Equine herpesviruses in the environment: what are the risks in terms of contamination?

Camille Normand (1, 2) , Pauline Defour (1, 2) , Aude Bonassies (3) , Philippe Ciantar (4) , Christine Fortier (1, 2) , Romain Paillot (1, 2, 5) , Christel Marcillaud-Pitel (6) , Pierre-Hugues Pitel (1) , François Meurens (3) , Stéphane Pronost (1, 2, 7) , Erika Hue (1, 7, 2)

1 LABÉO - LABÉO, Pôle d’analyses et de recherche de Normandie
2 BIOTARGEN - Biologie, génétique et thérapies ostéoarticulaires et respiratoires
3 BIOEPAR - Biologie, Epidémiologie et analyse de risque en Santé Animale
4 Clinique vétérinaire de Launay
5 School of Equine and Veterinary Physiotherapy
6 RESPE - Réseau d'Epidémio-Surveillance en Pathologie Équine
7 ImpedanCELL

Introduction: Nine equid herpesviruses have been described in horses (equid herpesvirus 1 (EHV-1) to EHV-9). EHV-1 and EHV-4 are highly contagious viruses with respiratory tropism that cause rhinopneumonitis. The primary form of the disease is an upper respiratory tract infection. However, EHV-1 can cause more severe secondary forms such as abortions and myeloencephalitis. Transmission of these viruses is mainly by direct contact with infectious secretions or by inhalation of aerosols. However, several studies highlight the involvement of inert surfaces as a source of contamination. The COVID-19 pandemic has highlighted the importance of taking into account the survival of the virus in the environment and has also underlined the scarcity of studies in this field. Objectives: 1/ To study the survival of EHV-1 and EHV-4 in rainwater at three different temperatures. 2/ To investigate the presence of the virus during an episodic EHV-4 in a stud farm on different surfaces (leather, metal grid and trough). Material and methods: The survival of EHV-1 and EHV-4 in rainwater was studied at +4°C, +20°C and +34°C for up to 21 days and 28 days, respectively. The infectivity of viruses was assessed by cell culture (conventional method and real-time cell analysis) and by qPCR. During an EHV-4 outbreak, samples were collected with wipes from different surfaces up to 45 days (D+7, D+11, D+17, D+24, D+45) after the start of the outbreak. The samples were analysed by qPCR. Results: EHV-1 remained infectious for 21 days in rainwater at +4°C and +20°C. Infectivity was lost on day +7 in water at +34°C. EHV-4 remained infectious for 28 days at +4°C while infectivity decreased after 7 days at +34°C. The presence of the EHV-4 genome, during monitoring at the stud, was found on the different surfaces studied at all times. Discussion and conclusion: These results demonstrate that equine herpesviruses can survive in water, and maintaining their infectivity, on different surfaces. The survival of the virus in water and on different surfaces should be a warning in case of an epidemic to take measures to avoid contamination by contact.

Mots clés: Equine herpesviruses; environment; survival

Domaines: Médecine vétérinaire et santé animale

Camille Normand, Pauline Defour, Aude Bonassies, Philippe Ciantar, Christine Fortier, et al.. Equine herpesviruses in the environment: what are the risks in terms of contamination?. 12th International congress for veterinary virology, Sep 2022, Ghent, Belgium. ⟨hal-03808188⟩