Transcript Prezentation_BAKU_EIA_final

Workshop on Equine identification and prophylaxis
Legislative background of horse infectious disease
surveillance principles in EU –
with particular reference to Equine infectious anaemia
Kristīne Lamberga
Food and Veterinary Service, Latvia
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Baku,13 - 14 December
2010
Content
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EU legislation related to EIA
Map - EIA situation in EU /November, 2010, ADNS/
Equine infectious anaemia (EIA)
Transmission of the EIA virus
Incubation period
Course of infection
Clinical signs
Differential diagnosis
Testing
Information from the First Workshop for EIA, by EU Reference
Laboratory
Action if EIA is confirmed
Criteria for eradication programs
Vaccination
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1. EU legislation related to EIA (1)
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Council Directive 2009/156/EC on animal health conditions governing the
movement and importation from third countries of equidae
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Council Directive 82/894/EEC on the notification of animal diseases within the
Community
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Commission Decision 2010/346/EU on protective measures with regard to EIA
in Romania
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Commission Regulation (EC) No 180/2008 concerning the Community
reference laboratory for equine diseases
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Council Directive 92/65/EEC laying down animal health requirements
governing trade in and imports into the EU of animals, semen, ova and embryos
not subject to animal health requirements laid down in specific Community rules
referred to in Annex A (I) to Directive 90/425/EEC
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Regulation (EC) No 1774/2002 laying down health rules concerning animal byproducts not intended for human consumption
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1. EU legislation related to EIA (2)
Council Directive 2009/156/EC
on animal health conditions governing the movement and importation from
third countries of equidae
Defines rules for the movement of equidae between MS
Sets common standard form for health attestation for registered equidae and form of
health certificate for movement of equidae for breeding, production and slaughter
Defines rules for importation of equidae in EU from third countries (only from countries
included in the list of countries and territories from which equidae may be imported
(Council Decision 79/542/EEC))
Provides for restrictions concerning the movement of equidae from holdings where the
presence of EIA has been confirmed until, following the slaughter of the infected
animals, the remaining animals have undergone two Coggins tests with negative
results:
Article 4 point 5 Equidae must not come from a holding which has been subject of prohibitions:
(a) prohibition period concerning holding of origin must be at least:
(iii) in case of EIA until the date on which the infected animals have been slaughtered, the
remaining animals have shown a negative reaction to 2 Coggins tests carried out 3 months
apart
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1. EU legislation related to EIA (3)
EIA is a compulsorily notifiable disease in accordance with Annex A to Council
Directive 90/426/EEC
In addition, Council Directive 82/894/EEC on the notification of animal diseases
within the Community provides that outbreaks of EIA are to be notified to the
Commission and other Member States through the Animal Disease Notification
System (ADNS)
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1. EU legislation related to EIA (4)
The disease situation (endemic disease) in Romania presents an animal health
risk for equidae in the EU. Therefore protective measures are adopted laying
down a specific regime for the movement of and trade in equidae and equine
semen, ova and embryos and certain equine blood products from Romania
(Commission Decision 2010/346/EU)
Regulation No 180/2008 concerning the Community reference laboratory for
equine diseases lays down the functions, tasks and procedures of the reference
laboratory in the EU for equine diseases
Council Directive 92/65/EEC laying down animal health requirements governing
trade in and imports into the EU of animals, semen, ova and embryos includes
test requirements for EIA
Regulation (EC) No 1774/2002 laying down health rules concerning animal byproducts sets out the requirements for serum of equidae.
