Search Results (169)

Arboviral diseases are emerging public health challenges in Burkina Faso, largely driven by the proliferation of Aedes aegypti mosquitoes in the environment. Effective surveillance of arbovirus circulation is critical to inform interventions. From August 2022 to June 2023, we implemented a comprehensive entomological surveillance platform in five sectors of Bobo-Dioulasso. Surveillance methods included oviposition traps to collect eggs, larval surveys in some concessions per sector conducted bimonthly, and adult mosquito collections using BG-Sentinel traps and Prokopack aspirators. Mosquito samples colonized by Ae. aegypti were identified morphologically, confirmed by conventional PCR, and screened by RT-PCR for dengue (DENV), chikungunya (CHIKV), yellow fever (YFV), and Zika (ZIKV) viruses. Molecular analysis detected dengue virus and yellow fever virus in mosquito pools from sector 22 and chikungunya virus in sectors 9 and 26; no Zika virus was found. This study demonstrates the successful establishment of an integrated entomological surveillance platform capable of capturing the spatial and temporal dynamics of arboviral vectors and virus circulation in Bobo-Dioulasso. The identification of active dengue and chikungunya transmission underlines the urgent need for sustained vector monitoring and targeted control strategies. Our approach provides a scalable model for arboviral disease surveillance and epidemic preparedness in West African urban settings. Full article

Arthropod-borne viruses (arboviruses) such as dengue, chikungunya, Zika, and yellow fever pose significant global health risks, with mosquitoes from the Aedes genus as the primary vectors responsible for human transmission. The Republic of the Marshall Islands (RMI), particularly the urbanized areas of Kwajalein and Majuro atolls, has experienced multiple outbreaks of dengue, Zika, and chikungunya with substantial health and economic impacts. Vector control remains the most effective method for reducing disease risk, but comprehensive data on local mosquito vector composition, distribution, and abundance are needed to guide new, effective control efforts. From 2022 to 2024, we conducted a longitudinal baseline assessment of mosquito abundance and species composition on Ebeye and nearby islets in Kwajalein Atoll, RMI, using BG-Sentinel traps and ovitraps. Aedes aegypti was the most prevalent species, accounting for 58% of all adult females collected across study locations, with higher relative abundances on Ebeye than on northern islets (4.7 vs. 2.3 per trap/night). Aedes albopictus was more abundant on northern islets (0.7 vs. 3.2 per trap/night), and Culex quinquefasciatus showed similar abundances (1.2 vs. 1.7 per trap/night). Rainfall and anthropogenic factors, including water storage practices and housing density, influenced mosquito abundance. These findings provide multi-seasonal baseline data to support targeted vector control strategies in RMI. Full article

Zoological gardens represent unique sites for vector and vector-borne disease studies. They offer suitable breeding habitats for vector development and a diverse range of vertebrate hosts for blood feeding of insect vectors. This study aimed to assess the prevalence of avian blood parasites (Haemosporida, Trypanosomatida) in wild-caught mosquitoes (Culicidae) and Culicoides biting midges (Ceratopogonidae) from the largest and oldest zoo in Lithuania. Insects were collected in May–August 2023 using UV-light, CDC and BG-Sentinel traps; collected material was analysed using both microscopy and PCR-based methods for parasite detection. Overall, 504 parous biting midges (10 species) and 59 mosquitoes (three species) were investigated. Haemosporidians (Haemoproteus minutus (hTURDUS2), H. homogeneae (hSYAT16), and H. asymmetricus (hTUPHI01)) were identified in 5.4% of the 174 tested biting midges. Haemoproteus asymmetricus hTUPHI01 sporozoites were seen in only one individual of Culicoides kibunensis. Of 108 Culicoides females, 3.7% carried trypanosomatids—parasites infecting birds (Trypanosoma bennetti group) and mammals (T. theileri group). Among the 59 tested mosquitoes, two (3.4%) Cx. pipiens/torrentium mosquitoes were found to be PCR-positive for trypanosomatids (T. culicavium and Crithidia brevicula). No haemosporidian parasite DNA was detected in the mosquitoes examined. This pilot study indicates that avian blood parasites circulate within the Lithuanian Zoo, highlighting the need for further research on transmission pathways, vector–host interactions, and potential risks. Full article

