Evaluation of transplacental transmission of bovine viral diarrhea virus in pregnant GLITS experimentally inoculated

Abstract

The pig production system has undergone intense changes and technifications, with the objective of optimizing the production process and fomenting the demands of the world market with respect to the generation of animal protein, since Brazil is the 4th largest importer and exporter of pig meat. However, in combination with the intensification of production, new challenges arise that interfere in the production chain, such as the appearance of diseases due to overcrowding of animals or inadequate management in some stages of growth. Some of the animal health protection actions implemented in Brazil where the incentive to prevent, control and eradicate diseases listed by the World Health Organization (WHO), in which bovine viral diarrhea virus (BVDV) was included only in 2012. More information and disclosure about the action of this virus becomes necessary because the infection caused by it is virtually unknown in swine farming. The infection caused by the classical swine fever virus (CSFV), for example, is a notifiable disease, and as the virus belongs to the same family as the BVDV virus, are genetically and antigenically related. By sharing such common antigenic structures, the serological tests used to detect CSFV may cross-react with antibodies against BVDV, resulting in false-positive reactions, which may interfere with official disease monitoring programs. Considering the information gathered in the literature, this project aims to evaluate the transplacental transmission capacity of BVDV-2 in experimentally inoculated sows in the final third of gestation. For this purpose, 8 large white females, of commercial strain, nulliparous and from a specialized company will be used. The inoculated group will consist of six females (G1; n = 6), and the control group by two females (G2; n = 2). Samples of blood piglets will be collected on days 0, 7, 14 and 21, and on day 0 the collection will be done before the colostrum is ingested. The blood will be deposited in sterile tubes, with EDTA, to obtain the whole blood; and in tubes free of anticoagulants to obtain serum of the blood. Samples of whole blood, navel, and placenta collected will be destined to RT-PCR, while the serum, for virus neutralization. The hypothesis is that inoculation with the virus at the end of gestation leads to the transplacental transmission of it, causing the piglets born to show viremia or antibodies against the agent before the colostrum is ingested.