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2. Map - EIA situation in EU /November, 2010, ADNS/ (1)
2010: UK, Belgium, France, Greece, Italy, Hungary, Germany, Romania, (Croatia)
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2. Map - EIA situation /November, 2010 WAHID OIE/ (2)
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2. Map EIA
situation in
EUROPE
/November,
2010,
WAHID
OIE/ (3)
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3. Equine infectious anaemia (EIA)
- EIA is an exotic viral disease that affects horses, mules and donkeys (donkeys
are naturally protected against disease and are asymptomatic carriers)
- EIA caused by Genus: lentivirus, Family: Retroviridae
- Disease is notifiable
- Affected animals remains a lifelong carrier of the disease, it is infectious to
other animals
- Therefore infected animals should be humanely destroyed
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4.Transmission of the EIA virus
- biting insects - large biting flies (tabanid species) or stable flies (stomoxys calcitrans)
Adult flies are transmitting the virus. Flies overwinter as larvae and the larvae cannot
transmit the disease
- when travelling to territories where disease is endemic
- from the use of biological products infected with EIA virus
- contaminated equipment (by blood, milk or placental fluid), veterinarian instruments
- saliva, nasal secretions, feces, semen, ova and embryos (acute infection)
- pregnant mares may pass the disease to their foals via placenta or rarely via virus
contaminated colostrum
(transmission through semen uncommon)
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5. Incubation period
- Generally 1 - 3 weeks (days till few months)
- Antibodies usually develop 7-14 days after infection and last for life
- Horses have been known to take several months before clinical signs or
antibodies are apparent
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6. Course of infection
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Acute
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Subacute
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Chronic (If disease become chronical, animals are predisposed to
secondary infectious)
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Sub-clinical (latent)
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7. Clinical signs
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Recurring fever, anaemia, oedema, death
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Signs may be very mild and only serological testing then will show the
infection
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Acute form - fever, depression, increased heart and respiratory rate,
haemorrhaging, bloody diarrhoea, loss of coordination, ataxia, rapid weight loss,
skin swelling (carry high level of virus in the blood)
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Chronic form – recurring fever, depression, anaemia, weakness and weight loss
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8. Differential diagnosis
African horse sickness, Anthrax, Dourine, Equine viral arteritis,
Japanese encephalitis, Equine influenza, Equine herpes virus,
Babesiosis, Leptospirosis, Fascioliasis, other causes of oedema,
abscess, fever and anaemia etc.
Laboratory diagnosis (blood testing) is essential
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9. Testing (1)
Blood sample to test for the presence of antibodies against EIAV
proteins
Antibodies at detectable level may be present in the blood 7-14 days
after infection, but horses in the first 2-3 weeks after infection will
usually give negative serological reactions (in rare cases – 60 days)
Virus isolation is usually not necessary to make diagnosis
Virus titer is higher in horses with clinical signs
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9. Testing (2)
Methods
- Coggins test – agar gel immuno-diffusion (AGID) – currently officially recognized for international
movement or trade
According to relevant Chapter of the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals
of the OIE the agar gel immunodiffusion (AGID) is used for the detection of EIA in horses
(It is an accurate and reliable test except in certain circumstances specified in the Manual therefore
two AGID tests for EIA with negative results are used to compensate the limitations of that test)
- ELISA also used as screening test in some MS (ELISA detects antibody earlier and at lower
concentrations, but positive samples should be confirmed by Coggins due to false positives)
For confirmation also:
- PCR (complementary test if serology unclear, confirmation of infection before antibodies develop,
confirmation of the status of a foal from an infected mare, ensuring freedom from disease if horse is
used for production of antiserum, vaccine or used as blood donor)
- IB (immunoblot technique)
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10. Information from the First Workshop for EIA, by EU
Reference Laboratory for Equine Diseases
Paris, October, 2010
Recommendations:
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Harmonization of the serology tests for EIA in Europe (regarding 2010 proficiency
testing results): training session are planned for NRLs in November 2011
2. Some ELISA kits might be used for screening:
- ELISA positive samples should be confirms by AGID or IB
- ELISA negative samples are AGID negative
3. Implementing PCR reaction for EIA diagnosis (project under development with other NRL)
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Molecular characterization of EIA viruses circulating in Europe. The EU-RL has started a
collaborative project with NRL from Belgium, Italy, Germany and Romania. By the end of the
year, the EU-RL should receive biological samples (tissue, blood) and then will start the
molecular characterization of those isolates
The aim of this study is to better understand and describe the different populations of EIA
