Epidemiological Survey of Four Reproductive Disorder Associated Viruses of Sows in Hunan Province during 2019–2021

Abstract

Porcine reproductive disorders have been considered as the major factors that threaten pig industries worldwide. In this study, 407 aborted-fetus samples were obtained from 89 pig farms in Hunan province, to investigate the prevalence of four viruses associated with porcine reproductive disease, including porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), pseudorabies virus (PRV), and classical swine fever virus (CSFV). Meanwhile, the target gene sequences of representative PRRSV (ORF5), PCV2 (ORF2), CSFV (E2), and PRV (gE) strains were amplified, sequenced, and analyzed. The results showed that the positive rates of PRRSV, PCV2, PRV, and CSFV among the collected samples were 26.29% (107/407), 52.83% (215/407), 6.39% (26/407), and 12.29% (50/407), respectively. Moreover, co-infection with two and three pathogens were frequently identified, with PCV2/PRRSV, PRRSV/CSFV, PRRSV/PRV, PCV2/CSFV, PCV2/PRV, and PRRSV/PCV2/CSFV mix infection rates of 9.09%, 3.19%, 2.95%, 3.69%, 2.21%, and 0.49%, respectively. Moreover, ORF5-based phylogenetic analysis showed that 9, 4, and 24 of 37 PRRSV strains belonged to the PRRSV2 lineages 1, 5, and 8, respectively. ORF2-based phylogenetic analysis revealed that PCV2d and PCV2b were prevalent in Hunan province, with the proportions of 87.5% (21/24) and 12.5% (3/24), respectively. An E2-based phylogenetic tree showed that all 13 CSFV strains were clustered with 2.1 subgenotypes, these isolates were composed of 2.1b (10/13) and 2.1c (3/13) sub-subgenotypes. A gE-based phylogenetic tree showed that all six PRV strains belonged to the genotype II, which were genetically closer to variant PRV strains. Collectively, the present study provides the latest information on the epidemiology and genotype diversity of four viruses in sows with reproductive diseases in Hunan province, China, which would contribute to developing effective strategies for disease control.

Simultaneous Detection of Porcine Respiratory Coronavirus, Porcine Reproductive and Respiratory Syndrome Virus, Swine Influenza Virus, and Pseudorabies Virus via Quadruplex One-Step RT-qPCR

“…This indicates that multiple-pathogen co-infections at pig farms are still an important problem in pig herds. Co-infections cause more heterogeneous responses than do single infections [ 24 , 25 , 49 ]. In particular, PRRSV causes immunosuppression [ 50 ], and co-infection of PRRSV with other pathogens can exacerbate the diseases [ 27 ].…”

“…The presence of SIV and PRRSV co-infections was reported at pig farms in Colombia in 2014 [ 52 ], and co-infections with PRCoV and SIV were common in the fattening herds at one pig farm in Belgium from 1991 to 1992 [ 53 ]. Co-infections of PRRSV/PRV and PRRSV/SIV were also reported in Chinese pig herds [ 25 , 54 ]. The significance of co-infections of PRCoV, PRRSV, SIV, and/or PRV requires further evaluation, and the developed quadruplex RT-qPCR can provide a useful method for rapid and accurate detection and investigation of PRCoV, PRRSV, SIV, and PRV.…”

“…PRCoV, PRRSV, SIV, and PRV infections cause respiratory symptoms, resulting in difficulty differentiating them, based only on their clinical manifestations. Unfortunately, PRCoV, PRRSV, SIV, and/or PRV co-infections often occur in pig herds, leading to complications in the diagnosis and treatment of these diseases [ 24 , 25 ]. In particular, PRCoV and SIV co-infections enhance the clinical signs and lung lesions in infected pigs [ 26 ], and PRRSV and PRCoV co-infections exacerbate viral infections and clinical processes [ 27 ].…”

Development of a quadruplex real-time quantitative RT-PCR for detection and differentiation of PHEV, PRV, CSFV, and JEV

“…Overall, PHEV, PRV, CSFV, and JEV are still popular in many countries around the world, and cause different degrees of damages to the pig industry (5,6,13,14,20,21,28,29,57). In China, some provinces have recently reported the prevalence of PHEV, PRV, CSFV, and JEV (41,47,51,(58)(59)(60)(61)(62)(63)(64)(65). The nasal cavity or throat swabs from 1-to 3-week-old piglets in Jilin province in 2010 showed a positivity rate of 44.23% (207/468) for PHEV (58).…”