Abundance Of Malaria Vectors Research Articles

The efficacy of attractive targeted sugar baits in reducing malaria vector abundance in low-endemicity settings of northwest Mali

BackgroundAttractive targeted sugar baits (ATSBs) have the potential to significantly reduce infective female Anopheles mosquitoes in arid areas, such as in Northern Mali. Malaria is epidemic in the north due to the limited viability of Anopheles species in the desert climate.The goal of this study was to determine of the effect of ATSB on the number of older female An. gambiae and on the number of sporozoite-positive females in villages in northern Mali.MethodsVillages were located in the north of Mali. In this study, 5677 ATSB stations were deployed, two on each home, in ten villages during late July and early August 2019. Ten villages served as controls. After a pre-treatment monitoring period in July, An. gambiae populations were monitored again from August to December using CDC-UV light traps, pyrethrum spray catches (PSC), and human landing catches (HLC). Mosquitoes were dissected to estimate their age, while ELISA detected sporozoite positivity. The monthly entomological inoculation rates (EIRs) were calculated for HLC indoors and outdoors. Data from villages were compared using t-tests, while bait station weighted density versus amount of collected females was checked with a Pearson’s correlation.ResultsA total of 2703 female An. gambiae were caught from treated villages, 4582 from control villages, a 41.0% difference. Dissection of 1759 females showed that ATSB significantly reduced the number of older females. The proportion of older females in treated villages was 0.93% compared to 9.4% in control villages. ELISA analysis of 7285 females showed that bait stations reduced the number of sporozoite-positive females. The infective females in treated villages was 0.30% compared to 2.73% in the controls. The greater the density of bait stations deployed, the fewer the older, infective females (P < 0.05).EIRs were low in control villages except in months when An. gambiae populations were high. EIRs in ATSB placement villages remained zero. Significant reductions (P < 0.0001) in An. gambiae males were observed.ConclusionsBait stations reduced all measures of vector populations in this study. In a low-transmission setting, ATSB has the potential to greatly reduce malaria.

Landscape and meteorological determinants of malaria vectors' presence and abundance in the rural health district of Korhogo, Côte d'Ivoire, 2016-2018, and comparison with the less anthropized area of Diébougou, Burkina Faso.

Understanding how weather and landscape shape the fine-scale distribution and diversity of malaria vectors is crucial for efficient and locally tailored vector control. This study examines the meteorological and landscape determinants of (i) the spatiotemporal distribution (presence and abundance) of the major malaria vectors in the rural region of Korhogo (northern Côte d'Ivoire) and (ii) the differences in vector probability of presence, abundance, and diversity observed between that area and another rural West African region located 300 km away in Diébougou, Burkina Faso. We monitored Anopheles human-biting activity in 28 villages of the Korhogo health district for 18 months (2016 to 2018), and extracted fine-scale environmental variables (meteorological and landscape) from high-resolution satellite imagery. We used a state-of-the-art statistical modeling framework to associate these data and identify environmental determinants of the presence and abundance of malaria vectors in the area. We then compared the results of this analysis with those of a similar, previously published study conducted in the Diébougou area. The spatiotemporal distribution of malaria vectors in the Korhogo area was highly heterogeneous and appeared to be strongly determined and constrained by meteorological conditions. Rice paddies, temporary sites filled by rainfall, rivers and riparian forests appeared to be the larval habitats of Anopheles mosquitoes. As in Diébougou, meteorological conditions (temperatures, rainfall) appeared to significantly affect all developmental stages of the mosquitoes. Additionally, ligneous savannas were associated with lower abundance of malaria vectors. Anopheles species diversity was lower in Korhogo compared to Diébougou, while biting rates were much higher. Our results suggest that these differences may be due to the more anthropized nature of the Korhogo region in comparison to Diébougou (less forested areas, more agricultural land), supporting the hypothesis of higher malaria vector densities and lower mosquito diversity in more anthropized landscapes in rural West Africa. This study offers valuable insights into the landscape and meteorological determinants of the spatiotemporal distribution of malaria vectors in the Korhogo region and, more broadly, in rural west-Africa. The results emphasize the adverse effects of the ongoing landscape anthropization process in the sub-region, including deforestation and agricultural development, on malaria vector control.

