- Email: [email protected]
First detection of Schmallenberg virus in elk (Alces alces) indicating infection of wildlife in Białowieża National Park in Poland
The Veterinary Journal 198 (2013) 279–281
Contents lists available at ScienceDirect
The Veterinary Journal journal homepage: www.elsevier.com/locate/tvjl
Short Communication
First detection of Schmallenberg virus in elk (Alces alces) indicating _ National Park in Poland infection of wildlife in Białowieza _ ´ ski a Magdalena Larska a,⇑, Michał Krzysiak b, Marcin Smreczak a, Mirosław P. Polak a, Jan F. Zmudzin a b
Department of Virology, National Veterinary Research Institute, Al. Partyzantów 57, 24-100 Puławy, Poland European Bison Breeding Centre, Białowiez_ a National Park, Park Pałacowy 11, 17-230 Białowiez_ a, Poland
a r t i c l e
i n f o
Article history: Accepted 8 August 2013
Keywords: Schmallenberg virus Wildlife Elk Bison Poland
a b s t r a c t Schmallenberg virus (SBV) RNA was detected in the serum of an elk (Alces alces) calf captured on the out_ National Park (BNP) in December 2012, and shortly afterwards the calf died of acute skirts of Białowieza bronchopneumonia. Serum samples from 169 animals, including bison, red and fallow deer, originating from eight locations situated in four Polish Provinces, were tested for the presence of SBV-specific antibodies between 2011 and 2013. Although no antibodies were found in samples collected up to July 2012, positive samples subsequently appeared between November 2012 and January 2013 in all of the sampled regions. The introduction of SBV infection to the European bison (Bison bonasus) population of BNP between July and November 2012 was also confirmed. Ó 2013 Elsevier Ltd. All rights reserved.
Schmallenberg virus (SBV) is a novel Orthobunyavirus infecting ruminants which emerged in North Rhine-Westphalia, Germany in August/September 2011 (Hoffmann et al., 2012). Transmission is thought to occur through midge vectors such as Culicoides spp., and infection is mostly sub-clinical in adult animals, occasionally causing clinical signs (such as a drop in milk yield, pyrexia, anorexia, and diarrhoea) which correlate with the viraemia and persist between days 2 and 5 post-infection (Hoffmann et al., 2012). Losses in SBV-infected herds are associated with infection of susceptible pregnant animals resulting in abortion, stillbirth and, most frequently, congenital musculoskeletal and neural malformations observed in new-born animals leading to their death shortly after birth (Steukers et al., 2012). The susceptibility of wild red (Cervus elaphus) and roe (Capreolus capreolus) deer to SBV infection has been confirmed on only one occasion in Belgium in the autumn of 2011 (Linden et al., 2012). Antibodies were found in 43% of animals hunted between October and December 2011 in an area approximately 250 km from the city of Schmallenberg, where the virus was first identified. SBV has spread across Europe infecting most domestic ruminant species, reaching Poland in the late summer and autumn of 2012 (Kaba et al., 2013; Larska et al., 2013a). The first cases of malformations in bovine and ovine new-borns caused by SBV infection were detected in the Western part of the country in November 2012 and January 2013, respectively (Larska et al., 2013b).
