Field responses of Anopheles gambiae complex (Diptera: Culicidae) in Liberia using yeast-generated carbon dioxide and synthetic lure-baited light traps

Effect of ultraviolet LED and trap height on catches of host-seeking anopheline mosquitoes by using a low-cost passive light trap in northeast Brazil

Light traps have been widely used for monitoring malaria vectors, although drawbacks remain. In this context, new tools and attractants are always becoming available to perform monitoring tasks, like the Silva trap, a passive and low-cost LED-light trap for host-seeking anopheline mosquitoes. In this work, the effectiveness of the Silva trap by using UV-LED and at different heights as well as a comparison with the conventional CDC-type (HP) light trap was studied. A total of 9009 mosquitoes and nine species were caught, Anopheles triannulatus, An. argyritarsis, and An. goeldii being the most frequent species. The green (520 nm) and blue (470 nm) LEDs attracted almost equal numbers of anopheline mosquitoes, but UV LEDs (395 nm) attracted a significantly lower number of individuals (Kruskal-Wallis = 19.68, P = 0.0001). Even with the predominance of mosquitoes trapped at the height of 1.5 m, no significant statistical difference was found among the four heights tested (0.5 m; 1.0 m; 1.5 m; 2.0 m). Green-baited Silva traps collected significantly more individuals than incandescent-baited CDC-type traps (U = 60.5; P = 0.0303). LEDs have been useful as light sources for attracting insect vectors and together with a low-cost trap, as the Silva trap, a feasible alternative to conventional trap-based monitoring Anopheles mosquitoes that can be implemented in the field.

Spatial Distribution of PCR-Identified Species of Anopheles gambiae senu lato (Diptera: Culicidae) Across Three Eco-Vegetational Zones in Cross River State, Nigeria

Anopheles gambiae sensu lato complex (An. gambiae s.l.) describes a group of nine morphologically indistinguishable members that vary in their distribution, ability to transmit malaria, and susceptibility to pyrethroids. Here, we recorded the spatial patterns of PCR-identified An. gambiae s.l. complex species collected from four sites in Cross River State, Nigeria that represented three different ecological zones. Trapping was conducted between October 2015 and June 2016. Anopheles gambiae s.l. complex species identification was performed using species-specific primers followed by An. gambiae and An. coluzzii differentiation using the restriction fragment length polymorphism (RFLP) method. Bivariate and multivariate logistic regression models were used to identify ecological and seasonal variables closely associated with An. coluzzii and An. gambiae distribution. Out of 1,388 An. gambiae s.l. successfully amplified, 1,074 (77.4%) were An. coluzzii, 278 (20%) were An. gambiae, and 25 (1.8%) were hybrids (An. coluzzii/An. gambiae). A very small number of An. arabiensis (0.8%, n = 11) were also collected. Statistical analysis indicated that An. coluzzii is predominant in Guinea-savannah and tropical rainforest, and is highly associated with rainy seasons, while, An. gambiae is prevalent in mangrove swamp forest during dry seasons. Only 13 An. gambiae s.l. females were infected with Plasmodium falciparum (P. falciparum). The sporozoite infection rate was higher in mangrove swamp forest (53.8%, n = 7) than in rain forest (38.5%, n = 5) followed by Guinea-savannah (7.7%, n = 1) ecological zones. These results provide important insights for strategic planning of malaria control programs in Nigeria.

Assessing Anopheles vector species diversity and transmission of malaria in four health districts along the borders of Côte d'Ivoire

BACKGROUND

Although malaria and Anopheles mosquito vectors are highly prevalent in Côte d'Ivoire, limited data are available to help understand the malaria vector density and transmission dynamics in areas bordering the country. To address this gap, the Anopheles mosquito species diversity, the members of the Anopheles gambiae complex and the transmission of malaria were assessed in four health districts along the borders of Côte d'Ivoire.

