
Intestinal parasites such as hookworms and roundworms can be a troublesome concern, especially for very young animals. Most puppies/kittens are born with worms and dogs/cats remain susceptible to the harmful parasites throughout their lives. Worms live inside your pet, making the symptoms difficult to pinpoint, and are therefore detected through an intestinal parasite test. Internal parasites can not only harm your pet, but they can also be transferred to children and adults, making them sick as well.
Our hospital recommends a fecal evaluation examination on all new puppies and kittens even if diarrhea or worms were not observed. If your pet does have a parasite problem, our veterinarians can provide you with different medications and treatments to remedy the problem and steer your pet back to good health. Preventive care and prescription heartworm medication are key, because of the damages presented by intestinal parasites to both pets and people, all dogs and cats. Our primary focus is to provide your pet with the safest and most effective ongoing preventive care.
We first recommend that we test your pet to see if they are infected with heartworms. If they are negative we highly recommend keeping them on preventatives monthly, if they are positive your vet can discuss a treatment plan with you. Treating positive patients is very costly and risky- this is why we recommend that we try to prevent heartworms in the first place.
Please call to set up an appointment to have your cat tested or talk to a doctor with any questions.
Read more about what the Heartworm Society has to say about Heartworm Disease (Click on the titles below to expand).
As adults, the heartworms can mate and the females can release offspring called microfilariae (pronounced: micro-fil-ar-ee-a) into the blood stream. The cycle begins again when a mosquito takes a blood meal from the newly infected cat and draws the microfilariae into its system.
Cats are resistant hosts of heartworms, and microfilaremia, (the presence of heartworm offspring in the blood of the host animal), is uncommon (usually less than 20% of cases). When present, microfilaremia is inconsistent and short-lived. Some cats appear to be able to rid themselves of the infection spontaneously. It is assumed that such cats may have developed a strong immune response to the heartworms, which causes the death of the parasites. These heartworms may die as a result of an inability to thrive within a given cat's body.
Cats typically have fewer and smaller worms than dogs and the life span of worms is shorter, approximately two to three years, compared to five to seven years in dogs. In experimental infections of heartworm larvae in cats, the percentage of worms developing into the adult stage is low (0% to 25%) compared to dogs (40% to 90%).
However, heartworms do not need to develop into adults to cause significant pulmonary damage in cats, and consequences can still be very serious when cats are infected by mosquitoes carrying heartworm larvae. Newly arriving worms and the subsequent death of most of these same worms can result in acute pulmonary inflammation response and lung injury. This initial phase is often misdiagnosed as asthma or allergic bronchitis but in actuality is part of a syndrome now known as Heartworm Associated Respiratory Disease (HARD). Which Cats Are Susceptible?
Although outdoor cats are at greater risk of being infected, a relatively high percentage of cats considered by their owners to be totally indoor pets also become infected. Overall, the distribution of feline heartworm infection in the United States seems to parallel that of dogs but with lower total numbers. There is no predictable age in cats for becoming infected with heartworms. Cases have been reported in cats from nine months to 17 years of age, the average being four years at diagnosis or death.
Dogs are considered the definitive host for heartworms ( Dirofilaria immitis). However, heartworms may infect more than 30 species of animals (e.g., coyotes, foxes, wolves and other wild canids, domestic cats and wild felids, ferrets, sea lions, etc.) and humans as well. When a mosquito carrying infective heartworm larvae bites a dog and transmits the infection, the larvae grow, develop and migrate in the body over a period of several months to become sexually mature male and female worms. These reside in the heart, lungs and associated blood vessels. As mature adults, the worms mate and the females release their offspring (microfilariae), pronounced: (micro-fil-ar-ee-a), into the blood stream.
Offspring can be detected in the blood (pre-patent period) about six to seven months after the infective larvae from the mosquito enter the dog. The male heartworms (four to six inches in length) and the females (10-12 inches) become fully grown about one year after infection, and their life span in dogs appears to average up to five to seven years.
In experimentally induced infections of heartworms in dogs, the percentage of infective larvae developing to adults is high (40% to 90%). However, the percentage of experimentally infected dogs from which adult worms are recovered is virtually 100%. The number of worms infecting a dog can be very high, with the number of worms in dogs ranging from one to approximately 250.
Microfilaremia, the presence of heartworm offspring in the blood of infected dogs, is relatively common. However, not all heartworm infections result in such offspring circulating in the blood. These are known as occult heartworm infections and may be the result of a number of factors such as single sex heartworm infections, host immune responses affecting the presence of circulating offspring (microfilariae) and most significantly, the administration of heartworm preventives.
The onset and severity of disease in the dog is mainly a reflection of the number of adult heartworms present, the age of the infection and the level of activity of the dog. Dogs with higher numbers of worms are generally found to have more severe heart and lung disease changes. Until the number of mature heartworms exceeds 50 in a 25-kg dog (approximately 55 pounds), nearly all of the heartworms reside in the lower caudal pulmonary arteries (the arteries of the lower lung lobes). Higher numbers of heartworms result in their presence in the right chambers of the heart. In such infections, the most common early pathological changes caused by heartworms are due to inflammatory processes that occur in and around the arteries of the lower portion of the lungs in response to the presence of heartworms. Later, the heart may enlarge and become weakened due to an increased workload and congestive heart failure may occur. A very active dog (e.g., working dog) is more likely to develop severe disease with a relatively small number of heartworms than an inactive one (e.g., a lap dog or couch potato). Occasionally, a dog with a large number of heartworms may not only have worms in the heart, but also in the caudal vena cava (large primary vein of the lower body) between the liver and the heart. If the heartworms are not removed surgically, this syndrome causes sudden collapse and death within two to three days.
Canine heartworm infection is widely distributed throughout the United States. Heartworm infection has been found in dogs native to all 50 states. All dogs, regardless of their age, sex, or habitat, are susceptible to heartworm infection. The highest infection rates (up to 45%) in dogs (not maintained on heartworm preventive) are observed within 150 miles of the Atlantic and Gulf coasts from the Gulf of Mexico to New Jersey and along the Mississippi River and its major tributaries. Other areas of the United States may have lower incidence rates (5% or less) of canine heartworm disease, while some regions have environmental, mosquito population and dog population factors that allow a higher local incidence of heartworm infection. Regions where heartworm disease is common have diagnosed infections in dogs as young as one year of age, with most areas diagnosing infections primarily between the ages of three and eight years. Although there are differences in frequency of infection for various groups of dogs, all dogs in all regions should be considered at risk, placed on prevention programs and frequently examined by a veterinarian.
Clinical Signs
Heartworm disease may cause a combination of medical problems in the same dog including dysfunction of the lungs, heart, liver and kidneys. The disease may have an acute onset but usually begins with barely detectable signs resulting from a chronic infection and a combination of physiologic changes. Dogs with a low number of adult worms in the body that are not exercised strenuously may never have apparent signs of heartworm disease. However, in most dogs, the heart and lungs are the major organs affected by heartworms with varying degrees of clinical signs.