FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Tropical animal health and production2026; 58(5); 298; doi: 10.1007/s11250-026-05070-1

Seroprevalence of Orthoflaviviruses in horses in 3 different Algerian climatic zones between 2021 and 2023.

Abstract: Orthoflaviviruses are etiological agents of neurological diseases in equines. Horses are susceptible to equine Tick-borne encephalitis virus (TBEV), Usutu virus (USUV), and West Nile virus (WNV), although mostly WNV has been associated with clinical disease. The aim of the present study was to estimate the prevalence of TBEV, USUV and WNV in 289 healthy horses from nine provinces of Algeria. This study was conducted between March 2021 and December 2023. Sera that tested positive, doubtful, or negative close to the doubtful threshold in the Orthoflavivirus-ELISA were further tested by the virus neutralization test (VNT), using TBEV, USUV, and WNV strains. The prevalence of Orthoflaviviruses antibodies by ELISA was 23.18% (67/289) compared with 16.95% (49/289) and 0.69% (2/289) detected by WNV and USUV VNT, respectively. TBEV antibodies were not detected in any samples. WNV seroprevalence varied with age, breed, climatic zones and altitude of the horses' locations. This is the first screening of horse sera for TBEV in Algeria. This study indicates that WNV and USUV have circulated/are circulating in the horse population in three Algerian climatic zones, unlike TBEV, which does not seem to be present.
© 2026. The Author(s), under exclusive licence to Springer Nature B.V.
Get Full Text
Publication Date: 2026-05-28 PubMed ID: 42207390PubMed Central: 6208007DOI: 10.1007/s11250-026-05070-1Google Scholar: Lookup
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.
LinkedInCopy
  • Journal Article

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 research investigated the presence of antibodies against three Orthoflaviviruses—Tick-borne encephalitis virus (TBEV), Usutu virus (USUV), and West Nile virus (WNV)—in horses across different climatic regions of Algeria to assess their exposure to these viruses.
  • The study found evidence of WNV and USUV circulation among healthy horses, but no signs of TBEV infection were detected.

Background

  • Orthoflaviviruses are viruses that can cause neurological diseases in horses.
  • Among these, WNV is commonly associated with clinical disease in horses, while TBEV and USUV are less frequently studied in equines.
  • Understanding the prevalence of these viruses in horse populations helps assess the risk of outbreaks and informs preventive measures.

Study Objectives

  • To estimate the prevalence of antibodies against TBEV, USUV, and WNV in horses from Algeria.
  • To analyze differences in virus exposure based on geographic location, climate zone, age, breed, and altitude of horse habitats.
  • To provide the first serological evidence regarding TBEV presence or absence in Algerian horses.

Methodology

  • The study was conducted from March 2021 to December 2023.
  • Samples were collected from 289 healthy horses located in nine provinces representing three different climatic zones in Algeria.
  • Initial screening for Orthoflavivirus antibodies was done using an ELISA test specific for Orthoflaviviruses.
  • Sera that tested positive, doubtful, or borderline-negative via ELISA were further analyzed using the Virus Neutralization Test (VNT) for each specific virus (TBEV, USUV, WNV).
  • The VNT helps confirm which specific virus the antibodies detected by ELISA were targeting, improving specificity of the results.

Results

  • By ELISA, 23.18% (67 out of 289) of horses had antibodies indicative of Orthoflavivirus infection.
  • Upon VNT confirmation:
    • 16.95% (49/289) had antibodies specific to West Nile virus (WNV).
    • 0.69% (2/289) had antibodies specific to Usutu virus (USUV).
    • No antibodies against Tick-borne encephalitis virus (TBEV) were detected.
  • WNV seroprevalence was found to vary depending on:
    • Age of the horses: older horses may have had greater exposure over time.
    • Breed: different breeds may have varying susceptibility or exposure risks.
    • Climatic zones: environmental factors affect virus prevalence and vector distribution.
    • Altitude: elevation influences the presence and activity of virus-carrying ticks and mosquitoes.

