BackgroundAvian origin canine influenza virus was reported in Korea. The dog to dog contact transmission of the avian origin canine influenza virus (CIV) H3N2 and CIV H3N8 was shown by experimental contact transmission. This study was focused on viral excretion and fever in order to elucidate the epidemiological associations which might be helpful to control the disease transmissions in CIV outbreak in dogs.MethodsAn influenza seronegative 10-week-old Beagle dog was experimentally inoculated with the canine influenza virus A/canine/01/2007, subtype H3N2. Eight hours after inoculation, the infected dog was cohoused with seven uninfected Beagle dogs. Clinical signs including fever were recorded for 14 days post inoculation.ResultsThe infected dog and four of seven contact dogs in the study showed clinical signs (sneezing, nasal discharge and coughing) during the study. Viral shedding occurred in all of the animals tested and began on 1 to 6 DPI in dogs with clinical signs. Elevated body temperatures above 39.5°C (geometric mean temperature of 39.86°C±0.49) were observed in all symptomatic dogs. The mean viral titer during fever was 2.99 log EID50/ml, which was significantly higher than the viral titer detected in the non fever.ConclusionsThe data show that contact dogs with a canine influenza infected dog shed different levels of virus in their nasal excretions and demonstrate that clinical signs, including fever, significantly correlate with the viral shedding.

During recent canine influenza surveillance in South Korea, a novel H3N1 canine influenza virus (CIV) that is a putative reassortant between pandemic H1N1 2009 and H3N2 CIVs was isolated. Genetic analysis of eight genes of the influenza virus revealed that the novel H3N1 isolate presented high similarities (99.1–99.9 %) to pandemic influenza H1N1, except for in the haemagglutinin (HA) gene. The HA gene nucleotide sequence of the novel CIV H3N1 was similar (99.6 %) to that of CIV H3N2 isolated in Korea and China. Dogs infected with the novel H3N1 CIV did not show any notable symptoms, in contrast to dogs infected with H3N2 CIV. Despite no visible clinical signs of disease, nasal shedding of virus was detected and the infected dogs presented mild histopathological changes.

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...

Since severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses (CoVs) share similar characteristics with respect to clinical signs, etiology, and transmission, methods for a rapid and accurate differential diagnosis are important. Therefore, the aim of this study was to develop a duplex real-time reverse transcription (RT)-PCR method for the simultaneous detection of these viruses. Primers and probes that target the conserved spike S2 region of human SARS-CoV, MERS-CoV, and their related bat CoVs were designed. The results of real-time RT-PCR showed specific reactions for each virus with adequate detection limits of 50-100 copies/mL and 5-100 copies/mL using pUC57-SARS-pS2 (a template for SARS-CoV) and pGEM-MERS-S2 (a template for MERS-CoV), respectively. In addition, this real-time RT-PCR system was able to detect the target viruses SARS-like bat CoV and MERS-CoV in bat fecal samples and sputum of MERS patients, respectively. Therefore, this newly developed real-time RT-PCR method is expected to detect not only SARS-CoV and MERS-CoV in humans but also several bat CoVs that are closely related to these viruses in bats.

Bat species around the world have recently been recognized as major reservoirs of several zoonotic viruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), Nipah virus and Hendra virus. In this study, consensus primer-based reverse transcriptase polymerase chain reactions (RT-PCRs) and high-throughput sequencing were performed to investigate viruses in bat faecal samples collected at 11 natural bat habitat sites from July to December 2015 in Korea. Diverse coronaviruses were first detected in Korean bat faeces, including alphacoronaviruses, SARS-CoV-like and MERS-CoV-like betacoronaviruses. In addition, we identified a novel bat rotavirus belonging to group H rotavirus which has only been described in human and pigs until now. Therefore, our results suggest the need for continuing surveillance and additional virological studies in domestic bat.