Acanthopanax senticosus cultures fermented by Lactobacillus rhamnosus enhanced immune response through improvement of antioxidant activity and inflammation in crucian carp (Carassius auratus).

Lactic acid bacteria (LAB) have been recognized as safe microorganism that improve micro-flora disturbances and enhance immune response. A well-know traditional herbal medicine, Acanthopanax senticosus (As) was extensively utilized in aquaculture to improve growth performance and disease resistance. Particularly, the septicemia, skin wound and gastroenteritis caused by Aeromonas hydrophila threaten the health of aquatic animals and human. However, the effects of probiotic fermented with A. senticosus product on the immune regulation and pathogen prevention in fish remain unclear. Here, the aim of the present study was to elucidate whether the A. senticosus fermentation by Lactobacillus rhamnosus improve immune barrier function. The crucian carp were fed with basal diet supplemented with L. rhamnosus fermented A. senticosus cultures at 2 %, 4 %, 6 % and 8 % bacterial inoculum for 8 weeks. After trials, the weight gain rate (WGR), specific growth rate (SGR) were significantly increased, especially in LGG-6 group. The results confirmed that the level of the CAT, GSH-PX, SOD, lysozyme, and MDA was enhanced in fish received with probiotic fermented product. Moreover, the L. rhamnosus fermented A. senticosus cultures could trigger innate and adaptive immunity, including the up-regulation of the C3, C4, and IgM concentration. The results of qRT-PCR revealed that stronger mRNA transcription of IL-1ß, IL-10, IFN-γ, TNF-α, and MyD88 genes in the liver, spleen, kidney, intestine and gills tissues of fish treated with probiotic fermented with A. senticosus product. After infected with A. hydrophila, the survival rate of the LGG-2 (40 %), LGG-4 (50 %), LGG-6 (60 %), LGG-8 (50 %) groups was higher than the control group. Meanwhile, the pathological damage of the liver, spleen, head-kidney, and intestine tissues of probiotic fermentation-fed fish could be alleviated after pathogen infection. Therefore, the present work indicated that L. rhamnosus fermented A. senticosus could be regard as a potential intestine-target therapy strategy to protecting fish from pathogenic bacteria infection.

Changes of intestinal barrier in the process of intestinal inflammation induced by Aeromonas hydrophila in snakehead (Channa argus).

Bacterial intestinal inflammation frequently occurs in cultured fish. Nevertheless, research on intestinal barrier dysfunction in the process of intestinal inflammation is deficient. In this study, we explored the changes of intestinal inflammation induced by Aeromonas hydrophila (A. hydrophila) in snakehead and the relationship between intestinal barrier and inflammation. Snakehead [(13.05 ± 2.39) g] were infected via anus with A. hydrophila. Specimens were collected for analysis at 0, 1, 3, 7 and 21 d post-injection. The results showed that with the increase of exposure time, the hindgut underwent stages of normal function, damage, damage deterioration, repair and recovery. Relative to 0 d, the levels of IL-1ß and TNF-α in serum, and the expression of nod1, tlr1, tlr5, nf-κb, tnf-α and il-1ß in intestine were significantly increased, and showed an upward then downward pattern over time. However, the expression of tlr2 and il-10 were markedly decreased, and showed the opposite trend. In addition, with the development of intestinal inflammation, the diversity and richness of species, and the levels of phylum and genus in intestine were obviously altered. The levels of trypsin, LPS, AMS, T-SOD, CAT, GPx, AKP, LZM and C3 in intestine were markedly reduced, and displayed a trend of first decreasing and then rebounding. The ultrastructure observation showed that the microvilli and tight junction structure of intestinal epithelial cells experienced normal function initially, then damage, and finally recovery over time. The expression of claudin-3 and zo-1 in intestine were significantly decreased, and showed a trend of first decreasing and then rebounding. Conversely, the expression of mhc-i, igm, igt and pigr in intestine were markedly increased, and displayed a trend of increasing first and then decreasing. The above results revealed the changes in intestinal barrier during the occurrence and development of intestinal inflammation, which provided a theoretical basis for explaining the relationship between the two.

