If your cat lives in an area where there are mosquitoes all throughout the year, then you should be concerned with heartworm infection. Mosquitoes are carriers of this disease and can easily enter your house and infect your beloved pet. While cats are not the preferred hosts of heartworms as dogs are, but can also become infected through mosquito bites.
Adult heartworms lay very tiny larvae called microfiliariae, which can enter a mosquito when it sucks blood from an infected animal. Microfilariae usually develop into larger larvae and migrate to the mosquito´s mouth. When the mosquito bites another animal, the larvae then enter the animal´s skin. The larvae grow and finish their migration to the heart, where they grow into adults. These larvae can live in the mosquito for 2–3 weeks, about one month in a cat´s blood stream, and three years in dogs.
Infected cats usually sustain 1–4 adults heartworms, where as dogs can have hundreds. Estimated life cycle of these organisms (meaning, from the time from when an animal gets bitten until adult heartworms develop, mate, and lay microfiliariae) is about 8 months in cats as compared to 6–7 months in dogs.
If you are considering implementing a seasonal preventive measure, remember that this will only kill larvae your pet was exposed to in the last 30 days. For instance, a monthly preventive given on June 1 will only kill larvae that your cat has acquired from May 1 to June1. This preventive measure does not give protection to your cat against other larvae that can infect your pet in the next 30 days.
Unlike dogs, cats often present varying symptoms of heartworm infection, making them very difficult to diagnose. During physical exam, a heartworm–positive cat can present itself as healthy, or with subtle signs such as increased lungs sounds or abnormal heart sounds. However, signs of chronic infection in cats may include vomiting, rapid breathing, coughing, decreased appetite, loss of weight, and listlessness. Blindness, and seizures and in some cases, acute death can also occur.
Since the symptoms of heartworm disease in cats can be similar to many other diseases, often your pet´s health care provider may recommend radiographs, blood chemistries, blood counts, urinalysis, ultrasound, as well as specific tests that can detect circulating heartworm antibodies or antigens.
While there exist a variety of medications to cure heartworm disease in cats, prevention is absolutely the best treatment. Monthly preventives are available in oral or topical form. Some products also contain mechanisms for flea control and intestinal parasite control of hookworms and roundworms, and will also treat ear mites. To avail of these treatments for your cat, you will need a prescription from your veterinarian.
Sharon E. Anderson, DVM, answers medically–related questions, but will not attempt to diagnose or recommend specific treatments. Her advice is not meant to replace professional care. If your pet is ill, contact your veterinarian immediately.
