Mosquitoes pose threat to pets

WOODSTOCK – The McHenry County Animal Control and Adoption Center reports that three dogs, brought to the shelter as strays from Algonquin, Crystal Lake and Woodstock, have tested positive in recent weeks for heartworm.

These cases are more than all the previous months of 2013 combined. It is believed these animals were infected at least six months ago or perhaps earlier, according to a news release from the McHenry County Department of Health.

Heartworm is the animal side of mosquito-borne illness.

Heartworm disease cannot pass directly from dog to dog but is transmitted by mosquitoes, of which the area has seen a dramatic increase after a wet spring and summer.

An annual blood test for heartworm disease is recommended for dogs. Untreated dogs become a source of infection for other dogs as mosquitoes carry the disease from one dog to another.

Heartworms live inside the circulatory system, not the intestine. It can take six months from the time an infection occurs before the test is positive. Veterinarians encourage medication that can be administered once a month to prevent heartworm; many veterinarians advise using it year-round.  

Failure to treat dogs with heartworm can lead to death from congestive heart failure.  Prescription oral, topical and injectable products are available.

For information about preventing heartworm, visit or view a short video from the American Veterinary Medical Association at