Aedes aegypti is the primary urban vector for several important arboviruses, including dengue, chikungunya, yellow fever, and Zika viruses. Traditional dengue virus (DENV) surveillance relies on passive reporting of human cases, which often underestimates transmission due to asymptomatic or unreported infections. This study evaluated the utility of monitoring DENV in Ae. aegypti mosquitoes to improve detection of local dengue transmission and inform vector control strategies during the 2024 dengue epidemic in Puerto Rico. Mosquito surveillance was conducted in 15 neighborhoods within the San Juan metropolitan area where confirmed dengue cases had been recently reported. Adult female Ae. aegypti were collected weekly using Autocidal Gravid Ovitraps (AGO traps) placed within a 200 m radius of index cases. Pools of 1–20 mosquitoes were tested for DENV RNA and serotype using RT-PCR. Surveillance continued for up to 91 days in study areas, depending on virus detection. A total of 29,354 female Ae. aegypti were collected, of which 29,211 females were pooled (1–20 specimens per pool) into 3878 pools and analyzed. DENV was detected in 49 pools across 11 neighborhoods, with serotypes DENV-1, DENV-2, and DENV-3 identified. Multiple serotypes were sometimes detected in mosquitoes from the same neighborhood. Minimum infection rates and vector indices were higher during the epidemic than in previous inter-epidemic periods, and mosquito densities exceeded thresholds considered protective against outbreaks. Entomo-virological surveillance detected a greater variety and evenness of serotypes than passive human surveillance. These findings suggest that entomo-virological surveillance can complement passive case surveillance, providing a more comprehensive detection of DENV circulation. Integrating mosquito-based and human surveillance can improve outbreak detection, guide vector control, and aid in reducing dengue burden in affected communities. Full article

Background and Objectives: Climate change is modifying the ecological and climatic conditions that influence the distribution and activity of arthropod vectors. Rising temperatures and prolonged warm seasons have favored the establishment of Aedes albopictus in Mediterranean regions, increasing the risk of autochthonous Dengue transmission. Therefore, this study describes the evolution of Dengue surveillance in Sardinia between 2018 and 2024, integrating human and entomological data to assess trends, system performance, and implications for prevention and control. Materials and Methods: Data on human cases were retrieved from national notification systems (namely PREMAL, arbo.iss.it) and the New Health Information System. Entomological surveillance data were obtained from the Experimental Zooprophylactic Institute of Sardinia. Mosquitoes were collected using BG-Sentinel^® traps and ovitraps, covering major cities and points of entry. Descriptive analyses were conducted for both datasets. Results: Sixteen Dengue cases were reported during the study period, all imported and laboratory-confirmed in 81% of cases. Most patients were adults (mean age 38 years), and 77% required hospitalization. The most frequent travel origins were Southeast Asia, Africa, and Latin America. No autochthonous cases were identified. Entomological surveillance showed a progressive increase in Aedes albopictus captures from 2020 onwards, with seasonal peaks between September and October. Despite intensified sampling and expanded geographic coverage, no mosquito pools tested positive for the Dengue virus. Conclusions: Although no locally acquired Dengue infections have been detected, the widespread and increasing presence of Aedes albopictus indicates that Sardinia meets the ecological prerequisites for possible autochthonous transmission. Strengthening the timeliness and completeness of human surveillance, improving clinicians’ awareness of reporting requirements, promoting vaccination for travelers, and maintaining continuous entomological monitoring are essential to prevent and promptly manage future outbreaks. Full article

West Nile Virus (WNV) is an emerging arboviral threat in Europe, with rising incidence in Spain since 2004. In 2024, Spain experienced its largest outbreak, primarily in small urban areas of south-western regions. We report a subset of an emergency integrated vector management program, focusing on six municipalities accounting for one-third of all human WNV cases nationwide. Over four months, 725 potential larval sites were inspected during 4026 visits. Adult mosquitoes (n = 2553) were collected with suction traps, and immature stages (n = 4457) with dipper techniques, yielding 11 species. Culex pipiens s.l. was predominant, while Cx. perexiguus, though less abundant, was epidemiologically significant. Cytochrome Oxidase I (COI) gene phylogenetic analysis confirmed Cx. perexiguus, forming a distinct clade from Cx. univittatus. Immature mosquitoes were found in 18.6% of sites, especially irrigation canals, ditches, and backwaters near urban areas. Habitat differences in larval abundance were analyzed using generalized linear mixed models. Targeted larviciding with Bacillus thuringiensis var. israelensis (Bti) and focal adulticiding with cypermethrin totaled 259 interventions (70.4% larviciding, 29.6% adulticiding). A significant 63.9% reduction in larval abundance was observed after five consecutive Bti treatments, with some variation among treatment cycles (52.2–75.5%). Adult activity persisted into late autumn. This study provides the first comprehensive characterization of larval mosquitoes in Spain’s main WNV hotspot, highlighting the need for rapid, coordinated expert interventions and extended seasonal control to prevent future outbreaks. Full article

