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Home / Equine Research Bank / Open Vet J / First detection of West Nile virus seropositivity in horses ...
Open veterinary journal2025; 15(5); 2016-2020; doi: 10.5455/OVJ.2025.v15.i5.17

First detection of West Nile virus seropositivity in horses in southern Iraq.

Abstract: West Nile virus (WNV) circulates between birds and mosquitoes, with horses and humans as incidental dead-end hosts. Despite documented cases in neighboring countries and human cases in southern Iraq, no previous studies have investigated WNV in Iraqi horses. Unassigned: To determine the seroprevalence of WNV in horses from three southern Iraqi governorates (Thi-Qar, Misan, and Basrah) between March and June 2024. Unassigned: Blood samples were collected from 236 horses regardless of age, sex, or health status. Serum samples were analyzed using commercial competitive enzyme-linked immunosorbent assay kits to detect specific anti-Pr E IgG and IgM antibodies. Unassigned: The overall IgG seropositivity rate was 30.08%, with similar rates reported for Misan (30.66%), Basrah (30.12%), and Thi-Qar (29.48%). IgM seropositivity was 11.86% overall, with 14.67%, 7.22%, and 14.1% in Misan, Basrah, and Thi-Qar, respectively. No statistically significant differences were observed among governorates ( > 0.05). Females had a slightly increased positivity rate (42.7%) when placed alongside males (38%), and with respect to age, the positivity rates for three distinct age categories: 1 to 2 years (no.64), 2 to 5 years (no.135), and above 5 years (no.37) were recorded as 45.31%, 41.48%, and 37.83%, respectively. Unassigned: This is the first study to demonstrate WNV seropositivity in Iraqi horses, revealing active virus circulation in southern Iraq, particularly in marshland areas suitable for mosquito vectors and migratory birds. The findings highlight the need for surveillance programs and preventive measures to control WNV transmission throughout the region.
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Publication Date: 2025-05-31 PubMed ID: 40557085PubMed Central: PMC12184482DOI: 10.5455/OVJ.2025.v15.i5.17Google Scholar: Lookup
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Summary

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 reports the first detection of West Nile virus (WNV) antibodies in horses from southern Iraq, indicating the virus is actively circulating amongst the horse population in that region.

Introduction and Background

  • West Nile virus (WNV) is a mosquito-borne flavivirus primarily maintained through a bird-mosquito transmission cycle.
  • Horses and humans are considered incidental dead-end hosts, meaning they can be infected but do not contribute significantly to virus spread.
  • Although WNV cases exist in neighboring countries and some human infections have been reported in southern Iraq, no prior studies had assessed WNV exposure in Iraqi horses.

Objectives

  • The main aim was to determine the seroprevalence of WNV in horses from three southern Iraqi governorates: Thi-Qar, Misan, and Basrah, during the period from March to June 2024.

Methods

  • Sample Collection:
    • Blood samples were taken from 236 horses without discrimination based on age, sex, or health condition.
  • Laboratory Analysis:
    • Serum was tested using commercial competitive enzyme-linked immunosorbent assay (ELISA) kits.
    • These kits detect specific antibodies (IgG and IgM) against the virus’s envelope protein (Pr E), indicating past or recent infection.

Results

  • IgG Seropositivity (Indicates past or ongoing exposure):
    • Overall rate was 30.08% across all horses tested.
    • Rates were similar across the three governorates: Misan (30.66%), Basrah (30.12%), and Thi-Qar (29.48%).
  • IgM Seropositivity (Indicative of recent or active infection):
    • Overall IgM positivity was 11.86%.
    • By region: Misan (14.67%), Basrah (7.22%), Thi-Qar (14.1%).
    • No statistically significant differences in seroprevalence were found among the governorates (p > 0.05).
  • Sex Differences:
    • Female horses showed a slightly higher positivity rate (42.7%) compared to males (38%).
  • Age Group Differences:
    • Horses aged 1 to 2 years had a seropositivity rate of 45.31%.
    • Horses aged 2 to 5 years had 41.48% positivity.
    • Horses older than 5 years had 37.83% positivity.

Discussion and Significance

  • This study is the first to document WNV antibodies in horses in Iraq, providing evidence of active virus circulation.
  • The presence of both IgG and IgM antibodies indicates not just prior exposure, but ongoing or recent infections.
  • The regions studied include marshland environments conducive to mosquito breeding and frequented by migratory birds, which are vital for WNV transmission.
  • The similar rates across governorates suggest widespread exposure rather than localized outbreaks.
  • Higher positivity in younger horses might reflect recent increased virus activity or different exposure dynamics deserving further study.
  • Slightly higher female seropositivity may be due to behavioral, management, or immune factors but requires further investigation.

Implications and Recommendations

  • The detection of WNV in horses underscores the need for nationwide surveillance programs including both equine and mosquito populations.
  • Preventive measures, such as mosquito control and vaccination campaigns for horses, could be important to reduce the risk of WNV transmission.
  • Public health awareness should be raised due to the zoonotic potential of WNV affecting humans.
  • Further research should focus on virus molecular characterization, vector ecology, and risk factors influencing infection rates.

Cite This Article

APA
Al-Rammahi HM, Mohsen RK, Othman RM. (2025). First detection of West Nile virus seropositivity in horses in southern Iraq. Open Vet J, 15(5), 2016-2020. https://doi.org/10.5455/OVJ.2025.v15.i5.17

Publication

Open veterinary journal
ISSN: 2218-6050
NlmUniqueID: 101653182
Country: Libya
Language: English
Volume: 15
Issue: 5
Pages: 2016-2020

Researcher Affiliations

Al-Rammahi, Hayder Mohammad
  • Department of Internal and Preventive Medicine, College of Veterinary Medicine, Basrah University, Basrah, Iraq.
Mohsen, Rahman Kadhum
  • Department of Internal and Preventive Medicine, College of Veterinary Medicine, Basrah University, Basrah, Iraq.
Othman, Rasha Monther
  • Department of Microbiology, College of Veterinary Medicine, Basrah University, Basrah, Iraq.

MeSH Terms

  • Animals
  • Iraq / epidemiology
  • West Nile Fever / veterinary
  • West Nile Fever / epidemiology
  • West Nile Fever / virology
  • Horses
  • Horse Diseases / epidemiology
  • Horse Diseases / virology
  • West Nile virus / isolation & purification
  • Seroepidemiologic Studies
  • Female
  • Male
  • Antibodies, Viral / blood
  • Immunoglobulin M / blood
  • Enzyme-Linked Immunosorbent Assay / veterinary

Conflict of Interest Statement

The authors declare no conflicts of interest.

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