Search Results (394)

Vector-borne diseases (VBDs) continue to pose a persistent global health challenge, disproportionately impacting low- and middle-income countries where surveillance and healthcare infrastructure are constrained. Within these countries, residents of remote island communities are particularly vulnerable to emerging VBD threats; however, they remain critically understudied. We conducted a community-based cross-sectional survey of 300 residents from Shahpori Island, Bangladesh, and Gaya Island, Malaysia, to assess knowledge, attitudes, and practices (KAP) related to VBDs. Using a structured questionnaire and mixed-effects Poisson regression modeling, we identified socio-demographic predictors of VBD-related knowledge and compared KAP outcomes across the two islands. Significant disparities were observed between the two settings: the Gaya Island residents demonstrated a higher level of awareness regarding VBDs and preventive practices compared to the Shahpori residents. Education was a strong predictor of VBD knowledge, with individuals possessing secondary education or above exhibiting significantly better knowledge (β = 0.2024, p = 0.0003). Marital status was also a significant factor, with unmarried respondents showing lower levels of knowledge (β = –0.1657, p = 0.0372). Age was positively correlated with VBD knowledge (β = 0.0051, p = 0.0119), indicating a gradual increase with age, while income, gender, occupation, and household size were not significantly associated. Despite basic awareness of VBD symptoms and transmission, detailed understanding of mosquito ecology, disease symptoms, and breeding prevention strategies was remarkably poor, especially among the Shahpori residents. Our findings highlight critical gaps in VBD-related knowledge and prevention behaviors shaped by socio-economic and educational disparities. Community-focused public health strategies including educational campaigns, establishment of health infrastructure, access to trained healthcare providers, and integrated vector control interventions are urgently needed to enhance resilience against emerging VBD threats such as drug-resistant malaria in remote island populations. Full article

Between 2016 and 2018, the state of Minas Gerais, Brazil, experienced its most significant yellow fever (YF) outbreak in 80 years. Yellow fever virus (YFV) circulation persisted afterward, with continued non-human primate (NHP) epizootics and, recently, human cases. In June 2024, YFV RNA was detected in a dead marmoset (Callithrix penicillata) in an urban square in Belo Horizonte (BH), prompting a field investigation in an adjacent park to assess infection in potential mosquito vectors and NHPs. A total of 250 mosquitoes representing nine species were collected at ground and canopy level, of which Aedes fluviatilis and Aedes scapularis comprised 78.8% of the specimens. Haemagogus spp. and Sabethes spp. mosquitoes were not collected, possibly due to the short sampling window during the dry season. No active YFV infection was detected in any of the mosquito pools tested. Eight marmosets (Callithrix penicillata) were captured and tested for arboviral infections. Five out of eight sera, representing both adult and juvenile (less than 17 months old) animals, tested positive for anti-YFV IgM. Interestingly, two adults recaptured in later expeditions revealed seroconversion. One was IgM-positive in July 2024 but negative by September 2024, consistent with the expected decline in IgM levels. The other, initially IgM-negative (as of July 2024), tested positive in April 2025, indicating recent exposure to YFV. These findings provide evidence for the ongoing, low-level circulation of YFV among urban NHPs, posing a continued risk of viral spillover to humans. Moreover, these results highlight the importance of active surveillance in detecting recent infections that would likely be missed by passive monitoring. This integrated approach enhances our understanding of local YF epidemiology and supports early, evidence-based public health interventions to prevent future human outbreaks. Full article

The spread of the invasive mosquitoes Aedes albopictus, Aedes aegypti, and Aedes japonicus in Spain represents an increasing public health risk due to their capacity to transmit arboviruses such as dengue, Zika, and chikungunya, among others. Traditional field entomological surveillance remains essential for tracking their spread, but it faces limitations in terms of cost, scalability, and labor intensity. Since 2014, the Mosquito Alert citizen-science project has enabled public participation in surveillance through the submission of geolocated images via a mobile app, which are identified using AI in combination with expert validation. While field surveillance provides high accuracy, citizen science offers low-cost, large-scale, real-time data collection aligned with open data management principles. It is particularly useful for detecting long-distance dispersal events and has contributed up to one-third of the municipal detections of invasive mosquito species since 2014. This study assesses the value of integrating both surveillance systems to capitalize on their complementary strengths while compensating for their weaknesses in the areas of taxonomic accuracy, scalability, spatial detection patterns, data curation and validation systems, geographic precision, interoperability, and real-time output. We present the listing of municipal detections of these species from 2004 to 2024, integrating data from both sources. Spain’s integrated approach demonstrates a pioneering model for cost-effective, scalable vector surveillance tailored to the dynamics of invasive species and emerging epidemiological threats. 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

