (62.5 to 88.8%). The 1534C kdr and 1016I kdr alleles were common in all sites (0.65 to 1) and may be on a trajectory toward fixation. In addition, a third kdr mutant, V410L, was detected at lower frequencies (0.03 to 0.31). Pre-exposure to PBO significantly increased the susceptibility of Ae. aegypti to deltamethrin and permethrin (P < 0.001). This indicates that in addition to kdr mutants, metabolic enzymes (monooxygenases) may be involved in the resistance phenotypes observed in the Ae. aegypti populations in these sites. Conclusion Insecticide resistance underpinned by multiple mechanisms in Ae. aegypti indicates the need for surveillance to assist in developing appropriate vector control strategies for arboviral disease control in Ghana. Graphical Abstract

Background: Vector control is the main intervention to control arboviral diseases transmitted by Aedes mosquitoes because for most there are no effective vaccines or treatment. This vector control relies heavily on the use of insecticides, effectiveness of which may be impacted by resistance. In addition, rational insecticide application requires detailed knowledge of vector distribution, dynamics, resting, and feeding behaviours, which are poorly understood for Aedes vectors in Africa. This study investigated the spatio-temporal distribution and insecticide resistance status of Ae. aegypti from across ecological extremes of GhanaMethods: Immature mosquitoes were sampled from containers in and around human dwellings at each of seven study sites in urban, suburban, and rural areas of Ghana. Adult Aedes mosquitoes were sampled indoor and outdoor using Biogent sentinel-2 mosquito traps, human landing catches, and prokopack aspiration. Distributions of immatures and adult Aedes mosquitoes were determined indoors and outdoors during dry and rainy seasons at all sites. Phenotypic resistance status of Aedes mosquitoes to insecticides was determined using WHO bioassays. Host blood meal source was determined by PCR.Results: A total of 16,711 immature Aedes were sampled, with over 70% found in car tires. Significantly more breeding containers had Aedes immatures during the rainy season 70.95% (11,856) compared to the dry season 29.05% (4,855). A total of 1,895 adult Aedes mosquitos were collected, including Ae. aegypti (97.8%), Ae. africanus (2.1%) and Ae. Luteocephalus (0.1%). Indoor sampling of adult Aedes mosquitoes yielded a total of 381 (20.1%) and outdoor a total of 1,514 (79.9%) (z = -5.427; p = 0.0000) over the entire sampling period. Aedes aegypti populations were resistant to DDT at all study sites. Vectors showed suspected resistance to Bendiocarb (96-97%), Permethrin (90-96%) and Deltamethrin (91-96%) and were susceptible to the organophosphate malathion from all study sites.Blood meal analysis showed that the Aedes mosquitoes were mostly anthropophilic with HBI of 0.9 i.e. [(human = 90%), (human and dog = 5%), (dog and cow = 5%)].Conclusion: Aedes mosquitoes were found at high densities in all ecological zones of Ghana. Resistance to pyrethroids and carbamates may limit control efficacy and requires careful monitoring.

The success of mass drug administration (MDA) campaigns to control and eliminate neglected tropical diseases (NTDs) in Ghana depends, to a large extent, on the essential role community drug distributors (CDDs) play. This study aimed to investigate community’s perceptions of CDDs’ roles, impact of CDDs’ work, challenges faced by CDDs and views on resources required to enhance CDDs’ work to sustain MDA campaigns. Methods: A cross-sectional qualitative study employing the use of focus group discussions (FGDs) with community members and CDDs in selected NTD endemic communities together with individual interviews with district health officers (DHOs)was conducted. We interviewed 104 people aged 18 and over, purposively selected, through eight individual interviews, and 16 focus group discussions. Results: Participants in the community FGDs noted that health education and distribution of drugs were the main roles of CDDs. Participants also perceived that the work of CDDs had prevented the onset of NTDs, treated symptoms of NTDs and generally reduced the incidence of infections. In the interviews with CDDs and DHOs, lack of cooperation/non-compliance by community members, demands by community members, lack of working resources and low financial motivation were mentioned as the main challenges to the work of CDDs. Moreover, provision of logistics and financial motivation for CDDs were identified as factors that will enhance their work. Conclusions: Incorporating more attractive schemes shall incentivise CDDs to improve output. Addressing the challenges highlighted is an important step for the work of CDDS to be effective in controlling NTDs in difficult-to-access communities in Ghana.

Within the past 10 years, there has been a resurgence of arboviral disease outbreaks within the sub-Saharan region of Africa due to the geographic expansion of both the mosquito vectors and their resistance to insecticides. The reasons for this resurgence are not well understood, migration of people, movement of disease vectors, and deforestation as a result of rapid and unplanned urbanization may lead to increased erosion of their natural habitats leading to contact with humans, and/or previously obligate sylvatic species might acclimatize to new urban environments and hosts, potentially with a greater role as vectors. And lack of effective control methods for Aedes mosquitoes. The possibility of arboviruses to adapt to new vectors rapidly occur, and this can have great significant consequences. Other Aedes species such as Aedes africanus and Ae. luteocephalus. play a vital role in the transmission of arboviruses in Africa because they are involved in sylvatic arbovirus transmission cycles and can also act as a bridge vector to humans. Bridge vectors may initiate a human outbreak, but large epidemics typically occur only when virus transmission involves urban populations of Ae. aegypti or Ae. albopictus, which has the ability to feed on both humans and other vertebrates.