Infection of epithelioma papulosum cyprini (EPC) cells with spring viremia of carp virus (SVCV) induces autophagy and apoptosis through endoplasmic reticulum stress.

Spring viremia of carp virus (SVCV) is a lethal freshwater pathogen of cyprinid fish that has caused significant economic losses to aquaculture. To reduce the economic losses caused by SVCV, its pathogenic mechanism needs to be studied more thoroughly. Here, we report for the first time that SVCV infection of Epithelioma papulosum cyprini (EPC) cells can induce cellular autophagy and apoptosis through endoplasmic reticulum stress. The presence of autophagic vesicles in infected EPC cells was shown by transmission electron microscopy. Quantitative fluorescence PCR and Western blot results showed that p62 mRNA expression was decreased, and the expression of Beclin1 and LC3 mRNA was increased. The p62 protein was decreased, and the Beclin1 protein and LC3 were increased in the endoplasmic reticulum stress activation state. To further clarify the mode of death of SVCV-infected EPC cells, we examined caspase3, caspase9, BCL-2, and Bax mRNA, which showed that they were all increased. Apoptosis of SVCV-infected cells increased upon activation of endoplasmic reticulum stress. Our results suggest that endoplasmic reticulum stress can regulate SVCV infection-induced autophagy and apoptosis. The results of this study provide theoretical data for the pathogenesis of SVCV and lay the foundation for future drug development and vaccine construction.

Immunization effect of recombinant Lactobacillus casei displaying Aeromonas veronii Aha1 with an LTB adjuvant in carp.

Aeromonas veronii is an important aquatic zoonotic, which elicits a range of diseases, such as haemorrhagic septicemia. To develop an effective oral vaccine against Aeromonas veronii infection in carp, the Aeromonas veronii adhesion (Aha1) gene was used as a target molecule to attach to intestinal epithelial cells. Two anchored recombinant. Lactic acid bacteria strains (LC-pPG-Aha1 1038 bp and LC-pPG-Aha1-LTB 1383 bp) were constructed by fusing them with the E. coli intolerant enterotoxin B subunit (LTB) gene and using Lactobacillus casei as antigen delivery vector to evaluate immune effects of these in carp. Western blotting and immunofluorescence were used to confirm that protein expression was successful. Additionally, levels of specific IgM in serum and the activities of ACP, AKP, SOD, LYS, C3, C4, and lectin enzymes-were assessed. Cytokines IL-10, IL-1ß, TNF-α, IgZ1, and IgZ2 were measured in the liver, spleen, kidney, intestines, and gills tissue by qRT-PCR, which showed an increasing trend compared with the control group (P < 0.05). A colonization assay showed that the two L. casei recombinants colonized the middle and hind intestines of immunized fish. When immunized carp were experimentally challenged with Aeromonas veronii the relative percentage protection of LC-pPG-Aha1 was 53.57%, and LC-pPG-Aha1-LTB was 60.71%. In conclusion, these results demonstrate that Aha1 is a promising candidate antigen when it is displayed on lactic acid bacteria (Lc-pPG-Aha1 and Lc-pPG-Aha1-LTB) seems promising for a mucosal therapeutic approach. We plan to investigate the molecular mechanism of the L. casei recombinant in regulating the intestinal tissue of carp in future studies.

Transcriptomic insights into the immune response of the intestine to Aeromonas veronii infection in northern snakehead (Channa argus).

