Porcine Reproductive and Respiratory Syndrome (PRRS) and CD163 Resistance Polymorphic Markers: What Is the Scenario in Naturally Infected Pig Livestock in Central Italy?

Abstract

Porcine Reproductive and Respiratory Syndrome (PRRS) caused by the PRRS virus affects farmed pigs worldwide, causing direct and indirect losses. The most severe manifestations of PRRS infection are observed in piglets and pregnant sows. The clinical outcome of the infection depends on the PRRSV strain’s virulence, the pregnancy state of the female, environmental factors, the presence of protective antibodies due to previous infections, and the host’s genetic susceptibility. The latter aspect was investigated in this study, in particular, evaluating the most significant polymorphisms (SNPs) of the CD163 gene in slaughtered pigs reared in Central Italy. Total RNAs were extracted from 377 swine samples and subjected to RT-PCR targeted to the CD163 gene, followed by sequencing analysis. Contextually, the viral RNA was detected by RT-qPCR in order to phenotypically categorize animals into infected and not infected. In particular, 36 haplotypes were found, and their frequencies ranged from 0.13% to 35.15%. There were 62 resulting genotypes, three of which were associated with a putative resistance to the disease. Both the haplotypes and genotypes were inferred by PHASE v.2.1 software. To the best of our knowledge, this type of investigation was conducted for the first time on pig livestock distributed in different regions of Central Italy. Thus, the obtained findings may be considered very important since they add useful information about swine genetic background in relation to PRRS infection, from the perspective of adopting Marker-Assisted Selection (MAS) as a possible and alternative strategy to control this still widespread disease.

“One Health” Goal: Novel Preliminary Study on Putative Pig Immuno-Genetic Resistance to <em>Toxoplasma gondii</em> and Serologi-Cal Survey in Central Italy Regions

“…In this regard, the host's genetic attitude towards pathogens of different nature has been evaluated over time. These kinds of studies were conducted for pathogens of prionic origin like Scrapie in ovine and caprine [21,22]; pathogens of viral origin such as Lentivirus infection in sheep and goats [23][24][25] and PRRSV (Porcine Reproductive and Respiratory Syndrome) in swine [26,27]; pathogens of bacterial origin such as Paratuberculosis [28,29].…”

Genetic determination of piglet survival upon PRRSV outbreaks

“…The GBP family are interferon-induced GTPases which play a role in protective immunity against pathogens through cell-autonomous defense and inflammasome-driven responses [13]. Natural mutations in the CD163 gene have also been associated to changes in the susceptibility of pigs to PRRSV infection and enhanced weight gain [10,[14][15][16][17]. CD163 encodes a member of the scavenger receptor cysteine-rich (SRCR) superfamily and is exclusively expressed in cells from the monocyte/macrophage lineage.…”