Conclusions and Significance

  • This is the first study screening for TBEV antibodies in horses in Algeria, and no evidence was found of this virus circulating in the equine population there.
  • The presence of antibodies against WNV and USUV indicates these viruses have circulated or are currently circulating among horses in different Algerian climatic regions.
  • These findings emphasize the importance of continued surveillance to monitor the prevalence and spread of Orthoflaviviruses in horses, which can have implications for animal health and potentially human health, given the zoonotic nature of these viruses.
  • Understanding geographic and environmental factors that affect virus prevalence can aid in targeting preventative and control measures in high-risk areas.

Cite This Article

APA
Boukabache H, Gonzalez G, Helle T, Boudjadi Y, Migné C, Zientara S, Azizi A, Durand B, Laabassi F. (2026). Seroprevalence of Orthoflaviviruses in horses in 3 different Algerian climatic zones between 2021 and 2023. Trop Anim Health Prod, 58(5), 298. https://doi.org/10.1007/s11250-026-05070-1

Publication

Tropical animal health and production
ISSN: 1573-7438
NlmUniqueID: 1277355
Country: United States
Language: English
Volume: 58
Issue: 5
PII: 298

Researcher Affiliations

Boukabache, Hadjer
  • PIAD Research Team, ESPA Laboratory, Department of Veterinary, Institute of Veterinary Sciences and Agronomic Sciences, University of Batna-1, Batna, 05000, Algeria.
Gonzalez, Gaëlle
  • UMR Virologie, Laboratoire de Santé Animale, ANSES, INRAE, École Nationale Vétérinaire d'Alfort, Maisons-Alfort, 94700, France.
Helle, Teheipuaura
  • UMR Virologie, Laboratoire de Santé Animale, ANSES, INRAE, École Nationale Vétérinaire d'Alfort, Maisons-Alfort, 94700, France.
Boudjadi, Yasmine
  • UMR Virologie, Laboratoire de Santé Animale, ANSES, INRAE, École Nationale Vétérinaire d'Alfort, Maisons-Alfort, 94700, France.
Migné, Camille
  • UMR Virologie, Laboratoire de Santé Animale, ANSES, INRAE, École Nationale Vétérinaire d'Alfort, Maisons-Alfort, 94700, France.
Zientara, Stéphan
  • UMR Virologie, Laboratoire de Santé Animale, ANSES, INRAE, École Nationale Vétérinaire d'Alfort, Maisons-Alfort, 94700, France.
Azizi, Abdennour
  • PIAD Research Team, ESPA Laboratory, Department of Veterinary, Institute of Veterinary Sciences and Agronomic Sciences, University of Batna-1, Batna, 05000, Algeria.
Durand, Benoît
  • EPIMIM, Laboratoire de Santé Animale, Anses, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France.
Laabassi, Farouk
  • PIAD Research Team, ESPA Laboratory, Department of Veterinary, Institute of Veterinary Sciences and Agronomic Sciences, University of Batna-1, Batna, 05000, Algeria. farouk.laabassi@univ-batna.dz.

MeSH Terms

  • Animals
  • Horses
  • Algeria / epidemiology
  • Seroepidemiologic Studies
  • Horse Diseases / epidemiology
  • Horse Diseases / virology
  • Antibodies, Viral / blood
  • Enzyme-Linked Immunosorbent Assay / veterinary
  • Climate
  • Flaviviridae Infections / veterinary
  • Flaviviridae Infections / epidemiology
  • Flaviviridae Infections / virology
  • West Nile virus / isolation & purification
  • Flavivirus / isolation & purification
  • Male
  • Encephalitis Viruses, Tick-Borne / isolation & purification
  • Female
  • Flavivirus Infections / veterinary
  • Flavivirus Infections / epidemiology
  • Flavivirus Infections / virology
  • Prevalence

Conflict of Interest Statement

Declarations. Ethical approval: The authors confirm that ethical review is not required from this work in their region. Blood samples were collected by the researchers (veterinarians) after getting informed consent from the owners of the horses. All efforts were made to minimize animal suffering during sample collection. Oral and written informed consent was obtained from all people who participated in the study. Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