Intestinal inflammation is a protective response that is implicated in bacterial enteritis triggered by gastrointestinal infection. The immune mechanisms elicited in teleost against the infection of Aeromonas veronii are largely unknown. In this study, we performed a de novo northern snakehead (Channa argus) transcriptome assembly using Illumina sequencing platform. On this basis we performed a comparative transcriptomic analysis of northern snakehead intestine from A. veronii-challenge and phosphate buffer solution (PBS)-challenge fish, and 2076 genes were up-regulated and 1598 genes were down-regulated in the intestines infected with A. veronii. The Gene Ontology (GO) enrichment analysis indicated that the differentially expressed genes (DEGs) were enriched to 27, 21 and 20 GO terms in biological process, cellular component, and molecular function, respectively. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that 420 DEGs were involved in 194 pathways. Moreover, 33 DEGs were selected for quantitative real-time PCR analysis to validate the RNA-seq data. The results reflected the consistency of the expression levels between qRT-PCR and RNA-seq data. In addition, a time-course analysis of the mRNA expression of 33 immune-related genes further indicated that the intestinal inflammation to A. veronii infection simultaneously regulated gene expression alterations. The present study provides transcriptome data of the teleost intestine, allowing us to understand the mechanisms of intestinal inflammation triggered by bacterial pathogens. DATA AVAILABILITY STATEMENT: All data supporting the findings of this study are available within the article and Supplementary files. The RNA-seq raw sequence data are available in NCBI short read archive (SRA) database under accession number PRJNA615958.

Dietary supplementation of probiotics fermented Chinese herbal medicine Sanguisorba officinalis cultures enhanced immune response and disease resistance of crucian carp (Carassius auratus) against Aeromonas hydrophila.

Aeromonas hydrophila, a Gram-negative bacterium, is one of the major pathogens causing bacterial sepsis in aquatic animals due to drug resistance and pathogenicity, which could cause high mortality and serious economic losses to the aquaculture. Sanguisorba officinalis (called DiYu in Chinese, DY) is well known as herbal medicine, which could inhibit the growth of pathogenic bacteria, hemostasis and regulate the immune response. Moreover, the active ingredients in DY could remarkably reduce drug resistance. In this study, we investigated the effects of probiotic fermentation cultures on A. hydrophila through in vitro and in vivo experiments. Three lactic acid bacteria, including Lactobacillus rhamnosus (LGG), Lactobacillus casei (LC) and Lactobacillus plantarum (LP), were selected to ferment the Chinese herbal medicine DY. The assays of antagonism showed that all three fermented cultures could influence the ability of A. hydrophila growth, among which L. rhamnosus fermented DY cultures appeared to be the strongest inhibitory effect. In addition, the biofilm determination revealed that L. rhamnosus fermented DY cultures could significantly inhibit the biofilm formation of A. hydrophila compared to the other groups. Furthermore, protease, lecithinase and urease activities were found in the three fermentation cultures. Three probiotics fermented DY cultures were orally administration with crucian carp to evaluate the growth performance, immunological parameters and pathogen resistance. The results showed that the three fermentation cultures could promote the growth performance of crucian carp, and the immunoglobulins, antioxidant-related enzymes and immune-related genes were significantly enhanced. Besides, the results showed that crucian carp received L. rhamnosus (60.87%), L. casei (56.09%) and L. plantarum (41.46%) fermented DY cultures had higher survival rates compared with the control group after infection with A. hydrophila. Meanwhile, the pathological tissue results revealed that the probiotic fermented cultures could largely improve the tissues damage caused by the pathogenic bacteria. In conclusion, this study proved that the fermentation cultures of three probiotics could effectively inhibit the growth of A. hydrophila, regulate the level of immune response and improve the survival rate against A. hydrophila in crucian carp. The present data suggest that probiotic fermented Sanguisorba officinalis act as a potential gut-targeted therapy regimens to protecting fish from pathogenic bacteria infection.

Comparative genomics analysis of strains from diverse sources reveals the evolutionary relationship of Aeromonas veronii.