Background: In recent decades, malaria vector species distribution and insecticide resistance have taken new colonization steps across Africa. Understanding the malaria vector insecticide resistance status, blood meal source, and species composition is of paramount importance in designing evidence-based vector control strategies. This study assessed the blood meal sources, sporozoite (infectivity) rate, and knockdown resistance allele’s frequency in female Anopheles arabiensis in chosen villages of Jabi Tehnan District, Northwest Ethiopia. Methods: The host-seeking and resting Anopheles gambiae s.l. were collected using human landing catches (HLCs), CDC light traps (CDC-LTs), pyrethrum spray catches (PSCs), and pit shelters (PSs) both indoors and outdoors. The analysis of both blood meal sources and circumsporozoite proteins was performed using enzyme-linked immunosorbent assay (ELISA). The detection of knockdown resistance gene mutations and species identification were conducted using a polymerase chain reaction (PCR). Results: A total of 5098 female Anopheles gambiae s.l. were collected. Of these, 1690 (33.2%) were collected from HLCs, 1423 (27.9%) from CDC light traps, 1635 (32.0%) from PSCs, and only 350 (6.9%) from pit shelters (PSs). Of these, 57.2% (n = 2915) female Anopheles mosquitoes were collected indoors using CDC light traps (CDC-LTs), human landing catches (HLCs), and pyrethrum spray catches (PSCs), while 38.2% (n = 2183) were collected outdoors using human landing collection (HLC), CDC light traps (CDC-LTs), and artificial pit shelters (PSs). Molecular identification to the species level showed that among the 530 An. gambiae s.l. samples analyzed using PCR, 96.03% (509) were An. arabiensis, and 3.97% (21) were unidentified species. The biting peak was found to be from 22:00 to 00:00 h for An. arabiensis. However, their activity decreased sharply after 23:00 to 00:00 h. The distribution of knockdown resistance genes in the tested specimens of An. arabiensis consisted of 1.4% (n = 3) heterozygous resistant (RS), 17.9% (n = 38) homozygous resistant (RR), and 80.7% (n = 171) homozygous susceptible (SS) genotypes. A higher proportion of Anopheles mosquitoes analyzed for blood meal analysis had a human blood meal origin at 13.1% (n = 47), followed by bovine at 8.9% (n = 32) and mixed at 5.8% (n = 21). Conclusions: The dominant malaria vector species was Anopheles arabiensis in the study area with a higher human blood meal origin. The Kdr gene was confirmed in the tested An. arabiensis, indicating that an alternative insecticide class should be used in the study area. Full article

The Amazon hosts one of the richest diversities of mosquitoes in the family Culicidae, which are key both as arbovirus vectors and as environmental bioindicators. However, the state of Amapá remains poorly studied regarding its mosquito fauna. This study aimed to characterize the diversity and seasonal composition of Culicidae in the municipality of Mazagão, Eastern Amazon, within a rural landscape influenced by human activity and extreme climatic events. Three sampling campaigns were conducted between 2023 and 2024, covering rainy, intermediary, and dry periods. Mosquitoes were collected using Protected Human Attraction (PHA) and CDC light traps at both ground and canopy strata. A total of 3500 specimens were obtained, representing 38 species across 15 genera. The intermediary period yielded the highest abundance and richness, whereas the dry season presented very low diversity, probably because of severe drought and forest fires. Dominant species included Coquillettidia (Rhy.) venezuelensis, Cq. albicosta, and Mansonia titillans. There were significant differences in community diversity between dry and wetter periods, underscoring the strong role of seasonality in shaping mosquito populations. These findings represent the entomofaunistic survey of the region, contributing to biodiversity knowledge and highlighting potential public health risks, thus reinforcing the need for continuous entomological monitoring. Full article