⇑ Corresponding author. Tel.: +48 818893068. E-mail address: [email protected] (M. Larska). 1090-0233/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.tvjl.2013.08.013
In this paper, we report the first case of SBV infection in elk (Alces alces), and provide evidence of the farthest North-eastern spread of the virus within Europe to date. An elk calf, approximately 6-months of age, was found wandering alone on the out_ National Park (BNP), which is a European skirts of the Białowieza bison (Bison bonasus) Primeval Forest Reserve. The BNP forms part of an ancient woodland included in the UNESCO World Heritage Site list, and extends over approximately 150 km2 straddling Poland (41% of forest area) and neighbouring Belarus (59% of area). The calf was rescued following chemical immobilisation and transferred to the BNP Animal Rehabilitation Centre on the 7 December 2012. It exhibited general weakness, slight pyrexia (39.8 °C), hyperventilation (22 respirations/min), muscle tremors, hind-limb paresis and bilateral ‘crackles’ discernible on lung auscultation. Following a clinical diagnosis of acute pneumonia, the animal was treated with oxytetracycline 10% (1 mL/kg bodyweight IM; Engemycin, Intervet), the choleretic drug menbutone (100 mg/ mL, 10 mL/kg bodyweight IM; Vetahepar, Vet-Agro), and ivermectin 1% (200 lg/kg bodyweight SC; Merial). Despite initial clinical improvement, the calf died 5 days later and dermal oedema, pulmonary oedema, focal pulmonary emphysema and purulent bronchopneumonia were observed at necropsy. Serum, spleen and lung samples were subjected to virological examination. Pestivirus (bovine viral diarrhoea virus [BVDV] and border disease virus) and bovine alpha-herpesvirus-1 and -4 infections were excluded following PCR (Ros and Belák, 1999; Polak et al., 2008), and serology (BVDV total antibody test, and infectious bovine rhinotracheitis virus [BHV-1] gB antibody test kit [both supplied by IDEXX]). A serum sample tested positive for SBV by
280
M. Larska et al. / The Veterinary Journal 198 (2013) 279–281
Table 1 Details of serological survey for Schmallenberg virus (SBV) in free-living and farmed wild ruminants in eight geographical locations in four Provinces of Poland (Podlaskie, PD; Lublin, LU; Pomerania, PM; and Warmia-Mazuria, WM). Sampling took place between January 2011 and March 2013. FD, fallow deer (Dama dama); EB, European bison (Bison bonasus); RD, red deer (Cervus elaphus). Province
Location
Species
SBV seropositive/animals tested January 2010
PD PD PD PD LU LU PM WM Total % Seropositive a b
1 2 3 4 5 6 7 8
FDa EBb RDb RDa RDb RDb RDb RDb
% Seropositive
February 2011– April 2011
December 2011– June 2012
November 2012
December 2012
January 2013
February 2013
March 2013
0/23
0/16 0/12
3/3
3/3
7/7
4/6
5/6
4/6 67
5/6 83
0/8 0/24 8/17 0/2 2/23
4/11 1/8 0/8 0
0/23 0
0/52 0
7/14 50
12/28 43
9/32 39
Total 0/16 22/60 0/8 0/24 8/17 0/2 6/34 1/8
0 37 0 0 47 0 18 13
37/169 22
22
Farmed animals. Free-living animals.
Fig. 1. Map of Poland illustrating geographical locations of wild ruminants tested for Schmallenberg virus antibodies between January 2010 and March 2013. ‘E’ indicates where an infected elk was captured (location ‘2’, Table 1). The map was plotted using ArcView8 software (ESRI). The numbers correspond to the eight locations where the sampled animals originated. Province abbreviations: Podlaskie (PD); Lublin (LU); Pomerania (PM); Warmia-Masuria (WM).
real-time RT-PCR (Ct = 35.27; SD 0.72) (Hoffmann et al., 2012). Possible sample contamination from the positive controls was excluded by including negative controls and confirming the result by re-testing the sample using freshly extracted RNA. Serology for IgG against the SBV nucleocapsid protein using an indirect ELISA (v.2 kit ID.vet, Innovative Diagnostics) proved negative. This test had previously been validated for use in cervid species (Linden et al., 2012). It remains unclear whether the clinical signs observed in this case were associated with SBV infection, as pneumonia and dermal oedema have not previously been reported as clinical signs of infection (Hoffmann et al., 2012; Larska et al., 2013a). It is possible that SBV infection attenuated the calf’s immune system, facilitating the activity of other pathogens. The fact that the animal had not yet seroconverted suggests infection was relatively recent, a hypothesis consistent with the extended activity of Culicoides spp. in this geographical location: activity continued until 7 November
