Is the presence of mosquitoes an indicator of poor environmental sanitation?

Living organisms such as bacteria, plankton, plants, and animals can be bio-indicators and they can be used to examine the condition of the environment's typical ecosystem. They are engaged to appraise the condition of the surroundings and biogeographic variations that are happening (Parmar et al. 2016; Khatri et al. 2017). Major mosquito habitats are often located adjacent to community areas, notably residential areas. According to earlier entomological investigations, some dengue vectors have been found in forested spaces (Vezzani et al. 2005; Hayden et al. 2010), marshy swamps (Sarfraz et al. 2012), and brackish lakes (Ramasamy et al. 2011; Idris et al. 2013). The value of insects in the monitoring and evaluation of environmental contamination was highlighted by Parikh et al. (2020).

Due to the environmental conditions, whether indoors or outdoors, residential areas are typically a prospective source for the establishment of breeding sites (Azura et al. 2021). The existence of stark disparities, which reduces political attention to enhancing hygienic settings in underdeveloped regions, is a factor driving Zika outbreaks. Residents are always in danger from dengue and malaria, two vector-borne diseases, because of water collection near their homes (Sharma et al. 2021). Arbovirus epidemics are widespread issues that result from particular ways in which people interact with their environment (Valle et al. 2016).

The abundance and composition of many species of mosquitoes are significantly impacted by the environmental changes (Figure 4) brought on by human activity (Ferraguti et al. 2016). Artificial recipients, such as rain catch basins, water storage containers, old tires, flower vases, and tins, have emerged as the primary breeding grounds for invasive species like Aedes albopictus and the common yellow fever mosquito Aedes aegypti in urban settings. Mosquito hotspots typically develop under ideal circumstances: in areas with lots of breeding habitats, lots of human hosts, and little mosquito control (LaDeau et al. 2013). Ae. albopictus and Ae. aegypti are anthropophilic biting insects that can breed in a range of human-made habitats, including areas with uncontrolled vegetation, rubbish, decaying structures, and insufficient sewerage (Figure 4). Therefore, it is essential for disease vector management and elimination need to comprehend household risk variables that are linked to a decrease in indoor mosquito bites and disease transmission in various contexts (Lwetoijera et al. 2013).

Larson et al. (2005) reported that urban landscapes frequently receive greater water additions than wild landscapes, which promotes mosquito breeding and survival. For instance, urban mosquitoes exploit human-made objects and structures like abandoned tires and flowerpots that contain water, frequently choosing these artificial breeding locations over ones that are found in nature (Keating et al. 2004; Wilke et al. 2020). Additionally, human-made bodies of water frequently lack natural mosquito predators. Other aspects of cities that are favorable to mosquitoes include the urban heat island (Townroe & Callaghan 2014; Akhtar et al. 2016). Living in the poorest residences in unhygienic environments increases the chances of being exposed to vector-transmitted diseases, it has been discovered that house types and other factors have a profound impact on the incidence of vector-borne diseases (Uttah 2013).

In the past 20 years, there has been a major upsurge in the number of studies examining the relationship between environmental degradation and infectious diseases (Gottdenker et al. 2014). Urbanization growth, inadequate or nonexistent drainage facilities, and the disorganized placement of homes and factories in most towns all have an impact on the mosquito population and the severity of dengue transmission. Despite the unfavorable environmental situations brought on by standing pools of water, poor sanitation, and other factors, open-air dumpsites typically serve as significant mosquito breeding grounds (Cruvinel et al. 2020).

Most arboviruses are maintained in complex sylvatic cycles that involve mosquitoes and vertebrates that live in forests and are considered reservoirs, such as birds, small mammals, and nonhuman primates. Humans can interfere with those cycles due to their anthropogenic activities and cause the spread of zoonotic diseases, and consequently, viral adaptation can give rise to urban cycles and epidemics. There is mounting proof that certain infectious diseases can be transmitted more easily due to deforestation since it alters the ecology of the vectors (Morris et al. 2016; Burkett-Cadena & Vittor 2018).