It is widely recognized that mosquitoes are attracted to ultraviolet (UV) light traps in field and semi-field trials. However, the specific characteristics of mosquito behavioral responses to UV light remain poorly defined. Moreover, the molecular mechanisms underlying their phototactic behavior remain unexplored. Here, we characterized mosquito photobehavior under UV light in a laboratory setting using three experimental apparatuses. Our findings indicate that mosquitoes exhibit strong attraction to low-intensity UV light, yet show no preference between high-intensity UV light and darkness. Video recordings and automatic analyses of photobehavior under low-intensity UV light revealed that mosquitoes preferred the window illuminated by UV light over an unilluminated window and were more active when exposed to UV light. Through RNA interference (RNAi)-mediated knockdown of opsins highly expressed in the adult stage of Culex quinquefasciatus, we identified CqOpsin3, CqOpsin5, and CqOpsin6 as crucial mediators of UV phototaxis. This study provides methods for characterizing mosquito photobehavior under UV light in the laboratory, and represents the first mechanistic investigation into UV light-mediated attractive behavior in mosquitoes. Full article

To prepare for a boosted sterile insect technique (SIT) field trial in Saint-Joseph, Reunion island, we compared the attractiveness of two adult mosquito traps for Aedes albopictus and Aedes aegypti. In addition, we explored the co-occurrence of these species in their usual larval habitats. Two traps were compared with two conditions each using a Latin square design: BG Sentinel trap baited with carbon dioxide (CO₂) with/without addition of BG Lure and ovi-sticky trap with/without hay. The ovi-sticky traps proved ineffective. For both Aedes species, CO₂-baited traps were equally effective at catching females when baited with the lure or not. In contrast, they were more attractive to males than for females with the lure. Aedes aegypti larvae were found in four of six vacoas (Pandanus utilis), and one of four anthropogenic breeding sites. In vacoas, the densities of Aedes albopictus and Aedes aegypti larvae were negatively correlated, whereas the correlation was positive between chironomids and Aedes aegypti. The abundance of adults and larvae varied according to weather conditions. Finally, CO₂-baited traps were used without lure for the entomological monitoring to assess the effectiveness of the area-wide boosted SIT intervention to reduce costs and logistics. Full article

Malaria remains a significant public health challenge in Angola, particularly in Cuando Cubango province. This study aimed to characterize the local Anopheles mosquito population, evaluate the impact of indoor residual spraying (IRS) on key entomological indicators, and assess the community knowledge, attitudes, and practices (KAP) related to malaria and vector control. Mosquito collections were conducted indoors at three sites over five months using CDC light traps and Prokopack aspirators. Ten Anopheles species were identified, with An. funestus s.s. being the predominant vector, accounting for 91.7% of the Funestus group. The overall Plasmodium falciparum circumsporozoite protein (CSP) infection rate was 9.2%, with Makua exhibiting the highest rate (10.2%). Following IRS, the indoor resting density of the Funestus group decreased significantly in Makua and Agostinho Neto. In Makua, An. funestus s.s. CSP infection rates decreased by 55% following IRS implementation; however, this reduction was not statistically significant. Knockdown resistance mutations were detected in An. arabiensis and An. gambiae s.s. The 2020/2021 IRS campaign achieved 95% spray coverage and reached 421,856 individuals. Complementary KAP surveys with 647 households showed that 87% of respondents correctly identified mosquitoes as malaria vectors, 78% recognized key symptoms, and 89% supported continued IRS. Reported adherence to post-IRS precautions exceeded 70% and preference for IRS over ITN was expressed by most households. These findings highlight both biological and social dimensions of malaria control, demonstrating that vector control, community acceptance, and entomological surveillance are essential for effective and sustainable malaria interventions in Cuando Cubango. Full article

Background: Aedes albopictus, the tiger mosquito, is an invasive exotic species native to Southeast Asia, currently established in Europe, including Spain and the region of Navarre. This vector poses an emerging public health threat due to its ability to transmit dengue, Zika, and chikungunya viruses, which cause diseases in humans. This study presents novel findings by documenting the progression of the invasion of Aedes albopictus in the Navarre region in northern Spain, tracing its status from initial absence to its definitive establishment in certain areas. Methods: Surveillance in Navarre within the LIFE-IP NAdapta-CC project was conducted through a network of strategically placed ovitraps and adult traps to collect eggs and adult mosquitoes. Awareness campaigns and outreach events were organized to inform local authorities and the public about monitoring results and preventive measures. Results: Monitoring confirms Aedes albopictus’ expansion across Navarre despite training, information dissemination, and control efforts, including entomological containment in targeted areas. Conclusions: Eliminating breeding sites remains the most effective strategy to limit its spread. Complete eradication is unlikely given its invasive nature, and the species is expected to expand and colonize at least part of the region in the coming years. Full article

