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.
Publication Date: 2025-11-20 PubMed ID: 41304321PubMed Central: PMC12654757DOI: 10.3390/microorganisms13112637Google Scholar: Lookup
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Summary
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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 Publication
Researcher Affiliations
Conflict of Interest Statement
The authors declare no conflicts of interest.
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