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Bluetongue in Spain (February 2014)

Almudena Sánchez Matamoros & José Manuel Sánchez-Vizcaíno
February 19th, 2014. SUAT-UCM

EPIDEMIOLOGIC SITUATION

In the vector activity period 2013-2014 has been a major change in the epidemiological situation of Bluetongue virus (BTV). This has led to the decision to enhance current surveillance, control and eradication measures against the disease, highlighting the changes in the vaccination program.

Epidemiological evolution vector activity period 2013-2014

Since the re-emergence of bluetongue (BTV) in October 2013 in Toledo (serotype 1) and Cadiz (serotype 4), new outbreaks of both serotypes have been reported (Figure 1).

From October to date, 5 new outbreaks of BTV-1have been notified. The primary mentioned in Toledo, others 3 in Salamanca and 1 in Cáceres.

Regarding serotype 4, 70 new outbreaks of serotype 4 have been reported in Andalucía. These reported outbreaks has been located in Cádiz (19 outbreaks), Málaga (19 outbreaks) and Huelva (32 outbreaks). All are situated within the boundaries of the restricted zone for serotypes 1 and 4.

Distribución de los focos lengua azul notificados en el periodo 2013-2014 (a fecha 26/12/2013)
Fig. 1: Distribution of bluetongue outbreaks reported in 2013-2014 (as of 26/12/2013)
Source: Ministry of Agriculture, Food and Environment, 2014.


Restricted zones for bluetongue: December 2013

The current restricted zones for bluetongue (Figure 2):

a) Restricted zones against BTV-1 and BTV-4: Provinces of Cádiz , Huelva and Málaga and livestock regions of Utrera (Bajo Guadalquivir), Osuna (Campiña/Sierra Sur), Lebrija (Las Marismas), Sanlúcar la Mayor (Poniente de Sevilla) and Marchena (Serranía Sudoeste) in the province of Seville.
b) Restricted zones against BTV-1: Ceuta and Melilla and the rest of the Spanish peninsular territory not covered in paragraph a).
c) Free Zone: Canary Islands and Balearic Islands.

Distribución de las zonas de restricción respecto a la lengua azul en España a fecha de diciembre 2013
Fig. 2: Distribution of the restriction zones regarding bluetongue in Spain as of 12/2013.
Source: Ministry of Agriculture, Food and Environment, 2014.


Surveillance,control and eradication program against bluetongue virus, 2014

Due to the current epidemiological situation, surveillance, control and eradication measures against BTV comprises:

  • Active serological and virological surveillance program

    Serological surveillance on the coast of Andalusia and Balearic Islands has been improved by its geographical position close to other risk areas, as well as in areas of demonstrated circulation of serotype 1 and in those regions outside of the restricted zone to BTV 4. Using these parameters, two surveillance areas are distinguished: Risk area and no risk area (Figure 3), in which different surveillance criteria are established.

Distribución de la zona considerada de riesgo y la no considerada de riesgo para la lengua azul en España
Fig. 3: Distribution of the risk area and not considered at risk for bluetongue in Spain.
Source: Ministry of Agriculture, Food and Environment, 2014

  • Clinical passive surveillance program

    BTV passive surveillance program in 2014 is estimated that about 700 bovine and 420 ovine animals under will be sampled based on the number of animals sampled in previous years, when the situation epidemiological remains stable.
  • Entomological surveillance program

    Entomological surveillance program will be continued in 2014. This program has been designed taking into account the results of the first analysis of entomological surveillance program (2004-2011). These results have allowed the optimization of these sampling points:
    • 7 sampling point in the South: Main area of distribution and abundance of Culicoides imicola.
    • 11 sampling points in the North: Main area of distribution and abundance of Culicoides obsoletus.
    • 6 sampling points in the Center: Culicoides imicola and Culicoides obsoletus distribution.
    • 2 sampling points in each archipelago (Balearic and Canary Islands).
  • Vaccination program

    The current vaccination program against bluetongue is specified in the AAA/2201/2013 Order of 25 November, which specific protection measures are established in relation to BTV.

    The goal of vaccination is to control the movement of BTV-1 and BTV-4, facilitate the movement toward free areas and prevent the reintroduction of the virus in these areas. For this, two areas have been differentiated for each serotype in which compulsory or voluntary vaccination has been established.

    Regarding BTV-1, compulsory vaccination has been determined in sheep and bovine animals over 3 months present in "area of compulsory vaccination against serotype 1". The "area of compulsory vaccination against serotype 1" includes northern Cáceres and surrounding areas epidemiologically related (Figure 4). Moreover, vaccination against serotype 1 is recommended in the rest of the mainland.

Zonas de vacunación obligatoria y voluntaria frente al serotipo 1 de lengua azul en España
Fig. 4: Areas of voluntary and compulsory vaccination against serotype 1 bluetongue in Spain.
Source: Ministry of Agriculture, Food and Environment, 2014.

Regarding BTV-4, "area of compulsory vaccination against BTV 4" and "area of voluntary vaccination against BTV 4" have been delimited (Figure 5). The area of compulsory vaccination against serotype 4 matches the "restricted zone against BTV 4". Furthermore, the possibility of a voluntary vaccination is contemplated in areas with a high risk of reintroduction of this serotype basing on the previous experience, “area of voluntary vaccination against serotype 4".

Zonas de vacunación obligatoria y voluntaria frente al serotipo 4 de lengua azul en España

Fig. 5: Areas of voluntary and compulsory vaccination against bluetongue serotype 4 in Spain.
Source: Ministry of Agriculture, Food and Environment, 2014.


Related information: RASVE