H1N1 Influenza Virus Infection

13-year-old neutered male mixed-breed dog

History and Clinical Presentation
The 13-year-old neutered male mixed-breed dog was taken in on emergency to the Katonah Bedford Veterinary Center in Bedford Hills, New York, on Sunday, December 13, 2009. Two days prior, he was seen by his regular veterinarian after several days of not feeling well. The patient was placed on antibiotics and anti-inflammatories with no response. On presentation to the emergency veterinarian, the dog had dry cough, was reported to be lethargic and not eating; he was also febrile with a temperature of 103.6°F. The owner reported that he himself had tested positive earlier in the week for the H1N1 influenza virus.


Diagnostic Testing
The veterinarian informed the owner that there was an H1N1 influenza virus test available through IDEXX Reference Laboratories. The owner agreed to have the test run.

Thoracic radiographs were taken and revealed evidence of pneumonia with consolidation of the right cranial and middle lung lobes and prominent air bronchograms.

A tracheal wash was performed and submitted for culture and sensitivity and cytology.


The dog was hospitalized, placed on intravenous fluids and antibiotics.

In addition, the dog received saline nebulization and coupage four times daily.

The dog improved with treatment and was released after 48 hours of hospitalization and supportive care.


Laboratory Results
Culture and sensitivity results from the tracheal wash were negative.

Cytology of fluid recovered from tracheal wash revealed chronic active inflammation with the presence of degenerate neutrophils, and no organisms were seen.

The H1N1 Influenza Virus RealPCR™ Test result was positive. A complete Canine Respiratory RealPCR™ Panel was then performed, and all other respiratory pathogens, including canine influenza virus (H3N8), were negative.


Focal lung lobe consolidation can be a consequence of influenza infections; however, other possible etiologies need to be considered in this older dog. Therefore, it is unknown at this time if the H1N1 influenza virus infection is the primary cause of this dog’s illness; however, it is likely to have contributed to the dog’s clinical signs.


The dog is reported to be doing very well at home and is scheduled for a recheck visit with repeat thoracic radiographs this week.


For consultation on a possible H1N1 influenza virus case, please contact an IDEXX internal medicine specialist at 1-888-433-9987, option 4, option 2.