1 Report on entomologic monitoring of Culicoides spp. in Poland in 2012 released by the Chief Veterinary Officer.
2012,1 a likely consequence of the exceptionally high temperatures prevalent at that time (mean, 4.7 °C; minimum, 2 °C, maximum 12 °C).2 In order to determine the likely spread of SBV to other wild ruminant species in the area, 169 serum samples collected from free-living bison (n = 60), wild red (n = 69), farmed red (n = 24) and fallow (Dama dama) (n = 16) deer from eight different geographical locations, including the area surrounding the BNP (Podlaskie [PD] Province), as well as from three other Provinces: Lublin (LU), Pomerania (PM), and Warmia and Masuria (WM) (Fig. 1) were tested by ELISA. The samples from wild cervids and bison were collected during the post-mortem examination of animals hunted or culled because of poor health between January 2010 and March 2013. No ethical/welfare authority approval was required as samples were collected post-mortem. The animals were killed by certified hunters in accordance with the Amendment of the Hunting Act passed on 27 October 2005 (Journal 2002.42.372): Bison on Polish General Directorate for Environmental Protection regulations DOP-OZGIZ.6401.06.7.2012.1s and DOPOZ.6401.06.7.2012.1s1. The farmed deer were sampled during national monitoring for bluetongue virus as accredited by the Chief Veterinary Officer of Poland, and carried out at locations 1 and 4 at the end of 2011 and 2012 (Fig. 1). Antibodies against SBV were not detected in wild ruminants between January 2010 and June 2012 (n = 83), whereas 43% of animals sampled between November 2012 and March 2013 (n = 86) were seropositive (Table 1). The average percentage of seropositive bison detected in the autumn/winter of 2012– 2013 in BNP was 88%, while only 25% of the deer tested over this period had antibodies. The overall percentage of seropositive deer was less in the south and west of the park with values of 42%, 18%, and 13% in the LU, PM, and WM Provinces, respectively. These results may indicate a ‘reverse-direction’ to the SBV epizootic from that described in Western Europe3 and suggest movement and trade in domestic animals may be underestimated in terms of their role in SBV transmission (Larska et al., 2013a). The high SBV infection rate in bison may reflect a particular species susceptibility: bison are more closely related genetically to domestic ruminants than are cervid species (Buczyn´ska et al., 1999). Furthermore, the high density and favoured location of the bison population in the BNP may have resulted in their more frequent contact with 2 3
See: http://www.imgw.pl/. See: http://www.efsa.europa.eu/en/supporting/doc/360e.pdf.
M. Larska et al. / The Veterinary Journal 198 (2013) 279–281
Culicoides spp. The overall increase in the proportion of SBV-affected wild ruminants to 50% and 43% in November and December 2012, respectively, may also be connected to the peak of midge activity in the autumn months (Sanders et al., 2011). Infection of a single bison was reported by the Friedrich Loeffler Institute in Rhineland-Palatinate, Germany.4 Clinical consequences of virus transmission might be expected in the offspring of bison and red deer between approximately May and September 2013 as the emergence of the virus coincided with the period of greatest susceptibility to SBV infection, namely, early pregnancy prior to fetal immunocompetence (Linden et al., 2012).
Conflict of interest statement None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper.
Acknowledgments We would like to thank M. Sudowska, A. Kuta and W. Socha for laboratory assistance and J. Rola and M. Materniak for providing sera from deer. The authors received no financial support for the research, authorship or publication.
