First report of Schmallenberg Virus Infection in Cattle and Midges in Poland

Abstract

Two outbreaks of Schmallenberg virus (SBV) infection that coincided with the introduction of two bulls imported from France into two herds located in West Pomerania and Silesia provinces in Poland are described in detail. The first SBV real-time RT-PCR-positive result was obtained during routine testing of one of the imported bulls. The second bull and the affected farms were tracked by further investigation. Transmission of SBV into Polish cattle herds where the bulls were imported was confirmed by viral RNA detection in real-time RT-PCR, virus isolation followed by immunoperoxidase (IPX) staining and seroconversion. SBV RNA was detected also in Culicoides obsoletus pools caught in a trap located 5 km from one of the outbreaks. Testing nearly 900 samples collected prior to the two outbreaks from the same areas or provinces neighbouring with Germany where SBV cases had previously been detected gave negative results for the presence of SBV or specific antibodies. These cases are the first ones detected in cattle in Poland and provide evidence of recent transmission of the pathogen into the country and involvement of midge vectors.

Spread of Schmallenberg virus infections in the ruminants in Poland between 2012 and 2013

“…The first peak of SBV seroprevalence observed in the winter 2012 was shifted with respect to the peak of midges activity, probably due to the later transmission of SBV into the country in late summer, as suggested by this and previous study (13,15). Using quantitative methods like ELISA, it should be also remembered that the observed seroprevalence does not indicate seroconversion at the time of testing.…”

“…The infections in both herds were asymptomatic. The presence of virus RNA was also confirmed in Culicoides obsoletus, which were caught in August 2012 in Goleniow district, 5 km away from the examined herd (15).…”

“…While BTV ability to survive the winter has not been explained, the transovarial transmission of SBV in the midges has been suggested (14). SBV infection in Polish cattle was first reported in August 2012 (15). The outbreak coincided with the introduction of two French bulls into the herds in Goleniow (Zachodniopomorskie province) and Czestochowa districts (Slaskie province), which were SBV positive during the quarantine.…”

A review on Schmallenberg virus infection: a newly emerging disease of cattle, sheep and goats

“…In Belgium, a serological survey of 1082 sheep and 142 goats to detect SBV-specific antibodies by ELISA revealed a 98.03% overall between-herd seroprevalence in sheep and a 40.68% within-herd seroprevalence in goats (Meroc et al 2013b). So far, infections with SBV have been detected in Germany, the Netherlands, Belgium, the United Kingdom, France, Italy, Luxembourg, Spain, Denmark, Estonia, Switzerland, Ireland, Northern Ireland, Norway, Sweden, Finland, Poland, Austria, Switzerland and Turkey (Elbers et al 2012;Azkur et al 2013;FLI 2013a;Larska et al 2013;Meroc et al 2013a,b;Sailleau et al 2013). According to unconfirmed reports there could be infection in further European countries.…”

“…Field evidence from Europe shows that many animals are infected with SBV without any clinical signs (DEFRA 2013). Typically, the impact in most affected herds or flocks has been low, although a small number of farms have reported more significant losses (DEFRA 2013;FLI 2013a;Azkur et al 2013;Larska et al 2013;Meroc et al 2013a,b).…”