Abundance and characterization of malaria vectors in Sakassou, Central Côte d’Ivoire

Abundance and characterization of malaria vectors in Sakassou, Central Côte d’Ivoire

Malaria transmission heterogeneity in different eco-epidemiological areas of western Kenya: a region-wide observational and risk classification study for adaptive intervention planning

BackgroundUnderstanding of malaria ecology is a prerequisite for designing locally adapted control strategies in resource-limited settings. The aim of this study was to utilize the spatial heterogeneity in malaria transmission for the designing of adaptive interventions.MethodsField collections of clinical malaria incidence, asymptomatic Plasmodium infection, and malaria vector data were conducted from 108 randomly selected clusters which covered different landscape settings including irrigated farming, seasonal flooding area, lowland dryland farming, and highlands in western Kenya. Spatial heterogeneity of malaria was analyzed and classified into different eco-epidemiological zones.ResultsThere was strong heterogeneity and detected hot/cold spots in clinical malaria incidence, Plasmodium prevalence, and vector abundance. The study area was classified into four zones based on clinical malaria incidence, parasite prevalence, vector density, and altitude. The two irrigated zones have either the highest malaria incidence, parasite prevalence, or the highest malaria vector density; the highlands have the lowest vector density and parasite prevalence; and the dryland and flooding area have the average clinical malaria incidence, parasite prevalence and vector density. Different zones have different vector species, species compositions and predominant species. Both indoor and outdoor transmission may have contributed to the malaria transmission in the area. Anopheles gambiae sensu stricto (s.s.), Anopheles arabiensis, Anopheles funestus s.s., and Anopheles leesoni had similar human blood index and malaria parasite sporozoite rate.ConclusionThe multi-transmission-indicator-based eco-epidemiological zone classifications will be helpful for making decisions on locally adapted malaria interventions.

Characterization of environmental drivers influencing the abundance of Anopheles maculipennis complex in Northern Italy

BackgroundIn Italy, malaria was endemic until the 1970s, when it was declared eradicated by WHO. Nowadays, with the persistence of competent mosquito populations, the effect of climate change, and increased possibility of importing malaria parasites from endemic counties due to growing migration, a malaria resurgence in Italy has become more likely. Hence, enhancing the understanding of the current distribution of the Anopheles maculipennis complex and the factors that influence the presence of this malaria vector is crucial, especially in Northern Italy, characterised by a high density of both human population and livestock.MethodsTo assess the presence and abundance of malaria vectors, a 4-year field survey in the plain areas of Lombardy and Emilia-Romagna region in Italy was conducted. Every sampling point was characterised in space by the land use in a 500-m radius and in time considering meteorological data collected in the short and long time periods before sampling. We combined the results of a linear regression model with a random forest analysis to understand the relative importance of the investigated niche dimensions in determining Anopheles mosquito presence and abundance.ResultsThe estimated normalised variable importance indicates that rice fields were the most important land use class explaining the presence of Anopheles, followed by transitional woodlands and shrubland. Farm buildings were the third variable in terms of importance, likely because of the presence of animal shelters, followed by urbanised land. The two most important meteorological variables influencing the abundance of Anopheles in our study area were mean temperature in the 24 h before the sampling date and the sum of degree-days with temperature between 18 °C and 30 °C in the 14 days before the sampling date.ConclusionsThe results obtained in this study could be helpful in predicting the risk of autochthonous malaria transmission, based on local information on land cover classes that might facilitate the presence of malaria vectors and presence of short- and medium-term meteorological conditions favourable to mosquito development and activity. The results can support the design of vector control measures through environmental management.Graphical

Dynamics of malaria vector composition and Plasmodium falciparum infection in mainland Tanzania: 2017–2021 data from the national malaria vector entomological surveillance