281
References Buczyn´ska, B., Olech, W., Topczewski, J., 1999. Phylogeny and genetic variation of the European bison Bison bonasus based on mitochondrial DNA D-loop sequences. Acta Theriologica 44, 253–262. Hoffmann, B., Scheuch, M., Höper, D., Jungblut, R., Holsteg, M., Schirrmeier, H., Eschbaumer, M., Goller, K.V., Wernike, K., Fischer, M., et al., 2012. Novel orthobunyavirus in cattle, Europe, 2011. Emerging Infectious Diseases 18, 469– 472. Kaba, J., Czopowicz, M., Witkowski, L., 2013. Schmallenberg virus antibodies detected in Poland. Transboundary Emerging Diseases 60, 1–3. _ ´ ski, J.F., Larska, M., Polak, M.P., Grochowska, M., Lechowski, L., Zwia˛zek, J.S., Zmudzin 2013a. First report of Schmallenberg virus infection in cattle and midges in Poland. Transboundary Emerging Diseases 60, 97–101. _ ´ ski, J.F., 2013b. Clinical cases of Schmallenberg virus Larska, M., Jasik, A., Zmudzin infections in Poland. Medycyna Wet 69, 428–431. Linden, A., Desmecht, D., Volpe, R., Wirtgen, M., Gregoire, F., Pirson, J., Paternostre, J., Kleijnen, D., Schirrmeier, H., Beer, M., et al., 2012. Epizootic spread of Schmallenberg virus among wild cervids, Belgium, fall 2011. Emerging Infectious Diseases 18, 2006–2008. Polak, M.P., Tucholski, A., Rola, J., 2008. Identification of a herd infected with bovine viral diarrhoea virus based on laboratory diagnosis. The Bulletin of the Veterinary Institute in Pulawy 52, 497–500. Ros, C., Belák, S., 1999. Studies of genetic relationships between bovine, caprine, cervine, and rangiferine alphaherpesviruses and improved molecular methods for virus detection and identification. Journal of Clinical Microbiology 37, 1247– 1253. Sanders, C.J., Shortall, C.R., Gubbins, S., Burgin, L., Gloster, J., Harrington, R., Reynolds, D.R., Mellor, P.S., Carpenter, S., 2011. Influence of season and meteorological parameters on flight activity of Culicoides biting midges. Journal of Applied Ecology 48, 1355–1364. Steukers, L., Bertels, G., Cay, A.B., Nauwynck, H.J., 2012. Schmallenberg virus: Emergence of an orthobunyavirus among ruminants in Western Europe. Vlaams Diergeneeskundig Tijdschrift 81, 119–127.
Contents lists available at ScienceDirect
The Veterinary Journal journal homepage: www.elsevier.com/locate/tvjl
Short Communication
First detection of Schmallenberg virus in elk (Alces alces) indicating _ National Park in Poland infection of wildlife in Białowieza _ ´ ski a Magdalena Larska a,⇑, Michał Krzysiak b, Marcin Smreczak a, Mirosław P. Polak a, Jan F. Zmudzin a b
Department of Virology, National Veterinary Research Institute, Al. Partyzantów 57, 24-100 Puławy, Poland European Bison Breeding Centre, Białowiez_ a National Park, Park Pałacowy 11, 17-230 Białowiez_ a, Poland
a r t i c l e
i n f o
Article history: Accepted 8 August 2013
Keywords: Schmallenberg virus Wildlife Elk Bison Poland
a b s t r a c t Schmallenberg virus (SBV) RNA was detected in the serum of an elk (Alces alces) calf captured on the out_ National Park (BNP) in December 2012, and shortly afterwards the calf died of acute skirts of Białowieza bronchopneumonia. Serum samples from 169 animals, including bison, red and fallow deer, originating from eight locations situated in four Polish Provinces, were tested for the presence of SBV-specific antibodies between 2011 and 2013. Although no antibodies were found in samples collected up to July 2012, positive samples subsequently appeared between November 2012 and January 2013 in all of the sampled regions. The introduction of SBV infection to the European bison (Bison bonasus) population of BNP between July and November 2012 was also confirmed. Ó 2013 Elsevier Ltd. All rights reserved.
