TY - JOUR T1 - Transplacental infection and apparently immunotolerance induced by a wild-type bluetongue virus serotype 8 natural infection. JF - Transbound Emerg Dis Y1 - 2008 A1 - Kris De Clercq A1 - Ilse De Leeuw A1 - Verheyden, B A1 - Vandemeulebroucke, E A1 - Vanbinst, T A1 - Herr, C A1 - Estelle Méroc A1 - Bertels, G A1 - Steurbaut, N A1 - Miry, C A1 - De Bleecker, K A1 - Maquet, G A1 - Bughin, J A1 - Saulmont, M A1 - Lebrun, M A1 - Sustronck, B A1 - De Deken, R A1 - Hooyberghs, J A1 - Houdart, P A1 - Raemaekers, M A1 - Mintiens, K A1 - Pierre Kerkhofs A1 - Goris, N A1 - Frank Vandenbussche KW - Abortion, Veterinary KW - Animals KW - Animals, Newborn KW - Belgium KW - Bluetongue KW - Bluetongue virus KW - Cattle KW - Cattle Diseases KW - Female KW - Infectious Disease Transmission, Vertical KW - Pregnancy KW - Pregnancy Complications, Infectious KW - RNA, Viral KW - Serotyping AB -

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.

VL - 55 CP - 8 U1 - http://www.ncbi.nlm.nih.gov/pubmed/18673339?dopt=Abstract M3 - 10.1111/j.1865-1682.2008.01044.x ER -