Background: Mosquitoes from the Aedes (Ae.) genus are vectors of dengue, Zika, chikungunya, and other arboviruses, posing a significant public health threat. In 2005, Aedes aegypti was detected for the first time in Madeira Island, Portugal, in the city of Funchal, and has since become established in the region. In 2017, Aedes albopictus was detected for the first time in mainland Portugal. These invasion events require targeted entomological surveillance, which demands substantial human resources and a high management capacity for traditional vector monitoring. Following promising results obtained in laboratory conditions, a field-deployable model of a bioacoustic sensor for the automatic classification of mosquitoes integrated with a Biogents Sentinel trap as part of the VECTRACK system was tested in three regions in Portugal. Methods: The VECTRACK system was deployed in three locations: Funchal on Madeira Island, and Palmela and Algarve on mainland Portugal. Catch bags were manually inspected at intervals ranging from daily to weekly, resulting in a total of 38 captures in Madeira, 10 in Palmela, and 7 in the Algarve. Manual identifications were compared with those generated by the VECTRACK system, and the degree of correlation between the two datasets was assessed using Spearman’s rank correlation coefficient. Results: A total of 176 mosquitoes were captured in Madeira, 732 in Palmela, and 143 in the Algarve. Both manual and sensor-based identifications demonstrated similar performance, with high correlation observed between the two methods. Spearman’s rank correlation coefficients indicated high agreement for both female and male mosquitoes across all sites: Madeira: females = 0.84, males = 0.92, Palmela: females = 0.99, males = 0.84, Algarve: females = 0.98, and males = 0.99, all with p-values < 0.001. Conclusions: The VECTRACK system demonstrated strong performance in accurately distinguishing mosquitoes from non-mosquitoes, differentiating between Aedes and Culex genera, and identifying the sex of individual specimens. These promising results provide a solid foundation for the development of automated early warning systems and enhance mosquito surveillance strategies, which are critical for timely responses to potential vector-borne disease outbreaks. Full article

Background: Arthropod-borne diseases primarily affect tropical and subtropical regions, exhibiting seasonal patterns that peak during hot and rainy months when conditions favor mosquito vector proliferation. Factors such as high temperatures, elevated humidity, rainfall, urbanization, and the abundance of natural and artificial breeding sites influence Aedes vector dynamics. In this context, arboviruses pose significant public health challenges, likely worsened by global warming. In Brazil, Aedes (Stegomyia) aegypti (Linnaeus, 1762) is the primary vector for yellow fever, dengue, chikungunya, and Zika. Aedes (Stegomyia) albopictus (Skuse, 1894) is an important global arbovirus vector and is considered a potential vector in Brazil. Entomological surveillance of these species often uses oviposition traps targeting immature stages. Evaluating studies that use ovitraps to collect Ae. aegypti and Ae. albopictus egg is essential for improving mosquito surveillance strategies. This study systematically reviewed peer-reviewed articles on ovitrap-based surveillance of Aedes mosquitoes in Brazil, published in Portuguese and English from 2012 to 2022. The findings suggest that ovitraps are an effective method for detecting the presence or absence of Ae. aegypti and Ae. albopictus, serving as a reliable proxy for estimating mosquito abundance in Brazilian contexts. Full article

The Centers for Diseases Control (CDC) light trap is widely used for malaria vector surveillance, but its acquisition logistics pose challenges in Africa. Evaluating new traps can improve surveillance tools. This study compared the efficiency of the BG-Pro UV and Silver Bullet 2.1 UV (SB 2.1 UV) against the UV LED CDC trap in western Kenya’s rice irrigation area. The traps were tested indoors in eight houses over 64 nights. Light properties and fan speed were analyzed using spectrometry and an anemometer. The BG-Pro UV trap performed better than the UV LED CDC trap for An. gambiae s.l. (RR 2.0, 95% CI 0.9–3.9) and An. funestus s.l. (RR 3.5, 95% CI 1.9–6.4). The SB 2.1 UV trap was more effective in capturing An. gambiae s.l. (RR 4.3, 95% CI 2.5–7.3) and An. funestus s.l. (RR 7.1, 95% CI 3.9–13.1), and also caught three times more Culex spp. (RR 2.7, 95% CI 1.2–6.0). SB 2.1 UV had the highest downstream force, and all traps emitting UV-A light had consistent wavelengths. Overall, the BG-Pro and SB 2.1 traps’ trapping efficiency was three to six times more than the CDC trap, making them promising surveillance tools, particularly in low-density malaria settings. Full article