BackgroundIn 2015, Tanzania National Malaria Control Programme (NMCP) established a longitudinal malaria vector entomological surveillance (MVES). The MVES is aimed at a periodical assessment of malaria vector composition and abundance, feeding and resting behaviours, and Plasmodium falciparum infection in different malaria epidemiological strata to guide the NMCP on the deployment of appropriate malaria vector interventions. This work details the dynamics of malaria vector composition and transmission in different malaria epidemiological strata.MethodsThe MVES was conducted from 32 sentinel district councils across the country. Mosquitoes were collected by the trained community members and supervised by the NMCP and research institutions. Three consecutive night catches (indoor collection with CDC light trap and indoor/outdoor collection using bucket traps) were conducted monthly in three different households selected randomly from two to three wards within each district council. Collected mosquitoes were sorted and morphologically identified in the field. Thereafter, the samples were sent to the laboratory for molecular characterization using qPCR for species identification and detection of P. falciparum infections (sporozoites). ELISA technique was deployed for blood meal analysis from samples of blood-fed mosquitoes to determine the blood meal indices (BMI).ResultsA total of 63,226 mosquitoes were collected in 32 district councils from January 2017 to December 2021. Out of which, 39,279 (62%), 20,983 (33%) and 2964 (5%) were morphologically identified as Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l., and as other Anopheles species, respectively. Out of 28,795 laboratory amplified mosquitoes, 13,645 (47%) were confirmed to be Anopheles arabiensis, 9904 (34%) as An. funestus sensu stricto (s.s.), and 5193 (19%) as An. gambiae s.s. The combined average entomological inoculation rates (EIR) were 0.46 (95% CI 0.028–0.928) for An. gambiae s.s., 0.836 (95% CI 0.138–1.559) for An. arabiensis, and 0.58 (95% CI 0.165–0.971) for An. funestus s.s. with variations across different malaria transmission strata. Anopheles funestus s.s. and An. arabiensis were predominant in the Lake and South-Eastern zones, respectively, mostly in high malaria transmission areas. Monthly mosquito densities displayed seasonal patterns, with two peaks following the rainy seasons, varying slightly across species and district councils.ConclusionAnopheles arabiensis remains the predominant vector species followed by An. funestus s.s. in the country. Therefore, strengthening integrated vector management including larval source management is recommended to address outdoor transmission by An. arabiensis to interrupt transmission particularly where EIR is greater than the required elimination threshold of less than one (< 1) to substantially reduce the prevalence of malaria infection.

Impact of urbanization on the abundance and distribution of Anophelines population in Ghaziabad district, Uttar Pradesh, India.

In urban areas, upsurge in population has resulted in more breeding sites for malaria vectors, and hence this scenario potentially undermine malaria elimination and control programs. The change in land use due to urbanization may result in the presence and distribution of malaria vectors. Understanding potential malaria vectors is essential for current and future malaria transmission control strategies. This study investigated the effects of rapid urbanization on malaria vectors An. culicifacies s.l. and An. stephensi L. in Ghaziabad district. Ghaziabad district which presents several levels of urbanization was selected for this study. Entomological investigations were conducted seasonally from 2014-2016 in the rural, urban, and peri-urban regions. Vector incrimination study was done using ELISA (confirmation by PCR) on suspected Anopheles vectors viz. An. culicifacies, An. stephensi, An. annularis and An. subpictus. An. culicifacies showed alteration in distribution influenced by rural and agricultural land whereas An. stephensi was found to be influenced by artificial habitats and population growth. The study also confirms the association between the abundance of malaria vectors and land use change.

Species abundance and density of malaria vectors in Western Thailand and implications for disease transmission

Understanding the dynamics of malaria vectors and their interactions with environmental factors is crucial for effective malaria control. This study investigated the abundance, species composition, seasonal variations, and malaria infection status of female mosquitoes in malaria transmission and non-transmission areas in Western Thailand. Additionally, the susceptibility of malaria vectors to pyrethroid insecticides was assessed. Entomological field surveys were conducted during the hot, wet, and cold seasons in both malaria transmission areas (TA) and non-transmission areas (NTA). The abundance and species composition of malaria vectors were compared between TA and NTA. The availability of larval habitats and the impact of seasonality on vector abundance were analyzed. Infection with Plasmodium spp. in primary malaria vectors was determined using molecular techniques. Furthermore, the susceptibility of malaria vectors to pyrethroids was evaluated using the World Health Organization (WHO) susceptibility test. A total of 9799 female mosquitoes belonging to 54 species and 11 genera were collected using various trapping methods. The number of malaria vectors was significantly higher in TA compared to NTA (P < 0.001). Anopheles minimus and An. aconitus were the predominant species in TA, comprising over 50% and 30% of the total mosquitoes collected, respectively. Seasonality had a significant effect on the availability of larval habitats in both areas (P < 0.05) but did not impact the abundance of adult vectors (P > 0.05). The primary malaria vectors tested were not infected with Plasmodium spp. The WHO susceptibility test revealed high susceptibility of malaria vectors to pyrethroids, with mortality rates of 99–100% at discriminating concentrations. The higher abundance of malaria vectors in the transmission areas underscores the need for targeted control measures in these regions. The susceptibility of malaria vectors to pyrethroids suggests the continued effectiveness of this class of insecticides for vector control interventions. Other factors influencing malaria transmission risk in the study areas are discussed. These findings contribute to our understanding of malaria vectors and can inform evidence-based strategies for malaria control and elimination efforts in Western Thailand.