The impact of poor environmental sanitation on the dispersion and quantity of mosquitoes has not received much attention in the literature. While there have been several programs to educate the public about the connection between poor environmental sanitation and the spread of diseases carried by mosquitoes in developed nations like the USA, there have been relatively few campaigns in developing and undeveloped nations. The objective of this paper is to increase public awareness of the need for public participation in mosquito control and to explore that necessity.

Publications indexed in PubMed, Google Scholar, and ResearchGate were examined. Included in the list of search keywords are ‘mosquito,’ ‘Aedes,’ ‘Culex,’ ‘Anopheles,’ ‘Mosquito-borne diseases,’ ‘malaria,’ ‘yellow fever,’ ‘dengue,’ ‘West Nile,’ ‘Zika,’ ‘chikungunya,’ ‘environment,’ ‘sanitation,’ ‘housing,’, ‘mosquito control’, and ‘breeding sites’.

English was used for the search. Posters, conference abstracts, and short communications were not taken into consideration; only original research works with quantitative analysis and reviews were taken into account. Only open-access papers were reviewed.

The reason behind selecting the databases is that they are relatively simple to use, they allow users to search for a wide variety of materials and they are more up-to-date.

A total of 150 articles met the inclusion criteria and were used for this study. Accordingly, 51 papers were from PubMed, 98 from Google Scholar, and 1 from ResearchGate.

A significant correlation between climate change, temperature, rainfall, landscape, land use, and MBD transmission was found, using the BODMAS procedure, to be 16.6% of these publications.

The three mosquito genera (Aedes, Culex, and Anopheles) and environmental elements such as illegal dumps, water storages, sewage, cemeteries, and human movement were found to be associated with MBDs such as malaria.

The state of housing conditions as a risk factor for encountering MBDs was discussed in 20% of the publications. Artificial containers, tree holes, freshwater ditches, ponds, drains, and gutters as breeding sites for mosquitoes were stated by 26.7% of the publications. Meanwhile, 11.3% of respondents discussed cemeteries as a potential risk for MBDs.

Insects were only recognized as indicators of environmental degradation in 2.7% of the papers. MBD prevention, mosquito transmission dynamics, and the link between nutritional and architectural risk factors were explored by 4.0% of the studies. Another 4.7% of the papers brought up the relationship between locals’ exposure to mosquitoes and related ailments and forest degradation/vegetation.

During the 2012 dengue outbreak in Ecuador, poor housing conditions and the percentage of households receiving remittances were the two main risk factors for both the presence and an elevated burden of dengue (Lippi et al. 2018). According to Ningsih et al. (2016) findings, an indoor cement water tub with well water as the water supply was the most conducive microhabitat for Aedes larvae.

As stated by Lwetoijera et al. (2013), some house characteristics affect the density of malaria vectors and the danger of disease transmission indoors that goes along with it. Additionally, as stated by Morakinyo et al. (2018), improved housing offers a promising way to support a more comprehensive and long-term strategy for combating MBDs.

Homes in underprivileged areas, which are generally in poor conditions such as lack of environmental sanitation, appear to be built in a way that allows for a greater relative humidity and, as a result, a more hospitable environment for adult Ae. aegypti mosquitoes. Additionally, there are more breeding locations and environmental factors that can help adult forms of Ae. aegypti survive. This results in more water being stored in containers because the piped water supply is inconsistent (Caprara et al. 2009). In agreement with other studies, Liu et al. (2014) found a link between the prevalence of malaria and housing quality.

According to Chirebvu et al. (2014), homesteads’ proximity to mosquito breeding grounds exposed people to mosquito bites. Additionally, the Yibikon et al. (2020) investigation discovered that residents who lived close to the breeding location had a higher likelihood of contracting malaria.

While Madewell et al. (2019) emphasized the significance of curricula that consider neighborhood-level threats and mitigation plans when advocating for the prevention of vector-borne diseases.

In a study published in 2019, Ngatu et al. (Ngatu et al. 2019) found that household size, WASH (water, sanitation, and hygiene) status, and rural site were the main factors linked to malaria. This study, which was conducted in Congolese households, revealed a high incidence of malaria in a setting of extreme poverty. Because environmental factors found inside tires are closely linked to larval survival, determining all the factors relevant to species composition will be a significant task for eventually understanding patterns of disease transmission (Yee et al. 2010) because tires are anticipated to continue to be a habitat for larvae of disease-carrying mosquitoes soon (Yee 2008).