Aeromonas veronii (A. veronii, AV) strains are emerging zoonotic and aquatic pathogens, yet we know very little about their genomics. This study aims to utilize comparative genomics to investigate the intraspecific genetic diversity, differences in virulence factors and evolutionary mechanisms of A. veronii strains from diverse sources and to fundamentally demonstrate their pathogenic mechanisms. We conducted comparative genomics analysis of 39 A. veronii strains from different sources and found that 1993 core genes are shared by these strains and that these shared core genes may be necessary to maintain the basic characteristics of A. veronii. Additionally, phylogenetic relationship analysis based on these shared genes revealed that a distant relationship between the AMC34 strain and the other 38 strains but that, the genetic relationship among the 38 strains is relatively close, indicating that AMC34 may not belong to A. veronii. Furthermore, analysis of shared core genes and average nucleotide identity (ANI) values showed no obvious correlation with the location of A. veronii isolation and genetic relationship. Our research indicates the evolutionary mechanism of A. veronii from different sources and provides new insights for a deeper understanding of its pathogenic mechanism.

Construction and immune efficacy of recombinant Lactobacillus casei strains expressing Malt from Aeromonas veronii.

Aeromonas veronii is an important zoonotic pathogen that causes significant economic losses in the aquaculture industry. The use of probiotics in aquaculture is a practical alternative to antibiotics to promote animal health and aid in disease prevention. In the present study, we aimed to construct a recombinant Lactobacillus casei(surface-displayed or secretory) strain containing Malt from A. veronii TH0426 and assess its potential as an oral vaccine. A 1314-bp Malt gene fragment was successfully amplified and cloned into a prokaryotic protein expression system. Protein expression in resulting recombinant strains Lc-MCS-Malt (surface-displayed) and Lc-pPG-Malt (secretory) was then verified by Western blotting and indirect immunofluorescence. A single band was observed on the Western blots, with the molecular weight of the corresponding protein shown to be 48 kDa. Furthermore, a fluorescent signal for Lc-MCS-Malt was observed by fluorescence microscopy. At 0, 7, 16, 25, and 34 days post-immunization, tissue and blood samples were collected from common carp orally administered with the recombinant L. casei strains for immune-related index analyses. Treatment of common carp with the recombinant vaccine candidate stimulated high serum or skin mucus specific antibody titers and induced a higher lysozyme, ACP, SOD activity, while fish fed with Lc-pPG or PBS had no detectable immobilizing immune responses. Expression of IL-10, IL-1ß, TNF-α, and IFN-γ genes in the group immunized with recombinant L. casei were significantly (P < 0.05) up regulated as compared with control groups, indicating that inflammatory response and cell immune response were triggered. Results also showed that recombinant L. casei could stimulate the mucosa through colonization of the intestine, resulting in increased transcription of IL-10, IL-1ß, TNF-α, and IFN-γ. Immunity and colonization assays also showed that after 34 days of fasting, recombinant L. casei were still present in the intestines of the immunized fish. Common carp that received Lc-MCS-Malt(53.3%) and Lc-pPG-Malt (46.7%) exhibited higher survival rates than the controls after challenge with the pathogen A. veronii. Our findings suggested that recombinant L. casei can adequately protect fish and improve immunity, providing a theoretical basis for the future development of an oral Lactobacillus vaccine for use in aquaculture.

Great effect of porin(aha) in bacterial adhesion and virulence regulation in Aeromonas veronii.

Aeromonas veronii is a serious pathogen which can infect mammals and aquatic organisms and causes irreparable damage to fish aquaculture. It has been demonstrated that adhesion to host surface and cells is the initial step in bacterial pathogenesis. Previous study found that bacterial weaken motility probably caused by the absence of flagellar related genes. In this study, we generated the aha deletion and complementary strains and found that two strains can be stably inherited for more than 50 generations. No significant change was found in the growth of mutant △aha. But the ability of biofilm formation, the adhesion and invasion to EPC cells significantly decreased for 3.7-fold and 2.3-fold respectively. Due to aha gene deletion, the stability of A. veronii flagellar was severely declined and the mutant △aha with no mobility. Compared with the wild-type TH0426, the pathogenicity of A. veroniiaha-deleted strain to zebrafish and mice reduced significantly and virulence attenuated severely. Cytotoxicity experiment also proved that mutant △aha showed much weaker virulence at the same time infection. The consequences declared that the stability of flagellar decreased severely with porin missing and lost the motility. Porin regulated by aha gene is essential for the adhesion and virulence of A. veronii. Thence, the mutant △aha of A. veronii provides an important tool for further concentration on the pathogenic mechanism of A. veronii.

