Transplacental and oral transmission of wild-type bluetongue virus serotype 8 in cattle after experimental infection

Anoek Backx , René Heutink , Eugene van Rooij , Piet van Rijn

Potential vertical transmission of wild-type bluetongue virus serotype 8 (BTV-8) in cattle was explored in this experiment. We demonstrated transplacental transmission of wild-type BTV-8 in one calf and oral infection with BTV-8 in another calf. Following the experimental BTV-8 infection of seven out of fifteen multi-parous cows eight months in gestation, each newborn calf was tested prior to colostrum intake for transplacental transmission of BTV by RRT-PCR. If transplacental transmission was not established the calves were fed colostrum from infected dams or colostrum from non-infected dams spiked with BTV-8 containing blood. One calf from an infected dam was born RRT-PCR positive and BTV-specific antibody (Abs) negative, BTV was isolated from its blood. It was born with clinical signs resembling bluetongue and lived for two days. Its post-mortem tissue suspensions were RRT-PCR positive. Of the seven calves fed colostrum from infected dams, none became infected. Of the six calves fed colostrum from non-infected dams spiked with infected blood, one calf became PCR-positive at day 8 post partum (dpp), seroconverted 27 days later, and remained RRT-PCR and Abs positive for the duration of the experiment (i.e. 70 dpp). This work demonstrates that transplacental transmission in late gestation and oral infection of the neonate with wild-type BTV-8 is possible in cattle under experimental conditions.

Mots clés: Bluetongue; Transplacental and oral transmission; Pregnant cattle; Vertical transmission; Late gestation

Anoek Backx, René Heutink, Eugene van Rooij, Piet van Rijn. Transplacental and oral transmission of wild-type bluetongue virus serotype 8 in cattle after experimental infection. Veterinary Microbiology, 2009, 138 (3-4), pp.235. ⟨10.1016/j.vetmic.2009.04.003⟩. ⟨hal-00514605⟩