Mosquitoes are known to be a deadly species of arthropods responsible for the transmission of vector–borne diseases such Malaria, Yellow Fever, Dengue, Filariasis/Elephantiasis, Zika, Chikunguya and Rift Valley fever) to humans and animals [1]. Vector-borne diseases (VBDs) such as dengue fever, chikunguya, yellow fever, and Zika virus are transmitted to humans through the bite of Aedes albopictus (Asian tiger mosquito) and Aedes aegypti (Linnaeus) infected female mosquitoes [2–3].
Malaria is a global major public health burden. Malaria vector control (infective female mosquito) which transmit this infectious disease is chiefly through larval control. This method has been documented to be very vital stage amongst malaria control programmes worldwide via eradicating of major known breeding sites by means of larval source management and/or reduction coupled with robust adulticiding (killing of adults mosquitoes)[4–5]. Malaria infection arises as a result of a bite of an infective female Anopheles mosquitoes in man. These mosquitoes migrate from breeding sites (habitats) that are natural or man-made which readily available at all times in the communities due to the activities of the residents in producing these vector breeding sites [6].
In 1881, according to [7], Carlos Finlay theorized the causative agent responsible of causing yellow fever disease to be harbored by mosquitoes. However, in 1900, Major Walter Reed proved Carlos Finlay’s theory to be true through his maiden observation that yellow fever virus (YFV), was possible to be transmitted by Aedes mosquitoes. Yellow Fever (YF) is endemic in Ghana, and is noted to be associated with severe disease in approximately 15% of cases with a high case fatality ratio (CFR). Ghana recorded 202 suspected cases of YF comprising of 70 confirmed cases with 35 deaths from Savannah, Upper West, Bono and Oti regions in 2021 [8].
The long history about the abundance of mosquitoes of many different species in our communities has called for the study of mosquito-borne communicable diseases for instance malaria, dengue, yellow fever as well as other known health-related concerns has becomes very eminent [9]. However, not much attention is given to the larval ecology of Anopheles mosquitoes across many African countries. The microhabitat elements that impact the existence and abundance of Anopheles larvae characterization is not adequately done most especially for malaria vector species, the female Anopheles. Categorization of mosquito larval habitats has been found to include marshy/swampy areas, rain pools, man-made pools etc. despite the availability of this key information, these habitat classifications are not detailed enough to delineate indigenous environmental factors connected with the exact Anopheline species for designing and executing applicable larval control interventions [4–5].
Currently, as a result of the rapidly changing ecological and environmental conditions, it is very paramount to continuously monitor and study the bionomics of diseases associated with vectors such as mosquitoes more often in recent times [10]. Water storage facilities and/or receptacles are known to be breeding ground of mosquitoes. These breeding habitats or sites are readily associated with the development of eggs, larvae and pupae of mosquitoes before they emerge as adults. Therefore, it is important to gather empirical data of breeding sites of mosquitoes prior to planning any feasible and workable control programmes [11].
Indispensably, the act of analyzing the mosquito breeding habitats to determine the characteristics of the sites such as whether they are temporary or permanent habitats, water level, its cleanliness or otherwise as well as the resting position of mosquito larva present, is deemed to be very vital and critical for effective control of breeding habitats and mosquitoes in our communities [9]. According to [10], mosquito vector species such as Aedes aegypti and Aedes albopictus were responsible for vector borne diseases Juba, Cid City and Philippines. As Aedes and Culex mosquitoes are reported to breed in different types of receptacle as their habit, the permanent removal of these known receptacles and or containers as well as altering these habitats of breeding of these vectors will go a long way in controlling them [12].
The availability of data on the distribution and abundance of mosquito vectors of malaria in a particular geographical area could be an effective control strategy of the deadly disease (malaria) as well as considering its vector management [13]. Amongst the topical reasons accounting for the lack of studies conducted on the ecology of anopheline larvae could be attributed to the recorded challenges associated with larval sampling ranging from aquatic habitats from the field due to the temporary nature of majority of the known larval habitats [14]. Receptive environment for breeding is fundamental for malarial mosquito population dynamics due to the fact that, the breeding sites are places where key processes of the life cycle of the vector ensued which includes the laying of the eggs, the larval development, pupation and adults’ growth originates [15].
Entomological surveillance should take into account regular assessment of vector species and behaviours with regards to their presence, abundance and seasonality, time and habitation of biting, resting and host inclination, insecticide resistance status and basic resistance machineries in ensuring the forecasting of susceptible interventions [16]. Population dynamics of mosquito species are substantially diverse with regards to the species’ biology, climatic settings that is rainfall, temperature and season, water management, execution of mosquito control interventions and site usage [17].
