In South Korea, where avian infl uenza virus subtypes H3N2, H5N1, H6N1, and H9N2 circulate or have been detected, 3 genetically similar canine infl uenza virus (H3N2) strains of avian origin (A/canine/Korea/01/2007, A/canine/ Korea/02/2007, and A/canine/Korea/03/2007) were isolated from dogs exhibiting severe respiratory disease. To determine whether the novel canine infl uenza virus of avian origin was transmitted among dogs, we experimentally infected beagles with this infl uenza virus (H3N2) isolate. The beagles shed virus through nasal excretion, seroconverted, and became ill with severe necrotizing tracheobronchitis and bronchioalveolitis with accompanying clinical signs (e.g., high fever). Consistent with histologic observation of lung lesions, large amounts of avian infl uenza virus binding receptor (SAα 2,3-gal) were identifi ed in canine tracheal, bronchial, and bronchiolar epithelial cells, which suggests potential for direct transmission of avian infl uenza virus (H3N2) from poultry to dogs. Our data provide evidence that dogs may play a role in interspecies transmission and spread of infl uenza virus.

The open reading frame (ORF3) genes of the parent DR13, attenuated DR13, KPED-9, P-5V, and 12 field samples were cloned and sequenced to further explore the functions of wild- and attenuated-type porcine epidemic diarrhea viruses (PEDVs). Sequencing revealed that wild-type PEDVs ORF3 genes had a single ORF of 675 nucleotides encoding a protein of 224 amino acids with a predicted M (r) of 25.1-25.3 kDa. Attenuated-type PEDVs ORF3 genes had a single ORF of 624 nucleotides encoding a protein of 207 amino acids with a predicted M (r) of 23.4 kDa. The coding region of the ORF3 gene of attenuated-type PEDVs including attenuated DR13, KPED-9, and P-5V had 51 nucleotide deletions that were not found in the ORF3 genes of wild-type PEDVs including CV777, Br1/87, LZC, parent DR13, and 12 field samples. In addition, attenuated-type PEDVs have previously been found to exhibit reduced pathogenicity in pigs. Therefore, 51 nucleotide deletions appear to be meaningful and may be significant for PEDV pathogenicity, because they lead to changes in the predicted amino acid sequences of attenuated-type PEDVs. Reverse transcriptase-polymerase chain reaction (RT-PCR) on the partial ORF3 gene including 51 nucleotide deletions revealed that all PEDVs fell into two types, wild- and attenuated-type PEDVs. Wild-type PEDVs containing parent DR13 and 12 field samples had RT-PCR products of 245 bp in size, while attenuated-type PEDVs containing PEDV vaccine strains (attenuated DR13, KPED-9, P-5V) had products of 194 bp. In addition, all PEDV vaccine strains were used as live virus vaccine, because they previously exhibited a reduced pathogenicity in pigs. Therefore, large deletion region, which is comprise 17 amino acid deletions caused by 51 nucleotide deletions and is seen in all PED live vaccine strains, may be important site for PEDV pathogenicity, and we can use it for differentiation of wild- and attenuated-type PEDVs.

