Heartworms Flashcards
How are heartworms transmitted?
When a mosquito bites and takes a blood meal from an infected animal, it picks up these baby worms, which develop and mature into “infective stage” larvae over a period of 10 to 14 days. Then, when the infected mosquito bites another dog, cat, or susceptible wild animal, the infective larvae are deposited onto the surface of the animal’s skin and enter the new host through the mosquito’s bite wound. Once inside a new host, it takes approximately 6 months for the larvae to mature into adult heartworms. Once mature, heartworms can live for 5 to 7 years in dogs and up to 2 or 3 years in cats. Because of the longevity of these worms, each mosquito season can lead to an increasing number of worms in an infected pet.
What happens to heartworms in cat?
The cat is an atypical host for heartworms, and most worms in cats do not survive to the adult stage. Cats with adult heartworms typically have just one to three worms, and many cats affected by heartworms have no adult worms. While this means heartworm disease often goes undiagnosed in cats, it’s important to understand that even immature worms cause real damage in the form of a condition known as heartworm associated respiratory disease (HARD).
What is the treatment for heartworms in cats?
Medication used to treat heartworm infections in dogs cannot be used in cats, so prevention is the only means of protecting cats from the effects of heartworm disease.
What are the signs of heartworm disease?
Asymptomatic at first, later developing: • Mild, persistent cough • Lethargy • Exercise intolerance • Reduced appetite
What are some lab abnormalities of heartworms?
Weight loss Eosinophilia Azotemia Increased liver enzymes Proteinuria
What is azotemia?
An excess level of nitrogen-based substances compounds such as urea, creatinine, and other body waste compounds in the blood is defined as azotemia
What can cause azotemia?
It can be caused by higher than normal production of nitrogen-containing substances (with high protein diet or gastrointestinal bleeding), improper filtration in the kidneys (kidney disease), or reabsorption of urine back to bloodstream.
How do monthly preventatives work?
All approved heartworm medications work by eliminating the immature (larval) stages of the heartworm parasite. This includes the infective heartworm larvae deposited by the mosquito as well as the following larval stage that develops inside the animal. Unfortunately, in as little as 51 days, immature heartworm larvae can molt into an adult stage, which cannot be effectively eliminated by preventives. Because heartworms must be eliminated before they reach this adult stage, it is extremely important that heartworm preventives be administered strictly on schedule (monthly for oral and topical products and every 6 months for the injectable). Administering prevention late can allow immature larvae to molt into the adult stage, which is poorly prevented.
What should you do if you miss 2 months of preventatives?
Immediately restart your dog on monthly preventive—then retest your dog 6 months later.
What is the treatment for heartworm infection?
If microfilariae are detected pre-treat with antihistamine and prednisone (glucocorticosteroids) to reduce the risk of anaphylaxis, begin heartworm prevention to avoid additional heartworms. Begin doxycycline for 4 weeks to weaken adult heartworm, followed by 1 month strict rest period, then injection of Diroban (melarsomine) IM back muscles, followed 30 day strict rest , the 2 additional IM injections given 24 hours apart followed by 30 day confinement. Recommend microfilaria blood smear check 1 month after treatment and snap 4dx test 9 months after treatment.
Why is strict rest recommended while going through treatment?
complete rest is essential after treatment. The adult worms die in a few days and start to decompose. As they break up, they are carried to the lungs, where they lodge in the small blood vessels and are eventually reabsorbed by the body. This resorption can take several weeks to months, and most post-treatment complications are caused by these fragments of dead heartworms.
Why is prednisone used in the treatment?
To help reduce inflammation in the lungs and vessels, caused by the worms before and after they die. Prednisone also helps reduce the risk of an acute pulmonary embolism (clot)
What is the heartworm scientific name?
Dirofilaria Immitis
