Mosquito Exposure Risks in Equine Facilities: An Environmental-Managerial Assessment in Western Romania.
Abstract: West Nile Virus (WNV) is a mosquito-borne zoonosis with recurrent equine and human cases in Romania. Horses, although dead-end hosts, act as sentinels for local viral circulation. Farm-level risk conditions remain under-characterized. This pilot, exploratory cross-sectional study assessed 42 equine facilities in western Romania (2024). A standardized 10-item checklist was applied and a Composite Environmental Risk Score (CERS) (0-10, unweighted) was computed per facility. Spatial analysis in QGIS included distances to nearby water bodies. No serological or entomological data were collected; these are recommended for future validation. Stagnant water occurred at 71.4% (30/42) of facilities, uncovered rain-collecting containers at 64.3% (27/42), and outdoor housing of horses at 81.0% (34/42). Insect screens were present at 21.4% (9/42) and chemical/biological control at 33.3% (14/42). By design, the CERS ranged from 0 to 10; in our sample the observed range was 0-8 because not all assessed risk conditions co-occurred across sites. Overall, 42.9% (18/42) were classified as high risk (≥6). Neurological signs were reported anecdotally by some managers but were not analyzed. Mosquito-favorable conditions are widespread in Romanian equine facilities. CERS shows promise as a low-cost, rapid tool for routine facility-level assessment of environmental conditions favoring mosquito presence and prioritization of preventive actions. Integrating environmental risk scoring with entomological and serological surveillance could strengthen One Health early-warning systems. Such integration would support prevention of WNV and other mosquito-borne zoonotic pathogens in endemic European settings.
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
Overview
This study evaluated the environmental and managerial factors that influence mosquito exposure risks at horse facilities in western Romania, a region affected by West Nile Virus (WNV).
The goal was to develop and test a simple risk assessment tool to identify equine sites with higher potential for mosquito-borne disease transmission and to inform preventive measures.
Background
West Nile Virus (WNV) is a mosquito-transmitted disease affecting both humans and horses.
In Romania, WNV periodically causes cases in horses and people, with horses serving as indicators (“sentinels”) of local virus circulation despite being dead-end hosts (they do not spread the virus further).
Despite ongoing cases, little is known about specific farm-level risk factors or how to systematically identify high-risk equine environments.
Study Design and Methods
This was a cross-sectional, observational study conducted in 2024 involving 42 horse facilities in western Romania.
Researchers used a standardized 10-item checklist to assess each facility’s environmental and managerial conditions related to mosquito breeding and exposure.
A Composite Environmental Risk Score (CERS) from 0 to 10 was calculated for each facility by summing the presence of risk factors, without weighting any item.
Spatial analysis using QGIS software examined the proximity of each facility to nearby water bodies, which can be mosquito breeding sites.
No direct testing of horses for WNV antibodies (serological data) or mosquito population surveys (entomological data) were performed; future work is recommended to include these for validating the risk assessments.
Key Findings
Common mosquito breeding and exposure risk conditions were frequently detected:
Stagnant water at 71.4% of facilities, which provides breeding sites for mosquitoes.
Uncovered rain-collecting containers at 64.3%, another common breeding habitat.
Outdoor housing of horses was common (81.0%), increasing horses’ exposure to mosquitoes.
Only 21.4% of facilities had insect screens to reduce mosquito entry.
Only a third (33.3%) implemented chemical or biological mosquito control methods.
The risk scores across facilities ranged from 0 to 8 (on a 0-10 scale), reflecting varied but not all-encompassing risk conditions.
Nearly 43% of locations were classified as high risk with a CERS score of 6 or higher.
Some managers noted neurological signs among horses anecdotally, suggestive of possible WNV infections, but these were not systematically analyzed.
Significance and Implications
The study demonstrates that mosquito-favorable environmental factors are common at equine facilities in western Romania, increasing potential risk for WNV transmission.
The Composite Environmental Risk Score (CERS) shows promise as an easy-to-use, low-cost tool that facility managers or health officials could use to rapidly identify and prioritize sites for mosquito risk mitigation.
Integrating environmental risk assessments like the CERS with entomological monitoring (mosquito surveys) and serological testing of horses and humans can create a more comprehensive surveillance system.
This integrated “One Health” approach could enhance early warning systems to prevent and control outbreaks of WNV and other mosquito-borne zoonoses in European endemic areas.
Routine implementation of such assessments could inform targeted preventive actions, such as removing stagnant water, installing insect screens, and applying mosquito control methods to reduce WNV exposure risk.
