Summertime in Arkansas and the mosquitoes are buzzing. They're buzzing and biting -- people and pets. With that in mind, it seems an opportune time to revisit the mosquito-transmitted disease that can create serious health problems for our pets.
Heartworm disease is caused by parasitic worms that are spread through mosquito bites. The American Heartworm Society says the foot-long worms live in the heart and lungs as well as some blood vessels. If an infected pet isn't treated, the disease can damage the lungs, heart and arteries. Heartworm disease also can be fatal.
Dogs are more likely to be hosts for heartworms than are cats. The society describes dogs as "natural hosts," which means the worms mature and breed inside their bodies. When cats are infected with heartworms, the worms seldom survive to be adults, which is why heartworm disease is hard to diagnose in cats. An infected cat can have adult heartworms, but usually only two or three. When heartworms are untreated in a dog, they can multiply into the hundreds.
Here are some pertinent heartworm facts provided by the American Heartworm Society and the American Mosquito Control Association.
TRANSMISSION
When a mosquito bites an infected animal, it picks up microfilaria, or baby heartworms, that then grow into "infective state" larvae within 10 to 14 days. When the carrier mosquito bites a dog or cat (and some wild animals), it deposits the larvae, which then enter the bloodstream. Within six months, the larvae mature into adult heartworms. The adults breed, creating more microfilaria that are picked up by the next mosquito that stops for a bite -- thus beginning the cycle again.
PREVENTION
Heartworm preventive medications attack heartworms at the larval stage. Unfortunately, preventives don't kill adult heartworms so it's important the preventives be given on a strict schedule. Medications are available in pill, topical and injection form, so talk to your veterinarian about which is best for your pet. Topical and pill forms are given every month while injections are administered every six months.
Another preventive measure involves reducing a pet's exposure to mosquitoes. To do this, the American Mosquito Control Association recommends making your yard unappealing to mosquitoes to keep them from hanging around and breeding.
Because mosquitoes are drawn to murky water, the association suggests keeping the yard free of water-filled containers such as birdbaths, wading pools, old tires and swimming pool covers. If you have a birdbath or wading pool, you can prevent it from becoming a haven for mosquitoes by emptying, cleaning and refilling it daily.
Along with water, the biting insects also like cool, dark places so be sure to clear away ivy and decaying leaves.
Mosquitoes typically feed at dawn, dusk and during the night, so it helps to keep pets indoors at night.
Because people associate mosquitoes with warm weather, it may seem reasonable to conclude that heartworm prevention is seasonal and pets don't need preventives in the winter. Don't bet on it, the heartworm society says. It's hard to guess exactly when mosquitoes will be buzzing about, which is why veterinarians advocate year-round heartworm prevention.
TREATMENT
The society points out that prevention is much easier on a pet than the treatment for the disease. Heartworm treatment isn't as simple as taking a pill to clean up an infection. Treatment takes weeks, during which the animal receives a series of injections to kill the adult worms.
As the drugs kill the worms, fragments of worms move through the blood vessels. These fragments can block vessels to the lungs. Since physical activity increases blood flow, there's the danger of the dead worms blocking the lungs, which can lead to death. For that reason, dogs must be kept calm and still while undergoing treatment. They won't be allowed to exercise or play. Even leaping on and off the sofa can be too much exertion.
There is no drug treatment available for infected cats, but a cat with a healthy immune system may spontaneously clear itself of the worms. Nevertheless, heartworms can cause long-term damage to a cat's lungs. As with dogs, prevention is key and preventive medication is available.
For more information about heartworm disease, check out heartwormsociety.org.
Family on 06/22/2016