Published Date: 2017-02-23 15:20:44
Subject: PRO/AH/EDR> Bluetongue - Europe: (France) bovine, ovine, st 8, update
Archive Number: 20170223.4859510
BLUETONGUE - EUROPE: (FRANCE) BOVINE, OVINE, SEROTYPE 8, UPDATE
A ProMED-mail post http://www.promedmail.org
ProMED-mail is a program of the International Society for Infectious Diseases http://www.isid.org
[Since the fall of 2015, ProMED-mail has been receiving and posting periodic reports from France, addressing new outbreaks of bluetongue in cattle and sheep, caused by BTV-8. Such reports have been received also during the winter months, informing about outbreaks involving single cases in cattle herds. Since they came during the "non-vector season", when new outbreaks are not expected to occur, it was suggested that those single positives, named "outbreaks", may just reflect the recordings of seropositive animals, obtained within the ongoing BT surveillance, representing old infections. This led to relevant commentaries (such as those in postings 20160222.4042179, 20160312.4088596).
Such reports have been received also during the current winter months. Consequently, ProMED-mail contacted the 'French Platform for epidemiological surveillance, animal health' in Lyon, for their 1st-hand assessment and clarification of the factual situation regarding active circulating virus and new outbreaks. The kind, immediate response, which is hereby published, is gratefully acknowledged. -Mod.AS]
Date: Mon 20 Feb 2017
From: Laure Bournez <email@example.com> [edited]
Re: ProMED-mail's questions about bluetongue surveillance in France
The confirmation of bluetongue outbreaks in France is based on PCR positive results. Since the BTV-8 viral genome in cattle can be detected by PCR up to 6 months post infection (references 1,2), it is expected that bluetongue outbreaks keep being detected, even in free-vector periods. BTV-8 monitoring is on-going even during the vector free periods through different surveillance schemes (programmed surveillance, clinical surveillance, RT-PCR analyses on animals leaving the restricted zone). Several programmed surveillance systems were launched since the detection of the virus in September 2015. Since July 2016 a sentinel surveillance system is implemented in "départements" (department, an administrative unit in France) that are located in the free zone and at the periphery of the restricted zone and of the free area. Every month 180 sentinel animals at risk (young animals, generally cattle except in the departments with few cattle in which small ruminants are sampled, which were never vaccinated against bluetongue) are sampled and tested by ELISA in each department. Until now no outbreak was detected in these areas. Moreover a survey is currently ongoing in other departments to ensure the absence of exotic serotypes according to EU regulations.
From 11 Sep 2015 (confirmation date of the 1st BTV-8 outbreak of the current episode) to 2 Feb 2017, the total number of bluetongue outbreaks in France was 1924. Since July 2016 (date we have defined as the start of the bluetongue activity for the season 2016-2017), we have detected 1740 outbreaks (based on RT-PCR results): 1681 were detected on animals leaving the restricted zone and 59 related to clinical suspicions (general clinical signs or abortions).
An entomological surveillance was also implemented. No vector activity was evidenced in most East and centre of France (where most outbreaks are found) since the end of December . The western and southern parts of France have a milder climate and vector activity was low from early January to early February.
Updated epidemiological situation of bluetongue in France are regularly published on http://plateforme-esa.fr/fco-actualites- (in French). [For the most recent report, issued 24 Jan 2017, as available at the said URL, see http://goo.gl/Wylgl3. - Mod.AS]
1. Di Gialleonardo L, Migliaccio P, Teodori L, Savini G: The length of BTV-8 viraemia in cattle according to infection doses and diagnostic techniques. Res. Vet. Sci. 2011; 91(2): 316-20; abstract available at https://www.ncbi.nlm.nih.gov/pubmed/21324498.
2. Zanella G, Martinelle L, Guyot H, et al: Clinical pattern characterization of cattle naturally infected by BTV-8. Transbound. Emerg. Dis. 2013; 60(3): 231-7; abstract available at https://www.ncbi.nlm.nih.gov/pubmed/22571462.
Epidemiologist, on behalf of the French Platform for epidemiological surveillance
Anses - Direction des laboratoires
UCAS - Unité de coordination et d'appui à la surveillance
French Platform for epidemiological surveillance, animal health (Plateforme ESA)
[France's 1st BTV-8 epizootic started in late 2006; the epizootic was announced as "resolved" at the end of 2012, when France regained its BTV-free status. A 2nd epizootic started in August 2015. Since then, 64 follow-up reports have been submitted, informing about a total of 1644 outbreaks. The 5 recent follow-up reports, in 2017, were submitted on 16 Jan (no. 60), 20 Jan (no. 61), 30 Jan (no. 62), 2 Feb (no. 63), and on 16 Feb 2017 (no. 64). No outbreaks were reported in follow-up reports 61-64. In follow-up report no. 60, submitted 16 Jan 2017, epidemiological statistics of 277 outbreaks were included, covering the outbreaks which reportedly started between 10 Oct 2016 and 11 Jan 2017 (last outbreak). They were summarised (accumulated) as follows:
Total outbreaks: 277
Total animals affected
Species / Susceptible / Cases / Deaths / Destroyed / Slaughtered
Cattle / 41 035 / 358 / 0 / 0 / 0
Sheep* / 50 / 1 / 0 / 0 / 0
*The single event in sheep (outbreak no. 4 in the report) was, reportedly, located in Coublanc, Saône-et-Loire department; it started on 20 Oct 2016.
A summary of the epizootic, including a map showing all 1644 accumulated outbreaks and links to the 64 follow-up reports, is available at http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review/viewsummary?fupser=&dothis=&reportid=18642.
ProMED-mail will commence reporting BTV-8 outbreaks in France if/when clinical cases reappear in ruminants. - Mod.AS
A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/promed/p/100.]