Oral immunization with recombinant Lactobacillus casei expressing OmpAI confers protection against Aeromonas veronii challenge in common carp, Cyprinus carpio.

Aeromonas veronii is a gram-negative pathogen capable of infecting both fish and mammals, including humans, and natural infection in fish results in irreparable damage to the aquaculture industry. Lactic acid bacteria (LAB) have a number of properties that make them attractive candidates as delivery vehicles for presentation to the mucosa sites of compounds with pharmaceutical interest, in particular vaccines. In this study, we generated two recombinant Lactobacillus casei (surface-displayed or secretory) expressing the OmpAI of A.veronii and evaluated the effect on immune responses in fish model. A 1022 bp gene fragment of the 42 kDa OmpAI antigen of A.veronii was cloned into pPG-1 (surface-displayed) and pPG-2 (secretory) and electrotransformed into Lactobacillus casei CC16. The recombinant plasmid in L.casei could be stably inherited over 50 generations, and production of OmpAI protein had slight limited effects on cells growth. Treatment of common carp with the recombinant vaccine candidate stimulated high serum or skin mucus specific antibody titers and induced a higher lysozyme, ACP, SOD activity, while fish fed with Lc-pPG or PBS had no detectable immobilizing immune responses. Expression of IL-10, IL-ß, IFN-γ, TNF-α genes in the group immunized with recombinant L.casei were significantly (P < 0.05) up regulated as compared with control groups, indicating that inflammatory response and cell immune response were triggered. Further, viable recombinant L.casei strains were directly delivered and survive throughout the intestinal tract, the recombinant OmpAI was also detected in intestine mucosal. The results showed that common carp received Lc-pPG1-OmpAI (66.7%) and Lc-pPG2-OmpAI (50.0%) had higher survival rates compared with the controls after challenge with A.veronii, indicating that Lc-pPG1-OmpAI and Lc-pPG2-OmpAI had beneficial effects on immune response and enhanced disease resistance of common carp against A.veronii infection. Our study here demonstrates, for the first time, the ability of recombinant L.casei as oral vaccine against A.veronii infection in carps. The combination of OmpAI delivery and LAB approach may be a promising mucosal therapeutic agent for treating and controlling A.veronii.

Immunogenicity of extracellular products from an inactivated vaccine against Aeromonas veronii TH0426 in koi, Cyprinus carpio.

Aeromonas veronii is a type of human-livestock-aquatic animal pathogen; it is widely found in nature and causes many deaths among aquatic animals. Extracellular products (ECPs) are secreted by the pathogen during growth and reproduction. These products are considered effective protective antigens that can induce the host to produce an immune response. In this study, the ECPs of A.veronii TH0426 were prepared by ultrafiltration, and then the pathogenicity and enzymatic activity of the ECPs were determined. All the groups were injected intraperitoneally, as follows: group one: ECP protein with an equal volume of Freund's adjuvant; group two: ECPs and formalin-killed cells (FKC) of A.veronii combined with an equal volume of Freund's adjuvant (FKC + ECPs); group three: formalin-killed cells (FKC) of A.veronii combined with an equal volume of Freund's adjuvant (FKC); and, group four: sterile PBS as the control group. The expression levels of IgM, IL-1ß, and TNF-α and the lysozyme activity in blood were examined at 7, 14, and 21 days after the immunizations. The results show that the ECPs can produce protease, lipase, amylase and hemolyase, and there was no lecithinase, urease, or gelatinase activity. The results indicate that the ECPs were clearly pathogenic to koi fish, and the LD50 dose was 391.6 µg/fish. Throughout this study, the RPS of the three experimental groups were 75%, 50%, and 70%. This study indicates that the ECPs of A.veronii can effectively enhance the ability of kio fish to resist bacterial invasion.

Genetic analysis of three porcine bocaparvoviruses and identification of a natural recombinant breakpoint in NS1.

