H1N1 Influenza Virus Infection—California

8-year-old female domestic shorthair cat

History and Clinical Presentation
An 8-year-old female domestic shorthair cat was taken in to the Pico Boulevard Pet Hospital in West Los Angeles on Sunday, December 20, 2009. On presentation, the cat had mild respiratory symptoms including sneezing, nasal discharge, and occasional cough. The owner reported that she herself had tested positive earlier in the week for the H1N1 influenza virus.

Diagnostic Testing
The veterinarian informed the owner that an H1N1 influenza virus test is available through IDEXX Reference Laboratories. He recommended the Feline Upper Respiratory Disease (FURD) RealPCR™ Panel, which includes the H1N1 Influenza Virus Real PCR Test™, as a more comprehensive workup to allow identification of other more common infectious causes of upper respiratory disease in cats. A conjunctival and a deep pharyngeal swab were collected and submitted for the FURD panel.

The cat was treated symptomatically with supportive care, including antibiotics and fluids, and was released the same day.


Laboratory Results
In addition to the H1N1 Influenza RealPCR Test, the FURD panel includes five of the most frequent infectious agents known to cause respiratory problems in cats. Of the six tests, the H1N1 Influenza Virus RealPCR™ Test and the Mycoplasma felis RealPCR™ Test results were positive and reported to Pico Boulevard Pet Hospital on Monday, December 21, 2009. Subsequently, sample material was submitted to the California Animal Health and Food Safety (CAHFS) Laboratory System at the University of California, Davis, and confirmed positive for the 2009 pandemic H1N1 influenza virus.


A diagnosis of feline upper respiratory disease secondary to coinfection with H1N1 influenza virus and Mycoplasma felis was made. Coinfections in cats with upper respiratory disease are common and may result in more serious illness. Identification of all infectious components is important to allow initiation of appropriate therapy.


The cat is reported to sleep more but otherwise is doing very well at home. A recheck on December 22 showed the cat continues to sneeze but otherwise is free of other respiratory signs. A second recheck will be performed subsequently.


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.