METHODS

From July 2016 through December 2016 and July 2017 through December 2017, adult Anopheles mosquitoes were collected in four health districts of Côte d'Ivoire (Aboisso, Bloléquin, Odienné and Ouangolodougou) using standardized window exit trap (WET) and pyrethrum knockdown spray collection (PSC) methods. The collected mosquitoes were identified morphologically at species level and the members of the An. gambiae complex were separated using short interspersed nuclear element-based polymerase chain reaction (SINE-PCR). Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l. and Anopheles nili specimens were analysed for malaria Plasmodium parasite detection using the cytochrome oxidase I gene (COX-I), and malaria prevalence among human population through local Ministry of Health (MoH) statistical yearbooks.

RESULTS

A total of 281 female Anopheles were collected in Aboisso, 754 in Bloléquin, 1319 in Odienné and 2443 in Ouangolodougou. Seven Anopheles species were recorded including An. gambiae s.l. (94.8-99.1%) as the main vector, followed by An. funestus s.l. (0.4-4.3%) and An. nili (0-0.7%). Among An. gambiae s.l., Anopheles coluzzii represented the predominant species in Aboisso (89.2%) and Bloléquin (92.2%), while An. gambiae sensu stricto (s.s.) was the major species in Odienné (96.0%) and Ouangolodougou (94.2%). The Plasmodium sporozoite infection rate in An. gambiae s.l. was highest in Odienné (11.0%; n = 100) followed by Bloléquin (7.8%, n = 115), Aboisso (3.1%; n = 65) and Ouangologoudou (2.5%; n = 120). In An. funestus s.l., Plasmodium falciparum sporozoite infection rate was estimated at 6.2% (n = 32) in Bloléquin, 8.7% (n = 23) in Odienné. No An. funestus s.l. specimens were found infected with P. falciparum sporozoite infection in Ouangolodougou and Aboisso. No P. falciparum sporozoite was detected in An. nili specimens in the four health districts. Among the local human populations, malaria incidence was higher in Odienné (39.7%; n = 45,376) and Bloléquin (37.6%; n = 150,205) compared to that in Ouangolodougou (18.3%; n = 131,629) and Aboisso (19.7%; n = 364,585).

CONCLUSION

Anopheles vector species diversity, abundance and Plasmodium sporozoite infection were high within the health districts along the borders of the country of Côte d'Ivoire, resulting in high malaria transmission among the local populations. Anopheles gambiae s.l. and An. funestus s.l. were found to be highly infected with Plasmodium in the health districts of Bloléquin and Odienné where higher malaria incidence was observed than the other districts. This study provides important information that can be used to guide Côte d'Ivoire National Malaria Control Programme for vector control decision-making, mainly in districts that are at the country borders.

Urban malaria in sub-Saharan Africa: dynamic of the vectorial system and the entomological inoculation rate

Sub-Saharan Africa is registering one of the highest urban population growth across the world. It is estimated that over 75% of the population in this region will be living in urban settings by 2050. However, it is not known how this rapid urbanization will affect vector populations and disease transmission. The present study summarizes findings from studies conducted in urban settings between the 1970s and 2020 to assess the effects of urbanization on the entomological inoculation rate pattern and anopheline species distribution. Different online databases such as PubMed, ResearchGate, Google Scholar, Google were screened. A total of 90 publications were selected out of 1527. Besides, over 200 additional publications were consulted to collate information on anopheline breeding habitats and species distribution in urban settings. The study confirms high malaria transmission in rural compared to urban settings. The study also suggests that there had been an increase in malaria transmission in most cities after 2003, which could also be associated with an increase in sampling, resources and reporting. Species of the Anopheles gambiae complex were the predominant vectors in most urban settings. Anopheline larvae were reported to have adapted to different aquatic habitats. The study provides updated information on the distribution of the vector population and the dynamic of malaria transmission in urban settings. The study also highlights the need for implementing integrated control strategies in urban settings.