This article includes 44 references
  1. Aberle SW, Kolodziejek J, Jungbauer C, Stiasny K, Aberle JH, Zoufaly A, Nowotny N. Increase in human West Nile and Usutu virus infections, Austria, 2018. Euro Surveill 23(43):1800545.
    doi: 10.2807/1560-7917.ES.2018.23.43.1800545pubmed: 30376913pmc: 6208007google scholar: lookup
  2. Ahmadnejad F, Otarod V, Fathnia A, Ahmadabadi A, Fallah MH, Zavareh A, Miandehi N, Durand B, Sabatier P. Impact of Climate and Environmental Factors on West Nile Virus Circulation in Iran. J Arthropod Borne Dis 10(3):315–327.
    pubmed: 27308290pmc: 4906738
  3. Bażanów B, van Jansen P, Szymański P, Stygar D, Frącka A, Twardoń J, Kozdrowski R, Pawęska JT. A survey on West Nile and Usutu viruses in horses and birds in Poland. Viruses 10:12–14.
    doi: 10.3390/v10020087google scholar: lookup
  4. Bakonyi T, Jungbauer C, Aberle SW, Kolodziejek J, Dimmel K, Stiasny K, Nowotny N. Usutu virus infections among blood donors, Austria, July and August 2017 – Raising awareness for diagnostic challenges. Euro Surveill 22(41):17–00644.
    doi: 10.2807/1560-7917.ES.2017.22.41.17-00644pubmed: 29043962pmc: 5710119google scholar: lookup
  5. Barbic L, Vilibic-Cavlek T, Listes E, Stevanovic V, Gjenero-Margan I, Ljubin-Sternak S, Pem-Novosel I, Listes I, Mlinaric-Galinovic G, Di Gennaro A, Savini G. Demonstration of Usutu virus antibodies in horses, Croatia. Vector-Borne Zoonotic Dis 13:772–774.
    doi: 10.1089/vbz.2012.1236pubmed: 23808977google scholar: lookup
  6. Beck C, Lowenski S, Durand B, Bahuon C, Zientara S, Lecollinet S. Improved reliability of serological tools for the diagnosis of West Nile fever in horses within Europe. PLoS Negl Trop Dis 11(9):e0005936.
    doi: 10.1371/journal.pntd.0005936pubmed: 28915240pmc: 5617233google scholar: lookup
  7. Benbetka S, Hachid A, Benallal K, Benbetka C, Khaldi A, Bitam I, Harrat Z. First Field Evidence Infection of Culex Perexiguus byWest Nile Virus in Sahara Oasis of Algeria. J Vector Borne Dis 55(4):305–309.
    doi: 10.4103/0972-9062.256566pubmed: 30997891google scholar: lookup
  8. Ben Hassine T, De Massis F, Calistri P, Savini G, BelHaj Mohamed B, Ranen A, Di Gennaro A, Sghaier S, Hammami S. First detection of co-circulation of West Nile and Usutu viruses in equids in the south-west of Tunisia. Transbound Emerg Dis 61:385–389.
    doi: 10.1111/tbed.12259pubmed: 25065813google scholar: lookup
  9. Ben-Mostafa KK, Savini G, Di Gennaro A, Teodori L, Leone A, Monaco F, Alaoqib MMA, Rayes AA, Dayhum A, Eldaghayes I. Evidence of West Nile Virus Circulation in Horses and Dogs in Libya. Pathogens 13:1–13.
    doi: 10.3390/pathogens13010041google scholar: lookup
  10. Cardinale E, Bernard C, Lecollinet S, Rakotoharinome VM, Ravaomanana J, Roger M, Olive MM, Meenowa D, Jaumally MR, Melanie J, Héraud JM, Zientara S, Cêtre-Sossah C. West Nile virus infection in horses, Indian ocean. Comp Immunol Microbiol Infect Dis 53:45–49.
    doi: 10.1016/j.cimid.2017.06.006pubmed: 28750867google scholar: lookup
  11. Castillo-Olivares J, Mansfield KL, Phipps LP, Johnson N, Tearle J, Fooks AR. Antibody response in horses following experimental infection with West Nile Virus lineages 1 and 2. Transbound Emerg Dis 58(3):206–212.