Recommendations for Future Research
Include serological testing of horses to confirm WNV exposure correlates with environmental risk scores.
Conduct entomological surveys to directly measure mosquito abundance and species at each facility.
Analyze reported neurological symptoms in horses to investigate possible links with detected environmental risks and WNV infection.
Test the CERS tool in larger and diverse geographic areas and refine its scoring system, potentially adding weighted factors based on their relative importance.
Evaluate the effectiveness of interventions prompted by CERS in reducing mosquito populations or WNV cases at facilities.
Cite This Article
APA
(2025).
Mosquito Exposure Risks in Equine Facilities: An Environmental-Managerial Assessment in Western Romania.
Microorganisms, 13(11), 2637.
https://doi.org/10.3390/microorganisms13112637
Vargas Campos C.A., García-Pérez S., Figuerola J., la Puente J.M.-D., Polo I., Rodríguez-De-Fonseca B., Fernández-Álvarez S., Fraile V.G., Martín-Rey M., Lacasaña M.. Comprehensive analysis of West Nile Virus transmission: Environmental, ecological, and individual factors. An umbrella review.. One Health 2025;20:100984.
Savuła G., Luanda O., Aniłă A., Aniłă D.. West Nile Virus infections in Romania—Past, present and perspective.. Lucr. Științifice Med. Vet. Timișoara 2008;XLI:301–308.
Simonin Y.. Circulation of West Nile Virus and Usutu Virus in Europe: Overview and Challenges.. Viruses 2024;16:599.
Wang H.R., Liu T., Gao X., Wang H.B., Xiao J.H.. Impact of climate change on the global circulation of West Nile virus and adaptation responses: A scoping review.. Infect. Dis. Poverty 2024;13:38.
Gizaw Z., Salubi E., Pietroniro A., Schuster-Wallace C.J.. Impacts of climate change on water-related mosquito-borne diseases in temperate regions: A systematic review of literature and meta-analysis.. Acta Trop. 2024;258:107324.
Dinu S., Stancu I.G., Cotar A.I., Ceianu C.S., Pintilie G.V., Karpathakis I., Fălcuță E., Csutak O., Prioteasa F.L.. Continuous and dynamic circulation of West Nile Virus in mosquito populations in Bucharest area, Romania, 2017–2023.. Microorganisms 2024;12:2080.
Horváth C., Cazan C.D., Mihalca A.D.. Emergence of the invasive Asian bush mosquito, Aedes (Finlaya) japonicus japonicus, in an urban area, Romania.. Parasites Vectors 2021;14:192.
Crivei L.A., Moutailler S., Gonzalez G., Lowenski S., Crivei I.C., Porea D., Anita D.C., Ratoi I.A., Zientara S., Oslobanu L.E.. Detection of West Nile Virus Lineage 2 in Eastern Romania and first identification of Sindbis Virus RNA in mosquitoes analyzed using high-throughput microfluidic real-time PCR.. Viruses 2023;15:186.
European Centre for Disease Prevention and Control. West Nile Virus Outbreak in Romania, July to October 1996.. ECDC; Stockholm, Sweden: 2011.
Oslobanu L.E., Pâslaru A., Savuța G.. West Nile Virus seroprevalence in horses from Romania: First step in the infection risk assessment.. Bull. Univ. Agric. Sci. Vet. Med. Cluj-Napoca Vet. Med. 2015;72:5–9.
Kirov P., Iancu I., Panayotova E., Petrov R., Imre M., Herman V., Hristov H., Abudalleh A., Alexandrova R., Gligor A.. First trans-border serological evidence of West Nile Virus infection in horses in Romania and Bulgaria.. Int. J. Vet. Sci. 2025;14:777–781.
Calzolari M., Angelini P., Bolzoni L., Bonilauri P., Cagarelli R., Canziani S., Cereda D., Cerioli M.P., Chiari M., Galletti G.. Enhanced West Nile Virus circulation in the Emilia-Romagna and Lombardy Regions (Northern Italy) in 2018 detected by entomological surveillance.. Front. Vet. Sci. 2020;7:243.
Honnen A., Kypke J., Hölker F., Monaghan M.. Artificial light at night influences clock-gene expression, activity, and fecundity in the mosquito Culex pipiens f. molestus.. Sustainability 2019;11:6220.
Riccardo F., Bolici F., Fafangel M., Jovanovic V., Socan M., Klepac P., Plavsa D., Vasic M., Bella A., Diana G.. West Nile Virus in Europe: After action reviews of preparedness and response to the 2018 transmission season in Italy, Slovenia, Serbia and Greece.. Glob. Health 2020;16:47.