Relative abundance and molecular identification of Culex pipiens complex (Diptera: Culicidae), in Kura Local Government Area, North-western Nigeria

Culex species are the most widespread mosquito species across the world and are known to be highly opportunistic, feeding on humans and livestock. They are known to acquire the potential to transmit zoonotic diseases, including Rift Valley Fever (RVF). However, despite their public health significance, they remain understudied in North-western Nigeria, compared to Anophelines. This study was therefore aimed at determining the relative abundance and Multiplex polymerase chain reaction (Multiplex PCR) identification of members of the Culex pipiens complex, in Kura Local Government Area (LGA), North-western, Nigeria. Adult mosquitoes were collected using Center for Disease Control (CDC) miniature light traps from August to October 2019. Mosquitoes were identified using morphological identification keys. Members of the Culex pipiens complex were further identified using Multiplex PCR to assess the presence of sibling species. A total of 413 mosquitoes, belonging to 3 genera, Culex, Anopheles and Aedes were collected. Of this figure, 120 Culex spp. females were collected. Homes with livestock had the highest occurrence of mosquitoes, 123 (61.19%) compared to those without livestock, 78 (38.81%). There was no statistical difference among the two (2) categories of homes (P ≥ 0.005). Culicoides spp. were the most common with 130 collected (65.38%). Again, homes with livestock had the highest occurrence, 85 whilst homes without livestock had 45 of the other flies caught. Multiplex- PCR revealed no expected bands for Cx. quinquefasciatus and Cx. pipiens from the DNA obtained from field collected mosquitoes as confirmed by using genomic DNA of an insectary Culex quinquefasciatus as control. Cx. spp. is presently regarded as a biting nuisance having no significant epidemiological importance. Efforts at its control should be intensified before it is too late. This study provides useful information on the occurrence and multiplex PCR of Culex spp in Kura Local Government Area, North-western Nigeria. These results have implications for the control of Culex spp. mosquito populations and the spread of human, livestock and avian diseases.

Mosquito Attractants

Vector control and personal protection against anthropophilic mosquitoes mainly rely on the use of insecticides and repellents. The search for mosquito-attractive semiochemicals has been the subject of intense studies for decades, and new compounds or odor blends are regularly proposed as lures for odor-baited traps. We present a comprehensive and up-to-date review of all the studies that have evaluated the attractiveness of volatiles to mosquitoes, including individual chemical compounds, synthetic blends of compounds, or natural host or plant odors. A total of 388 studies were analysed, and our survey highlights the existence of 105 attractants (77 volatile compounds, 17 organism odors, and 11 synthetic blends) that have been proved effective in attracting one or several mosquito species. The exhaustive list of these attractants is presented in various tables, while the most common mosquito attractants - for which effective attractiveness has been demonstrated in numerous studies - are discussed throughout the text. The increasing knowledge on compounds attractive to mosquitoes may now serve as the basis for complementary vector control strategies, such as those involving lure-and-kill traps, or the development of mass trapping. This review also points out the necessity of further improving the search for new volatile attractants, such as new compound blends in specific ratios, considering that mosquito attraction to odors may vary over the life of the mosquito or among species. Finally, the use of mosquito attractants will undoubtedly have an increasingly important role to play in future integrated vector management programs.

Artificial light and biting flies: the parallel development of attractive light traps and unattractive domestic lights

Light trapping is an important tool for monitoring insect populations. This is especially true for biting Diptera, where light traps play a crucial role in disease surveillance by tracking the presence and abundance of vector species. Physiological and behavioural data have been instrumental in identifying factors that influence dipteran phototaxis and have spurred the development of more effective light traps. However, the development of less attractive domestic lights has received comparatively little interest but could be important for reducing interactions between humans and vector insects, with consequences for reducing disease transmission. Here, we discuss how dipteran eyes respond to light and the factors influencing positive phototaxis, and conclude by identifying key areas for further research. In addition, we include a synthesis of attractive and unattractive wavelengths for a number of vector species. A more comprehensive understanding of how Diptera perceive and respond to light would allow for more efficient vector sampling as well as potentially limiting the risk posed by domestic lighting.