viruses circulating in Europe. This phylogenetic analysis will help to develop a molecular
diagnostic tool (PCR) allowing detection of EIA viruses in biological samples
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11. Action if EIA is confirmed (1)
- Positive animal should be humanely euthanized or slaughtered
- Each animal traced as contact with infected animals should be kept under
restrictions and tested
- Restriction period concerning infected holding must be at least until the date on
which the infected animals have been slaughtered, the remaining animals have
shown a negative reaction to 2 Coggins tests carried out 3 months apart
- Detection of infected animals and their prompt destruction, prevention of all
modes of transmission are basic control measures
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11. Action if EIA is confirmed (2)
- stop all movement of horses
- isolate the horse
- implement vector control
- appropriate treatment of equipment (including veterinary equipment)
- disinfect equipment, stable, vehicles
- implement good hygiene
- quarantine in-contact horse for 90 days post exposure, blood test
- Depending EIA situation in country – surveillance and/or eradication
program should be implemented
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12. Criteria for eradication programs
(Council Decision 90/638/EEC) (1)
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Description on epidemiological situation
Designation of competent authority for supervision and coordination
of program implementation
Objective and likely duration of the program
Estimated costs
Description of area in which the program will be implemented
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12. Criteria for eradication programs
(Council Decision 90/638/EEC) (2)
6. Notification system of suspected and confirmed cases or outbreaks
7. Control procedures (movement restrictions, on farm inspections, etc.)
8. Registration of holdings (animals) involved in the program
9. System of traceability of animals
10. Different statuses applicable to holdings or areas, conditions of
movement of animals between holdings (areas) of different statuses
11. Consequences of loosing the status
12. Sampling, testing principles
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12. Criteria for eradication programs
(Council Decision 90/638/EEC) (3)
13. Measures to be taken if positive results are found:
- slaughter of animals
- restrictions on meat
- destruction/ treatment of products which could transmit the disease to
avoid possible contamination
- disinfection procedures of infected holdings, equipment
- procedures for re-stocking with healthy animals
14. Compensation to farmers (if possible)
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13. Vaccination (1)
Although live attenuated vaccines are available internationally, these
are not considered to be sufficiently effective or safe!
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13. Vaccination (2)
WHAT DO WE EXPECT FROM A SAFE AND EFFICIENT LENTIVIRAL VACCINE?*
A vaccine strain should:
– protect from disease and/or infection
– elicit protection from a large spectrum of infecting viruses (homologous and
heterologous strains)
– induce and maintain broad, specific and mature humoral and cellular immune
responses
– be genetically stable over years and not display genetic reversion to virulence
– not have an increased pathogenicity in individuals with minor or major immune
disorders
– keep its protective effect in immunosuppressed horses
In 2010, the best candidates are 2 live attenuated EIAV vaccines: American and
Chinese
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* Information from the First Workshop for EIA, by EU Reference Laboratory for Equine Diseases, Paris, October, 2010
13. Vaccination (3)
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Only live-attenuated vaccines are able to protect horses
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Both the Chinese and the American vaccines elicit good levels of protection
from disease and infection
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They elicit broad and mature immune responses
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The Chinese vaccine protects against heterologous strains, the American
vaccine protects only against homologous strains
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Protective vaccine immunity is maintain even after dexamethasonemediated
immunosuppression
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The Chinese live-attenuated vaccine developed 30 years ago is probably the
first successful lentivirus vaccine
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EIAV vaccination seems reachable
… but they are live attenuated vaccines and may potentially
revert and give rise to new pathogenic EIAVs
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oie
Recommendations for the importation of equines:
- Veterinary authorities of importing countries should require the presentation of
an international veterinary certificate attesting that:
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the animals showed no clinical sign of equine infectious anaemia (EIA) on the
day of shipment and during the 48 hours prior to shipment; and
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no case of EIA has been associated with any premises where the animals were
kept during the 3 months prior to shipment; and
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if imported on a permanent basis, the animals were subjected to a diagnostic
test for EIA with negative results on blood samples collected during the 30 days
prior to shipment; or
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if imported on a temporary basis, the animals were subjected to a diagnostic test
for EIA with negative results on blood samples collected during the 90 days prior
to shipment
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Thank you for attention!
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