Malaria, caused by a protozoan parasite of the genus Plasmodium and transmitted by mosquitoes of the genus Anopheles, remains a significant vector-borne disease worldwide. In 2018, Paraguay became the first country in the Americas in 45 years to be certified malaria-free by the World Health Organization. Between 2016 and 2017, a period with no reported human malaria cases, the presence of Plasmodium spp. in Anopheles mosquitoes was investigated in the departments of Caaguazú and Alto Paraná. These studies found that the most prevalent Anopheles species in Paraguay, including Anopheles albitarsis (59.4%), Anopheles strodei (21.5%), and other Anopheles species in smaller proportions, were all negative to the parasite. The objective of this study was to re-evaluate these presence data and to define environmentally suitable areas for Anopheles spp. and their association with bioclimatic variables using DIVA-GIS/MaxEnt software for the entomological surveillance of malaria risk in Paraguay. Results showed that areas of bioclimatic suitability included the Humid Chaco, Cerrado, Paraná Atlantic Forest, and Southern Cone Mesopotamian savanna ecoregions. The most relevant climatic variables were the precipitation of the wettest month (contribution of 80.4%) and the precipitation of the driest month (contribution of 18.4%). Anopheles albitarsis, also reported as a vector of the Venezuelan equine encephalitis virus in neighbouring countries, was the most abundant mosquito species. Anopheles darlingi, the main vector of malaria in Paraguay, was not found. However, species richness indices (Chao/ACE) suggest that cryptic or sibling species may be present. Finally, the possible succession of Anopheles species and their geographical segregation are discussed in scenarios of entomological surveillance and epidemiological risk. Full article

In the absence of commercialized vaccines for most arboviruses, including dengue, chikungunya, and Zika, which are transmitted by Aedes aegypti, the management of vector populations to prevent disease transmission remains the cornerstone of arbovirus control strategies. Larviciding targets the early stages of the mosquito life cycle and subsequently reduces the capacity of adult population to transmit pathogens. Here, we report the susceptibility profile of Ae. aegypti larval populations from two West Africa cities, namely Niamey and Ouagadougou, to organophosphates larvicides. In Niamey, sampling was carried out using ovitraps at two sites, whereas in Ouagadougou, larvae were collected from three different types of larval containers at a single site. Temephos and fenitrothion were tested at six different concentrations each. Mosquito populations from Niamey and Ouagadougou were found susceptible to temephos and fenitrothion, with LD₅₀ < 0.015 mg/L and RR₅₀ < 5. However, Ae. aegypti populations from Ouagadougou showed reduced susceptibility to temephos compared to baseline data from 2016, as indicated by RR₅₀ values. This observation highlights the need for regular surveillance of larval susceptibility, as it may signal the emergence of temephos resistance in Ouagadougou. The acetylcholinesterase (AChE) mutation and the expression levels of metabolic genes Carboxy-/Cholinesterase (CCE) should be characterized to understand the molecular mechanisms underlying the observed phenotype response. Our results provide up-to-date data that could inform the potential deployment of these larvicides for the prevention and control of dengue and chikungunya outbreaks in Ouagadougou and Niamey. Full article

Since there are no available vaccines against some arboviruses, vector control is the most effective way to reduce their incidence. In this context, mechanical control is one of the most cost-effective ways to suppress Aedes populations, but it requires knowledge about vector breeding ecology in varied landscapes and climates. Here we investigated the infestation levels and container types used as larval habitats by Aedes aegypti and Aedes albopictus in an urban gradient of Vassouras, a countryside city in Rio de Janeiro. Larval surveys were conducted bimonthly from January 2017 to December 2018. Infestation was measured through the House (HI) and Breteau indexes (BI). Container types found with Aedes spp. immatures were correlated with temperature and rainfall and were compared between urbanization zones. The distribution of positive containers was mapped. The HI for Ae. aegypti increased during rainy seasons, but the HI and BI were always <1% for both mosquito vectors. More reservoirs were found harboring Ae. albopictus than Ae. aegypti, but in general their relative distribution into types was similar between species. On the other hand, the amount and distribution of containers into types varied across urbanization zones. Finally, the spatial distribution of larval habitats was similar between species, as well as often constant between seasons and study years. 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

