From Pet Health Learning Center
A parasitic roundworm (whose scientific name is Dirofilaria immitis) that is spread via mosquitoes, heartworm can affect dogs, cats, wolves, coyotes, foxes, and even humans. Heartworm is a filarial which looks something like a thread which in its final reproductive stage lives in the heart of its host. Heartworm, left untreated, can be very serious as it can result in congestive heart failure and likely death. Heartworm can live in the heart for several years and treatment can be exhausting and very uncomfortable. Prevention is the best approach to heartworm and there are a number of monthly treatments that you can give your pet to circumvent any problems.
Symptoms and Diagnosis
Before heartworms reach maturation they go through a 6 month prepatent stage wherein symptoms in your pet will begin to be noticed. Sometimes, heartworm larvae find their way into other organs such as the eye or brain or even arteries in the limbs which can result in rare symptoms such as blindness and seizures. Once the heartworms have reached maturation there are few signs of the disease as most animals will show no symptoms. Aging seems to be slightly accelerated in animals with heartworm but other than this, symptoms are very subtle. Damage to the lungs, kidneys, and liver are not uncommon however meaning the results of a heartworm infection are very serious.
Early symptoms of the disease are noticeable however and you should be vigilant if you notice any of theses symptoms. Some of these symptoms include a cough, especially when you are exercising your pet. Also, you will notice your pet will have less energy than normal and will grow tired more from exercise than normal. In advanced cases of heartworm infection your pet may start to rapidly lose weight, cough up blood, faint, or develop congestive heart failure.
Diagnosing heartworm usually involves a simple blood test. These blood tests are focused on identifying female heartworm antigens but diagnosis is not 100%. False negatives are possible especially if there is a low worm count, immature infections, or if they are male infections.
Heartworm really needs to be diagnosed early in order for treatment to be most effective. Your pet must have a healthy heart, liver, and kidney in order to undergo the treatment so in advanced cases of heartworm this may be a problem. Any sickness in these organs is treated first in order that your pet is healthy to undergo heartworm treatment.
To start, mature heartworms are killed with an arsenic-based substance, usually melasomine dihydrochloride as it has been found to be more effective with less side effects than other prescriptions. After treatment with one of these arsenic-based substances, your veterinarian will recommend several weeks rest for your pet. In order to give your petâ€™s body enough time to absorb and excrete the dead worms without side effects your pet must conserve as much energy as possible. If your animal is too active, dead heartworms can travel to the respiratory system and cause failure and possible death. Treatment usually requires several weeks since after mature heartworms are killed the immature forms have to be killed via a different type of treatment. Sometimes, surgical removal of the heartworms is necessary.