In this study, we obtained the whole genomes of three porcine bocaparvovirus (PBoV) strains (GD6, GD10, and GD23) by polymerase chain reaction. Sequence analysis showed that all three field strains belonged to PBoV group 3 (G3). The phylogenetic trees based on NS1, NP1, and VP1 differed to the extent that these PBoVs were potentially more closely related to bocaparvoviruses known to infect other animals than to other PBoVs. GD6, GD10, and GD23 all included the conserved sequences YLGPF and HDXXY, with known phospholipase A2 activity. Using recombination-detection software we identified a natural recombinant breakpoint in the NS1 region of PBoV G3. The results of this study will further the epidemiological characterization of PBoVs.

Prevalence of antibodies against Toxoplasma gondii in pets and their owners in Shandong province, Eastern China.

BACKGROUND: Pet ownership in China has been steadily increasing over recent years. However, the risk of pet-associated zoonotic infection with the protozoan parasite Toxoplasma gondii remains poorly defined. METHODS: In a cross-sectional survey, we have determined the seroprevalence of T. gondii infection in pet dogs and cats, and pet owners. Serum samples were collected from 360 pets and 460 corresponding pet owners between March 2016 to June 2017, from Shandong province, eastern China. Sera from the animals were tested for anti-T. gondii antibodies using an indirect haemagglutination assay (IHA) and from the pet owners using an enzyme-linked immunosorbent assay (ELISA). RESULTS: Antibodies against T. gondii were detected in 67 of 360 (18.61%) pets. Seroprevalence of T. gondii in pet cats and dogs was 21.67% and 15.56%, respectively. IgG and IgM antibodies were detected in 79 (17.17%) and 4 (0.87%) of pet owners, respectively; with a total of 83 of 460 (18.04%) pet owners testing seropositive for T. gondii. Our seroprevalence data also suggest that cat owners in general and female pet owners in particular could face a higher risk of acquiring T. gondii infection. CONCLUSIONS: Significant levels of anti-T. gondii antibodies were detected in the pets and their owners in Shandong province, eastern China, indicating a potential zoonotic risk. Prophylactic measures should be implemented to reduce the risk of pet owner's exposure to T. gondii infection.

Toxoplasma gondii and Neospora caninum in Tolai Hares (Lepus tolai) Intended for Human Consumption in China: Seroprevalence, DNA Detection, and Genotyping.

Currently, there is no information available on the detection of Toxoplasma gondii and Neospora caninum in the tissues of Tolai hares in China. This study aimed to investigate the prevalence of these protozoan parasites in Tolai hares obtained from Shandong province, eastern China, between January 2016 and June 2017. Serum and brain tissue samples of 358 Tolai hares were obtained and detected for the presence of antibody and parasite DNAs by serodiagnosis and polymerase chain reaction (PCR), respectively. The seroprevalence of T. gondii and N. caninum infection in Tolai hares was 8.10% (29/358) and 0.84% (3/358), respectively. However, all the 358 tested Tolai hares were negative for N. caninum by PCR and T. gondii DNA was detected in 23 Tolai hares (6.42%, 23/358). The positive T. gondii DNA was genotyped at 11 genetic markers using multilocus PCR-restriction fragment length polymorphism technology. Of the 23 positive samples, only 2 of them produced complete genotyping results, and were identified as ToxoDB Genotype #9. This is the first report to detect T. gondii in the tissues of Tolai hares from China and the first study to focus on N. caninum in Tolai hares from China.

Hepatitis E virus seroprevalence among farmers, veterinarians and control subjects in Jilin province, Shandong province and Inner Mongolia Autonomous Region, China.