Petrović T., Šekler M., Petrić D., Lazić S., Debeljak Z., Vidanović D., Ćupina A.I., Lazić G., Lupulović D., Kolarević M.. Methodology and results of integrated WNV surveillance programmes in Serbia.. PLoS ONE 2018;13:e0195439.
García-Bocanegra I., Arenas-Montes A., Napp S., Jaén-Téllez J.A., Fernández-Morente M., Fernández-Molera V., Arenas A.. Seroprevalence and risk factors associated with West Nile Virus in horses from Andalusia, Southern Spain.. Vet. Microbiol. 2012;160:341–346.
Leblond A., Sandoz A., Lefebvre G., Zeller H., Bicout D.J.. Remote sensing-based identification of environmental risk factors associated with West Nile disease in horses in Camargue, France.. Prev. Vet. Med. 2007;79:20–31.
Naveed A., Eertink L., Wang D., Li F.. Lessons Learned from West Nile Virus Infection: Vaccinations in Equines and Their Implications for One Health Approaches.. Viruses 2024;16:781.
Dapari R., Fadzil M., Hanzir M., Jais J., Safarudin N., Albar A.. Factors Associated with Mosquito Control among Construction Workers: A Systematic Review.. PLoS ONE 2024;19:e0303330.
Tai Z., Connelly C., Lange S., Foley N., De J., Rivera L., Lozano S., Nett R.. A Scoping Review to Determine if Adverse Human Health Effects Are Associated with Use of Organophosphates for Mosquito Control.. J. Med. Entomol. 2024;62:8–18.
Miranda L., Rudd S., Mena O., Hudspeth P., Barboza-Corona J., Park H., Bideshi D.. The Perpetual Vector Mosquito Threat and Its Eco-Friendly Nemeses.. Biology 2024;13:182.
García-Suárez O., Tolsá-García M., Arana-Guardía R., Rodríguez-Valencia V., Talaga S., Pontifes P., Machain-Williams C., Suzán G., Roiz D.. Seasonal Mosquito (Diptera: Culicidae) Dynamics and the Influence of Environmental Variables in a Land Use Gradient from Yucatán, Mexico.. Acta Trop. 2024;257:107275.
Velde F., Overgaard H., Bastien S.. An Integrated Human Behavioral Model for Mosquito-Borne Disease Control: A Scoping Review of Behavior Change Theories Used to Identify Key Behavioral Determinants.. Heliyon 2024;10:e26488.
Mader E., Clements N., Lehane Á., Gangloff-Kaufmann J., Crans S., Horton C., Safi A.. A Qualitative Analysis of Perceived Risks and Benefits of Mosquito Abatement and Bite Prevention Strategies in Northeastern U.S. Communities.. J. Med. Entomol. 2024;62:435–448.
Al-Eitan L, Alnimri M, Ali H, Alkhawaldeh M, Mihyar A. Mosquito-Borne Diseases: Assessing Risk and Strategies to Control Their Spread in the Middle East. J. Biosaf. Biosecurity 2024;6:1–12.
Nejati J, Azari-Hamidian S, Oshaghi M, Vatandoost H, White V, Moosa-Kazemi S, Bueno-Marí R, Hanafi-Bojd A, Endersby-Harshman N, Axford J. The Monsoon-Associated Equine South African Pointy Mosquito Aedes caballus: The First Comprehensive Record from Southeastern Iran with a Description of Ecological, Morphological, and Molecular Aspects. PLoS ONE 2024;19:e0298412.
Wouters R, Beukema W, Schrama M, Biesmeijer K, Braks M, Helleman P, Schaffner F, Van Slobbe J, Stroo A, Van Der Beek J. Local Environmental Factors Drive Distributions of Ecologically-Contrasting Mosquito Species (Diptera: Culicidae). Sci. Rep. 2024;14:19315.
Chuchuy A, Rodriguero M, Alonso A, Stein M, Micieli M. Wolbachia Infection in Natural Mosquito Populations from Argentina. Parasitol. Res. 2024;123:343.
Abbasi M, Yousefi S. Assessing Insecticide Susceptibility of Culex pipiens Linnaeus (Diptera: Culicidae) in the Aras River Basin: Implications for Disease Control. BMC Infect. Dis. 2025;25:247.
Zhang Y, Wang M, Huang M, Zhao J. Innovative Strategies and Challenges in Mosquito-Borne Disease Control Amidst Climate Change. Front. Microbiol. 2024;15:1488106.