Canine Influenza

What you need to know……

The canine influenza virus first appeared in 2004 & 2005 in several Florida racing greyhound track facilities. Research since this suggests this virus mutated from the equine influenza virus. Influenza antibodies, however, have been found in samples from the 1990’s, suggesting a milder form likely predates this one. There is no evidence to suggest this virus can be transmitted to humans.

In the years since it first appeared, the feared deadly epidemic never occurred. We did have a scare in Chicago and in Atlanta in 2015 with many cases of influenza, which thankfully was far milder and had less impact than the original strain that was so dangerous at the dog tracks in the previous decade. Interestingly, these 2015 outbreaks were of a different strain, H3N2, so likely more mutation has occurred or it is a completely different origin, perhaps Asia. To the best of our knowledge, the Canine Influenza Vaccine originally developed for the H3N8 strain, is not effective in preventing this new strain, H3N2. Crowded housing facilitates the spread of the virus from dog to dog, as is typical of most contagious respiratory diseases, so the best prevention is to reduce exposure to other dogs during an outbreak such as occurred in Chicago.

Of those dogs exposed to the virus, it is estimated 20-50% will show no visible evidence of disease. Evidence suggests that perhaps 50% of infected dogs develop antibodies without ever showing any clinical disease at all. The remainder will have symptoms typical of infectious respiratory disease including cough, fever, decreased appetite and lethargy. Approximately 1% of infected dogs will develop serious complications as a result of canine influenza, most typically secondary bacterial pneumonia. These patients do require intensive treatment, preferably early in the course of the disease.

In 2009, a Canine Influenza vaccine was released. The vaccine carries a conditional license by the FDA, indicating that efficacy has not yet been proven although safety studies have been performed in over 700 dogs. The vaccine is intended as an aid in the control of disease associated with Canine Influenza virus infection. Although the vaccine is not expected to prevent infection altogether, efficacy trials have shown that the vaccination may significantly reduce the severity and duration of clinical illness, including the incidence and severity of damage to the lungs. In addition, the vaccine reduces the amount of virus shed and shortens the shedding interval; therefore, vaccinated dogs that become infected develop less severe illness and are less likely to spread the virus to other dogs.

Locally, there have been no reports from our specialty hospitals of any Canine Influenza cases in Hillsborough, Pinellas or Pasco counties. Given the frequency with which pets travel, this certainly could change in the future. At this time, we heartily recommend vaccination only for dogs traveling to areas with known risk of Canine Influenza, particularly if this travel will include exposure at dog shows, boarding or grooming facilities. Since the influenza virus is only causing problems in certain regions within certain states, it is advisable to check with veterinarians in that specific area prior to travel to determine if there is a known risk locally. The initial dose of vaccine requires a booster 2 to 4 weeks after the first dose is given, and the second dose should be given at least 7 days prior to the dog entering the at-risk situation (boarding kennel, dog show, etc.) , so the vaccine series should be started at least 4 weeks prior to travel.

Links for Canine Influenza ….

www.veterinarypartner.com/Content.plx
www.cdc.gov/flu/canine/
http://www.veterinarypartner.com/Content.plx?P=A&A=3610
www.veterinarypracticenews.com/web-exclusives/emerging-threat-of-canine-influenza.aspx
http://www.avma.org/public_health/influenza/canine_bgnd.asp


Leptospirosis

Leptospirosis is a bacterial infection resulting from contact with infected wildlife, urine from infected dogs or contaminated water or food. Twenty and thirty years ago, this was primarily a rural disease and often associated with cattle. Unfortunately, the two strains (or serovars) that used to cause most of the Leptospirosis in pet dogs have been surpassed by two additional strains which are now causing the majority of disease in dogs. Furthermore, these two new strains (serovars) seem to be flourishing in suburban and urban environments and are increasing in prevalence nationwide. Pinellas, Pasco & Hillsborough counties have joined the ranks of Florida counties with confirmed cases of Leptospirosis in pet dogs. A vaccine to help protect against these four pathogenic strains is finally available from a reputable vaccine manufacturer (Pfizer). Two additional strains or serovars are currently being studied to determine if they are also contributing to the recent increases in cases of Leptospirosis in pet dogs.

Most dogs in populated areas become infected from drinking contaminated water or coming in contact with contaminated urine. This water (puddles, ponds, outdoor water bowls, creeks) may become contaminated by infected carriers such as raccoons, opossums, citrus rats and other rodents. The Leptospira bacteria can live in the water for months.

Leptospira bacteria infect the kidneys and liver, causing fever, anorexia, depression and generalized pain initially. Diagnosis is complicated by the fact that the early signs of Leptospirosis are vague and nonspecific. Most animals will progress to acute kidney failure and mortality rates in untreated, unvaccinated dogs may vary from 10% to 75%, depending on the serovar involved. Vaccination will not only help prevent the disease, but will also reduce the symptoms and prevent shedding of the bacteria should a breakthrough occur. Two vaccinations are given 3 weeks apart and then followed by an annual booster.

Leptospirosis is also contagious to humans (although uncommon) and this further adds to our concern with this reemerging disease. It is also a potentially life threatening disease in humans, again primarily by causing kidney damage. The mortality rate in humans with the kidney and liver form is about 10%. There currently is no vaccination for humans.

Given the current increase in prevalence of the emerging strains of Leptospira bacteria, we are recommending this vaccine for all our canine patients over the age of 10-11 weeks.

Links for Leptospirosis …….

Disease in Animals
Disease in Animals & Humans
Disease in Humans
More on Disease in Humans (CDC)