摘要：
Pasteurella multocida (P. multocida), an opportunistic zoonotic pathogen associated with high morbidity and mortality in livestock, shows significant temporal and geographical variation in its serotype distributions and phenotypic characteristics. The aim of this study was To investigate capsular types, lipopolysaccharide (LPS) genotypes, and virulence-associated genes of P. multocida strains isolated from pigs. A total of 801 samples (lungs, tonsils, nasal swabs) were collected from slaughterhouses and various regions of the Hunan province. P. multocida strains were isolated from various samples, classified, and virulence-associated genes were detected by polymerase chain reaction (PCR). 124P. multocida strains were assigned to six groups based on both capsular type and LPS genotype, namely A: L3 (capsular type A and LPS genotype 3, 64/124); A: L6 (16/124); D: L6 (38/124); F: L3 (4/124); L3 (1/124) and 1 untypable strain. Of the 23 virulence-associated genes investigated in this study, 14 were highly expressed in 98% to 100% of the 124 strains. While tbpA was undetectable in any of the isolated strains, hsf-1, pfhA, tadD, toxA, pmHAS, hgbA, hgbB, and nanB showed differential distribution among the strain groups. Interestingly, pfhA (Mutation or inactivation of pfhA was reported to decrease the virulence of P. multocida) was found in 46% of group A: L3 strains and in 100% of group F: L3 strains, but not found in other groups. Further investigation is needed to determine whether strains in group A: L3 show greater virulence than the A: L6 P. multocida strains.
摘要：
Neospora caninum is a protozoan parasite which can infect many mammals and birds with a worldwide distribution. However, no molecular data are available about the occurrence of N. caninum in pigs. In this study, the serological and molecular prevalence of N. caninum infection in farmed pigs were investigated in Hunan province, China, between January 2017 and December 2018. A total of 1,500 serum samples collected from 10 herds in Hunan province were evaluated using a competitive-inhibition enzyme-linked immunoassay assay (cELISA). The overall seroprevalence of N. caninum in the examined pigs was 1.9%. The seroprevalence of N. caninum ranged from 0.3% to 4.6% among different regions in Hunan province of China (p < .05). DNA was extracted from brain samples, and the Nc-5 gene and ITS-1 region were amplified and then sequenced. Three (0.5%) of the examined 600 brain tissues were found to contain N. caninum DNA. Our phylogenetic analyses indicated that N. caninum samples were classified into two distinct groups. Although the prevalence is low within the pig groups investigated, our results revealed the emergence of N. caninum infection in pigs in China. The finding of the present study provides molecular evidence that the pigs are the natural intermediate host of N. caninum and may have major epidemiological importance.
摘要：
Two commercial porcine reproductive and respiratory syndrome virus (PRRSV) antibody ELISA kits (IDEXX and LSI) are currently in extensive use. To determine which kit is more suitable for the evaluation of HP-PRRSV vaccine efficacy, the two kits were used to test 546 serum samples. The agreement between the results was unsatisfactory, with a kappa statistic of 0.681 and a linear correlation coefficient of 0.665. In tests of samples from experimentally vaccinated and PRRSV-negative herds, IDEXX-ELISA identified antibody-positive conversion earlier and showed a higher specificity compared to LSI-ELISA. The serological profile obtained by neutralization testing was closer to that obtained by IDEXX-ELISA than by LSI-ELISA in the late immunization period. The findings reveal that IDEXX-ELISA is the more suitable for the evaluation of antibody response to HP-PRRSV vaccine and for guiding vaccination strategies.
期刊：
VECTOR-BORNE AND ZOONOTIC DISEASES,2019年19(12):945-949 ISSN：1530-3667
通讯作者：
Liu, Guo-Hua;Ge, Meng
作者机构：
[Wang, Yu-Gui; Gui, Bin-Ze; Li, Run-Cheng; Wang, Gui-Ping; Liu, Guo-Hua] Hunan Agr Univ, Coll Vet Med, Hunan Prov Key Lab Prot Engn Anim Vaccines, Changsha 410128, Hunan, Peoples R China;[Li, Run-Cheng; Wang, Gui-Ping; Liu, Guo-Hua] Hunan Coinnovat Ctr Anim Prod Safety, Changsha, Hunan, Peoples R China;[Ge, Meng] Hunan Agr Univ, Coll Vet Med, Hunan Engn Technol Res Ctr Vet Drugs, Changsha 410128, Hunan, Peoples R China
通讯机构：
[Liu, Guo-Hua; Ge, Meng] H;Hunan Agr Univ, Coll Vet Med, Hunan Prov Key Lab Prot Engn Anim Vaccines, Changsha 410128, Hunan, Peoples R China. Hunan Agr Univ, Coll Vet Med, Hunan Engn Technol Res Ctr Vet Drugs, Changsha 410128, Hunan, Peoples R China.
关键词：
Toxoplasma gondii;pigs;risk factors;seroprevalence;subtropical China
摘要：
Toxoplasma gondii infection is prevalent in humans and animals worldwide. In the present study, a total of 612 serum samples were examined using indirect hemagglutination test (IHAT) for T. gondii infection. Antibodies to T. gondii were detected in 49 (8.0%, confidence interval [95% CI]: 5.9-10.2) serum samples (IHA titer >/=1:16). The T. gondii seroprevalence ranged from 4.4% (95% CI: 0-10.5) to 14.3% (95% CI: 0-40.2) among different regions in Hunan province of subtropical China. The highest seroprevalence was found in breeding sows (18.8%). The T. gondii seroprevalence was higher in winter (18.3%, 95% CI: 8.5-28.1) and spring (10.9%, 95% CI: 5.7-16.1) than in summer (6.4%, 95% CI: 2.8-10.1) and autumn (4.9%, 95% CI: 2.2-7.7), and the differences were statistically significant excepting summer. In addition, developmental stage and season were identified as risk factors for T. gondii infection. Our findings revealed the seroprevalence of T. gondii in growth stages of pigs in the Hunan province of subtropical China, indicating that it may cause public health and economic problems. To our knowledge, this is the first report of the comprehensive survey of T. gondii seroprevalence in pigs in the Hunan province of subtropical China.
通讯机构：
[Yu, Xinglong] H;Hunan Agr Univ, Coll Vet Med, Changsha 410128, Hunan, Peoples R China.
摘要：
Porcine circovirus 2 (PCV2) has been widely prevailing in China since the first report in 2001, causing huge economic losses to the pig industry. In the present study, 674 samples were collected from 2006 to 2016 in Hunan province, and 62% were positive for PCV2. An increase was observed from 2006 to 2011 (72.1%-89.1%), and a decrease was observed from 2012 to 2016 (78.9%-36.8%). The prevalence of genotype PCV2a, PCV2b, and PCV2d was 0, 44.7% and 67%, respectively. During 2006-2007, PCV2b was the main genotype circulating in Hunan, while, in 2008, PCV2d became the predominant one. Coinfection with PCV2b and PCV2d was observed frequently, and the positive rates of coinfection ranged from 6.3% to 18.9% during 2006-2016. The complete genome was sequenced for 54 positive samples, and four were identified as PCV2b-1, 22 as PCV2b-2, four as PCV2d-1 and 24 as PCV2d-2, based on phylogenetic analysis of the complete genome and ORF2 region. Recombination analysis using the complete genome sequences of these isolates revealed a high recombination rate of 27.7% (17/54), and showed that recombination occurred mainly in the ORF1 region. This shows that the prevalence of PCV2 has clearly decreased in recent years and that PCV2d has become a predominant genotype since 2008. In addition, frequent recombination events were observed in the PCV2 isolates from Hunan, China.
