%0 Journal Article %J Transbound Emerg Dis %D 2008 %T Transplacental infection and apparently immunotolerance induced by a wild-type bluetongue virus serotype 8 natural infection. %A Kris De Clercq %A Ilse De Leeuw %A Verheyden, B %A Vandemeulebroucke, E %A Vanbinst, T %A Herr, C %A Estelle Méroc %A Bertels, G %A Steurbaut, N %A Miry, C %A De Bleecker, K %A Maquet, G %A Bughin, J %A Saulmont, M %A Lebrun, M %A Sustronck, B %A De Deken, R %A Hooyberghs, J %A Houdart, P %A Raemaekers, M %A Mintiens, K %A Pierre Kerkhofs %A Goris, N %A Frank Vandenbussche %K Abortion, Veterinary %K Animals %K Animals, Newborn %K Belgium %K Bluetongue %K Bluetongue virus %K Cattle %K Cattle Diseases %K Female %K Infectious Disease Transmission, Vertical %K Pregnancy %K Pregnancy Complications, Infectious %K RNA, Viral %K Serotyping %X

Until recently, bluetongue (BT) virus (BTV) serotypes reportedly causing transplacental infections were all ascribed to the use of modified live virus strains. During the 2007 BT epidemic in Belgium, a significant increase in the incidence of abortions was reported. A study including 1348 foetuses, newborns and young animals with or without suspicion of BTV infection, was conducted to investigate the occurrence of natural transplacental infection caused by wild-type BTV-8 and to check the immunocompetence of newborns. BTV RNA was present in 41% and 18.5% of aborted foetuses from dams with or without suspected BTV involvement during pregnancy, respectively. The results of dam/calf pairs sampled before colostrum uptake provide evidence of almost 10% transplacental BTV infection in newborns. Apparently immunotolerant calves were found at a level of 2.4%. The current study concludes that the combined serological and real-time PCR (RT-qPCR) result of pregnant dams gives no indication of the infection status of the offspring except in the case of a double negative result. In a group of 109 calves with clinical suspicion of BT, born during the vector-free period, 11% were found to be RT-qPCR positive. The true prevalence was estimated to be 2.3%, indicating the extent of transplacental infection in a group of 733 calves of one to 4 months of age without BT suspicion. Moreover, virus isolation was successful for two newborn calves, emphasizing the need for restricting trade to BT-free regions of pregnant dams possibly infected during gestation, even if they are BTV RT-qPCR negative.

%B Transbound Emerg Dis %V 55 %P 352-9 %8 2008 Oct %G eng %N 8 %1 http://www.ncbi.nlm.nih.gov/pubmed/18673339?dopt=Abstract %R 10.1111/j.1865-1682.2008.01044.x