For essential operational vector control programs execution, there must be an adequate entomological capability and surveillance which could create vigorous entomological acumen to champion policymaking on specific local tailor-made, empirically-based and less costly vector control interventions. Vector-borne diseases monitoring is very key and offers significant knowledge about vector species, their categorical population dynamics, and behavioural characters which can influence the malaria infection transmission, intervention efficacy, and residual transmission. This acumen directs strategies choice and placement interval, period and gives a podium to appraise supplementary approaches and methods. In elimination situations, entomological surveillance befits progressive essential in foci of transmission targeting and eliminating areas of residual transmission [18].
Larval control must be included as part of a central chunk of integrated vector management (IVM) programmes with the ultimate goal of malaria elimination in the long term. Consequently, the importance of employment of larval control strategies in malaria control has received much attention and consideration lately [19]. Understanding the ecological features of the breeding habitats as well as the environmental influences affecting mosquito population density could aid in planning optimum vector control strategies [4].
Malaria is prevalent in tropical and subtropical continents comprising greatly of Sub-Saharan Africa, Asia, and the Americas. The highest period of malaria transmission transpires in the course of the rainy season which corresponds with farming activities like planting and harvesting. Malaria hinders these essential industrious schedules intimidate individuals and family lively-hood, as well as approaching developmental plans when a great chunk of the human resource is affected by the infection [20].
[21] expounded that, malaria widespread could largely be considered as a disruption of a formerly prevailing epidemiological balance. For example, malaria prevalence could arise as results of dam construction for agricultural purposes including irrigation that seems to change extensively the indigenous environment thereby affecting ecosystem function. Moreover, epidemic could arise wherever mass relocation of fractional or vulnerable populaces into region of greater endemicity following political and economic insecurity. Intermittently, epidemics transpire through important or attack of an unusual vector species into an area, in so doing fluctuating the vector capability of indigenous transmission. Nonetheless, commonest causative element in malaria epidemics is abnormal climatological settings which momentarily alter the environmental balance among human host and parasite.
[22], pointed out that, since environmental factors play key important role in maintaining malaria transmission, the infection could be introduced or reintroduced in regions where there is substantial alteration in the environment. Flagship national economic development plans and agendas such as agriculture activities (e.g. irrigation, farming), construction of roads, minerals exploitation provides conducive environment for malaria transmission as a results of creation of fresh vector breeding sites (habitats) and affects under-five mortality and morbidity in known malarious communities. Furthermore, malaria that arise from anthropogenic activities together with insecticide and drug resistance and the declining of malaria control effort has resulted in reappearance of the infection among several countries globally. The frequently upsurge of malaria prevalence had been affirmed from the Amazon region of South America, Ethiopia, Madagascar, Sri Lanka and Solomon Island. Formerly a major rural infection, malaria has now been a challenge in cities and pre-urban regions due to rapid urbanization in the developing world. The unswerving costs of malaria are economic loss, cost of treatment and expenditure on hospital visitations had assisted the high incidence of malaria.
Implementation of environmental management and sanitation, biological and chemical control measures by 1984 such as flushing of temporal ponds,, trimming of tree holes, clearing of weeds, removal of water receptacles and containers, application of larvicides on swampy and marshes areas such as kerosene, dichloro-diphenyl-trichloroethane (DDT), indoor residual or aerosol spraying, screening of windows of houses and use of mosquito coils almost brought about the disappearance or elimination of Anopheles funestus breeding sites (habitats) and adult mosquitoes in Accra, Ghana [23].
Street cleansing, unswerving and consistent street cleansing system that eliminates unwanted water-habouring receptacles and cleans drainage systems by entrusting that these facilities does not turn out to be still (stagnant) thereby resulting to mosquitoes breeding would assist in helping to decrease larval habitats of malarial vector (mosquito) by eliminating the source of some urban vectors. Construction of structures, in the course of development and erection of houses and as well as additional groundwork, such as urban restoration systems, and over laws and guidelines, occasions arise to modify prospective larval habitations of built-up disease vectors such as malarial vector (mosquito). Interestingly, with reviewed laws in Singapore, roof gutters are not allowed on houses in new projects due to the difficult in accessing and maintaining them regularly. In addition, landlords are obliged to get rid of prevailing gutters on their premises if they are unable to maintain them satisfactorily [24].
According to [25], poor sanitation situation has been understood to be a perilous environmental health difficulty with regards to morbidity and mortality globally. It is a known fact that, the transmission of vector-borne diseases such as malaria and dengue fever is connected to poor disposal of solid wastes [26]. According to [27], several researchers have accredited the incidences of parasites, cholera, malaria and diarrhoea among African towns to poor sanitary settings as a result of the indiscriminate disposal of waste.
This current study was conducted with the aim to virtually sampled mosquito laraval habitats (breeding sites) and morphologically identify mosquito species of medical importance, their population density and dynamics as well as prevalence within the Sunyani Municipality, in the Bono region of Ghana. Data obained from the study is envisaged to greatly assist in the design, planning and excution and monitoring of mosquito vector control programmes in the study areas due to the recent outbreak of yellow fever and endemicity of malaria as the leading cause of disease in this region according to the Bono Regional Health Directorate (BRHD) Annual Reports.