This cross-sectional study evaluated the seroprevalence and clinical impact of West Nile virus (WNV) infection in horses from three ecologically high-risk counties in western Romania (Timiș, Arad, and Bihor) between 2023 and 2025. A total of 306 unvaccinated horses were tested using a commercial ELISA, with 8.17% testing positive for WNV antibodies, indicating prior exposure. Passive surveillance for clinical signs during mosquito seasons identified 16 horses with acute neurological symptoms, four of which were confirmed as clinical cases based on WNV-specific IgM positivity, suggesting probable silent WNV circulation in the region. The overall case fatality rate among confirmed clinical cases was 25.0%. WNV seropositivity was highest in Bihor (8.85%), followed by Arad (8.57%) and Timiș (7.32%). Statistical comparisons using χ² tests and binary logistic regression indicated no significant differences in seroprevalence between counties, sexes, or age groups, consistent with the overlapping 95% confidence intervals. These findings suggest the continued silent circulation of WNV in the region and support the integration of equine surveillance into the One Health framework as a potential tool for early detection and risk mitigation. However, in the absence of molecular confirmation (e.g., RT-PCR or virus isolation), these results should be interpreted as indicative of prior exposure rather than direct evidence of ongoing viral activity. Full article

The accurate identification of mosquito species is critical for effective mosquito surveillance and control, especially when presented with morphologically similar species like Aedes aegypti and Aedes sierrensis. Damaged specimens and morphologically similar life stages such as eggs and larvae make it difficult to distinguish Aedes aegypti from Aedes sierrensis using microscopy and taxonomic keys. To address this, the AegySierr.ID-qPCR assay, a multiplex quantitative PCR assay that utilizes single-nucleotide polymorphisms within the mitochondrial cytochrome oxidase subunit I gene, was developed to distinguish between these two species. The assay was tested on DNA extracted from the eggs, larvae, and adults of both species, as well as from environmental DNA (eDNA) collected from natural mosquito reproduction sites. It demonstrated a high diagnostic accuracy across multiple life stages, with a sensitivity exceeding 95% for most groups and specificity exceeding 90%, except for field-collected adult Ae. sierrensis (75%). For eDNA samples, the assay achieved 100% sensitivity and 94% specificity for samples classified as Ae. sierrensis and 91% sensitivity and 86% specificity for Ae. aegypti. A two-graph receiver operating characteristic analysis was also used as an alternate method with which to establish Ct thresholds for interpreting results from unknown samples. The AegySierr.ID-qPCR assay enables the rapid and sensitive identification of Ae. aegypti and Ae. sierrensis from specimens and eDNA, and may be of use in mosquito surveillance programs. Full article

The genus Orthoflavivirus includes several mosquito-borne pathogenic viruses, notably West Nile virus (WNV), which is endemic to the Mediterranean region. In Portugal, WNV circulation has been documented in equines, birds and mosquitoes, however human cases remain rare and no recent human seroprevalence studies have been conducted. This study aimed to estimate the national and regional seroprevalence of WNV among blood donors in mainland Portugal and explore associations with sociodemographic factors. A cross-sectional study conducted in 2022 included 3593 blood donors from across mainland Portugal. Serum samples were tested for WNV immunoglobulin G (IgG) by enzyme-linked immunosorbent assay (ELISA) and positive and borderline samples were confirmed using a virus neutralization test. Sociodemographic data were collected through a structured paper questionnaire. Statistical analyses, including multivariate logistic regression, identified factors associated with seropositivity. A total of 55 samples (1.5%) tested positive, and 21 samples (0.6%) were classified as borderline for WNV antibodies by ELISA. Of these, 47 were confirmed by viral neutralization, giving an estimated national seroprevalence of 1.4%. Significant regional variation was noted, with higher seroprevalence observed in the Beira Baixa, Grande Lisboa and Médio Tejo regions. Some seropositive individuals were identified in northern coastal regions such as Ave, Cávado and Área Metropolitana do Porto. In multivariate analysis, geographical area of residence was the only factor associated with seropositivity. This study highlights regions at potential higher risk for human WNV exposure, primarily in the southern half of Portugal. Continued and integrated surveillance is crucial to inform public health strategies to mitigate WNV transmission risks in these regions, as well as in other regions where WNV may be emerging as a relevant One Health concern. Implementing preventive measures for both animals and humans is critical to minimizing exposure and infection, and further confirmatory studies using virus neutralization tests will be important for refining these estimates. 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

