Heartworm in dogs is a terrible condition that causes severe lung disease, heart failure, organ damage, and death in dogs. Dirofilaria immitis is a parasitic worm that causes it. Mosquito bites transmit the worms.
The dog is the sole host, meaning the worms mature into adults, mate, and reproduce while living inside a dog.
The mosquito serves as an intermediate host, which means that the worms spend a brief period inside the mosquito before becoming infective (able to cause heartworm disease). The worms are known as “heartworms” because the adults dwell in an infected animal’s heart, lungs, and blood vessels.
How Dogs Contract Heartworm Diseases
As we’ve highlighted earlier, Dirofilaria immitis, a parasitic worm, causes heartworm illness. Because it is not contagious, a dog cannot contract the disease simply by being around an affected dog. It can, however, be transmitted by a single bite from an infected mosquito.
The heartworm life cycle begins with a mosquito bite. Then, tiny larvae (called microfilariae) start to move from the tissue to the bloodstream, eventually reaching the chambers of the heart or lungs, where they mature into adult heartworms.
Heartworms in dogs can grow 4 to 12 inches long and, if left untreated, can cause permanent damage to a dog’s heart, lungs, and arteries.
Heartworm Symptoms in Dogs
Many dogs will exhibit little or no symptoms of heartworm illness in the early stages, but as the infection persists and the disease advances, more severe symptoms are likely to emerge.
Subtle symptoms may include a minor cough, decreased activity, and a loss of appetite or weight. More severe symptoms may develop over time, including heart failure, muscle wasting, anemia, scar tissue in the lungs, and fluid accumulation in the lungs and abdomen.
How Heartworm Diseases Spread
The disease is not transmitted directly from dog to dog because transmission requires the mosquito as an intermediate host.
The disease’s spread thus correlates with mosquito season, which can extend all year in many parts of the United States. The number of affected canines and the length of the mosquito season are closely connected to the prevalence of heartworm disease in any given area.
Because heartworm larvae are spread by mosquitos, reducing mosquito exposure is a brilliant place to start. You can limit your dog’s outdoor time between dawn and dark when mosquitoes are most active.
In addition, reducing areas of standing water can assist, as this is where mosquitoes grow. Finally, while environmental management is crucial, you must collaborate with your veterinarian to develop a proactive medical preventative plan to protect your dog.
For dogs, the American Heartworm Society recommends annual heartworm testing. If the test results a negative result, your veterinarian will walk you through various preventive methods only available with a prescription.
Monthly chewable pills, topical solutions, and an injectable medicine administered every 6 or 12 months are examples of preventives. Many heartworm preventives are primarily effective against heartworms, but others can also protect pets against worms, fleas, ticks, and mites. Veterinarians are usually aware of which parasites are prevalent in your area and may advise you on the best preventative measures for your dog.
Heartworm treatment for dogs
Many dogs are already infected with heartworms when they are diagnosed. This indicates that the heartworms have been present long enough to cause significant harm to the heart, lungs, blood vessels, kidneys, and liver.
Dogs in this condition will likely die within a few weeks or months. Your veterinarian will advise you on the best course of therapy for dogs with advanced heartworm disease.
Adult heartworms are killed with this treatment. Melarsomine (brand name Immiticide®) is an injectable medication used to kill adult heartworms.
Melarsomine destroys adult heartworms in the heart and its surrounding arteries. This medication is given in a series of injections. The injection regimen will be determined by your veterinarian based on your dog’s condition. Most dogs are given an initial shot, then a 30-day rest period, and then two further injections 24 hours apart.
Many dogs will also be given an antibiotic (doxycycline) to prevent infection with the bacteria (Wolbachia) in the heartworm.
After therapy, complete rest is required. Adult worms die within a few days and begin to disintegrate. They are taken to the lungs when they break up, lodge in the small blood vessels, and are subsequently reabsorbed by the body.
This resorption can take weeks to months, and these pieces of dead heartworms are responsible for most post-treatment problems.
This can be a difficult time, so the dog must be kept as quiet as possible and not permitted to exercise for one month after the final injection of heartworm treatment.
The first week following the injections is essential since the worms die during this time. However, many heavily infected dogs have a cough for seven to eight weeks after treatment. If your dog’s cough is severe, contact your veterinarian in Houston TX to discuss treatment options.