    doi: 10.1111/j.1865-1682.2010.01197.xpubmed: 21223533google scholar: lookup
  12. Chevalier N, Migné CV, Mariteragi-Helle T, Dumarest M, De Mas M, Chevrier M, Queré E, Marcillaud-Pitel C, Lupo C, Bigeard C, Touzet T, Leblond A, Durand B, Depecker M, Gonzalez G. Seroprevalence of West Nile, Usutu and tick-borne encephalitis viruses in equids from south-western France in 2023. Vet Res 56(1):91.
    doi: 10.1186/s13567-025-01508-wpubmed: 40275349pmc: 12023385google scholar: lookup
  13. Chevalier V, Dupressoir A, Tran A, Diop OM, Gottland C, Diallo M, Etter E, Ndiaye M, Grosbois V, Dia M, Gaidet N, Sall AA, Soti V, Niang M. Environmental risk factors of West Nile virus infection of horses in the Senegal River basin. Epidemiol Infect 138:1601–1609.
    doi: 10.1017/S095026881000035Xpubmed: 20175940google scholar: lookup
  14. Dauphin G, Zientara S. West Nile virus: recent trends in diagnosis and vaccine development. Vaccine 25(30):5563–5576.
    doi: 10.1016/j.vaccine.2006.12.005pubmed: 17292514google scholar: lookup
  15. Fares W, Dachraoui K, Cherni S, Barhoumi W, Slimane TB, Younsi H, Zhioua E. Tick-Borne Encephalitis Virus in Ixodes Ricinus (Acari: Ixodidae) Ticks, Tunisia. Ticks Tick Borne Dis 12(1):101606.
    doi: 10.1016/j.ttbdis.2020.101606pubmed: 33189912google scholar: lookup
  16. García-Bocanegra I, Jaén-Téllez JA, Napp S, Arenas-Montes A, Fernández-Morente M, Fernández-Molera V, Arenas A. Monitoring of the West Nile virus epidemic in Spain between 2010 and 2011. Transbound Emerg Dis 59(5):448–455.
    doi: 10.1111/j.1865-1682.2011.01298.xpubmed: 22212118google scholar: lookup
  17. Girl P, Euringer K, Coroian M, Mihalca AD, Borde JP, Dobler G. Comparison of Five Serological Methods for the Detection of West Nile Virus Antibodies. Viruses 16:788.
    doi: 10.3390/v16050788pubmed: 38793670pmc: 11126072google scholar: lookup
  18. Gothe LMR, Ganzenberg S, Ziegler U, Obiegala A, Lohmann KL, Sieg M, Vahlenkamp TW, Groschup MH, Hörügel U, Pfeffer M. Horses as Sentinels for the Circulation of Flaviviruses in Eastern–Central Germany. Viruses 15:1–17.
    doi: 10.3390/v15051108google scholar: lookup
  19. Guerrero-Carvajal F, Bravo-Barriga D, Martín-Cuervo M, Aguilera-Sepúlveda P, Ferraguti M, Jiménez-Clavero MÁ, Llorente F, Alonso JM, Frontera E. Serological evidence of co-circulation of West Nile and Usutu viruses in equids from western Spain. Transbound Emerg Dis 68:1432–1444.
    doi: 10.1111/tbed.13810pubmed: 32853452google scholar: lookup
  20. Habarugira G, Suen WW, Hobson-Peters J, Hall RA, Bielefeldt-Ohmann H. West Nile virus: an update on pathobiology, epidemiology, diagnostics, control and “one health” implications. Pathogens 9(7):589.
    doi: 10.3390/pathogens9070589google scholar: lookup
  21. Im JH, Baek JH, Durey A, Kwon HY, Chung MH, Lee JS. Geographic distribution of Tick-borne encephalitis virus complex. J Vector Borne Dis 57(1):14–22.
    doi: 10.4103/0972-9062.308794google scholar: lookup
  22. Klaus C, Ziegler U, Kalthoff D, Hoffmann B, Beer M. Tick-borne encephalitis virus (TBEV) – findings on cross reactivity and longevity of TBEV antibodies in animal sera. BMC Vet Res 10:78.
