Serologic Survey of Birds for West Nile Flavivirus in Southern Moravia (Czech Republic)

Abstract

A serosurvey for West Nile virus (WNV) was carried out in 54 domestic birds (geese and ducks bred on fishponds) and 391 wild birds representing 28 migratory and resident species, using a plaque-reduction neutralization microtest with Vero cells and Egyptian topotype Eg-101 strain as test virus. The birds were sampled in the South-Moravian fishpond ecosystem between 2004 and 2006. Antibodies to WNV were not detected in domestic waterfowl, but 23 (5.9%) free-living birds of 10 species showed a positive response. These were the common coot (Fulica atra, 5 positive/18 examined), common kingfisher (Alcedo atthis, 1/1), reed warbler (Acrocephalus scirpaceus, 2/80), sedge warbler (A. schoenobaenus, 3/80), marsh warbler (A. palustris, 2/28), Savi's warbler (Locustella luscinioides, 3/12), reed bunting (Emberiza schoeniclus, 1/28), blackcap (Sylvia atricapilla, 2/11), penduline tit (Remiz pendulinus, 1/14), blue tit (Parus caeruleus, 1/1), and starling (Sturnus vulgaris, 2/4). The antibody titers were comparatively low (1:20-1:40), and the only high titer (1:160) was found in an adult marsh warbler. When 14 of the sera reacting with WNV were titrated in parallel with Usutu Flavivirus, 12 were interpreted as having specific antibodies to WNV, one coot had a higher titer against Usutu virus, and another one could not be attributed to either of the two viruses. In conclusion, 13 (3.3%) of 391 wild birds had specific antibodies to WNV. The results indicate that WNV activity in southern Moravia was limited during 2004-2006.

West Nile Virus

“…In both studies neutralizing antibodies against WNV were detected in a low percentage of migratory birds, but there was no evidence that the infections had been acquired in Germany. These results are consistent with studies reporting antibodies against WNV in free-living sedentary and migratory birds in the Czech Republic (Moravia) and Poland [125,126].…”

West Nile virus lineage 2 isolated from Culex modestus mosquitoes in the Czech Republic, 2013: expansion of the European WNV endemic area to the North?

“…Although neutralising antibodies against WNV have been found rarely in humans in the Czech Republic, two confirmed cases of WNF in humans were reported after heavy floods in 1997 [10]. In addition, WNV-specific antibodies have been detected in resident wild bird species [11]. The above rare traces of WNV infections in the Czech Republic before 2008 were most likely due to WNV lineage 1.…”

Vector Competence of Culex neavei (Diptera: Culicidae) for Usutu Virus

“…1,2 Since then, USUV has been isolated from mosquitoes or detected by serologic analysis in birds in Africa (Senegal, Central African Republic, Burkina Faso, Cô te d'Ivoire, Morocco, Nigeria, and Uganda) and Europe (Austria, Hungary, Switzerland, Italy, Spain, Germany, Poland, Czech Republic, and the United Kingdom). [3][4][5][6][7][8][9][10][11][12] In 2001, USUV emerged for the first time outside Africa, in Austria, and caused severe disease and high mortality rates among blackbirds and great gray owls. 13 Human infections with USUV reported in Central African Republic, Burkina Faso, and Italy in 1981, 2004, and 2009, respectively, have been associated with fever, rash, and jaundice among immunocompetent patients or a severe neurologic syndrome among immunodeficient patients, which emphasizes its potential threat to human health.…”