Susceptible dogs were brought into contact with dogs experimentally infected with an avian-origin infl uenza A virus (H3N2) that had been isolated from a pet dog with severe respiratory syndrome. All the experimentally infected and contact-exposed dogs showed elevated rectal temperatures, virus shedding, seroconversion, and severe necrotizing tracheobronchitis and bronchioalveolitis.T ransmission of highly pathogenic avian-origin canine infl uenza A viruses (H3N2) that spread across South Korea during May through December 2007 was observed repeatedly in the country's animal clinics (1). These viruses share >97% nucleotide sequence homology, suggesting that whole viruses were transmitted directly from birds to dogs. To determine whether these viruses can be transmitted directly from dog to dog, we experimentally infected beagles by direct contact. Dog-to-dog transmission of the virus raises questions about the interspecies transmission of avian infl uenza viruses and adaptation of these viruses to canine physiology. The StudyDogs in the study comprised 3 groups of beagles housed in different rooms of the isolation facility at Green Cross Veterinary Products (Yong-in, South Korea). The virus used was avian-origin canine infl uenza virus A/ canine/01/2007, subtype H3N2, which had been isolated from a pet dog with severe respiratory syndrome. In the fi rst group (challenge group), 4 beagles were inoculated intranasally with a 10 6.5 50% egg infectious dose (EID 50 ). Two hours later, the second group of 4 uninfected dogs (exposure group) was housed in the same contaminant room. These uninoculated dogs had frequent direct noseto-nose contact with the inoculated dogs. The third group of 4 dogs (control group) was housed separately as uninoculated controls. Rectal temperatures were checked and nasal swab samples were collected daily. We monitored clinical signs of infection 7 days postinoculation (dpi) and examined nasal swabs obtained 10 dpi for virus shedding; serum samples were collected at 0, 3, 7, 9, and 13 dpi. Serum antibodies against nucleoprotein were detected by using a commercial competitive ELISA (Animal Genetics, Inc., Suwon, South Korea). On 7 and 13 dpi, 2 dogs from each group were euthanized for gross and histopathologic examination. All organs from the dogs were rapidly immersed in 10% neutral formalin buffer to prevent autolysis and stored overnight. All animal experiments complied with the current laws of South Korea. Animal care and treatment were conducted in accordance with guidelines established by the Seoul National University Institutional Animal Care and Use Committee. A p value <0.01 was considered statistically signifi cant.Clinical signs, including sneezing, nasal discharge, and coughing, were observed 2-8 dpi in the challenge group and 5-8 dpi in the exposure group. Twenty-four hours after inoculation, fever developed in dogs in the challenge group (mean rectal temperature 39.85°C-39.75°C) that lasted until 3 dpi. Fever (39.5°C) developed in dogs in the exposure group 72 hours after exposu...

Porcine epidemic diarrhea virus (PEDV) causes a devastating enteric disease with acute diarrhea, dehydration and significant mortality in swine, thereby incurring heavy economic losses in Korea. Spike (S) glycoprotein has been suggested as an important determinant for PEDV biological properties. In this study, the nucleotide and deduced amino acid sequences of the partial S glycoprotein genes of Korean PEDV isolates, including epitope region that is capable of inducing PEDV-neutralizing antibodies, were determined. The partial S glycoprotein genes were amplified by RT-PCR, cloned, sequenced, and compared with each other as well as with reference PEDV strains. By phylogenetic analysis, the Korean PEDV isolates were divided into three groups (G1, G2, G3), which had three subgroups (G1-1, G1-2, G1-3). Group1 (G1) Korean PEDV isolates were highly homologous to CV777, Br1/87, JS-2004-2, KPED-9, P-5V, SM98-1, parent DR13, and attenuated DR13, group2 (G2) Korean PEDV isolates were highly homologous to Spk1, and group3 (G3) was Chinju99 at the nucleotide and deduced amino acid sequence levels. In addition, the G1 Korean PEDV isolates didn't had several specific nucleotides and amino acids which were found in the G2 and G3 Korean PEDV isolates, and especially the G1-1 Korean PEDV isolates had specific nucleotides and amino acids which were not found in the G1-2, G1-3, G2, and G3 Korean PEDV isolates. It was suggested that many Korean PEDV isolates are closely related to the G1 including CV777, Br1/87, JS-2004-2, KPED-9, P-5 V, SM98-1, parent DR13, and attenuated DR13 rather than to the G2 and G3 including Spk1 and Chinju99, and notably more prevalent PEDVs isolated in Korea are especially close to the Chinese PEDV strain JS-2004-2 rather than Korean PEDV strains Spk1, Chinju99, KPED-9, SM98-1, parent DR13, and attenuated DR13.

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