    doi: 10.1186/1746-6148-10-78pubmed: 24690234pmc: 3978054google scholar: lookup
  23. Laabassi F, Beck C, Gaudaire D, Lecollinet S, Zientara S, Hans A. Seroprevalence of equine infectious anaemia virus (EIAV), equine arteritis virus (EAV) and West Nile virus (WNV) in donkeys in eastern Algeria in 2015. Equine Vet J 53(S56):37.
    doi: 10.1111/evj.47_13495google scholar: lookup
  24. Laabassi F, Dheilly N, Beck C, Amaral R, Gonzalez G, Gaudaire D, Madeline A, Lecouturier F, Lecollinet S, Zientara S, Hans A, Valle-Casuso JC. Serological evidence of circulation of West Nile virus in equids in Algerian eastern drylands and its epidemiological risk factors. Comp Immunol Microbiol Infect Dis 94:101947.
    doi: 10.1016/J.CIMID.2023.101947pubmed: 36638646google scholar: lookup
  25. Magallanes S, Llorente F, Ruiz-López MJ, Martínez-de la Puente J, Soriguer R, Calderon J, Jímenez-Clavero MÁ, Aguilera-Sepúlveda P, Figuerola J. Long-term serological surveillance for West Nile and Usutu virus in horses in south-West Spain. One Heal 17.
    doi: 10.1016/j.onehlt.2023.100578google scholar: lookup
  26. Mechouk N, Mihalca AD, Deak G, Bouslama Z. Synopsis of the ticks of Algeria with new hosts and localities records. Parasit Vectors 15(1):302.
    doi: 10.1186/s13071-022-05424-2pubmed: 36028886pmc: 9419418google scholar: lookup
  27. M’ghirbi Y, Mousson L, Moutailler S, Lecollinet S, Amaral R, Beck C, Aounallah H, Amara M, Chabchoub A, Rhim A, Failloux AB, Bouattour A. West Nile, Sindbis and Usutu Viruses: Evidence of Circulation in Mosquitoes and Horses in Tunisia. Pathogens 12:1–17.
    doi: 10.3390/pathogens12030360google scholar: lookup
  28. Mittova V, Tsetskhladze ZR, Motsonelidze C, Palumbo R, Vicidomini C, Roviello GN. Tick-Borne Encephalitis Virus (TBEV): Epidemiology, Diagnosis, Therapeutic Approaches and Some Molecular Aspects—An Updated Review. Microbiol Res 15:2619–2649.
    doi: 10.3390/microbiolres15040174google scholar: lookup
  29. Niedrig M, Sonnenberg K, Steinhagen K, Paweska JT. Comparison of ELISA and immunoassays for measurement of IgG and IgM antibody to West Nile virus in human sera against virus neutralization. J Virol Methods 139(1):103–105.
    doi: 10.1016/j.jviromet.2006.09.009pubmed: 17084464google scholar: lookup
  30. Olufemi OT, Barba M, Daly JM. A scoping review of west nile virus seroprevalence studies among african equids. Pathogens 10:1–15.
    doi: 10.3390/pathogens10070899google scholar: lookup
  31. O.N.S. La production agricole, Campagne 2020/2021. 900:1–20.
  32. Pilo-Moron E, Vincent J, Le Corroller Y. Isolation of a West-Nile virus in the extreme south of the Algerian Sahara (Djanet). Arch Inst Pasteur Alger 48:181–184.
    pubmed: 4148584
  33. Rushton JO, Lecollinet S, Hubalek Z, Svobodova P, Lussy H, Nowotny N. Tickborne encephalitis virus in horses, Austria, 2011. Emerg Infect Dis 19(4):635–637.
    doi: 10.3201/eid1904.121450pubmed: 23631894pmc: 3647421google scholar: lookup
