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  News from the Maryland Veterinary Medical Association                                                    Fall   2013

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Canine Influenza in Maryland

by Guy Hohenhaus, DVM, MPH, State Veterinarian
Maryland Department of Agriculture

The recent outbreak of canine influenza in Maryland had dog owners across the state on heightened alert and veterinarians uncertain what to tell their clients.

Canine influenza is not currently a reportable disease so the Maryland Department of Agriculture (MDA) cannot give exact numbers on how many dogs or practices were affected; however, we are the agency most likely to hear from veterinarians and local animal health officials when such a contagious disease presents. According to our best information, the canine influenza outbreak was limited to Montgomery County where 21 dogs contracted the virus and two died from it. In addition, we believe that all of the dogs who came down with the influenza contracted it from the same place.

MDA sent out three “Maryland One Health Bulletins” to all veterinarians licensed in the state via email during the outbreak – one on August 22 that reported six cases; one on Aug. 29 that reported a total of 20 cases; and one on September 18 noting the most recent reported case from September 5, 2013. Veterinarians were urged to take extra precautions in isolating and disinfecting suspect cases to prevent further spread of the virus. In addition, we were initially concerned that the strain of influenza would be a new strain of avian origin that is now circulating through China and Korea; however, testing done at Cornell Diagnostic Laboratory and Iowa State University determined that it was the H3N8 strain previously seen in the U.S. Commercial vaccinations now on the market are generally effective against the strain, but only if they are given before exposure. (The vaccination requires 2 shots and takes 3 to 4 weeks to become fully effective.)

As of this writing (Sept. 30), the outbreak appears to have been contained since we have had no additional reports of confirmed cases; however, it is entirely possible that veterinarians are treating canine influenza without diagnostic confirmation or without letting us know. Although there is no requirement that they do so, we do ask that confirmed cases be reported to us so that we can provide technical assistance and testing required to prevent further spread of disease in the community.

The canine influenza virus is extremely contagious. It is important that veterinarians isolate dogs with influenza-like signs and be diligent about cleaning and disinfecting all areas that may be contaminated, including muzzles and other equipment, in order to control the spread.
Vaccinations for this strain of canine influenza are not generally included in annual vaccinations; however, clients who have dogs that come in very close contact with other dogs (kennels, doggy day care facilities, dog parks, etc.) may want to consider getting the vaccination now. Guidelines for prevention are provided in the AVMA Canine Influenza-Backgrounder; see link in Resources below.

Dogs infected with CIV may have secondary bacterial infections that might lead to fatal pneumonia. Mycoplasma cynos or Mycoplasma canis have been bacteria causing mortality in recent cases. High doses of doxycycline for extended periods are needed for successful treatment of Mycoplasma pneumonia.

Researchers at Iowa State University Veterinary Diagnostic Laboratory continue to be interested in conducting molecular testing of respiratory cases suspected to be CIV and may run these at no cost to the submitter. Acute phase samples are needed to reliably detect canine influenza virus. Veterinarians interested in submitting acute phase samples of CIV suspects should contact Dr. Jessie Trujillo, Veterinary Microbiologist at the Iowa State University College of Veterinary Medicine, at or 509-432-9683.

MDA’s authority to regulate companion animal diseases such as CIV has been reviewed by the office of the Attorney General in response to this recent outbreak, and it has been determined that MDA authority can apply to companion animals in certain instances. MDA is considering requiring reporting of canine influenza, and possibly other companion animal diseases of concern, in high risk environments such as shelters, clinics, kennels, exhibitions or other points of concentration in the near future. Maryland veterinarians will be notified directly of any official changes for reporting of companion animal diseases. If you are a veterinarian not currently receiving Maryland One Health Bulletins thru email and you wish to receive them, please contact MDA at 410-841-5810 or


Canine Influenza Resources
Canine influenza testing, vaccines, statistics and history: 

Canine influenza background information: 

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Canine Influenza Resources

Canine Influenza Background Information

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