Serological evidence of circulation of West Nile virus in equids in Algerian eastern drylands and its epidemiological risk factors

Farouk Laabassi (1) , Nolwenn Dheilly (2) , Cécile Beck (2) , Rayane Amaral (2) , Gaëlle Gonzalez (2) , Delphine Gaudaire (3) , Anthony Madeline (3) , Fanny Lecouturier (3) , Sylvie Lecollinet (2) , Stéphan Zientara (2) , Aymeric Hans (3) , José-Carlos Valle-Casuso (3)

1 University of Batna Hadj Lakhder [Algeria]
2 VIRO - Virologie UMR1161
3 PhEED - Physiopathologie et épidémiologie des maladies équines

In order to determine the prevalence of equine infectious anemia virus (EIAV), Usutu virus (USUV), and West Nile virus (WNV) in eastern Algerian drylands, 340 sera from distinct equids have been collected from 2015 to 2017. Serological analysis for the presence of antibodies against EIAV and flaviviruses was performed using commercially available ELISAs. Sera detected positive, doubtful, or negative close to the doubtful threshold in flavivirus ELISA were tested by the virus neutralization test (VNT), using WNV and USUV strains. The prevalence of WNV antibodies with ELISA was 11.47% (39/340) against 13.53% (46/340) by WNV VNT. EIAV antibodies were not detected in any samples. WNV seroprevalence varies with species, breed and location of horses. Only, one equid was positive for both WNV and USUV neutralizing antibodies. This is the first screening on equids sera of EIAV and USUV in Algeria. This study indicate that WNV and possibly USUV have circulated/are circulating in the Algerian equine population, unlike EIAV does not seem to be present.

In order to determine the prevalence of equine infectious anemia virus (EIAV), Usutu virus (USUV), and West Nile virus (WNV) in eastern Algerian drylands, 340 sera from distinct equids have been collected from 2015 to 2017. Serological analysis for the presence of antibodies against EIAV and flaviviruses was performed using commercially available ELISAs. Sera detected positive, doubtful, or negative close to the doubtful threshold in flavivirus ELISA were tested by the virus neutralization test (VNT), using WNV and USUV strains. The prevalence of WNV antibodies with ELISA was 11.47% (39/340) against 13.53% (46/340) by WNV VNT. EIAV antibodies were not detected in any samples. WNV seroprevalence varies with species, breed and location of horses. Only, one equid was positive for both WNV and USUV neutralizing antibodies. This is the first screening on equids sera of EIAV and USUV in Algeria. This study indicate that WNV and possibly USUV have circulated/are circulating in the Algerian equine population, unlike EIAV does not seem to be present.

Mots clés: Algeria; EIAV; Equine; Seroprevalence; USUV; VNT; WNV

Domaines: Sciences du Vivant [q-bio]

Farouk Laabassi, Nolwenn Dheilly, Cécile Beck, Rayane Amaral, Gaëlle Gonzalez, et al.. Serological evidence of circulation of West Nile virus in equids in Algerian eastern drylands and its epidemiological risk factors. Comparative Immunology, Microbiology and Infectious Diseases, 2023, 94, pp.101947. ⟨10.1016/j.cimid.2023.101947⟩. ⟨anses-04139016⟩