Topical issues in equine infectious disease Dr Richard Newton FRCVS Animal Health Trust
Overview Finding information on equine infectious disease occurrence Domestic UK International Some events of note in 2017 CEM unexpectedly found in France Break in supply of EVA vaccine EIA re-emerges in Europe Neurological EHV-1 affecting TBs
Overview Finding information on equine infectious disease occurrence Domestic UK International Some events of note in 2017 CEM unexpectedly found in France Break in supply of EVA vaccine EIA re-emerges in Europe Neurological EHV-1 affecting TBs
Unexpected CEM in France Contagious Equine Metritis (CEM) Bacterial cause of infertility in mares Natural & artificial venereal transmission T. equigenitalis carried subclinically by mares, stallions & teasers HBLB Code of Practice cornerstone of control Annual pre-breeding screening; approved labs CEM notifiable under IDHO 1987 Facilitates international trade in bloodstock
Unexpected CEM in France Reported by RESPE on 20 November 2017 Confirmed by reference lab on 27 October 2017 Subclinical infection of undetermined origin in yearling TB filly on routine pre-export testing Second sample negative, treatment completed
Unexpected CEM in France Further information provided by RESPE: Small mixed breed premises 4 Thoroughbred mares & offspring (incl. case) 1 Paint Horse broodmare 3 French Saddlebred broodmares 3 geldings Dam of case (based in UK) has tested CEMO negative
Overview Finding information on equine infectious disease occurrence Domestic UK International Some events of note in 2017 CEM unexpectedly found in France Break in supply of EVA vaccine EIA re-emerges in Europe Neurological EHV-1 affecting TBs
Break in supply of Artervac Equine Viral Arteritis (EVA) Acute viral disease of horses, incl. abortion Transmitted by respiratory & venereal routes Virus (EAV) shed long-term in semen in some recovered carrier stallions First recorded outbreak in UK in 1993 in imported non-thoroughbred carrier stallion EVA in stallions notifiable in EVA Order 1995 Artervac EVA vaccine used to protect stallions
Break in supply of Artervac Equip Artervac EVA vaccine (Zoetis) Requires booster doses every 6 months No new supply after batch expired 26 Nov 17 Date of resumption of supply not yet known Stallions will lapse in EVA vaccination in 2018! Seropositive stallions w. lapsed vaccination Hx may require semen testing under EVA Order 1995
Break in supply of Artervac Protocol agreed to avoid semen testing Blood testing to confirm no significant rise in antibody to EAV => no infection!
Break in supply of Artervac Protocol agreed to avoid semen testing Collect blood samples in January & July each year until Artervac available again
Break in supply of Artervac Vets submit blood samples to AHT on special submission form AHT registers samples and store them frozen for later testing All samples from same animal tested together on same test http://www.aht.org.uk/skins/default/pdfs/artervac_form_v2.pdf
Break in supply of Artervac Covered in 2018 EVA Code of Practice Page 21
Overview Finding information on equine infectious disease occurrence Domestic UK International Some events of note in 2017 CEM unexpectedly found in France Break in supply of EVA vaccine EIA re-emerges in Europe Neurological EHV-1 affecting TBs
EIA re-emerges in Europe Equine Infectious Anaemia (EIA) Retroviral disease of horses; cf human HIV Transmitted by blood transfer; including biting insects & contaminated needles & products Recovered horses can act as sources of infection; no treatment or vaccination Notifiable disease requiring mandatory slaughter Outbreaks in Ireland in 2006, UK in 2010 & 2012 & elsewhere in Europe in summer 2017
EIA re-emerges in Europe Italy & Romania considered endemic for EIA Isolated cases in Europe in last 5 years in Belgium, Bulgaria, Croatia, France, Germany, Greece, Hungary, Slovakia & Slovenia
EIA re-emerges in Europe
EIA re-emerges in Europe
Overview Finding information on equine infectious disease occurrence Domestic UK International Some events of note in 2017 CEM unexpectedly found in France Break in supply of EVA vaccine EIA re-emerges in Europe Neurological EHV-1 affecting TBs
Neurological EHV-1 in TBs Equine Herpes Virus-1 (EHV-1) Acute & latent viral infections of horses Latency makes EHV-1 impossible to eradicate Respiratory, abortion & neurological signs Need to manage outbreaks when they occur Use of clinical & laboratory monitoring to establish extent of infection & confirm when cleared
Neurological EHV-1 outbreaks Occasionally in horses in training & on studs Occasionally multiple outbreaks simultaneously November 2012 through to April 2013 After a quiet 2014 & 2015, increased EHV-1 activity seen in TBs in 2016 and 2017
Neurological EHV-1 in TBs Neurological EHV-1 in TBs since 2016 Confirmed at National Stud in late Jan 2016 Suspected cases investigated linked to TB yards in Newmarket & Epsom in 2016 & Devon in 2017 Confirmed in N. Yorks training yard in 2017
National Stud Ataxia in recently imported 4yo mare Seroconversion to EHV-1/-4 in 6 days But 4 NP swabs negative by qpcr Whole stud closed immediately & issued press release Biosecurity measures as per CoP All 24 mares in the isolation unit were screened clear No clinical disease, no seroconversions Post-foaling placentae PCR negative Main stud re-opened on 15/2/16 & isolation yard re-opened on 23/2/16
N. Yorkshire training yard Single fatal case confirmed 31 st May 2017 Positive EHV-1 qpcr on pre-mortem swab & postmortem tissues BHA informed & yard voluntarily closed Clinical & laboratory monitoring of 121 horses Infection risk categorisation adopted for clearance Racing from cleared barns allowed after 18 th June with negative NP swabs by qpcr within 48 hrs Yard declared clear by end of June 2017
N. Yorkshire training yard
Concluding remarks Recent issues in Europe with CEM & EIA Recent issues in UK with EVA vaccine availability & neurological EHV-1 All 4 diseases are covered by the HBLB Codes of Practice Still relevant as industry standard for infectious disease prevention & control after 40 years Some parts are still supported by UK legislation Use resources to monitor equine diseases Defra & International Collating Centre reports
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