Additionally, this study found that ineffective waste management was certainly a factor in the probable source of Aedes reproduction (Kamari et al. 2021). It is anticipated that if these wastes are produced and improperly managed, there will continue to be a risk of increasing mosquito breeding, especially of Aedes species. The most significant risk factor for the prevalence and abundance of the arbovirus vectors Ae. aegypti and Ae. bromeliae at hotel compounds examined in this study (Kampango et al. 2021) is the unmanaged solid waste from artificial and natural sources. Therefore, these household wastes should be the primary focus of effective Aedes population intervention in tropical nations (Banerjee et al. 2013). As reported by Abeyewickreme et al. (2012), successful and long-lasting dengue control requires increasing household responsibility for targeted vector treatments.

Alemu et al. (2011) stated that living close to possible mosquito breeding sites was positively correlated with the incidence of malaria. This finding suggests that human activity has a significant role in urban malaria, including the establishment of breeding grounds. To reduce malaria morbidity and mortality in the town, it is essential to raise knowledge about the proper use of insecticide-treated nets (ITNs) and to mobilize the community to change the environment. In places where there is a risk of MBDs or where there is a mosquito nuisance, Ensinka et al. (2007) recommended that vegetation management, upkeep of the concrete structures, and waste inflow to waste stabilization ponds be enhanced.

The results of Hasnan et al. (2017) suggest that the Aedes mosquito's breeding habitat is influenced by the local environment, such as stagnant water. The dengue disease outbreak can be permanently stopped by improving environmental conditions (Hasnan et al. 2017).

Kibret et al. (2018) reported that water level management could be used to suppress malaria mosquitoes in big reservoirs. Lower mosquito larval abundance is correlated with faster water drawdown rates, which ultimately lowers the risk of malaria for populations of people living near reservoirs. The study by Souza et al. (2017) shows how a straightforward storm drain modification can significantly reduce water retention and, as a result, have an impact on Ae. aegypti larval numbers.

A crucial component of any vector control program's surveillance should be how the community views a vector and the risk of disease transmission it carries (Juarez et al. 2021). Brown et al. (2021) concluded that understanding people's perceptions of mosquito abundance may permit improved management practices for mosquito populations.

Adeleke et al. (2013) concluded that the state government must maintain environmental sanitation and management to lower the incidence of MBDs. Additionally, residents should be made aware of mosquito breeding grounds and the necessity of getting rid of them. To prevent diseases, control the population, and stop the vector spread to urban areas in southern regions, Ruggerio et al. (2021) came to the same conclusion that governments and the community needed to be included in an active health strategy and a sustained commitment.

Currently, 6.01 billion people reside in places where the Ae. aegypti mosquito can spread disease (Ryan et al. 2019). Despite the circumstance that environmental sanitation is an essential component of mosquito nuisance prevention, little research has been done to-date on the connection between mosquito abundance, diversity, and disease transmission risk and how these factors relate to environmental sanitation at the household level.

Understanding the environmental influences underlying the circulation, abundance, and species composition of mosquito vector species – factors that eventually regulate the dispersal of vector-borne pathogens and play an important role in explaining the risk of pathogen transmission – will help us better understand the complexities of MBD risk (Lambin et al. 2010). For reproduction, mosquitoes require access to standing water. Using the neighborhood as the aggregate unit, vegetation coverage was positively associated with dengue in 2008–2009. At the more precise ‘block of home’ aggregation scale, it was associated with decreased incidence.

At both extensive and fine scales, shrubs and trees may have a sway on the spatial distribution and abundance of Culex larvae. At the neighborhood-level, the main street tree genus may have significant effects on larval production. For example, neighborhoods with great concentrations of oak trees may have lower mosquito populations because the tannins in oak leaves are toxic to mosquito larvae and pupae (Rey et al. 2000). Because they serve as resting places for both adult mosquitoes and the birds that serve as their blood meal hosts, trees and shrubs play a role in local mosquito dispersal by inducing gravid females to oviposit in neighboring catch basins and other nearby aquatic environments (Gardner et al. 2013). In Panama, Boshell discovered in 1940 that a forest with minor tree removal allowed for the capture of more Haemagogus mosquitoes (Bates 1944). The idea that differing leaf species in the aquatic environment affect mosquito production and longevity of the subsequent adult stage was supported by Muturi et al. (2012)'s study.

