Feline heartworm _ capc vet

• Testing cats for heartworm with antigen or antibody test prior to starting them on preventive.

• Protecting all cats from heartworm infection by using preventives year round.

• Maintaining infected cats on preventives to protect them from acquiring additional heartworms, and closely monitoring their health status, providing symptomatic care as needed.


Microfilariae (300 to 322 µm by 6.8 to 7.0 µm) are ingested by female mosquitoes when they feed on infected canids. Reduce heart disease (Felids are seldom microfilaremic; consequently, they are less likely sources of microfilariae for mosquitoes). Rheumatic heart disease prophylaxis After development through two molts (approximately 2 weeks), infective L3 larvae are present in mosquito mouth parts. Icd 9 hypertensive heart disease Development may require a longer period at cooler temperatures.

Third-stage larvae (L3) are 1,000 µm by 40 µm. Rheumatic heart disease medscape They are deposited by mosquitoes on the skin surface during subsequent feeding(s) and then enter the new host via the mosquito bite wound. Coronary heart disease wiki Most L3 larvae molt to fourth-stage larvae (L4) within 1 to 3 days in the subcutaneous, adipose, and muscle tissues.

The final molt to the juvenile worm occurs approximately 2 months (50 to 70 days) after infection.

Juvenile worms (1 to 3 cm in length) enter the vascular system and are carried to the heart and pulmonary arteries; they arrive as early as 70 days after infection. Congenital heart disease diagnosis Most feline infections are aborted at this time, resulting in inflammation in the pulmonary vessels, pulmonary parenchyma, and airways. Signs of heart disease in dogs In a small percentage of infections, further development to mature adult worms and mating may occur. Pulmonary heart disease Because of the typically small worm burdens in cats (often one to three worms), single-sex infections (i.e., male or female only) are common.

Maturation to adult worms occurs at about 6 months; development and release of microfilariae occurs about 7 or 8 months after initial infection.

As noted previously, microfilaremia is infrequent (typically less than 20% of naturally infected cats) and short-lived; the number of circulating microfilariae typically is low. Heart disease in america Microfilariae are seen in small numbers in experimentally infected cats and persist no more than a few weeks to months.

Mature heartworms in cats are smaller than those in dogs; 12-month-old female worms in cats average 21 cm in length, compare with longer than 26 cm in dogs.

Adult heartworms are believed to live for 2 to 4 years in cats.

Heartworm disease in the cat may involve some or all of the following:

Pulmonary arterial, bronchial, and alveolar disease—Heartworm Associated Respiratory Disease (HARD)—is associated with the death of developing juvenile worms. What is congestive heart disease Cats may present with cough, dyspnea, and/or wheezing.

Death of adult heartworms (if present) can potentiate HARD signs. Is cardiovascular disease the same as heart disease Sudden death occurs in approximately 10 to 20% of diagnosed cases. Signs of congenital heart disease Pathogenesis is unclear, but a condition (similar to acute respiratory distress syndrome [ARDS]) caused by the release of antigenic moieties from injured or dying adult worms is suspected.

Pulmonary thromboemboli (fragments from dead adult worms) may cause acute vascular and interstitial inflammatory events that lead to dyspnea and death.

Hematological abnormalities may include anemia, hyperglobulinemia, basophilia, and eosinophilia.

Neurological signs may indicate aberrant migration of the worm to the brain, eye, or spinal cord.

• Geographic prevalence of feline heartworm infection (adult worms) generally follows canine infections, but infection occurs at approximately 10% of the prevalence rate for dogs (see map below for canine prevalence). Feline heart disease Cats are infected with juvenile worms at a much higher rate than with adult worms; estimates based on necropsy and antibody studies suggest that cats are infected with juvenile worms at an infection rate similar to that of dogs. All about heart disease The greatest number of cases is seen in the southeastern U.S., the Mississippi River Valley, and Texas.

Necropsy-based data (percentage infected) for cats with adult heartworms in shelters is shown in the figure below.

A study involving more than 2,000 largely asymptomatic cats was conducted in 19 states comprising 21geographic regions (see figure below). Heart disease deaths For pet cats (excepting North Carolina, which surveyed shelter animals), the nationwide exposure rates (i.e., percentage of cats that were antibody-positive) were approximately 12%. Wikipedia heart disease Many of these cats were from areas not highly endemic for heartworm infection. Heart disease exercise Results do not confirm mature heartworm infection but imply infection with immature worms and increased risk of HARD.

