Abstract: Determination of the seroprevalence and risk factors that are associated with West Nile virus (WNV) in horses is essential for adoption of effective prevention strategies. Our objective in this study, therefore, was to determine the seroprevalence and to identify the risk factors associated with WNV infection in the most densely horse-populated governorates in Egypt. A cross-sectional study was conducted in 2018 on 930 horses, which were distributed over five governorates in the Nile delta of Egypt. The horses, which were randomly selected, were serologically tested through use of an ID screen West Nile competition enzyme-linked immunosorbent assay (ELISA) to detect anti-WNV immunoglobulin G (IgG) and plaque reduction neutralization tests (PRNT; gold standard) to confirm the seropositive status of animals and to avoid cross reaction with other flavi-viruses. Four variables (geographical location, breed, sex and age) were considered in the risk analysis. Univariable and stepwise forward multivariable logistic regression methods were used for risk-factor analysis. The odds ratio (OR) was used as an approximate measure of relative risk. A total of 156 (16.8%; 95% confidence interval (CI) 14.4-19.2; P < 0.001) serum samples were found to be serologically positive for WNV. The highest seroprevalence rate was detected in horses of age ≥ 15 years (68.1%; 95% CI 49.8-72.4), stallions (26.4%; 95% CI 22.7-30.4), and those of mixed breed (21.5%; 95% CI 17.7-27.5). Horses older than 15 years were found to be at increased risk of WNV infection with OR = 4.3 (95% CI 3.0-6.2, P < 0.001) compared with horses aged under 2.5 years. Also, when all the risk factors were considered, stallions were more likely than mares to be WNV seropositive (OR = 2.4, 95% CI 1.6-3.7, P < 0.001), and of the breeds, mixed-breed (OR = 1.9, 95% CI 1.2-2.8, P = 0.005) and Arabian horses (OR = 1.9, 95% CI 1.2-2.8, P = 0.005) were more likely to be seropositive. Geographical location seemed to have no impact on the seroprevalence of exposure to WNV among these horses. Due to these findings, we strongly recommend intensive surveillance and implementation of effective control and prevention strategies against WNV, especially in stallion, mixed-breed horses with ages ≥ 15 years.
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The research article describes a study conducted in Egypt to determine the prevalence of West Nile virus (WNV) in horses and associated risk factors. The study found that 16.8% of tested horses were seropositive for WNV, with older horses, stallions, and certain breeds showing higher risk.
Research Objective and Method
The objective of this research was to establish the prevalence of West Nile virus (WNV) and identify the associated risk factors in horses in several regions of Egypt.
The researchers used a cross-sectional study, conducted in 2018, that included 930 horses from five different governorates in the Nile delta.
Horses were randomly selected and serologically tested using an ID screen West Nile competition enzyme-linked immunosorbent assay (ELISA) to detect anti-WNV immunoglobulin G (IgG), with plaque reduction neutralization tests (PRNT) used to confirm any seropositive results and to prevent cross contamination with other flavi-viruses.
The considered risk factors included geographical location, breed, sex, and age of the horses.
Findings and Risk Factor Analysis
Out of all sampled horses, 16.8% were found serologically positive for WNV.
In terms of individual traits, the researchers found the highest seroprevalence among horses aged 15 or older (68.1%), stallions (26.4%), and mixed-breeds (21.5%).
Older horses showed an increased risk of WNV infection, with an odds ratio (OR) of 4.3 compared to horses under 2.5 years old.
When all risk factors were considered, stallions were more likely to be WNV seropositive than mares, with an OR of 2.4.
Mixed-breed and Arabian horses displayed a higher likelihood of being seropositive, with an OR of 1.9.
Geographical location appeared to have no significant impact on WNV seroprevalence among these horses.
Conclusions and Recommendations
The results revealed significant presence of WNV in the horse population of Egypt, with particular risk factors such as age, sex, and breed.
In response to their findings, the researchers strongly suggest intensive surveillance and implementation of effective control and prevention measures, particularly for stallions and mixed-breed horses aged 15 years or older.
Cite This Article
APA
Selim A, Megahed A, Kandeel S, Alouffi A, Almutairi MM.
(2021).
West Nile virus seroprevalence and associated risk factors among horses in Egypt.
Sci Rep, 11(1), 20932.
https://doi.org/10.1038/s41598-021-00449-6
Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Moshtohor-Toukh, 13736, Kalyobiya, Egypt. Abdelfattah.selim@fvtm.bu.edu.eg.
Megahed, Ameer
Department of Animal Medicine (Internal Medicine), Faculty of Veterinary Medicine, Benha University, Moshtohor-Toukh, 13736, Kalyobiya, Egypt.
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Illinois, IL, 61802, USA.
Kandeel, Sahar
Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Moshtohor-Toukh, 13736, Kalyobiya, Egypt.
Alouffi, Abdulaziz
King Abdulaziz City for Science and Technology, Riyadh, 12354, Saudi Arabia.
Vaccines Research of Infectious Diseases, King Saud University, Riyadh, 11495, Saudi Arabia.
Almutairi, Mashal M
Vaccines Research of Infectious Diseases, King Saud University, Riyadh, 11495, Saudi Arabia.
Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
MeSH Terms
Animals
Cross Reactions / immunology
Cross-Sectional Studies
Egypt / epidemiology
Enzyme-Linked Immunosorbent Assay / methods
Horse Diseases / epidemiology
Horse Diseases / immunology
Horse Diseases / virology
Horses
Immunoglobulin G / immunology
Neutralization Tests / methods
Risk Factors
Seroepidemiologic Studies
West Nile Fever / epidemiology
West Nile Fever / immunology
West Nile Fever / virology
West Nile virus / immunology
Conflict of Interest Statement
The authors declare no competing interests.
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