Species Composition of Anopheles (Diptera: Culicidae) in Selected Forested Tourist Areas of Nigeria Endemic for Malaria

The study was carried out to determine relative abundance, species diversity, of Anopheles species (Diptera: Culicidae) in selected forested areas in Cross River State, Nigeria and the prevalence of malaria infection in the specimens. Mosquitoes were collected using pyrethrum spray catch and Centre for Disease Control light traps modified with yeast and sugar to generate carbon dioxide (CO2) and identified using morphological identification keys. We used a multiplex polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) to simultaneously distinguish sibling species of the An. gambiae s.l, including separation of An. gambiae s.s. and An. coluzzii (Diptera: Culicidae). The samples were also screened for Plasmodium infection using the enzyme-linked immunosorbent assay. One hundred and four Anopheles specimens were collected during the study of which 97% was An. gambiae complex and 3% was An. rufipes (Diptera: Culicidae). Only 77% of the An. gambiae s.l. was identify to species level. The result shows that 41.6% was An. gambiae s.s. and 34.6% was An. coluzzii. No sporozoite of Plasmodium was detected in the Anopheles species. The study also found a hybrid form of An. gambiae s.s. and An. coluzzii. These findings suggest the first documented evidence of hybrid forms of An. gambiae s.s./An. coluzzii in South Eastern Nigeria although its epidemiological implication is still not clear.

Identification of Mosquito Bloodmeals Collected in Diverse Habitats in Malaysian Borneo Using COI Barcoding

Land cover and land use change (LCLUC) acts as a catalyst for spillover of arthropod-borne pathogens into novel hosts by shifting host and vector diversity, abundance, and distribution, ultimately reshaping host–vector interactions. Identification of bloodmeals from wild-caught mosquitoes provides insight into host utilization of particular species in particular land cover types, and hence their potential role in pathogen maintenance and spillover. Here, we collected 134 blood-engorged mosquitoes comprising 10 taxa across 9 land cover types in Sarawak, Malaysian Borneo, a region experiencing intense LCLUC and concomitant spillover of arthropod-borne pathogens. Host sources of blood were successfully identified for 116 (87%) mosquitoes using cytochrome oxidase subunit I (COI) barcoding. A diverse range of hosts were identified, including reptiles, amphibians, birds, and mammals. Sixteen engorged Aedes albopictus, a major vector of dengue virus, were collected from seven land cover types and found to feed exclusively on humans (73%) and boar (27%). Culex tritaeniohynchus (n = 2), Cx. gelidus (n = 3), and Cx. quiquefasciatus (n = 3), vectors of Japanese encephalitis virus, fed on humans and pigs in the rural built-up land cover, creating potential transmission networks between these species. Our data support the use of COI barcoding to characterize mosquito–host networks in a biodiversity hotspot.

Light-Emitting Diode (LED) Traps Improve the Light-Trapping of Anopheline Mosquitoes

Numerous advantages over the standard incandescent lamp favor the use of light-emitting diodes (LEDs) as an alternative and inexpensive light source for sampling medically important insects in surveillance studies. Previously published studies examined the response of mosquitoes to different wavelengths, but data on anopheline mosquito LED attraction are limited. Center for Disease Control and Prevention-type light traps were modified by replacing the standard incandescent lamp with 5-mm LEDs, one emitting at 520 nm (green) and the other at 470 nm (blue). To test the influence of moon luminosity on LED catches, the experiments were conducted during the four lunar phases during each month of the study period. A total of 1,845 specimens representing eight anopheline species were collected. Anopheles (Nyssorhynchus) evansae (35.2%) was the most frequently collected, followed by An. (Nys.) triannulatus (21.9%), An. (Nys.) goeldii (12.9%), and An. (Nys.) argyritarsis (11.5%). The green LED was the most attractive light source, accounting for 43.3% of the individuals collected, followed by the blue (31.8%) and control (24.9%) lights. The LED traps were significantly more attractive than the control, independent of the lunar phase. Light trapping of anopheline mosquitoes was more efficient when the standard incandescent lamp was replaced with LEDs, regardless of the moon phase. The efficiency of LEDs improves light trapping results, and it is suggested that the use of LEDs as an attractant for anopheline mosquitoes should be taken into consideration when sampling anopheline mosquitoes.