CHIKV is a re-emerging mosquito-borne arthritogenic alphavirus associated with large outbreaks and severe joint pain, and it poses a growing global health threat. Toll-like receptors (TLRs), as key pattern recognition receptors, detect viral components and initiate antiviral immune responses. Increasing evidence highlights the role of TLR signaling in shaping CHIKV infection outcomes, though its precise contribution remains unclear. CHIKV has developed mechanisms to evade host innate immune surveillance, promoting viral replication. TLR agonists show promise as vaccine adjuvants by enhancing immune responses. In this review, we summarize current insights into TLR-mediated immunity during CHIKV infection, the virus’s innate immune evasion strategies, and the potential of TLR agonists in improving vaccine efficacy. Full article

Climate change has magnified health disparities across the Southern African Development Community (SADC) region by destabilizing the critical natural systems, which include water security, food production, and disease ecology. The IPCC (2007) underscores the disproportionate impact on low-income populations characterized by limited adaptive capacity, exacerbating existing vulnerabilities. Rising temperatures, erratic precipitation patterns, and increased frequency of extreme weather events ranging from prolonged droughts to catastrophic floods have created favourable conditions for the spread of waterborne diseases such as cholera, dysentery, and typhoid, as well as the expansion of vector-borne diseases zone also characterized by warmer and wetter conditions where diseases like malaria thrives. This study employed a comparative analysis of climate and health data across Malawi, Zimbabwe, Mozambique, and South Africa examining the interplay between climatic shifts and disease patterns. Through reviews of national surveillance reports, adaptation policies, and outbreak records, the analysis reveals the existence of critical gaps in preparedness and response. Zimbabwe’s Matabeleland region experienced a doubling of diarrheal diseases in 2019 due to drought-driven water shortages, forcing communities to rely on unsafe alternatives. Mozambique faced a similar crisis following Cyclone Idai in 2019, where floodwaters precipitated a threefold surge in cholera cases, predominantly affecting children under five. In Malawi, Cyclone Ana’s catastrophic flooding in 2022 contaminated water sources, leading to a devastating cholera outbreak that claimed over 1200 lives. Meanwhile, in South Africa, inadequate sanitation in KwaZulu-Natal’s informal settlements amplified cholera transmission during the 2023 rainy season. Malaria incidence has also risen in these regions, with warmer temperatures extending the geographic range of Anopheles mosquitoes and lengthening the transmission seasons. The findings underscore an urgent need for integrated, multisectoral interventions. Strengthening disease surveillance systems to incorporate climate data could enhance early warning capabilities, while national adaptation plans must prioritize health resilience by bridging gaps between water, agriculture, and infrastructure policies. Community-level interventions, such as water purification programs and targeted vector control, are essential to reduce outbreaks in high-risk areas. Beyond these findings, there is a critical need to invest in longitudinal research so as to elucidate the causal pathways between climate change and disease burden, particularly for understudied linkages like malaria expansion and urbanization. Without coordinated action, climate-related health inequalities will continue to widen, leaving marginalized populations increasingly vulnerable to preventable diseases. The SADC region must adopt evidence-based, equity-centred strategies to mitigate these growing threats and safeguard public health in a warming world. Full article

Mosquito blood meals provide a biological sample of host blood which can then be used in downstream applications including host–pathogen detection. We conducted DNA barcoding to identify the host species of blood meals from 4557 blood engorged mosquitoes collected in south central Florida, USA. We identified 314 blood meals from invasive wild pigs, 219 wild turkey blood meals, and 1046 white-tailed deer blood meals. From a subset of these host blood meals, we used molecular assays to detect the nucleic acids of Torque teno sus virus 1 (TTSuV1) in wild pig blood meals, Lymphoproliferative virus (LPDV) in wild turkey blood meals, and bluetongue virus (BTV) in white-tailed deer blood meals. None of these wildlife pathogens are transmitted by mosquitoes, but viral nucleic acids circulate in the peripheral blood of host species during or post infection. Prevalence of TTSuV1 in wild pig blood meals was 34%; in wild turkey blood meals the prevalence of LPDV was 2.7%, and BTV prevalence in blood meals of white-tailed deer was 3.6%. These prevalence values were similar to estimates obtained from peripheral blood collected directly from these hosts in Florida. Our analysis suggests that mosquito blood meals are a valuable sampling tool for the detection of wildlife pathogens. We suggest that this type of exogenous xenosurveillance, using mosquitoes to infer information about the vertebrate host, is distinct from endogenous xenosurveillance in which the goal is to understand the role of the arthropod in vectoring a pathogen. Full article