A second study of 25,000 cats tested nationwide reported a 15.9% antibody positive rate.

More than 70 species of mosquito are capable of transmitting D. Coronary heart disease bitesize immitis. Coronary heart disease facts However, only about 22 species are common and important vectors.

Differences in biological behavior and host preferences by mosquitoes can affect the epidemiology of heartworms in a particular location.

Transmission can occur anytime infected mosquitoes are active and feeding.

Although L3 larvae taken from mosquitoes that had fed on experimentally infected cats were capable of infecting puppies, the infrequency, low numbers, and transient nature of microfilaremia in cats support that in many cases, cats are a dead-end host for D. Causes of heart disease immitis.

In dogs, adult heartworms reside largely in the pulmonary arteries. Congenital heart disease guidelines However, if numerous worms are present, worms may be found in the right ventricle and pulmonary trunk. Severe heart disease In cats, the relative size of the adult heartworm is such that it is much more likely that a portion of the worm can be observed in the right side of the heart.

Migration of immature heartworms to other anatomic sites can occur in cats, sometimes resulting in death.

Pulmonary intravascular macrophages—the primary component of the cat’s reticuloendothelial system—have been implicated in the unique pulmonary pathology found in cats.

Because of potentially lower worm burden, single-sex infections, and infrequency of microfilaremia, heartworm infection is more difficult to diagnose in cats than in dogs.

Fewer than 20% of cats with mature heartworm infection are microfilaremic. Ischemic heart disease ecg Because of the frequent absence of microfilariae, microfilarial testing (e.g., direct smear, microhematocrit tube, modified Knott test, millipore filter test) is less useful in the cat than in the dog. Chelation therapy for heart disease Nevertheless, a positive microfilariae test confirms active adult heartworm infection in the cat.

Eosinophilia (and possibly basophilia), although nonspecific, can support a diagnosis of heartworm infection. Ischemic heart disease wiki Eosinophilia, often transient, is most frequently observed 4 to 7 months after infection.

Antibody tests (available as both send-off and point-of-care tests) do not require the presence of circulating antigen produced by mature female worms for a positive test result. What is the definition of heart disease Different antibody tests may detect migrating larvae of different ages. Hypertensive heart disease definition If an exposed cat eliminates the infection at the juvenile worm stage, HARD may still result.

Antibody testing may not be effective for diagnosis of feline heartworm disease. Rheumatic heart disease pregnancy Approximately 15 to 25% of cats with adult infection are antibody-negative. Ischemic heart disease pdf Conversely, 80 to 90% of antibody-positive cats do not harbor mature heartworms.

Depending on the preventive product used, up to 30% of cats on preventives that are exposed to heartworms will convert to an antibody-positive state without mature infection or heartworm-related disease.

In a limited number of experimental studies, 50% of experimentally infected cats with confirmed pulmonary pathologic lesions (HARD) seroconverted to a negative antibody status within 8 months after infection. Heart disease heart attack Within 16 months after infection, 100% of experimentally infected cats (HARD) were negative for detectable antibodies. Stress heart disease However, after initial infection and induction of HARD lesions, these cats were restricted from further potential exposure to heartworm-infected mosquitoes.

Positive antibody tests may or may not support heartworms as a cause of respiratory signs or lesions. Heart disease statistics Additionally, a negative antibody test does not rule out current or previous infection.

Antigen testing is available as both send-off and point-of-care tests.

Only mature female worm infections (typically 7 to 8 months post-infection) are detected. Statistics of heart disease Rarely, in experimental infections, female heartworms may be detected as early as 6 months after infection. Heart disease pictures A positive antigen test indicates that the cat harbors mature female heartworms or that mature female heartworms were present but died recently.

One third of adult heartworm infections in cats consist only of male worms and will not be detected using available antigen tests.

Studies of naturally infected cats examined at necropsy have shown that some antigen tests are capable of detecting a single mature female heartworm.

A negative antigen test does not conclusively rule out adult heartworm infection nor will it detect juvenile worms often responsible for pulmonary disease (HARD).

Serum samples from cats may be false negative on antigen tests, particularly early in infection, presumably due to formation of antigen-antibody complexes. Most common heart disease Heat treatment of these samples prior to testing has been shown to destroy the complexes, allowing detection of antigen.