Field evaluation of two commercial mosquito traps baited with different attractants and colored lights for malaria vector surveillance in Thailand

BACKGROUND

Sampling for adult mosquito populations is a means of evaluating the efficacy of vector control operations. The goal of this study was to evaluate and identify the most efficacious mosquito traps and combinations of attractants for malaria vector surveillance along the Thai-Myanmar border.

METHODS

In the first part of the study, the BG-Sentinel™ Trap (BGS Trap) and Centers for Disease Control and Prevention miniature light trap (CDC LT) baited with different attractants (BG-lure® and CO₂) were evaluated using a Latin square experimental design. The six configurations were BGS Trap with BG-lure, BGS Trap with BG-lure plus CO₂, BGS Trap with CO₂, CDC LT with BG-lure, CDC LT with BG lure plus CO₂, and CDC LT with CO₂. The second half of the study evaluated the impact of light color on malaria vector collections. Colors included the incandescent bulb, ultraviolet (UV) light-emitting diode (LED), green light stick, red light stick, green LED, and red LED.

RESULTS

A total of 8638 mosquitoes consisting of 42 species were captured over 708 trap-nights. The trap types, attractants, and colored lights affected numbers of female anopheline and Anopheles minimus collected (GLM, P < 0.01). Results revealed that BGS Trap captured many anophelines but was significantly less than the CDC LT. The CDC LT, when baited with BG-lure plus CO₂ captured the greatest number of anopheline females with a catch rate significantly higher than the CDC LT baited with BG-lure or CO₂ alone (P < 0.05). The number of anopheline females collected from the CDC LT baited with CO₂ was greater than the CDC LT baited with BG-lure (646 vs 409 females). None of the alternative lights evaluated exceeded the performance of the incandescent light bulb in terms of the numbers of anopheline and An. minimus collected.

CONCLUSION

We conclude that the CDC LT augmented with an incandescent light shows high potential for malaria vector surveillance when baited with CO₂ and the BG-lure in combination and can be effectively used as the new gold standard technique for collecting malaria vectors in Thailand.

Comparison of Volatiles and Mosquito Capture Efficacy For Three Carbohydrate Sources In A Yeast-Fermentation CO2 Generator

Mosquito surveillance in remote areas with limited access to canisters of CO₂ or dry ice will benefit from an effective alternative CO₂ source, such as the natural production of CO₂ from yeast fermentation. In this study, we investigate differences in mosquito capture rates from the Centers for Disease Control and Prevention (CDC) light traps baited with dry ice compared with traps baited with yeast fermentation of several carbohydrate sources over 23 trap-nights. Results demonstrated the ability of yeast-generated CO₂ to effectively attract mosquitoes to a CDC trap, regardless of carbohydrate source. Total collections of mosquitoes using dry ice were significantly higher than collections from yeast-generated CO₂ sources. However, mosquito community structure, i.e., the species and relative capture rate of each species, was represented comparably across collections regardless of CO₂ source. Volatiles produced by yeast fermentation were analyzed by carbohydrate source, revealing a suite of compounds, possibly synergistic, enhancing effects with CO₂ on mosquito collection capability compared with the amount of CO₂ used to attract mosquitoes.

New Records and Updated Checklist of Phlebotomine Sand Flies (Diptera: Psychodidae) From Liberia

Phlebotomine sand flies from three counties in Liberia were collected from January 2011 to July 2013. In total, 3,118 sand flies were collected: 18 species were identified, 13 of which represented new records for Liberia. An updated taxonomic checklist is provided with a brief note on sand fly biology, and the disease vector potential for species is discussed.

Application of biogenic carbon dioxide produced by yeast with different carbon sources for attraction of mosquitoes towards adult mosquito traps

