Xiao-Hui Wen

Porcine circovirus type 2 in China: an update on and insights to its prevalence and control

Currently, porcine circovirus type 2 (PCV2) is considered the major pathogen of porcine circovirus associated-diseases (PCVAD) that causes large economic losses for the swine industry in the world annually, including China. Since the first report of PCV2 in 1998, it has been drawing tremendous attention for the government, farming enterprises, farmers, and veterinary practitioners. Chinese researchers have conducted a number of molecular epidemiological work on PCV2 by molecular approaches in the past several years, which has resulted in the identification of novel PCV2 genotypes and PCV2-like agents as well as the description of new prevalence patterns. Since late 2009, commercial PCV2 vaccines, including the subunit vaccines and inactivated vaccines, have already been used in Chinese swine farms. The aim of this review is to update the insights into the prevalence and control of PCV2 in China, which would contribute to understanding the epidemiology, control measures and design of novel vaccines for PCV2.

Comparative epidemiology of porcine circovirus type 3 in pigs with different clinical presentations

BackgroundPorcine circovirus type 3 (PCV3), as an emerging circovirus species, was reported to be widely circulating in the United States, China, South Korea and Poland. Previous studies revealed that PCV3 was mainly concentrated in sick animals with respiratory disease, skin disease, reproductive disorders and so on. However, the circulating status of PCV3 in pigs with other clinical presentations (especilly asymptomatic or diarrhea) was not well established.FindingsIn this study, to conduct a comparative epidemiological survey of PCV3, 80 weaned pig serum samples with severe respiratory disease (SRD), 175 weaned pig serum samples with mild respiratory disease (MRD), 216 asymptomatic weaned pig serum samples, 35 diarrheal weaned pig samples and 35 non-diarrheal weaned pig samples were collected from eight provinces of China. Via qPCR testing, PCV3 was circulating in all sampling provinces, with total positive rates varying from 1.04% to 100%. Interestingly, the PCV3-positive rate was significantly higher in weaned pigs with SRD (63.75%, 51/80) than in those weaned pigs with MRD (13.14%, 23/175) and asymptomatic pigs (1.85%, 4/216) (P < 0.01). Similarly, the PCV3-positive rate was significantly higher in diarrheal weaned pigs (17.14%, 6/35) than in non-diarrheal weaned pigs (2.86%, 1/35) (P < 0.05). Moreover, the lower Ct values of qPCR were frequently found in those weaned pigs or fattening pigs with respiratory disease and diarrhea rather than that in asymptomatic pigs. Sequence analysis showed that low genetic diversity existed among those PCV3 sequences collected from pigs with different clinical presentations.ConclusionsThe present study further extends evidence that newly described PCV3 widely circulates in six additional provinces of Southern and Northern China and has high similarity to previously reported isolates. As an emerging virus of swine, although the present case-control study reveals that PCV3 has a potential association with swine respiratory disease and diarrhea, further investigations into the pathogenesis are needed to ascertain the role of PCV3 in swine health.

Influenza D Virus in Animal Species in Guangdong Province, Southern China

Molecular tests revealed influenza D viruses of D/OK lineage widely circulating in farmed animal species in Guangdong Province, southern China. In particular, we found high levels of influenza D virus infection in goats and pigs. We also detected viral RNA in serum specimens and feces of animals with certain severe diseases.

Genome Sequence of a Novel Porcine Circovirus Type 2 Strain That Reemerged in Southern China

ABSTRACT Here, we describe a novel porcine circovirus type 2 (PCV2) variant (GD2014) found in the Guangdong province, southern China. Its complete genome is 1,766 nucleotides and contained a 708-nucleotide open reading frame 2 (ORF2). Sequence analysis suggested that GD2014 is closest to JS2015 originating from the Jiangsu province of China and belongs to the PCV2d genotype.

Erratum to: First molecular detection of porcine circovirus type 2 in bovids in China

For the worldwide pig industries, porcine circovirus type 2 (PCV2) is an economically important pathogen. At present, the prevalence of PCV2 is common in Chinese swine herds. However, there is little information on PCV2 prevalence in non-porcine animals in China, such as bovids. Therefore, the goal of this study is to obtain the firsthand prevalence data of PCV2 in bovids in China. Two hundred and eighty serum and muscle samples from dairy cows (n = 180), buffalo (n = 50), and yellow cattle (n = 50) were analyzed by PCR. The detection results show that PCV2 infections (16 %, 8/50) only exist in buffaloes. In addition, there are different PCV2 viral DNAs identified by differential PCR in the same buffalo sample. Nucleotide sequencing and phylogenetic analysis results based on partial ORF1 and ORF2 sequences suggest that PCV2 strains have genetic diversity in buffaloes and they are divided into three different genotypes (PCV2b, PCV2d, and PCV2e, respectively). Moreover, to our knowledge, the PCV2d and PCV2e genotypes have not been previously reported in bovids. Through this study, the firsthand data of PCV2 prevalence in bovids in China was documented.

Diversified Strains of Porcine Reproductive and Respiratory Syndrome Virus Circulating in China: A Mini-overview

Porcine reproductive and respiratory syndrome virus (PRRSV) was considered as an important pathogen, which caused huge economic losses for the world swine industry annually. Until now, according to antigenic and genetic characteristics, two genotypes were identified, European (EU genotype, or type 1) genotype and North American genotype (NA genotype, or type 2), respectively. In China, both of them co-existed in swine herds, and even some novel viral strains emerged in the lastest years. The aim of the review was to describe genetic diversity of PRRSV based on non-structural protein 2 (Nsp2) in China, which could help us better understand molecular

Ruminal impaction due to Ficus esquiroliana Levl. in Boer goats

Ruminal impaction is considered an important internal disease in ruminants, such as dairy cows, sheep, and goats. It has been reported that its occurrence is associated with many different causes. This study describes a novel case of ruminal impaction caused by a plant, Ficus esquiroliana Levl., in Boer goats. This case suggests that Ficus esquiroliana should be taken into consideration when providing food for ruminants.