Fig. 3
From: Revealing new tick-borne encephalitis virus foci by screening antibodies in sheep milk
Surveillance and detection of TBEV antibodies by screening of sheep and goat milk, Örebro County, Sweden. a Geographical locations of sampling sites and the study area of Örebro County, Sweden. Locations for sample-collection are indicated with red dots. Locations with TBEV antibody-positive milk samples are indicated with green circles, denoted I, II, III and Blidö. The clusters of human TBE cases are circled in red (dotted lines). b The milk samples were screened for the presence of anti-TBEV-IgG antibodies using a commercial ELISA (Immunozym FSME IgG All Species; Progen Biotechnik GMBH). Antibody titres > 126 VIEU/ml (dotted line) were considered positive, according to the manufacturer’s instructions. Blidö-1 represents the mean of 3 positive samples. Blidö-2 is a negative sample. Umeå represents the mean titer of 14 samples. c Western blot analysis of representative milk samples. BHK-21 cells were transfected with plasmid encoding TBEV membrane and envelope (ME) proteins. Cell lysate was separated on sodium dodecyl sulphate polyacrylamide gel and transferred to nitrocellulose membrane. The milk samples were then used as primary antibody to detect the envelope (E)-protein of TBEV (TBEV-E ≈ 50 kDa). Non-transfected cells are denoted as mock. The expression levels were verified by GAPDH (≈ 35 kDa). Abbreviations: SC, Stockholm County; VC, Västerbotten County; ÖC, Örebro County