Surveillance is a prime requisite for controlling arthropod vectors like mosquitoes that transmit diseases such as malaria, dengue and chikungunya. Carbon dioxide (CO2) is one of the main cues from vertebrate breath that attracts mosquitoes towards the host. Hence, CO2 is used as an attractant during surveillance of mosquitoes either from commercial cylinders or dry ice for mosquito traps. In the present study, the biogenic carbon dioxide production was optimized with different carbon sources such as glucose, simple sugar and jaggery with and without yeast peptone dextrose (YPD) media using commercial baker's yeast. The results showed that yeast produced more biogenic CO2 with simple sugar as compared to other carbon sources. Further substrate concentration was optimized for the continuous production of biogenic CO2 for a minimum of 12 h by using 10 g of baker's yeast with 50 g of simple sugar added to 1.5 l distilled water (without YPD media) in a 2-l plastic bottle. This setup was applied in field condition along with two different mosquito traps namely Mosquito Killing System (MKS) and Biogents Sentinel (BGS) trap. Biogenic CO2 from this setup has increased the trapping efficiency of MKS by 6.48-fold for Culex quinquefasciatus, 2.62-fold for Aedes albopictus and 1.5-fold for Anopheles stephensi. In the case of BGS, the efficiency was found to be increased by 3.54-fold for Ae. albopictus, 4.33-fold for An. stephensi and 1.3-fold for Armigeres subalbatus mosquitoes. On the whole, plastic bottle setup releasing biogenic CO2 from sugar and yeast has increased the efficiency of MKS traps by 6.38-fold and 2.74-fold for BGS traps as compared to traps without biogenic CO2. The present study reveals that, among different carbon sources used, simple sugar as a substance (which is economical and readily available across the world) yielded maximum biogenic CO2 with yeast. This setup can be used as an alternative to CO2 cylinder and dry ice in any adult mosquito traps to enhance their trapping efficiency of a mosquito surveillance programme.

Assessing Carbon Dioxide and Synthetic Lure-Baited Traps for Dengue and Chikungunya Vector Surveillance (3)

The Aedes mosquito vectors of dengue virus (DENV) and chikungunya virus (CHIKV) are attracted to specific host cues that are not generated by traditional light traps. For this reason multiple companies have designed traps to specifically target those species. Recently the standard trap for DENV and CHIKV vectors, the BG-Sentinel (BGS) trap, has been remodeled to be more durable and better suited for use in harsh field conditions, common during military operations, and relabeled the BG-Sentinel 2 (BGS2). This new trap was evaluated against the standard Centers for Disease Control and Prevention (CDC) light trap, Zumba Trap, and BG-Mosquitito Trap to determine relative effectiveness in collecting adult Aedes aegypti and Ae. albopictus. Evaluations were conducted under semifield and field conditions in suburban areas in northeastern Florida from May to August 2014. The BGS2 trap collected more DENV and CHIKV vectors than the standard CDC light trap, Zumba Trap, and BG-Mosquitito Trap, but attracted fewer species, while the BG-Mosquitito Trap attracted the greatest number of mosquito species.

The Seasonality and Ecology of the Anopheles gambiae complex (Dipetra: Culicidae) in Liberia Using Molecular Identification

Members of the Anopheles gambiae sensu lato (Giles) complex define a group of seven morphologically indistinguishable species, including the principal malaria vectors in Sub-Saharan Africa. Members of this complex differ in behavior and ability to transmit malaria; hence, precise identification of member species is critical to monitoring and evaluating malaria threat levels. We collected mosquitoes from five counties in Liberia every other month from May 2011 until May 2012, using various trapping techniques. A. gambiae complex members were identified using molecular techniques based on differences in the ribosomal DNA (rDNA) region between species and the molecular forms (S and M) of A. gambiae sensu stricto (s.s) specimens. In total, 1,696 A. gambiae mosquitoes were collected and identified. DNA was extracted from legs of each specimen with species identification determined by multiplex polymerase chain reaction using specific primers. The molecular forms (M or S) of A. gambiae s.s were determined by restriction fragment length polymorphism. Bivariate and multivariate logistic regression models identified environmental variables associated with genomic differentiation. Our results indicate widespread occurrence of A. gambiae s.s., the principal malaria vector in the complex, although two Anopheles melas Theobald/A. merus Donitz mosquitoes were detected. We found 72.6, 25.5, and 1.9% of A. gambiae s.s specimens were S, M, and hybrid forms, respectively. Statistical analysis indicates that the S form was more likely to be found in rural areas during rainy seasons and indoor catchments. This information will enhance vector control efforts in Liberia.

