HELLENIC REPUBLIC MINISTRY OF AGRICULTURE D.G.OF VETERINARY SERVICES ANIMAL HEALTH DIRECTORATE DEPT. OF INFECTIOUS DISEASES, EPIDEMIOLOGY & DOCUMENTATION 5 October 2001
FOLLOW-UP REPORT No.1 ON THE EVOLUTION OF BLUE TONGUE ( BT ) IN GREECE AUTUMN 2001
1. Introduction
A Preliminary Report on the recurrence of BT in Greece was released on 17/09/2001 and it was duly notified to the European Commission, the OIE and neighboring countries (Albania and FYROM).
The Preliminary Report was further disseminated in the OIE Bulletin Vol.14 / No.38 of 21/09/2001 and is available on the web at : minagric.gr/greek/2.3.1.html
The purpose of the Follow-up Report No.1 is to : Provide an up date on the features and the evolution of BT inside Greece, Explain the current control and safeguard measures in place, Review the epidemiological situation of BT in a Balkan context.
2. Evolution of BT inside Greece
2.1 Clinical aspects
Up to date (05/10/2001) a total of 19 outbreaks (= infected flocks) have been confirmed in 3 Prefectures, namely in Grevena, Ioannina and Kastoria, on the basis of clinical symptoms suggestive of BT and subsequent laboratory (serology) confirmation.
An account of clinical outbreaks is given in Table 1 and their exact location is indicated in Map 1 attached to this Report.
* NOTE : Map 2 also includes parts of the Prefecture of Kozani, where no clinical outbreaks have been recorded, but is located within the 20 km-radius zones of Grevena and Kastoria. No. of Prefecture Village Date of Date of Animals Animals Affected Outbreak Susp. Conf. present Schick Dead Killed ( S / G ) & Dest.
2001/01 Grevena Smixi 30.08 13.09 800 90 30 90
2001/02 Ioannina Karyes 29.08 13.09 100/10 11 1 0 2001/03 " Miliotades 07.09 13.09 32 / 7 3 0 0 2001/04 " Miliotades 07.09 13.09 100/20 7 1 0 2001/05 " Dilifo 05.09 13.09 60 3 0 0 2001/06 " Kefalovriso 06.09 13.09 70 13 3 0 2001/07 " Vissani 06.09 13.09 280/40 17 2 0 2001/08 " K.Meropi 06.09 13.09 130 7 0 0 2001/09 " Faraggi 06.09 13.09 220/20 14 0 0 2001/16 " M.Gotista 17.09 24.09 240 6 0 0 2001/17 " K.Lavdani 14.09 24.09 45/5 3 0 0 2001/18 " Oreokastro 18.09 24.09 600/200 7 1 0 2001/19 " K.Lavdani 14.09 24.09 305 8 1 0
2001/10 Kastoria Dipotamia 18.09 24.09 135/25 5 0 0 2001/11 " Chrysi 18.09 24.09 227 6 5 0 2001/12 " Spilaio 25.09 01.10 100/17 5 0 0 2001/13 " Spilaio 25.09 01.10 170/30 4 0 0 2001/14 " Gavros 25.09 01.10 320/40 3 0 0 2001/15 " Ag.Kiriaki 25.09 01.10 155/115 6 0 0 Table 1 : Summary account of clinical outbreaks of BT / Greece / 2001
On the basis of clinical data presented in Table 1 the following comments can be made : a) With the notable exception of outbreak 2001/01, The average morbidity in sheep is 3,9%, and The average mortality in sheep is 0,55%. b) In most cases clinical symptoms are mild and transitory lasting 3 - 4 days and the affected animals appear to recover fully. For this reason laboratory confirmation is sought for in most cases and by the time serological results become available it is possible to identify the affected animals only by the ear tag number. This explains why no clinically affected animals have been killed and destroyed. c) In the case of outbreak 2001/01, the morbidity and mortality are significantly higher (11,25% and 3,75% respectively).In order to investigate the reasons for this deviation from the general pattern, the following scenarios may be of relevance : Involvement of different BTV type. This hypothesis is not valid because provisional typing made by SNT (serum neuteralisation test) has indicated the presence of the same BTV type 2001/01 as well as in other outbreaks in Ioannina and Kastoria. Involvement of different BTV vector or varying competence of the same vector. This hypothesis is being currently investigated by setting up light traps and collecting insects from all affected areas. In this respect, however, it appears more likely that the same low-competence vector is involved in all outbreaks because of common climatic and terrain conditions in North - Western Greece, but in the case of 2001/01 its efficiency is increased due to large size of local vector population