  34. Savini G, Monaco F, Terregino C, Di Gennaro A, Bano L, Pinoni C, De Nardi R, Bonilauri P, Pecorari M, Di Gialleonardo L, Bonfanti L, Polci A, Calistri P, Lelli R. Usutu virus in Italy, an emergence or a silent infection?. Vet Microbiol 151(3–4):264–274.
    doi: 10.1016/j.vetmic.2011.03.036pubmed: 21550731google scholar: lookup
  35. Schwarzer A, Ziegler U, Fertey J, Kreuz M, Vahlenkamp TW, Groschup MH, Ulbert S. Serological differentiation of West Nile, Usutu, and tick-borne encephalitis virus antibodies in birds and horses using mutant E protein ELISAs. Sci Rep 15:28752.
    doi: 10.1038/s41598-025-14448-4pubmed: 40770485pmc: 12328586google scholar: lookup
  36. Semenza JC, Suk JE. Vector-borne diseases and climate change: A European perspective. FEMS Microbiol Lett 365:1–9.
    doi: 10.1093/femsle/fnx244google scholar: lookup
  37. Simmonds P, Becher P, Bukh J, Gould EA, Meyers G, Monath T, Muerhoff S, Pletnev A, Rico-Hesse R, Smith DB, Stapleton JT. ICTV Virus Taxonomy Profile: Flaviviridae. J Gen Virol 98:2–3.
    doi: 10.1099/jgv.0.000672google scholar: lookup
  38. Simonin Y. Usutu, West Nile, and Tick-Borne Encephalitis Viruses. Viruses 14(10):2120.
    doi: 10.3390/v14102120pubmed: 36298675pmc: 9608063google scholar: lookup
  39. Soverow JE, Wellenius GA, Fisman DN, Mittleman MA. Infectious disease in a warming world: how weather influenced West Nile virus in the United States (2001–2005). Environ Health Perspect 117(7):1049–1052.
    doi: 10.1289/ehp.0800487pubmed: 19654911pmc: 2717128google scholar: lookup
  40. Steffen R. Epidemiology of Tick-Borne Encephalitis (TBE) in International Travellers to Western/Central Europe and Conclusions on Vaccination Recommendations. J Travel Med 23:taw018.
    doi: 10.1093/jtm/taw018pubmed: 27087558google scholar: lookup
  41. Valiakos G, Papaspyropoulos K, Giannakopoulos A, Birtsas P, Tsiodras S, Hutchings MR, Spyrou V, Pervanidou D, Athanasiou LV, Papadopoulos N, Tsokana C, Baka A, Manolakou K, Chatzopoulos D, Artois M, Yon L, Hannant D, Petrovska L, Hadjichristodoulou C, Billinis C. Use of wild bird surveillance, human case data and GIS spatial analysis for predicting spatial distributions of West Nile virus in Greece. PLoS One 9(5):e96935.
    doi: 10.1371/journal.pone.0096935google scholar: lookup
  42. Vanhomwegen J, Beck C, Desprès P, Figuerola A, García R, Lecollinet S, López-Roig M, Manuguerra J-C, Serra-Cobo J. Circulation of Zoonotic Arboviruses in Equine Populations of Mallorca Island (Spain). Vector-Borne Zoonotic Dis 17(5):340–346.
    doi: 10.1089/vbz.2016.2042pubmed: 28346868google scholar: lookup
  43. World Organisation for Animal Health. Chap. 3.1.25. West Nil Fever. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals OIE, Paris.
  44. Zannoli S, Sambri V. West Nile virus and Usutu virus co-circulation in Europe: epidemiology 514 and implications. Microorganisms 7(7):184.
    doi: 10.3390/microorganisms7070184pubmed: 31248051pmc: 6680635google scholar: lookup

Citations

This article has been cited 0 times.
Subscribe to our newsletter
Join 106,836 horse owners like you who receive our email updates on horse health and nutrition.
OmegaPrime+ Extra-Strength Omega-3 Oil - Mad Barn
NEW PRODUCT
OmegaPrime+
Extra-Strength Omega-3 Oil
Shop Now
×