Spatial–temporal vector abundance and malaria transmission dynamics in Nchelenge and Lake Mweru islands, a region with a high burden of malaria in northern Zambia

BackgroundOver a decade of vector control by indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) distribution on the mainland, and only LLINs on islands had a minimal impact on disease burden in Nchelenge district, northern Zambia. Anopheles funestus and Anopheles gambiae are vectors known only from the mainland. Understanding vector bionomics in the district is necessary for planning and targeting effective vector control. This study aimed to provide information on abundance, seasonality, and Plasmodium falciparum sporozoite infectivity of malaria vectors in Nchelenge, including islands.MethodsMosquitoes were collected in 192 CDC indoor light traps set in 56 households between January 2015 and January 2016. Morphological and molecular species identifications and P. falciparum circumsporoites by ELISA were performed. Mosquito counts and relative abundances from the islands and mainland were compared, and household factors associated with vector counts were determined.ResultsA total of 5888 anophelines were collected during the study. Of these, 5,704 were female Anopheles funestus sensu lato (s.l.) and 248 female An. gambiae s.l. The highest proportion of An. funestus (n = 4090) was from Chisenga Island and An. gambiae (n = 174) was from Kilwa Island. The highest estimated counts per trap for An. funestus s.l. were from Chisenga island, (89.9, p < 0.001) and from the dry season (78.6, p < 001). For An. gambiae the highest counts per trap were from Kilwa island (3.1, p < 0.001) and the rainy season (2.5, p = 0.007). The highest estimated annual entomological inoculation rate was from Chisenga Island with 91.62 ib/p/y followed by Kilwa Island with 29.77 ib/p/yr, and then Mainland with 19.97 ib/p/yr.ConclusionsThere was varied species abundance and malaria transmission risk across sites and seasons. The risk of malaria transmission was perennial and higher on the islands. The minimal impact of vector control efforts on the mainland was evident, but limited overall. Vector control intervention coverage with effective tools needs to be extended to the islands to effectively control malaria transmission in Nchelenge district.

Determination of sporozoite infection rate of indoor resting female Anopheles mosquitoes in Gombe South, Gombe State, Nigeria

Infected female Anopheles mosquitoes are the culprits of malaria. The abundance and distribution of malaria vectors in communities contribute significantly in malaria transmission. Understanding the magnitude and intensity of sporozoite infection rates is very sensitive and powerful indices for describing the epidemiology of malaria which will aid in strategizing malaria control programme. The present study determines the sporozoite infection rates of female Anopheles mosquitoes in the four Local Government Areas (LGA) of Gombe South, Gombe State, Northeastern Nigeria. Mosquitoes were collected using Pyrethrum Spray Catch (PSC) and were dissected to check the presence of sporozoites. Out of the 1,860 female Anopheles mosquitoes dissected, 665(35.8%) were infected with sporozoites. The highest infection rate was observed from Kaltungo LGA 145(41.7%), followed by Billiri LGA 182(36.3%), and 205(35.4%) was recorded from Balanaga. The lowest infectivity rate was observed from Shongom LGA 133(30.9%), p&lt;0.005 which is highly significant statistically. With regards to monthly distribution of sporozoites, the highest infection rate was recorded in December (64.7%), January 60.0%, (64.5%), and August (60.7%) from Balanga, Billiri, Kaltungo and Shongom LGA respectively. Meanwhile the least was observed in July (2.8%), December (7.7%), April (20.0%), and March (11.6%) from Balanga, Billiri, Kaltungo and Shongom LGA respectively, p&lt;0.005 which is highly significant statistically. However, (0.0%) sporozoite infection was obtained in September and March from Billiri, Kaltungo and Shongom LGA respectively. The present study therefore recommends malaria vector control through community based efforts by destruction of mosquitoes breeding sites, use of insect’s repellents, environmental sanitation and application of oil in stagnant water in order to reduce vectors population.

