Pets We Live With: Mosquitoes

Summertime is such an enjoyable time on our island paradise, but it is also a time when we are besieged by our infamous trilogy of pests: mosquitoes, ticks and fleas. Not only are these pests annoying and unpleasant, they present very real health hazards both for us and for our pets.

Mosquitoes are certainly annoying when it comes to enjoying time out-of-doors, and their bites are uncomfortable to var ying degrees, but some can transmit serious diseases such as malaria, Eastern Equine Encephalitis, West Nile virus and the potentially fatal heartworm disease in dogs, cats, ferrets and certain wild animals.

The heavy rains we have been experiencing lately are expected to yield a large crop of mosquitoes this week because the downpours saturated freshwater wetlands that had dried out in the summer heat.

Mosquitoes lay their eggs on the surface of standing water, where they usually hatch within two to three days in optimum conditions, although the eggs can remain dormant for weeks until conditions are right. The larvae feed on organic matter in the water, hatching into pupae in about a week, becoming adults in another two or three days. Only the female bites, consuming more than her weight in blood every three to four days.

Heartworms are transmitted from animal to animal by mosquitoes. The heartworm parasite lives in the right side of an animal's heart. The female worm produces large numbers of microscopic, immature heartworms called microfilariae that circulate in the blood. If a mosquito bites an infected animal, the microfilariae are sucked up with the blood. After incubating in the mosquito 10 to 14 days, the infected microfilariae are deposited into a new host's blood stream by a mosquito bite. They travel to the heart, where they develop into adult heartworms, producing new microfilariae within three months. In 90 days, a dog bitten by an infected mosquito becomes a new source for spreading the disease.

"Our recommendations for heartworm prevention have changed," said Dr. Paula Klek, Director of Nantucket MSPCAAngell. "We now suggest year-round treatment for heartworm for dogs and we are also stressing the importance of heartworm prevention in cats. No longer is this a seasonal or single species issue."

Studies throughout the country show an increased presence of the deadly heartworm disease in pets in every state except Alaska. Shifting weather patterns can also cause burgeoning mosquito populations."

"Heartworm is such a preventable disease," Dr. Klek emphasized. "There is no need for a pet owner to put their pet at risk. Fortunately, to date, on Nantucket we have had a very low rate of adult heartworm cases. But just because we live on an island and our pets might not go anywhere else doesn't mean we can escape exposure. We have a highly transient pet population that has potential for infecting our mosquitoes at any time."

Dr. Klek explained how to get started.

"We encourage an active client/pet relationship, so if you haven't been in during the last year, we will want to see your pet before embarking on any prescription therapy. Your dog needs to be tested before beginning any heartworm preventive," he said.

Blood is drawn and tested in-house, with results usually available the same day. If there is no presence of heartworm detected, then your pet can begin a course of oral medication, usually given once a month, which kill heartworm larvae before they have a chance to grow and mature. There are a number of orally-administered preventive products available.

Cat preventive therapy is relatively new. Detecting heartworm in cats can be problematic and there is no approved treatment for the disease in cats. Detection may be difficult, but prevention is convenient, safe and reliable with oral or topical products. Even if they are indoor cats, mosquitoes can get into the house. Fifty-five percent of cats testing positive for heartworm infection were considered "strictly or mostly indoors."

To minimize your problems from mosquitoes, note the following. If your pet is not on a year-round or seasonal heartworm prevention program, make it a goal to get in for testing soon. Around the house, empty water from buckets, tin cans, barrels and plant saucers, and clean clogged gutters. Store boats covered or upside down and fill in any depressions or holes that hold water. Clean out lawn debris and keep weeds and tall grass cut short. Inspect window and door screens for rips and snug fit. Change water in birdbaths, plant pots and wading pools once a week.

If you are going to be out-of-doors at dusk or later, the peak biting hours for many mosquitoes, apply a good repellent and for extra protection, wear long sleeves, long pants and socks. Pet-friendly repellants will reduce the exposure for your pet.

Jan Jaeger is owner of Geronimo's, Ltd., Nantucket's pet supply and gift shop. Send e-mail to jan@geronimos.com .