Topical issues in equine infectious disease Dr Richard Newton FRCVS - - PowerPoint PPT Presentation

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

• n 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 31st May 2017

– Positive EHV-1 qPCR on pre-mortem swab & post- mortem tissues

• BHA informed & yard voluntarily closed
• Clinical & laboratory monitoring of 121 horses

– Infection risk categorisation adopted for clearance – Racing from cleared barns allowed after 18th 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
• f 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

Acknowledgements