Malaria Vector Abundance and Insecticides Susceptibility Status in Gidan-Yero Village, Sokoto State, Nigeria

Malaria Vector Abundance and Insecticides Susceptibility Status in Gidan-Yero Village, Sokoto State, Nigeria

Development of a Conceptual Framework for Integrated Vector Management in the Heterogeneous Malaria Ecosystem of Western Kenya Highlands

Malaria heterogeneity in the highlands is due to range of factors including seasonal weather changes, climate variability, land-use changes, topography, drug resistance, and malaria control programs. High coverage of long lasting insecticide treated nets is the basis of vector control in epidemic prone western Kenya highlands. Long lasting insecticide treated nets have effectively controlled malaria in the hypo-endemic zones, but not in meso-endemic and hyper-endemic zones where significant residue of transmission remains despite control efforts. Inadequate policy on integrated vector management application for ecologically heterogeneous ecosystems hinders effective malaria control. Advances in ecological and epidemiological studies have improved our understanding on vector distribution determinants and malaria transmission enabling us to effectively integrate indoor residual spraying into the existing long lasting insecticide treated nets programme. Data on malaria vector abundance and parasite prevalence for different malaria ecosystems within western Kenya highlands before and after mass insecticide treated bed-net distribution campaigns was gathered to assess the efficacy of the long lasting insecticide treated nets based control efforts. Field tests were carried out to determine the impact of combined indoor residual spray and long lasting insecticide treated nets on vector indoor resting densities in zones where insecticide treated nets alone had limited efficacy or zero efficacy was observed. Female An. gambiae s.l resting densities of 0.1 mosquitoes/ house/night were associated with a plasmodium falciparum (pf) prevalence rate of 10% or below. This observation enabled the development of a framework for the inclusion of indoor residual spray in integrated vector management with the suggestion that IRS should be applied in malaria eco-epidemiological zones where An. gambiae s.l resting densities exceeds 0.1 females/ house/ night. Similarly, only those houses with a resting density of 0.1 females An. gambiae s.l and above should be targeted during spraying. Such an approach would significantly reduce the cost associated with indoor residual spray and provides a rationale for judicious integration of indoor residual spray within existing long lasting insecticide treated nets control programmes.

Seasonal variation in abundance and blood meal sources of primary and secondary malaria vectors within Kilombero Valley, Southern Tanzania

BackgroundExisting control tools have significantly reduced malaria over the past two decades. However, progress has been stalled due to increased resistance in primary vectors and the increasing role of secondary vectors. This study aimed to investigate the impact of seasonal change on primary and secondary vector abundance and host preference. Understanding the impact of seasonal dynamics of primary and secondary vectors on disease transmission will inform effective strategies for vector management and control.MethodsVector abundance was measured through longitudinal collection of mosquitoes, conducted monthly during the wet and dry seasons, in Sagamaganga, a village in the Kilombero Valley, Tanzania. Mosquitoes were collected indoors using CDC light traps and backpack aspirators, and outdoors using resting buckets baited with cattle urine. In addition, a direct measure of host preference was taken monthly using human- and cattle-baited mosquito electrocuting traps. A host census was conducted to provide an indirect measure of host preference together with monthly blood meal source analysis. All collected mosquitoes were assayed for Plasmodium sporozoites.ResultsA total of 2828 anophelines were collected, of which 78.5% and 21.4%, were primary and secondary vectors, respectively. The abundance of the primary vectors, Anopheles arabiensis and Anopheles funestus, and of the secondary vectors varied seasonally. Indirect measures of host preference indicated that all vectors varied blood meal choice seasonally, with the direct measure confirming this for An. arabiensis. All anopheline mosquitoes tested negative for sporozoites.ConclusionsAt the study location, the abundance of both primary and secondary vectors changed seasonally. Indirect and direct measures of host preference demonstrated that An. arabiensis varied from being zoophilic to being more opportunistic during the wet and dry seasons. A similar trend was observed for the other vectors.Graphical

Exploratory studies of Anopheles species abundance in five selected communities of Emohua LGA, Rivers State