Schmallenberg virus (SBV) is a novel Orthobunyavirus infecting ruminants which emerged in North Rhine-Westphalia, Germany in August/September 2011 (Hoffmann et al., 2012). Transmission is thought to occur through midge vectors such as Culicoides spp., and infection is mostly sub-clinical in adult animals, occasionally causing clinical signs (such as a drop in milk yield, pyrexia, anorexia, and diarrhoea) which correlate with the viraemia and persist between days 2 and 5 post-infection (Hoffmann et al., 2012). Losses in SBV-infected herds are associated with infection of susceptible pregnant animals resulting in abortion, stillbirth and, most frequently, congenital musculoskeletal and neural malformations observed in new-born animals leading to their death shortly after birth (Steukers et al., 2012). The susceptibility of wild red (Cervus elaphus) and roe (Capreolus capreolus) deer to SBV infection has been confirmed on only one occasion in Belgium in the autumn of 2011 (Linden et al., 2012). Antibodies were found in 43% of animals hunted between October and December 2011 in an area approximately 250 km from the city of Schmallenberg, where the virus was first identified. SBV has spread across Europe infecting most domestic ruminant species, reaching Poland in the late summer and autumn of 2012 (Kaba et al., 2013; Larska et al., 2013a). The first cases of malformations in bovine and ovine new-borns caused by SBV infection were detected in the Western part of the country in November 2012 and January 2013, respectively (Larska et al., 2013b).
⇑ Corresponding author. Tel.: +48 818893068. E-mail address: [email protected] (M. Larska). 1090-0233/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.tvjl.2013.08.013
In this paper, we report the first case of SBV infection in elk (Alces alces), and provide evidence of the farthest North-eastern spread of the virus within Europe to date. An elk calf, approximately 6-months of age, was found wandering alone on the out_ National Park (BNP), which is a European skirts of the Białowieza bison (Bison bonasus) Primeval Forest Reserve. The BNP forms part of an ancient woodland included in the UNESCO World Heritage Site list, and extends over approximately 150 km2 straddling Poland (41% of forest area) and neighbouring Belarus (59% of area). The calf was rescued following chemical immobilisation and transferred to the BNP Animal Rehabilitation Centre on the 7 December 2012. It exhibited general weakness, slight pyrexia (39.8 °C), hyperventilation (22 respirations/min), muscle tremors, hind-limb paresis and bilateral ‘crackles’ discernible on lung auscultation. Following a clinical diagnosis of acute pneumonia, the animal was treated with oxytetracycline 10% (1 mL/kg bodyweight IM; Engemycin, Intervet), the choleretic drug menbutone (100 mg/ mL, 10 mL/kg bodyweight IM; Vetahepar, Vet-Agro), and ivermectin 1% (200 lg/kg bodyweight SC; Merial). Despite initial clinical improvement, the calf died 5 days later and dermal oedema, pulmonary oedema, focal pulmonary emphysema and purulent bronchopneumonia were observed at necropsy. Serum, spleen and lung samples were subjected to virological examination. Pestivirus (bovine viral diarrhoea virus [BVDV] and border disease virus) and bovine alpha-herpesvirus-1 and -4 infections were excluded following PCR (Ros and Belák, 1999; Polak et al., 2008), and serology (BVDV total antibody test, and infectious bovine rhinotracheitis virus [BHV-1] gB antibody test kit [both supplied by IDEXX]). A serum sample tested positive for SBV by
280
M. Larska et al. / The Veterinary Journal 198 (2013) 279–281
Table 1 Details of serological survey for Schmallenberg virus (SBV) in free-living and farmed wild ruminants in eight geographical locations in four Provinces of Poland (Podlaskie, PD; Lublin, LU; Pomerania, PM; and Warmia-Mazuria, WM). Sampling took place between January 2011 and March 2013. FD, fallow deer (Dama dama); EB, European bison (Bison bonasus); RD, red deer (Cervus elaphus). Province
Location
Species
SBV seropositive/animals tested January 2010
PD PD PD PD LU LU PM WM Total % Seropositive a b
1 2 3 4 5 6 7 8
FDa EBb RDb RDa RDb RDb RDb RDb
% Seropositive
February 2011– April 2011
December 2011– June 2012
November 2012
December 2012
January 2013
February 2013
March 2013
0/23
0/16 0/12
3/3
3/3
7/7
4/6
5/6
4/6 67
5/6 83
0/8 0/24 8/17 0/2 2/23
4/11 1/8 0/8 0
0/23 0
0/52 0
7/14 50
12/28 43
9/32 39
Total 0/16 22/60 0/8 0/24 8/17 0/2 6/34 1/8
0 37 0 0 47 0 18 13
37/169 22
22
Farmed animals. Free-living animals.
