With the weather warming up rapidly -and as summer approaches, A LOT of vets are pushing Heartworm testing to protect your pets and in dogs - absolutely without fail we believe you should do it. However, here is a bit of information about Heartworms straight from the eeer... horses mouth. We invite you to read the facts about Heartworms in cats - who are at best "resistant" hosts. Also please not at the bottom of the article that there are only 4 (count 'em 4) products approved for use in cats to prevent Heartworms. 1 of them is a product called Revolution - which we use regularly here at Kender Siberian Cattery. The whole article may be found at the link below :
http://www.heartwormsociety.org/pet-owner-resources/feline-heartworm.html
Pet Owner Resources | Feline Heartworm
Feline Heartworm Disease
Feline Heartworm Disease
Heartworm infection takes place when a mosquito carrying infective, microscopic-size heartworm
larvae, bites into a cat for a blood meal. The
larvae then actively migrate into the new host and develop further as they travel through the subcutaneous tissue in the cat's body. At about 3-4 months, they usually settle into the arteries and blood vessels of the lungs, where they continue to develop to sexual mature male and female worms (
Dirofilaria immitis). The average time from when the microscopic parasites enter the host until the females develop into mature worms and produce offspring is approximately eight months and is referred to as the prepatent period. This is about one month longer than in dogs.
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.
Clinical Signs
The clinical signs of heartworm infection in cats can be very non-specific, and may mimic many other feline diseases. Diagnosis by clinical signs alone is nearly impossible, but a cat may exhibit
generic signs of illness, such as vomiting intermittently (food or foam, usually unrelated to eating),
lethargy,
anorexia (lack of appetite), weight loss, coughing,
asthma-like signs (intermittent difficulty in breathing, panting, open-mouthed breathing), gagging, difficulty breathing (
dyspnea) or rapid breathing (
tachypnea).
Signs associated the first stage of heartworm disease, when the heartworms enter a blood vessel and are carried to the
pulmonary arteries, are often misdiagnosed as
asthma or allergic bronchitis, when in fact they are actually due to a syndrome newly defined as
Heartworm
Associated
R espiratory
Disease (
HARD).
Some cats exhibit
acute clinical signs, with disease often related to the organs where the adult heartworms are thriving. Occasionally such infected cats die quickly without allowing sufficient time to make a diagnosis or offer appropriate treatment.
Clinical Signs Associated with Feline Heartworm Disease
Diagnosis
Heartworm infection in cats is harder to diagnose than it is in dogs and it is easy to overlook. Diagnostic tests have limitations, so negative test results do not necessarily rule out an infection.
Antigen tests, for example, only detect adult female or dying male worms. Immature or male-only worm infections are rarely detected.
The diagnostic plan for heartworm disease in cats can include, but is not limited to, a physical examination, radiography (X-ray),
echocardiography (
ultrasound readings of the heart), angiocardiography (X-ray of the heart with injected contrast fluid),
CBC (complete blood count), serologic testing (
antigen and
antibody study),
microfilaria testing, and
necropsy (after death).
Physical Examination
The results of a physical examination may appear to be perfectly normal in cats infected with heartworms. Harsh lung sounds are a frequent abnormal finding and may be present in cats without any respiratory signs. The presence of a
heart murmur or abnormal rhythm is uncommon. Only rarely, have there been reports of
ascites (fluid in the abdomen), exercise intolerance and signs of right-sided heart failure. In cats, the primary response to the presence of heartworms occurs in the lungs.......
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Preventives
It is generally recommended that all cats be tested for both
antigens and
antibodies (
serology) prior to administration of a heartworm preventive. There are four heartworm disease preventive products approved by the
FDA for use in cats, Heartgard
® for Cats (Ivermectin, orally) from Merial, Interceptor
® (Milbemycin oxime, orally) from Novartis, Revolution
® (Selemectin, topically) from Pfizer and Advantage Multi™ for Cats (Moxidectin / imidacloprid, topically) from Bayer. All of these products are considered effective in preventing the development of adult heartworms when administered properly on a monthly basis relative to the period of transmission.