Malaria is one of the public health problems facing people in many parts of Nigeria. To effectively implement malaria control program, baseline studies of species abundance and their susceptibility status to insecticides is required. The aim of the study was to carry out baseline studies on malaria vectors, species abundance and susceptibility status of local malaria vectors in five communities in Emohua Local Government Area of Rivers State. Mosquito larvae were collected from different breeding sites, reared in the insectary and identified morphologically. Data collected were analyzed using SAS software and statistics software GraphPad Software. Spearman’s rank correlation coefficient (RHO) was used in comparing Indoor Resting Density (IRD) and Man Biting Rates (MBR). A Total of 1,415 adult indoor mosquitoes were caught comprising of two (2) genera. Of these, 87.21% were Anopheles gambiae s.l. and 12.79% were Culex spp. There was a statistical difference (p&lt;0.0001) in the distribution of Anopheles and Culex mosquitoes caught. The highest percentage of Anopheles mosquitoes were caught at Emohua 26.74%, followed by Rumuji 22.77%, Egbeda 21.96%, Akpabu 17.10% and the least was Elele 11.43%. Examination of their abdominal conditions to determine feeding frequency indicated that the average number of fed mosquitoes ranged from 0.17-15.13 with a peak of 15.13 in the month of September in Elele. There was a significant difference (p&lt;0.0001) in Indoor Resting Density (IRD) and Man Biting Rate (MBR) in the area. This study has contributed to the understanding of the distribution, composition and indoor resting behaviour of mosquito vectors in the study areas.

Vulnerability of populations to malaria after indoor residual spraying is withdrawn from areas where its use has previously been sustained: a protocol for a systematic review

IntroductionWith its proven effectiveness, indoor residual spraying (IRS) as a malaria vector control strategy forms one of the reliable vector control strategies, especially when at least 80% of the population...

Characterization of Breeding Habitats and Larval Abundance of Malaria Vectors across Selected Higher Education Institutions (HEIs), in Morogoro Region, Tanzania

Characterization of Breeding Habitats and Larval Abundance of Malaria Vectors across Selected Higher Education Institutions (HEIs), in Morogoro Region, Tanzania

Cattle-related risk factors for malaria in southwest Ethiopia: a cross-sectional study

BackgroundDespite the low to moderate intensity of malaria transmission present in Ethiopia, malaria is still a leading public health problem. Current vector control interventions, principally long-lasting insecticidal nets and indoor residual spraying, when deployed alone or in combination, are insufficient to control the dominant vector species due to their exophagic and exophilic tendencies. Zooprophylaxis presents a potential supplementary vector control method for malaria; however, supporting evidence for its efficacy has been mixed.MethodsTo identify risk factors of malaria and to estimate the association between cattle and Anopheles vector abundance as well as malaria risk, a cross-sectional study was conducted in a village near Arba Minch, Ethiopia. Epidemiological surveys (households = 95, individuals = 463), mosquito collections using CDC light traps and a census of cattle and human populations were conducted. To capture environmental conditions, land cover and water bodies were mapped using satellite imagery. Risk factor analyses were performed through logistic, Poisson, negative binomial, and spatial weighted regression models.ResultsThe only risk factor associated with self-reported malaria illness at an individual level was being a child aged 5 or under, where they had three times higher odds than adults. At the household level, variables associated with malaria vector abundance, especially those indoors, included socioeconomic status, the proportion of children in a household and cattle population density.ConclusionsStudy results are limited by the low abundance of malaria vectors found and use of self-reported malaria incidence. Environmental factors together with a household’s socioeconomic status and host availability played important roles in the risk of malaria infection in southwest Ethiopia. Cattle abundance in the form of higher cattle to human ratios may act as a protective factor against mosquito infestation and malaria risk. Humans should remain indoors to maximize potential protection against vectors and cattle kept outside of homes.

Beyond eves and cracks: An interdisciplinary study of socio-spatial variation in urban malaria transmission in Ethiopia.

