It’s heartworm and tick season again!
Is your dog protected?
Heartworm:
The scientific name of “heartworm” is Dirofilaria
immitis. Heartworm is endemic in Ontario, becoming more prevalent
the farther south you travel. The parasite is transmitted only
by mosquitoes. It takes at least 6 months from the time of exposure
before an active infection develops. The adult worms lodge themselves
in the heart and large pulmonary vessels.
Heartworm infection is a very serious disease. Infected dogs
will show signs of cardiac disease: coughing, exercise intolerance,
fatigue, panting, weight loss, decrease in appetite, and sometimes
sudden death.
Treatment does exist for heartworm positive dogs, but it is expensive
and does not come without significant side effects.
Because this disease can have devastating effects on your dog,
and can sometimes be fatal, we strongly recommend heartworm prevention
each summer.
Prevention starts with a blood test to ensure your dog is not
already carrying heartworm (the test also screens for exposure
to Lyme disease). As part of a heartworm surveillance program,
we recommend heartworm testing every other year.
There are many forms of heartworm preventative medications. The
“old standby” for heartworm prevention are chewable
tablets. However, we often recommend a topical liquid which also
help control many other parasites such as fleas, mange mites,
ear mites, intestinal worms, and ticks. These medications are
given once per month from June to November each year. If you travel
south during the winter months (e.g. to Florida) with your canine
friend, mosquitoes will be present so it is important to consider
heartworm prevention before heading on your trip.
Ticks:
Ticks are an ever-increasingly common type of arachnid external
parasite. They have a distinct body and eight legs, and their
favorite natural habitats include: edges of grassy fields, low-lying
underbrush, and urban areas, especially if deer are present.
We have many different canine tick-control products, which include
topical liquids and tick collars. Many tick control products can
be very dangerous, or even fatal to cats – so their use
around cats must be with the utmost level of caution.
Common species of ticks in our area:
a) The Groundhog Tick, Ixodes cookie - this species of tick will
attached and feed, but is not known to transmit disease
b) The American Dog Tick, Dermacentor variabilis – the preferred
host of the adult tick is the dog. This species of tick can transmit
Rocky Mountain spotted fever, and can cause “tick paralysis”.
c) The Deer Tick (aka The Blacklegged Tick), Ixodes scapularis
– adults prefer to feed on white-tailed deer, but all life-stages
of the tick will feed on dogs and humans. The Deer Tick is the
most important vector for the transmission of Lyme disease.
d) The Brown Dog Tick, Rhipicephalus sanguineus – is becoming
more and more common in Eastern Ontario. This species of tick
can live inside dwellings, or dog kennels.
There are two “blooms” in the tick population each
year, occurring in the early spring and late fall. During these
times, tick bites will be most common. Tick bites are usually
not painful, but cause irritation (reddening) of the skin, and
minor swelling. Even after the tick has been removed (or falls
off), swelling and/or redness in the area of the bite can last
for a few weeks.
Lyme disease is caused by the bacterium Borrelia burgdorferi.
In dogs, the first symptoms of Lyme disease may start 4-6 weeks
after a tick bite. They most commonly include: fever, fatigue,
lameness, or joint swelling. We recommend any dog showing these
signs be tested for Lyme disease.
Prevention of Lyme disease is multi-factorial. First, tick control
products will help repel or kill ticks before they attach, or
cause them to die and fall off shortly after attaching. Second,
daily “tick checks” done by the owner will help identify
and remove ticks. Third, a vaccine is available for canine Lyme
disease. We use a recombinant DNA, non-adjuvanted vaccine for
Lyme disease. The vaccine works by targeting an outer surface
protein which the Lyme bacteria uses to inject itself from the
tick into the dog.
An easy environmental control measure involves lining the perimeter
of your backyard with a border of cedar wood chips at least 8
inches wide – it is believed ticks won’t cross over
this “barrier”.
Please do not hesitate to contact us if you have any questions
about these diseases.
At Barriefield Animal Hospital preventative medicine is very important
to us, and we strive to help keep your dog healthy so you can
enjoy the summer!
Links:
http://www.heartwormsociety.org/article_21.html
- American Heartworm Society
http://www.uoguelph.ca/pdc/Factsheets/Other/Ticks.htm - University
of Guelph (tick info)
http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=1588
– more about Lyme disease
http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=615
– more about heartworm
