There is limited information available on the association between Enterocytozoon bieneusi and diseases in animals or on the characteristics of the strains involved. This study examined the occurrence of E. bieneusi in piglets with and without diarrhea to determine its involvement. Among 472 fecal samples from 472 piglets (237 with diarrhea and 235 without) up to 7 weeks of age, 67 (approximately 14%) were polymerase chain reaction (PCR) positive for E. bieneusi. Of the 237 piglets with diarrhea, 38 (approximately 16%) tested positive for E. bieneusi. Of the 235 healthy piglets, 29 (approximately 12%) tested positive for E. bieneusi. This species was detected only in the younger group of piglets with diarrhea, particularly those aged less than 1 week and between 1 and 2 weeks. This suggests that E. bieneusi is a possible cause of diarrhea in piglets. This organism, however, produced asymptomatic infections in the older piglets, as there was no significant difference in the rates of occurrence between the diarrheic and nondiarrheic older piglets (aged older than 4 weeks). The internal transcribed spacer (ITS) region of the ribosomal ribonucleic acid gene of the ten E. bieneusi-positive samples was amplified using nested PCR and subsequently sequenced. Genetic polymorphisms, which were represented by five distinct genotypes (PEbA-PEbE), were found among the E. bieneusi isolates. The five genotypes identified in this study differed from each other by two to six single-nucleotide polymorphisms. Nine isolates from four genotypes (PEbA-PEbD) were homologous to previously known types that had originally been isolated from pigs. However, one isolate from the PEbE genotype was identical to type CAF1, which was originally isolated from humans. In addition, the phylogenetic relationships determined by the neighbor-joining analysis of the ITS sequences indicated this genotype to be more distant from the other pig-specific genotypes. Thus, this isolate from pigs may be distantly related to the pig-specific genotypes and may be capable of infecting humans.
The colibacillosis caused by avian pathogenic (APEC) is responsible for a significant loss of productivity and mortality in the poultry industry. The pathogenicity of these bacteria is based on the presence and expression of various virulence factors. In this study, the presence of the virulence-associated genes in APEC was determined using PCR. Among the isolates from the chickens with colibacillosis, all contained at least one of the genes as approximately of the isolates contained Interestingly, the gene, which has not been detected in APEC previously, was detected in half of the isolates. The ColV plasmid-associated genes such as genes were also detected in. ,. ,. ,. ,. and. of isolates, respectively. With regard to the fimbrial genes, the (.), papC (.) and genes (.) were identified at relatively low rates, none of the isolates harbored or and only of the isolates (.) contained In this study, isolates harbored two or more of the genes, and there were di erent patterns of gene combination in the isolates. The most common pattern, which was found in. (isolates), was Overall, these results suggest that APEC strains in this area commonly contain multiple virulence factors and approximately half of the APEC strains contained the ColV plasmid-associated genes. Especially, and were detected more than half of the isoaltes. : APEC, broilers, molecular detection, virulence genes tsh fyu irp
The threat of a highly pathogenic avian influenza (HPAI) H5N1 virus causing the next pandemic remains a major concern. In this study, we evaluated the immunogenicity and efficacy of an inactivated whole-virus H5N1 pre-pandemic vaccine (MG1109) formulated by Green Cross Co., Ltd containing the hemagglutinin (HA) and neuraminidase (NA) genes of the clade 1 A/Vietnam/1194/04 virus in the backbone of A/Puerto Rico/8/34 (RgVietNam/04xPR8/34). Administration of the MG1109 vaccine (2-doses) in mice and ferrets elicited high HI and SN titers in a dose-dependent manner against the homologous (RgVietNam/04xPR8/34) and various heterologous H5N1 strains, (RgKor/W149/06xPR8/34, RgCambodia/04xPR8/34, RgGuangxi/05xPR8/34), including a heterosubtypic H5N2 (A/Aquatic bird/orea/W81/05) virus. However, efficient cross-reactivity was not observed against heterosubtypic H9N2 (A/Ck/Korea/H0802/08) and H1N1 (PR/8/34) viruses. Mice immunized with 1.9 μg HA/dose of MG1109 were completely protected from lethal challenge with heterologous wild-type HPAI H5N1 A/EM/Korea/W149/06 (clade 2.2) and mouse-adapted H5N2 viruses. Furthermore, ferrets administered at least 3.8 μg HA/dose efficiently suppressed virus growth in the upper respiratory tract and lungs. Vaccinated mice and ferrets also demonstrated attenuation of clinical disease signs and limited virus spread to other organs. Thus, this vaccine provided immunogenic responses in mouse and ferret models even against challenge with heterologous HPAI H5N1 and H5N2 viruses. Since the specific strain of HPAI H5N1 virus that would potentially cause the next outbreak is unknown, pre-pandemic vaccine preparation that could provide cross-protection against various H5 strains could be a useful approach in the selection of promising candidate vaccines in the future.
Avian pathogenic Escherichia coli (APEC) is a causative agent for a number of extra intestinal diseases and account for significant losses to the poultry industry. Since protective immunity against APEC is largely directed to virulence antigens, we have individually expressed four different viulence antigens, papA, papG, IutA, and CS31A, using an attenuated Salmonella Typhimurium and a plasmid pBB244. Following oral immunization of mice with combination of two or four of these strains, serum IgG and mucosal IgA responses were elicited against each antigen represented in the mixture. The antigen-specific mucosal IgA responses were significantly higher in the group of mice immunized with the heat-labile Escherichia coli enterotoxin B subunit (LTB) strain than those in the group of mice immunized without the LTB strain. While, there was no significant difference between these two groups in antigen-specific serum IgG responses. The results showed that LTB could act as mucosal immune adjuvant. To assess the nature of immunity, the distribution of antigen-specific IgG isotypes was analyzed. All groups promoted Th1-type immunity as determined by the IgG2a/IgG1 ratio. Thus, our findings provided evidence that immunization with a combination of several vaccine strains is one of the strategies of developing effective vaccines against APEC.
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