According to Brown et al. (2008), vegetation cover, demographic traits, and the layout of residential areas are all associated with adult Culex mosquito numbers and infection prevalence (Ruiz et al. 2004). A mosquito disposal route to community areas is provided by vegetation between the community area and the mosquito breeding place (Azura et al. 2021). When summer temperatures are high, the presence of plants helps prevent mosquito larva development, boosting survivability in an otherwise hostile environment (Yee 2008; Yang et al. 2019). Unkempt vegetation can also give male and female mosquitoes food supplies (such as plant sap, nectar, or honeydew) and resting places (Zhao et al. 2020). As stated by Castro et al. (2010), there was a favorable correlation between vegetation and the presence of mosquito larvae.

Artificially creating water sources has a cost in that it makes it more likely that mosquitoes will reproduce and spread diseases. The construction of dams, the creation of artificial wetlands, and agricultural irrigation are just a few examples of how changes to water resources may enhance mosquito reproduction and affect the spread of diseases linked with it (Jardine et al. 2008). The volume of water, containers’ size, site, container color, vegetation cover, water chemical characteristics, water surfaces size, material type, solar exposition, temperature, organic matter, detritus, micro-organisms, and intra- and inter-specific competition, among other things, all play a role in the choice of vessels or survivorships of larvae or pupae in culicids (Vezzani 2007; Getachew et al. 2015; Rey & Lounibos 2015). By drastically reducing the number of larvae that will eventually become adults, larval management is an effective method of lowering mosquito concentrations (Adeleke et al. 2008).

By destroying habitats, polluting the ecosystem with nutrients, and using agrochemicals, humans are changing the environment at previously unheard-of rates (Figure 4). This has lately been postulated to function as a possibly important driver of disease-vectoring mosquito species that pose a risk to human and animal health (Schrama et al. 2020).

Given that mature Aedes and Culex mosquitoes, such as Ae. aegypti, can disperse up-to several meters, González et al. (2019) emphasized the significance of cemeteries as centers with large densities of vector species.

Urbanization is a factor that may surge the quantity of Aedes mosquito-favored habitats, resulting in a rise in Aedes mosquito density and survival, particularly in residential areas (Saleeza et al. 2011). Even after adjusting for socioeconomic inequalities and preventive behaviors, this analysis of the risk variables for malaria in young children reveals that urbanization and housing materials, such as house screening and ceiling installation, may have some role in reducing risk (Liu et al. 2014).

The northeastern regions of Brazil were plagued with Aedes in January 2016, so the Brazilian government dispatched more than 200,000 soldiers there. In a big effort to stop the spread of this mosquito and show the administration's involvement in the Zika problem, the troops went from family to family, scattered insecticides, and made an effort to eradicate potential breeding sites for Aedes (Löwy 2017).

Wetlands have profuse inhabitant and wandering bird and mosquito populations coinciding in space and time (BØgh et al. 2007; Ezenwa et al. 2007), building them vital ecosystems for the enzootic cycles of West Nile Virus transmission (Roiz et al. 2015).

Increases in the trash and other rubbish (Figure 4), which are more prevalent in low-income areas and act as mosquito breeding grounds, may be related to the association between income and perceptions of mosquitoes as a problem (LaDeau et al. 2013). One of the most effective predictors of whether people convey mosquitoes as a problem is how filthy they think their communities are. Trash and waste are breeding grounds for mosquitoes in many metropolitan areas, which increases their population (LaDeau et al. 2013; Wilke et al. 2020).

First off, this topic is not sufficiently geographically represented (Table 1), which would have given it a more accurate context. Second, there is a lack of specificity about an environmental sanitation-related MBD and its vector.

