Heartworms are Transmitted
The most common
method of heartworm transmission is the mosquito.
An infected dog carries thousands of microscopic larvae in its bloodstream.
When a mosquito bites an infected dog, it swallows these tiny worms
and passes the infective larvae along to the next dog it bites.
When an infected mosquito bites another dog, it deposits the larvae
via its saliva into the wound site. Three to four days after the
second dog has been infected, the larvae begin their journey under
the dog's skin. There are two more molting periods within the dog.
The first lasts four to 10 days, the second 50 to 70 days.
As a result, any dog that is exposed to mosquitoes may be at risk,
even if you don't live in a designated heartworm area. The strain
of mosquitoes can vary from area to area, and the rate of transmission
is directly proportional to the number of mosquitoes in the area.
female heartworms release thousands of microfilariae (tiny larvae)
into the bloodstream of an infected dog. When the dog is bitten
by a mosquito, the mosquito swallows these microfilariae. Within
the mosquito, the microfilariae molt twice and grow to their infective
after the final molt, the worms reach sexual maturity, mate, release
microfilariae, and complete their life cycle. Millions of microfilariae
can be present in the blood of an infected dog.
It is very important
to be sure that your dog is tested for possible heartworm infection
before starting a prevention routine. Have your dog tested annually
for heartworms and talk to your veterinarian about the appropriate