The transferred microbiota from mother to baby constitutes the initial infant gastrointestinal microbiota and has an important influence on the development and health of infants in human. However, the reproductive tract microbiota of avian species and its inheritance have rarely been studied. We aimed to characterize the microbial community in the chicken reproductive tract and determine the origin of the chicken embryo gut microbiota. Microbiota in four different portions of chicken oviduct were determined using 16S rRNA metagenomic approach with the IonTorrent platform. Additionally, we analyzed the mother hen’s magnum and cloaca, descendent egg, and embryo gut microbiota. The microbial composition and relative abundance of bacterial genera were stable throughout the entire chicken reproductive tract, without significant differences between the different parts of the oviduct. The chicken reproductive tract showed a relatively high abundance of Lactobacillus species. The number of bacterial species in the chicken reproductive tract significantly increased following sexual maturation. Core genera analysis detected 21 of common genera in the maternal magnum and cloaca, descendent egg shell, egg white, and embryo gut. Some elements of the maternal oviduct microbiota appear to be transferred to the embryo through the egg white and constitute most of the embryo gut bacterial population.

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The oral microbiome, which is closely associated with many diseases, and the resident pathogenic oral bacteria, which can be transferred by close physical contact, are important public health considerations. Although the dog is the most common companion animal, the composition of the canine oral microbiome, which may include human pathogenic bacteria, and its relationship with that of their owners are unclear. In this study, 16S rDNA pyrosequencing was used to compare the oral microbiomes of 10 dogs and their owners and to identify zoonotic pathogens. Pyrosequencing revealed 246 operational taxonomic units in the 10 samples, representing 57 genera from eight bacterial phyla. Firmicutes (57.6%), Proteobacteria (21.6%), Bacteroidetes (9.8%), Actinobacteria (7.1%), and Fusobacteria (3.9%) were the predominant phyla in the human oral samples, whereas Proteobacteria (25.7%), Actinobacteria (21%), Bacteroidetes (19.7%), Firmicutes (19.3%), and Fusobacteria (12.3%) were predominant in the canine oral samples. The predominant genera in the human samples were Streptococcus (43.9%), Neisseria (10.3%), Haemophilus (9.6%), Prevotella (8.4%), and Veillonella (8.1%), whereas the predominant genera in the canine samples were Actinomyces (17.2%), Unknown (16.8), Porphyromonas (14.8), Fusobacterium (11.8), and Neisseria (7.2%). The oral microbiomes of dogs and their owners were appreciably different, and similarity in the microbiomes of canines and their owners was not correlated with residing in the same household. Oral-to-oral transfer of Neisseria shayeganii, Porphyromonas canigingivalis, Tannerella forsythia, and Streptococcus minor from dogs to humans was suspected. The finding of potentially zoonotic and periodontopathic bacteria in the canine oral microbiome may be a public health concern.

Vaccination has proven to be the most cost-effective strategy for controlling a wide variety of infectious diseases in humans and animals. For the last decade, veterinary vaccines have been substantially developed and demonstrated their effectiveness against many diseases. Nevertheless, new vaccines are greatly demanded to effectively control newly- and re-emerging pathogens in livestock. However, development of veterinary vaccines is a challenging task, in part, due to a variety of pathogens, hosts, and the uniqueness of host-susceptibility to each pathogen. Therefore, novel concepts of vaccines should be explored to overcome the limitation of conventional vaccines. There have been greatly advanced in the completion of genomic sequencing of pathogens, the application of comparative genomic and transcriptome analysis. This would facilitate to open opportunities up to investigate a new generation of vaccines; recombinant subunit vaccine, virus-like particle, DNA vaccine, and vector-vehicle vaccine. Currently, such types of vaccines are being actively explored against various livestock diseases, affording numerous advantages over conventional vaccines, including ease of production, immunogenicity, safety, and multivalency in a single shot. In this articles, the authors present the current status of the development of veterinary vaccines at large as well as research activities conducted in Korea.

The hepatitis E virus (HEV) is an emerging zoonotic agent, for which pigs are the most important reservoir. Complete genome sequences of two swine HEV strains, designated swKOR-1 and swKOR-2, were determined via RT-PCR and RACE-PCR. The strains contained genomes composed of 7,222- and 7,221-bp excluding the poly(A) tails, respectively. The swKOR-1 and swKOR-2 strains were classified into subtype 3a of genotype 3 via phylogenetic analysis. These strains formed a distinctive cluster in the phylogenetic tree with human and swine HEVs isolated in the USA and human HEVs isolated in Japan. Anti-HEV antibodies were identified via ELISA in 8 of 99 (8.1%) cats, whereas, among 115 cattle and 213 dogs, no HEV-specific antibodies were detected. The conserved RNA-dependent RNA polymerase (RdRp) gene of HEV could be detected via RT-PCR in 8.7% of raw oysters collected from coastal regions in Korea. The HEV RNAs detected in oysters were identified as belonging to subtype 3a. The HEV RNAs in oysters most closely resembled that of the swKOR-2 strain. They also showed a close genetic relationship with the swKOR-1 strain and the swine and human HEVs isolated in the USA. This is the first report describing the detection in oysters of HEV that may have originated from genotype 3 swine HEV in Korea. Pigs and cats infected with HEV, as well as oysters contaminated with HEV, are potential risk factors for HEV transmission to humans.

Hepatitis E outbreaks are a serious public health concern in developing countries. The disease causes acute infections, primarily in young adults. The mortality rate is approximately 2%; however, it can exceed 20% in pregnant women in some regions in India. The causative agent, hepatitis E virus (HEV), has been isolated from several animal species, including pigs. HEV genotypes 3 and 4 have been isolated from both humans and animals, and are recognized as zoonotic pathogens. Seroprevalence studies in animals and humans indirectly suggest that HEV infections occur worldwide. The virus is primarily transmitted to humans via undercooked animal meats in developed countries. Moreover, transfusion- and transplantation-mediated HEV infections have recently been reported. This review summarizes the general characteristics of hepatitis E, HEV infection status in animals and humans, the zoonotic transmission modes of HEV, and HEV vaccine development status.

Avian influenza virus (AIV) circulates among free-ranging, wild birds. We optimized and validated a DNA barcoding technique for AIV isolation and host-species identification using fecal samples from wild birds. DNA barcoding was optimized using tissue and fecal samples from known bird species, and the method was shown to distinguish 26 bird species. Subsequently, fecal samples (n=743) collected from wild waterfowl habitats confirmed the findings from the laboratory tests. All identified AIV-positive hosts (n=35) were members of the order Anseriformes. We successfully applied the DNA barcoding technique to AIV surveillance and examined AIV epidemiology and host ecology in these wild waterfowl populations. This methodology may be useful in the design of AIV surveillance strategies.

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