During the past century, the global trend of reduced malaria transmission has been concurrent with increasing urbanization. Although urbanization has traditionally been considered beneficial for vector control, the adaptation of malaria vectors to urban environments has created concerns among scientific communities and national vector control programs. Since urbanization rates in Ethiopia are among the highest in the world, the Ethiopian government developed an initiative focused on building multi-storied units organized in condominium housing. This study aimed to develop an interdisciplinary methodological approach that integrates architecture, landscape urbanism, medical anthropology, and entomology to characterize exposure to malaria vectors in this form of housing in three condominiums in Jimma Town. Mosquitoes were collected using light trap catches (LTCs) both indoor and outdoor during 2019's rainy season. Architectural drawings and ethnographic research were superposed to entomological data to detect critical interactions between uses of the space and settlement conditions potentially affecting malaria vector abundance and distribution. A total of 34 anopheline mosquitoes comprising three species (Anopheles gambiae s.l, An. pharoensis and An. coustani complex) were collected during the three months of mosquito collection. Anopheles gambiae s.l, the principal malaria vector in Ethiopia, was the predominant species of all the anophelines collected. Distribution of mosquito breeding sites across scales (household, settlement, urban landscape) is explained by environmental conditions, socio-cultural practices involving modification of existing spaces, and systemic misfits between built environment and territory. Variations in mosquito abundance and distribution in this study were mainly related to standard building practices that ignore the original logics of the territory, deficiency of water and waste disposal management systems, and adaptations of the space to fit heterogeneous lifestyles of residents. Our results indicate that contextualizing malaria control strategies in relation to vector ecology, social dynamics determining specific uses of the space, as well as building and territorial conditions could strengthen current elimination efforts. Although individual housing remains a critical unit of research for vector control interventions, this study demonstrates the importance of studying housing settlements at communal level to capture systemic interactions impacting transmission at the household level and in outdoor areas.

Temporal Monitoring and Predicting of the Abundance of Malaria Vectors Using Time Series Analysis of Remote Sensing Data through Google Earth Engine.

In many studies regarding the field of malaria, environmental factors have been acquired in single-time, multi-time or a short-time series using remote sensing and meteorological data. Selecting the best periods of the year to monitor the habitats of Anopheles larvae can be effective in better and faster control of malaria outbreaks. In this article, high-risk times for three regions in Iran, including Qaleh-Ganj, Sarbaz and Bashagard counties with a history of malaria prevalence were estimated. For this purpose, a series of environmental factors affecting the growth and survival of Anopheles were used over a seven-year period through the Google Earth Engine. The results of this study indicated two high-risk times for Qaleh-Ganj and Bashagard counties and three high-risk times for Sarbaz county over the course of a year observing an increase in the abundance of Anopheles mosquitoes. Further evaluation of the results against the entomological data available in previous studies showed that the high-risk times predicted in this study were consistent with an increase in the abundance of Anopheles mosquitoes in the study areas. The proposed method is extremely useful for temporal prediction of the increase in abundance of Anopheles mosquitoes in addition to the use of optimal data aimed at monitoring the exact location of Anopheles habitats.

Citizen science for monitoring the spatial and temporal dynamics of malaria vectors in relation to environmental risk factors in Ruhuha, Rwanda

BackgroundAs part of malaria prevention and control efforts, the distribution and density of malaria mosquitoes requires continuous monitoring. Resources for long-term surveillance of malaria vectors, however, are often limited. The aim of the research was to evaluate the value of citizen science in providing insight into potential malaria vector hotspots and other malaria relevant information, and to determine predictors of malaria vector abundance in a region where routine mosquito monitoring has not been established to support vector surveillance.MethodsA 1-year citizen science programme for malaria mosquito surveillance was implemented in five villages of the Ruhuha sector in Bugesera district, Rwanda. In total, 112 volunteer citizens were enrolled and reported monthly data on mosquitoes collected in their peridomestic environment using handmade carbon-dioxide baited traps. Additionally, they reported mosquito nuisance experienced as well as the number of confirmed malaria cases in their household.ResultsIn total, 3793 female mosquitoes were collected, of which 10.8% were anophelines. For the entire period, 16% of the volunteers reported having at least one confirmed malaria case per month, but this varied by village and month. During the study year 66% of the households reported at least one malaria case. From a sector perspective, a higher mosquito and malaria vector abundance was observed in the two villages in the south of the study area. The findings revealed significant positive correlations among nuisance reported and confirmed malaria cases, and also between total number of Culicidae and confirmed malaria cases, but not between the numbers of the malaria vector Anopheles gambiae and malaria cases. At the sector level, of thirteen geographical risk factors considered for inclusion in multiple regression, distance to the river network and elevation played a role in explaining mosquito and malaria mosquito abundance.ConclusionsThe study demonstrates that a citizen science approach can contribute to mosquito monitoring, and can help to identify areas that, in view of limited resources for control, are at higher risk of malaria.