Surveillance of equine influenza viruses through the RESPE network in France from November 2005 to October 2010.
Authors: Legrand L J, Pitel P-H Y, Marcillaud-Pitel C J, Cullinane A A, Couroucé A M, Fortier G D, Freymuth F L, Pronost S L
Journal: Equine veterinary journal
Summary
# Surveillance of Equine Influenza Viruses in France (2005–2010) The RESPE network, a sentinel-based epidemiological surveillance system operated by participating French veterinarians, demonstrated substantially superior detection rates for equine influenza virus compared to passive reporting, identifying 121 positive cases (13.1% positive rate) from 920 submissions versus only 26 cases (5.1%) from 607 non-network samples over a five-year period. Using real-time RT-PCR targeting the matrix protein gene and phylogenetic sequencing of the HA1 haemagglutinin region, researchers characterised circulating strains and documented a significant outbreak between February and May 2009 affecting 70 horses across 23 premises, predominantly involving American lineage viruses of Florida origin (Clades 1 and 2), with evidence of vaccine breakdown. The structured network approach enabled researchers not only to detect and genetically characterise EIV strains, but to establish clear epidemiological links between affected premises and identify temporal patterns of viral circulation that would have been missed through conventional diagnostic submission alone. For equine practitioners and veterinary authorities, these findings underscore the substantial added value of organised surveillance systems in capturing outbreak events early, informing targeted control measures, and generating evidence to evaluate vaccine strain matching—capabilities that have direct implications for herd health management and disease prevention protocols. Establishing analogous sentinel networks in other countries could significantly reduce the economic burden of influenza outbreaks through improved early detection and epidemiological characterisation of circulating strains.
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Practical Takeaways
- •Participation in organized surveillance networks like RESPE significantly improves detection of EIV (2.5x higher detection rate), enabling faster identification and response to outbreaks on your premises
- •Submitting nasopharyngeal swabs through established surveillance networks provides valuable strain characterization data that informs vaccine efficacy and outbreak management decisions
- •Establishing similar epidemiological surveillance networks in regions without them could substantially reduce economic losses from EIV outbreaks through earlier detection and targeted control measures
Key Findings
- •RESPE-associated veterinarians submitted samples with a 13.1% EIV positive rate (121/920) compared to 5.1% (26/607) from non-RESPE veterinarians
- •A major outbreak occurred between February-May 2009 affecting 70 horses across 23 premises, with 15 premises managed by RESPE-associated veterinarians
- •All identified strains belonged to the American lineage, Florida sublineage, with Clade 1 identified only during the Grosbois episode and Clade 2 identified in other outbreaks
- •The RESPE network successfully characterized virus strains, provided epidemiological data, and identified vaccine breakdown cases in France