Fig. 1. Map of Poland illustrating geographical locations of wild ruminants tested for Schmallenberg virus antibodies between January 2010 and March 2013. ‘E’ indicates where an infected elk was captured (location ‘2’, Table 1). The map was plotted using ArcView8 software (ESRI). The numbers correspond to the eight locations where the sampled animals originated. Province abbreviations: Podlaskie (PD); Lublin (LU); Pomerania (PM); Warmia-Masuria (WM).
real-time RT-PCR (Ct = 35.27; SD 0.72) (Hoffmann et al., 2012). Possible sample contamination from the positive controls was excluded by including negative controls and confirming the result by re-testing the sample using freshly extracted RNA. Serology for IgG against the SBV nucleocapsid protein using an indirect ELISA (v.2 kit ID.vet, Innovative Diagnostics) proved negative. This test had previously been validated for use in cervid species (Linden et al., 2012). It remains unclear whether the clinical signs observed in this case were associated with SBV infection, as pneumonia and dermal oedema have not previously been reported as clinical signs of infection (Hoffmann et al., 2012; Larska et al., 2013a). It is possible that SBV infection attenuated the calf’s immune system, facilitating the activity of other pathogens. The fact that the animal had not yet seroconverted suggests infection was relatively recent, a hypothesis consistent with the extended activity of Culicoides spp. in this geographical location: activity continued until 7 November
1 Report on entomologic monitoring of Culicoides spp. in Poland in 2012 released by the Chief Veterinary Officer.
2012,1 a likely consequence of the exceptionally high temperatures prevalent at that time (mean, 4.7 °C; minimum, 2 °C, maximum 12 °C).2 In order to determine the likely spread of SBV to other wild ruminant species in the area, 169 serum samples collected from free-living bison (n = 60), wild red (n = 69), farmed red (n = 24) and fallow (Dama dama) (n = 16) deer from eight different geographical locations, including the area surrounding the BNP (Podlaskie [PD] Province), as well as from three other Provinces: Lublin (LU), Pomerania (PM), and Warmia and Masuria (WM) (Fig. 1) were tested by ELISA. The samples from wild cervids and bison were collected during the post-mortem examination of animals hunted or culled because of poor health between January 2010 and March 2013. No ethical/welfare authority approval was required as samples were collected post-mortem. The animals were killed by certified hunters in accordance with the Amendment of the Hunting Act passed on 27 October 2005 (Journal 2002.42.372): Bison on Polish General Directorate for Environmental Protection regulations DOP-OZGIZ.6401.06.7.2012.1s and DOPOZ.6401.06.7.2012.1s1. The farmed deer were sampled during national monitoring for bluetongue virus as accredited by the Chief Veterinary Officer of Poland, and carried out at locations 1 and 4 at the end of 2011 and 2012 (Fig. 1). Antibodies against SBV were not detected in wild ruminants between January 2010 and June 2012 (n = 83), whereas 43% of animals sampled between November 2012 and March 2013 (n = 86) were seropositive (Table 1). The average percentage of seropositive bison detected in the autumn/winter of 2012– 2013 in BNP was 88%, while only 25% of the deer tested over this period had antibodies. The overall percentage of seropositive deer was less in the south and west of the park with values of 42%, 18%, and 13% in the LU, PM, and WM Provinces, respectively. These results may indicate a ‘reverse-direction’ to the SBV epizootic from that described in Western Europe3 and suggest movement and trade in domestic animals may be underestimated in terms of their role in SBV transmission (Larska et al., 2013a). The high SBV infection rate in bison may reflect a particular species susceptibility: bison are more closely related genetically to domestic ruminants than are cervid species (Buczyn´ska et al., 1999). Furthermore, the high density and favoured location of the bison population in the BNP may have resulted in their more frequent contact with 2 3
See: http://www.imgw.pl/. See: http://www.efsa.europa.eu/en/supporting/doc/360e.pdf.