China is commonly considered to be a HEV-endemic region but limited epidemiological data for HEV among farmers and veterinarians are available. Thus, a case-control study was carried out to detect the seroprevalence and assess potential risk factors associated with the acquisition of HEV infection by farmers and veterinarians in China from July 2013 to May 2015. Three hundred veterinarians and 600 farmers recruited from Jilin province, Shandong province, and Inner Mongolia Autonomous Region and 600 control subjects matched by gender, age, and residence were detected for the presence of anti-HEV IgG and IgM antibodies using enzyme immunoassays. The seroprevalences of HEV infection in farmers, veterinarians, and control subjects were 34.8%, 26.7%, and 20.2%, respectively. Farmers (P < 0.001) and veterinarians (P = 0.027) have significantly higher seroprevalence than control subjects. The highest seroprevalence of HEV infection was detected in swine farmers (49.1%) and the lowest seroprevalence was found in cattle farmers (26.5%). In veterinarians, farm animal veterinarians have a higher seroprevalence than pet veterinarians, but the difference was not significant (P > 0.05). Residence area, contact with swine and exposure with soil were significantly associated with HEV infection in the study farmers; contact with swine and source of drinking water were significantly associated with HEV infection in the study veterinarians. These results implied the high prevalence of HEV and the considerable potential for the dissemination of HEV infection in farmers and veterinarians in China. J. Med. Virol. 89:872-877, 2017. © 2016 Wiley Periodicals, Inc.

Toxoplasma gondii, Dirofilaria immitis, feline immunodeficiency virus (FIV), and feline leukemia virus (FeLV) infections in stray and pet cats (Felis catus) in northwest China: co-infections and risk factors.

This study was conducted to estimate the prevalence of Toxoplasma gondii, Dirofilaria immitis, feline immunodeficiency virus (FIV), and feline leukemia virus (FeLV) infections among stray and pet cats in Lanzhou, northwest China, and to identify the influence of age, gender, and regions on seropositivity. T. gondii antibodies were examined in cat sera by the modified agglutination test (MAT). The circulating antigens of D. immitis and FeLV and specific antibodies to FIV were examined using kits commercially available. The overall prevalence of T. gondii, FIV, FeLV, and D. immitis was 19.34, 9.12, 11.33, and 3.04 %, respectively. For the genetic characterization of T. gondii genotypes in cats, genomic DNA was extracted from the seropositive cats and the T. gondii B1 gene was amplified using a semi-nested PCR. DNA samples giving positive B1 amplification were then genotyped using multilocus PCR-RFLP. Two T. gondii genotypes (ToxoDB#9 and ToxoDB#1) were identified. Results of the multivariate logistic regression analysis showed that older cats are more likely to be seropositive than juveniles for T. gondii, FIV, FeLV, and D. immitis. This is the first report of T. gondii genotypes in cats in northwest China. Moreover, the present study is the first study of retrovirus and D. immitis seroprevalence in cats in China. The results revealed that T. gondii, FIV, and FeLV infections are common in stray and pet cats in northwest China.

Seroprevalence of hepatitis E virus among pregnant women and control subjects in China.

Hepatitis E infection, caused by the hepatitis E virus (HEV), is an important global public health concern, with particularly high mortality in pregnant women. China is generally judged to be an HEV-endemic area, but epidemiological data for HEV among pregnant women are limited. Between June 2011 and July 2013, a case-control study was conducted to estimate the seroprevalence and potential risk factors associated with the acquisition of HEV infection by pregnant women in China. Nine-hundred and ninety pregnant women who visited hospitals for antenatal follow-up or medication in Qingdao and Weihai and 965 control subjects matched by age, gender and residence were examined for the presence of anti-HEV IgG and IgM antibodies by enzyme immunoassays. Socio-demographic and behavioral characteristics from the study subjects were obtained. The overall prevalence of anti-HEV IgG in all 1,955 samples was 20.7%. In pregnant women, 16.2% of samples were anti-HEV IgG positive whereas, in control subjects 25.3% of samples were anti-HEV IgG positive, (P < 0.01). For anti-HEV IgM detection, 62 (3.2%) of the 1,955 serum samples were positive and the seroprevalence in pregnant women and control subjects was 2.6% and 3.6%, respectively. Age, contact with cats, contact with pigs and exposure to soil were found to be associated with HEV infection. These findings demonstrated the high prevalence of HEV and the considerable potential for the transmission of HEV infection in pregnant women in China.

