Xenotransplantation could offer an alternative source of organs from genetically modified animals, such as pigs, which share many physiological similarities with humans, thus making them a viable option for transplantation. However, successful xenotransplantation requires overcoming significant challenges, including immune rejection, physiological incompatibility, and the risk of zoonotic infections. In particular, optimal donor pigs for clinical xenotransplantation must be managed in a closed herd, bred in a well-controlled environment within Designated Pathogen-Free (DPF) facilities to ensure they are free from pathogens.

We have established and are currently operating a DPF facility for breeding miniature pigs for xenotransplantation. In accordance with the guidelines from the Ministry of Food and Drug Safety (MFDS) in Korea, we have developed analytical methods for a total of 148 pathogens, including 40 species of bacteria, 8 species of fungi, 13 species of parasites, 13 species of protozoa, and 74 species of viruses, to DPF transgenic pigs, the source animals for xenotransplantation

Most exogenous pathogens cannot pass through the placenta and are not transmitted from the sow to the fetus. Therefore, pigs are brought into the DPF facility through cesarean section (C-section). This method of introducing the animals is an effective way to block exogenous pathogens to the production site. Through C-section, most of the bacteria, viruses, parasites, and fungi listed in the exogenous pathogen list can be effectively blocked. Among the exogenous pathogens listed, nine viruses (Table 1) are known to be able to cross the placenta and cause infection. Therefore, we aimed to establish a real-time RT PCR method to detect the nine viruses  rapidly and efficiently.

For each virus, specific primers and probes were designed from the conserved regions, and gene synthesis was performed on the sequences containing these regions. Positive vectors were then independently constructed for each virus. After confirming the standard curve for the positive control of each virus, blood samples from randomly selected pigs of both commercial farm and DPF origins were tested for viruses. Most viruses were not detected from DPF facility; however, positive reactions were observed in samples from commercial farm pigs.

These results demonstrate that we have established testing methods for the nine viruses capable of crossing the placenta and confirmed the ability to detect these viruses.