M. Larska et al. / The Veterinary Journal 198 (2013) 279–281
Culicoides spp. The overall increase in the proportion of SBV-affected wild ruminants to 50% and 43% in November and December 2012, respectively, may also be connected to the peak of midge activity in the autumn months (Sanders et al., 2011). Infection of a single bison was reported by the Friedrich Loeffler Institute in Rhineland-Palatinate, Germany.4 Clinical consequences of virus transmission might be expected in the offspring of bison and red deer between approximately May and September 2013 as the emergence of the virus coincided with the period of greatest susceptibility to SBV infection, namely, early pregnancy prior to fetal immunocompetence (Linden et al., 2012).
Conflict of interest statement None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper.
Acknowledgments We would like to thank M. Sudowska, A. Kuta and W. Socha for laboratory assistance and J. Rola and M. Materniak for providing sera from deer. The authors received no financial support for the research, authorship or publication.
281
References Buczyn´ska, B., Olech, W., Topczewski, J., 1999. Phylogeny and genetic variation of the European bison Bison bonasus based on mitochondrial DNA D-loop sequences. Acta Theriologica 44, 253–262. Hoffmann, B., Scheuch, M., Höper, D., Jungblut, R., Holsteg, M., Schirrmeier, H., Eschbaumer, M., Goller, K.V., Wernike, K., Fischer, M., et al., 2012. Novel orthobunyavirus in cattle, Europe, 2011. Emerging Infectious Diseases 18, 469– 472. Kaba, J., Czopowicz, M., Witkowski, L., 2013. Schmallenberg virus antibodies detected in Poland. Transboundary Emerging Diseases 60, 1–3. _ ´ ski, J.F., Larska, M., Polak, M.P., Grochowska, M., Lechowski, L., Zwia˛zek, J.S., Zmudzin 2013a. First report of Schmallenberg virus infection in cattle and midges in Poland. Transboundary Emerging Diseases 60, 97–101. _ ´ ski, J.F., 2013b. Clinical cases of Schmallenberg virus Larska, M., Jasik, A., Zmudzin infections in Poland. Medycyna Wet 69, 428–431. Linden, A., Desmecht, D., Volpe, R., Wirtgen, M., Gregoire, F., Pirson, J., Paternostre, J., Kleijnen, D., Schirrmeier, H., Beer, M., et al., 2012. Epizootic spread of Schmallenberg virus among wild cervids, Belgium, fall 2011. Emerging Infectious Diseases 18, 2006–2008. Polak, M.P., Tucholski, A., Rola, J., 2008. Identification of a herd infected with bovine viral diarrhoea virus based on laboratory diagnosis. The Bulletin of the Veterinary Institute in Pulawy 52, 497–500. Ros, C., Belák, S., 1999. Studies of genetic relationships between bovine, caprine, cervine, and rangiferine alphaherpesviruses and improved molecular methods for virus detection and identification. Journal of Clinical Microbiology 37, 1247– 1253. Sanders, C.J., Shortall, C.R., Gubbins, S., Burgin, L., Gloster, J., Harrington, R., Reynolds, D.R., Mellor, P.S., Carpenter, S., 2011. Influence of season and meteorological parameters on flight activity of Culicoides biting midges. Journal of Applied Ecology 48, 1355–1364. Steukers, L., Bertels, G., Cay, A.B., Nauwynck, H.J., 2012. Schmallenberg virus: Emergence of an orthobunyavirus among ruminants in Western Europe. Vlaams Diergeneeskundig Tijdschrift 81, 119–127.