The breeding behaviors of mosquitoes, particularly Ae. aegypti and Ae. albopictus, must be thoroughly understood to manage mosquitoes in residential settings. The use of plastic, polystyrene containers, such as cups and bottles, and tin cans are becoming more frequent in modern communities. The number of containers available for mosquito breeding may grow as a result of improper disposal (Figure 4) or littering of these materials (Azura et al. 2021). Proper disposal methods for these materials must be applied.

Adding water crystals to flower vases can prevent water from stacking up. Vases can also be treated with a specific substance that transforms water into a gel to keep flowers fresh and inhibit mosquito growth (González et al. 2019). Through home repair and screening, current treatments with environmental management and socioeconomic development can be combined to offer a noninsecticidal, complementary method of enhancing resistance to mosquito bites (Baragatti et al. 2009; Graves et al. 2009).

Debris removal and routine inspection, when done continuously, minimize breeding in such places, as does the application of larvicide, the removal of surface waters from productive sites, adjusting the water level along the shoreline, and flooding areas where mosquitoes lay their eggs in the soil.

Anti-vector interventions like ITN and indoor residual spraying (IRS) should be made available to communities at risk to scale up the malaria program, together with the deployment of recurring WASH initiatives in residential areas (Maitland 2016). This could potentially result in effective malaria control (Ngatu et al. 2019). To reduce human-vector interaction, it is crucial to promote the proper use of long-lasting insecticidal nets at adult stages. This, along with community-level health promotion education that teaches people how to control mosquitoes, will help communities prevent the spread of disease (Mwangangi et al. 2012). Communities should be taught environmental management techniques such as draining and filling during the immature stages. They may also utilize larvicides like Bacillus thuringiensis var. Israelensis, which primarily targets Anopheline and Culicine habitats, as larvicides. Additionally, the Aedes populations will be controlled by sealing the water storage containers inside the dwellings and properly discarding containers inside the homesteads (Mwangangi et al. 2012).

To establish long-term control of malaria, the focus should be placed on eliminating mosquito breeding areas in the community. Health education regarding malaria control should be reinforced, particularly through the training and retraining of community health volunteers (Bamidele et al. 2012). To reduce Ae. aegypti populations, community involvement through sensitization, public awareness of the disease, and the best practices of water preservation and disposal of tires and containers would be crucial (Lutomiah et al. 2016).

In sub-Saharan Africa, housing quality is a significant risk factor for malaria in a variety of transmission environments. The gradual development of African housing in conjunction with socioeconomic progress should be viewed as having a significant potential to lower malaria transmission and as a promising approach to help the continent achieve and maintain malaria elimination over the long term (Tusting et al. 2017). By hindering host-seeking behavior, elevating homes on stilts can also decrease mosquito house entry (Hiscox et al. 2013).

Coagulation–flocculation technology was suggested as a novel strategy for a long-lasting, minimally disruptive solution to mosquito control by Ran et al. (2020). In the laboratory, chlorine-free tap water was treated with polyaluminum chloride. The oviposition fondness of Culex pipiens, the emerging mosquito eggs, and the survival amount of mosquito larvae were observed, and the pupa population was recorded on a daily basis. This method could efficiently kill early-stage larvae instars by reducing the amount of food available to larvae.

Poor sanitation is the main factor promoting the presence of mosquitoes in a location. The environmental factors of a place, such as vegetation cover, waste and tire disposal, housing conditions, and poor sewage and garbage disposal, affect whether mosquitoes are more or less likely to spread. Although there are additional factors outside environmental sanitation that affect the presence or absence of these disease vectors, such as climate change, migration, and insecticide resistance, this paper does not cover them all.

To stop the proliferation of mosquitoes, residents, the general public, and health professionals must collaborate. Maintaining good environmental sanitation will aid in reducing mosquito populations and the illnesses they carry.

Through environmental management, reducing aquatic habitats (breeding sites) decreases the spread of MBD, the appearance of host-seeking mosquitoes, and the time needed for vectors to find oviposition sites (Gu et al. 2006). Communities would be safer from MBDs if integrated vector and pest management strategies successfully incorporated environmental changes as a method of controlling pests (Lizzi et al. 2014).

This work was funded by the author's resources.

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.