Seroprevalence and risk factors of Chlamydia abortus infection in free-ranging white yaks in China.

BACKGROUND: Chlamydia is gram-negative obligate bacteria which causes a wide variety of diseases in humans and animals. To date, there are a few reports about the seroprevalence of Chlamydia and the risk factors associated with Chlamydia infection in yaks in the world. In this study, 974 blood samples were collected from white yaks (Bos grunniens) in Tianzhu Tibetan Autonomous County, Gansu province, northwest China from June 2013 to April 2014. RESULTS: Antibodies against Chlamydia abortus were examined by the indirect hemagglutination (IHA) test, and 158 of 974 (16.22%) white yaks were seropositive for C. abortus antibodies at the cut-off of 1:16. The risk factors associated with seroprevalence were evaluated by a multivariate logistic regression analysis. Region, gender and age of white yak were left out of the final model, due to its insignificance in the logistic regression analysis (P > 0.05). However, season was considered as a major risk factor associated with C. abortus infection in white yaks. CONCLUSIONS: To our knowledge, this is the first survey of C. abortus seroprevalence in white yaks in China, which extends the host range for C. abortus and has important implications for public health and the local Tibetan economy.

Herd-level prevalence and associated risk factors for Toxoplasma gondii, Neospora caninum, Chlamydia abortus and bovine viral diarrhoea virus in commercial dairy and beef cattle in eastern, northern and northeastern China.

Although the seroprevalence of Toxoplasma gondii, Neospora caninum, Chlamydia abortus and bovine viral diarrhea virus infection in cattle have been reported in some areas in China, most of them were conducted with small number of cattle samples and very limited districts and neglected the assessment of herd management factors associated with herd-level prevalence of these pathogen infections. Thus, from September 2013 to December 2014, a large-scale seroprevalence study was conducted to determine the animal-level and herd-level seroprevalence and identify herd-level risk factors associated with these pathogen infections in 4487 cattle from 134 herds in five provinces (Heilongjiang, Jilin, Liaoning, Shandong, Hebei) and Inner Mongolia Autonomous Region of China. At animal level, the true prevalence of antibodies against T. gondii, N. caninum, C. abortus and bovine viral diarrhoea virus (BVDV) was 10.48, 17.14, 11.92 and 50.10%, respectively. At herd level, the true prevalence of antibodies against T. gondii, N. caninum, C. abortus and BVDV was 27.16, 29.10, 37.31 and 40.30%, respectively. Multivariate analysis of these characteristics showed that source of water and presence of felids were significantly associated with T. gondii infection in the studied cattle herds. Source of water was significantly associated with N. caninum infection in the studied cattle herds. While herd size and management system were significantly associated with BVDV infection in the studied cattle herds, this is the first report of herd-level prevalence and associated risk factors of T. gondii, N. caninum, C. abortus and BVDV infection in cattle in China.

Seroprevalence and risk factors of Mycobacterium avium subspecies paratuberculosis infection in domestic sika deer in China.

Paratuberculosis or Johne's disease (JD), caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a chronic infectious granulomatous enteritis of ruminants and other animals, which has a worldwide occurrence, but little is known of MAP infection in domestic sika deer in Jilin Province, China. The objective of the present investigation was to examine seroprevalence and risk factors of MAP infection in Jilin Province. Serum samples collected from 1400 sika deer from 16 sika deer herds were collected in the 4 districts of the province between May 2013 and August 2014 and were tested independently for the presence of antibodies against MAP. A total of 247 (17.64 %) sika deer tested positive for MAP antibodies using a commercially available enzyme immunoassay kit. The management level of farm and collecting region of sika deer was the main risk factor associated with MAP infection. The present study revealed the seroprevalence of MAP infection in sika deer in Jilin Province, China, which provided the baseline data for taking comprehensive countermeasures and measures in effectively preventing and controlling MAP infection in sika deer.