Experimental Infections of Dogs with Type C Influenza Virus

Abstract

A study was performed to determine if type C influenza infection could be established in dogs as a model for human cases. Mongrel dogs were infected with the Ann Arbor/1/50 strain of type C influenza virus and were examined for clinical symptoms, virus isolation and antibody response. After the first exposure to the virus, all infected animals developed nasal discharge and some of them also showed swelling of the eyelids, and suffusion of the eyes with tears and eye mucus, within 1 to 4 days. The animals showed an increase in hemagglutination-inhibiting (HI) serum antibody, and recovery of the agent from the nasal swabs was successful. The symptoms lasted for as long as 10 days in most infected dogs, which was comparable to our human cases reported previously (Katagiri, S., Ohizumi, A., and Homma, M. 1983. J. Infect. Dis. 48: 51-56). After the second and third virus exposures at intervals of 50 days, all animals developed the same symptoms as those described above and the rise in antibody titer was evident. The virus could be recovered from four of the six dogs 2 to 5 days after the second exposure and from one dog as late as 10 days after the third exposure. Increases in antibody titer in the IgM fraction were observed after every infection. In control dogs which were mock-infected with UV-inactivated virus, no symptoms were evident and recovery of the virus was not successful although an increase in HI serum antibody titer was seen. These results show that mongrel dogs are sensitive to type C influenza virus and that repeated infections characteristic of human influenza C can be experimentally produced in dogs.

Rescue of Influenza C Virus from Recombinant DNA

“…Furthermore, human influenza C virus isolates were found to be closely related to pig isolates, suggesting that interspecies transmission of influenza C virus between humans and pigs has occurred in nature (24). Influenza C virus-specific antibodies were also detected in dogs (26,27,39), but detection or isolation of the virus from this animal species has not been documented, although experimental infection resulted in clinical symptoms and viral replication (38). Consequently, influenza C viruses are not restricted to humans, but the potential role of pigs or dogs as an animal reservoir for human influenza C virus remains to be elucidated.…”

Prevalence of the Antibody to Influenza C Virus in a Northern Luzon Highland Village, Philippines

“…Apparently, influenza C virus cannot be included in this category. It has been suggested, however, that recurrent infection with influenza C virus occurs frequently, even soon after primary infection (6,9,12). It is likely that reinfection occurred in Kadaklan as well since the HI titers were maintained at relatively high levels up to late in life (see Fig.…”

Influenza C Virus Infection in Rats

“…Additionally, Ohwada et al (13) showed that mongrel dogs could be repeatedly infected with influenza C virus, developing nasal discharge after each exposure to the virus. However, virus growth in the nose seemed to be suppressed considerably in the reinfected dogs since virus was isolated less frequently in the second and third infections than in the first one.…”

“…Earlier studies of Minuse et al (9) showed that no characteristic symptoms were produced in ferrets, hamsters, and monkeys inoculated intranasally with influenza C virus though the virus was recovered from the nasal turbinates and the animals developed serum HI antibodies. In contrast, pigs and dogs were shown to develop clinical symptoms characterized by difficulties in breathing (pigs) and increased nasal secretions (pigs and dogs) (2,13). Based on the studies on an outbreak of influenza C unassociated with other respiratory infections.…”