Field assessment of yeast- and oxalic Acid-generated carbon dioxide for mosquito surveillance

Carbon dioxide (CO2) sources improve the efficacy of mosquito traps. However, traditional CO2 sources (dry ice or compressed gas) may be difficult to acquire for vector surveillance during military contingency operations. For this reason, a new and convenient source of CO2 is required. Two novel CO2 generators were evaluated in order to address this capability gap: 1) an electrolyzer that converts solid oxalic acid into CO2 gas, and 2) CO2 produced by yeast as it metabolizes sugar. The flow rate and CO2 concentration produced by each generator were measured, and each generator's ability to attract mosquitoes to BG-Sentinel™ traps during day surveillance and to Centers for Disease Control and Prevention light traps with incandescent bulbs during night surveillance was compared to dry ice and compressed gas in Jacksonville, FL. The electrolyzed oxalic acid only slightly increased the number of mosquitoes captured compared to unbaited traps. Based on the modest increase in mosquito collection for traps paired with the oxalic acid, it is not a suitable stand-in for either of the 2 traditional CO2 sources. Conversely, the yeast-generated CO2 resulted in collections with mosquito abundance and species richness more closely resembling those of the traditional CO2 sources, despite achieving a lower CO2 flow rate. Therefore, if dry ice or compressed gas cannot be acquired for vector surveillance, yeast-generated CO2 can significantly improve trap capability.

A comparison of two commercial mosquito traps for the capture of malaria vectors in northern belize, central america

To achieve maximum success from any vector control intervention, it is critical to identify the most efficacious tools available. The principal aim of this study was to evaluate the efficacy of 2 commercially available adult mosquito traps for capturing Anopheles albimanus and An. vestitipennis, 2 important malaria vectors in northern Belize, Central America. Additionally, the impact of outdoor baited traps on mosquito entry into experimental huts was assessed. When operated outside of human-occupied experimental huts, the Centers for Disease Control and Prevention (CDC) miniature light trap, baited with human foot odors, captured significantly greater numbers of female An. albimanus per night (5.1 ± 1.9) than the Biogents Sentinel™ trap baited with BG-Lure™ (1.0 ± 0.2). The 2 trap types captured equivalent numbers of female An. vestitipennis per night, 134.3 ± 45.6 in the CDC trap and 129.6 ± 25.4 in the Sentinel trap. When compared to a matched control hut using no intervention, the use of baited CDC light traps outside an experimental hut did not impact the entry of An. vestitipennis into window interception traps, 17.1 ± 1.3 females per hour in experimental huts vs. 17.2 ± 1.4 females per hour in control huts. However, the use of outdoor baited CDC traps did significantly decrease the entry of An. albimanus into window interception traps from 3.5 ± 0.5 females per hour to 1.9 ± 0.2 females per hour. These results support existing knowledge that the underlying ecological and behavioral tendencies of different Anopheles species can influence trap efficacy. Furthermore, these findings will be used to guide trap selection for future push-pull experiments to be conducted at the study site.

Is there an efficient trap or collection method for sampling Anopheles darlingi and other malaria vectors that can describe the essential parameters affecting transmission dynamics as effectively as human landing catches? - A Review

Distribution, abundance, feeding behaviour, host preference, parity status and human-biting and infection rates are among the medical entomological parameters evaluated when determining the vector capacity of mosquito species. To evaluate these parameters, mosquitoes must be collected using an appropriate method. Malaria is primarily transmitted by anthropophilic and synanthropic anophelines. Thus, collection methods must result in the identification of the anthropophilic species and efficiently evaluate the parameters involved in malaria transmission dynamics. Consequently, human landing catches would be the most appropriate method if not for their inherent risk. The choice of alternative anopheline collection methods, such as traps, must consider their effectiveness in reproducing the efficiency of human attraction. Collection methods lure mosquitoes by using a mixture of olfactory, visual and thermal cues. Here, we reviewed, classified and compared the efficiency of anopheline collection methods, with an emphasis on Neotropical anthropophilic species, especially Anopheles darlingi, in distinct malaria epidemiological conditions in Brazil.