Although helpful when a diagnosis of heartworm is suspected but the initial antigen test is negative, routine heat treatment of all samples prior to testing is not recommended. Why is heart disease the leading cause of death Heat treatment of serum will destroy antibody, rendering results of subsequent feline antibody tests invalid.

The most common radiographic findings in feline heartworm disease are enlargement of the right caudal lobar artery and a bronchointerstitial inflammatory pattern in the caudal lung lobes.

Photo courtesy of Dr Clarke Atkins, North Carolina State University

Ultrasound in the hands of a skilled ultrasonographer may detect 68% of naturally infected cats. Congenital heart disease pregnancy However, the caudal pulmonary arteries must be examined to their point of bifurcation within the lung fields.

At present, removal of adult worms from cats using melarsomine dihydrochloride is not recommended.

Early data indicate that concurrent ivermectin and doxycycline therapy for Wolbachia reduces inflammation associated with worm death in dogs. Heart disease warning signs It is not yet known whether this same result can be achieved in cats.

Surgical removal of heartworms via the jugular vein can be performed. Definition for heart disease However, deaths have been reported during the use of this procedure. Ischemic heart disease icd 10 In addition, jugular venotomy is expensive and requires the use of a fluoroscope for anatomic guidance.

At present, no specific therapy is recommended for asymptomatic cats with confirmed heartworm infections. Heart disease in cats However, infected cats cats with symptomatic feline dirofilariasis should be treated with corticosteroids in decreasing dosages to minimize dyspnea, coughing, and wheezing caused by death of either juvenile (HARD) or adult worms. Heart failure disease Antileukotrienes also may be beneficial in reducing the risks associated with adult worm death. Type of heart disease Bronchodilators may be useful if there is radiographic evidence of air-trapping. Symptoms of heartworm disease in dogs Specific therapies should be used if vomiting and neurological signs are present.

Emergency treatment of symptomatic cats may include parenteral corticosteroid therapy, oxygen therapy via an oxygen cage or nasal insufflation, and furosemide in ARDS-like cases. Heart disease smoking If available, ventilator therapy may be utilized. Rheumatic heart disease murmur Xanthine bronchodilators (theophylline or aminophylline) may be used to dilate bronchioles and support the muscles of respiration.

The published life expectancy for cats with adult dirofilariasis is 1.5 years (median).

For cats surviving acute disease beyond day 1, the median survival is 4 years.

Current information suggests that more than 80% of cats diagnosed with heartworm infection survive the infection.

All cats, regardless of their lifestyle, should be on year-round heartworm prevention. Symtoms of heart disease Available preventives for cats include oral ivermectin, topical moxidectin/imidacloprid, and topical selamectin. Heart disease usa Topical moxidectin/imidacloprid is also approved for use in ferrets.

Although cats housed indoors have a lower risk for heartworm infection, studies have shown that 25 to 30% of heartworm-infected cats were characterized by their owners as “strictly” indoor cats. Ischemic heart disease myocardial infarction Furthermore, certain mosquitoes that typically are found indoors will feed on cats.

Available broad-spectrum feline heartworm preventives are also label-approved for other important feline internal or external parasites.

Advantage Multi® Topical Solution for Cats (imidacloprid/moxidectin) (Bayer Animal Health)*

Interceptor® Flavor Tabs® for Dogs & Cats (milbemycin oxime)(Elanco)

*Note: this product additionally has a label claim for prevention of heartworm disease in ferrets

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Lee AC, Aktkins CE. Sign of heart disease 2010 Understanding feline heartworm infection: disease, diagnosis, and treatment. Coronary heart disease vs cardiovascular disease Top Companion Anim Med Nov 25 (4):224-230

Little SE, Raymond MR, Thomas JE, et al. Coronary heart disease and obesity 2014. Heart cardiovascular disease Heat treatment prior to testing allows detection of antigen of Dirofilaria immitis in feline serum. Rheumatic heart disease in adults Parasit Vectors Jan 13;7:1

Maia FC, McCall JW, Valdimero AS, Jr. Congenital heart disease radiology assistant et al. Coronary heart disease and stress 2011 Structural and ultrastructual changes in the lungs of Felis catus (Linnaeus, 1758) experimentally infected with D. Is heart disease the leading cause of death immitis (Leidy, 1856). Heart disease children Vet Parasitol. Heart disease cardiovascular disease 176(4):304-12

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