Missions of the Community Veterinary Emergency Team to LATVIA

Transcription

1 Missions of the Community Veterinary Emergency Team to LATVIA SCOPE of the missions: African Swine Fever in Latvia 1 4 July August 2014

2 Terms of Reference To provide scientific, technical, managerial and practical on-the-spot assistance on the development of the most suitable control and eradication measures for African swine fever (ASF) under local conditions To support the Latvian authorities to elaborate a plan on the surveillance and possible eradication of ASF

3 CVET members Mission 1: 1-4 July 2014 K. Depner (team leader) C. Gallardo Mission 2: August 2014 K. Depner (team leader) V. Guberti J. Westergaard

4 Aspects covered: Wild boar biology and hunting activities Laboratory investigations ASF control measures Biosecurity measures

5 Latvia: places visited

6 Epidemiological background End of June 2014: First outbreak in domestic pigs (back yard) and several cases in wild boar at the border with Belarus (Kraslava region) During July 2014: Several outbreaks (21) in back yards and several cases (41) in wild boar in the Kraslava region Beginning of July 2014: ASFV detected in Valka region (Domestic pigs and wild boar), about 300 km from Kraslava region Beginning of August 2014: ASFV detected in Madona region (wild boar), about 180 km from Kraslava region

7 Working hypothesis: Movement of infected wild boar from other infected areas (Belarus) Infection of wild boar by uptake of infected material available in the area (e.g. infected kitchen waste disposed in the forest) Infection of wild boar coming from domestic pigs, particularly from the back yard sector Epidemic wave or multiple virus introductions???

8 A INDEX B INDEX 1 INDEX 2 INDEX 3 INDEX 4

9 Valka region The link between infected wild boar and domestic pig outbreaks was in most cases evident

10 KRASLAVA/DAGDAS BELARUS????

11 N. outnreaks N. outbreaks/week N. outbreaks = 21 N. weeks = y = x R 2 = 0, Weeks

12 Flock size and N. of outbreaks (n. 21) N. outbreaks >10 Flock size

13 Conclusions: Mission July (1) The first ASF events (both in wild boar and in domestic pigs) were detected in the frame of ASF and CSF early detection programmes which started already one year ago (e.g. compulsory checks of all home slaughtered pigs). The ASF virus introduction to Latvia was not older than 3 weeks and can be dated back to the first half of June. Introduction most probably from Belarus. At least two separate ASF clusters in wild boar were seen end of June 2014 direct at the border with Belarus.

14 Conclusions: Mission July (2) There was no epidemiological link between the two initial clusters of infections in wild boar as well as between the wild boar cases and the outbreak in domestic pigs (individual events) Most likely ASF in wild boar was introduced from Belarus by infected wild boar and/or infected material (illegal introduction) Most likely the ASF outbreak in domestic pigs was caused due to swill feeding. It appears that during May and June a huge virus pressure, either due to infected wild boar coming from Belarus or contaminated meat and meat products might have initiated the ASF events in Latvia.

15 Conclusions: Mission August Domestic pigs Nearly all outbreaks in the domestic pig sector were primary outbreaks. Several virus introductions occurred within a short period; so far no epidemic wave in the domestic pig sector. The outbreaks might be linked to the ASF mortality in the local wild boar population leading to an increased virus load in the environment. The poor biosecurity of the back yard farms can be considered as the main reason of not preventing ASF outbreaks. The virus spreading within a herd appears to be rather slow. In several herds only one or few infected animals were detected. Passive surveillance is functioning very well since the owners reported nearly all cases in an early stage of infection.

16 Conclusions: Mission August Wild boar In the area of first introduction (Kraslava/Dagdas) the virus might have initiated an epidemic wave with a westward direction It is highly probable that only a fraction of dead wild boar has been reported or found. The wild boar mortality resulted in a high environmental virus load enhancing its probability to spread to both wild boar and domestic pigs; No clear epidemiological links between the infected clusters could be identified; the source of virus introduction in Madona region remain unclear and undetermined; The passive surveillance is very efficient. Serological investigations in addition to the virus detection might help to better understand the epidemiology of ASF in wild boar

17 Recommendations: domestic pigs 1) Improvement of the biosecurity in domestic pig holdings is of paramount importance. Education of farmers is the most efficient tool to improve the biosecurity conditions. For back yard farms three basic biosecurity rules are recommended. No swill feeding No contact between the pig(s) of the back yard holding and susceptible animals The owner should change clothes on entering the stable and leaving the stable 2) The term back yard holding is not clearly defined. A clear definition taking into account the size of the holding, its production type as well as its biosecurity level would be desired. Based on such a classification control and eradication plans would become more clear and efficient.

18 Recommendations: wild boar The official wild boar estimates and local densities should be validated through different methodologies; The wild boar passive surveillance should be maintained in the already infected areas and re-enforced in the neighbouring areas; In the ASF wild boar clusters (25 km radius) all the shot wild boar should be tested for both virus and antibodies. Positive sera should be confirmed with a secondary confirmatory test. Hunting regime should not be abruptly changed; Wild boar winter-feeding and the use of dogs during driven hunts should be banned. Hay could be provided to sustain wild ruminants.

19 General recommendations Epidemiological evaluation of data Harmonized ASF control and eradication plans for all affected countries in Eastern Europe Mid-term to long-term strategy Back yard strategy needed!!!