Can canine heartworm spread to humans?

Canine heartworm is mainly spread by mosquitoes and does not usually infect people directly. If you have concerns, ask your vet or local public health authority.

How can I prevent canine heartworm infection?

Prevention focuses on reducing mosquito exposure and following your vet's recommended regular heartworm preventives and follow-up testing to lower the risk of infection.

What tests are needed to diagnose canine heartworm?

A blood antigen screening test is commonly used. Chest X-rays and echocardiography may also be recommended to assess severity and complications.

How long is follow-up needed after treatment?

Follow-up usually continues for several months after treatment and may include blood tests and imaging. Your vet will advise the appropriate recheck schedule.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Canine Heartworm Disease in Dogs: Coughing, Breathing Symptoms, Tests & Care [2025]

Canine heartworm disease is spread by mosquitoes, with adult worms living in the heart and pulmonary arteries. Treatment requires staged parasite control and close monitoring, and severe cases can be life-threatening. Regular preventive medication can help avoid infection effectively.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: AHS, AVMA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate emergency care

•Persistent difficulty breathing that does not resolve on its own
•Obvious blue or pale discoloration of the lips or gums
•Sudden collapse or prolonged loss of consciousness

Schedule a clinic visit soon (within 24–72 hours)

•Persistent dry cough that worsens noticeably after exercise
•Rapid breathing or markedly reduced stamina after exercise
•Ongoing loss of appetite or significant weight loss

01What symptoms suggest something is wrong?

Canine heartworm disease mainly affects heart and lung function. Clinical signs are often respiratory and cardiovascular, and early signs may be subtle.

Gradual weight loss or a noticeable decrease in appetite
Persistent dry cough or coughing more often than usual
Panting, wheezing, or rapid breathing after exercise
Fast heartbeat or signs of an irregular heartbeat
Fluid in the abdomen or a swollen-looking belly
Fainting or brief episodes of loss of consciousness

Seek emergency care immediately if you notice the following symptoms:

⚠️ Ongoing difficulty breathing or open-mouth breathing
⚠️ Lips or gums that look blue, purple, or very pale
⚠️ Sudden collapse or brief loss of consciousness

02How can I assess changes at home? Key observations and when to seek emergency care

Home observation can give your vet important clues. Keep notes on changes and prepare videos or written records to bring to the appointment.

Weigh your dog at the same time each week and record any changes
Record videos of coughing, wheezing, or laboured breathing on your phone
Track changes in exercise tolerance and tiredness after activity
Watch for changes in appetite, drinking, and toileting habits
If fainting occurs, note the time, duration, and circumstances
If symptoms worsen, arrange a veterinary consultation promptly

03How will the vet diagnose it? Common tests

At the clinic, your vet will start with a physical examination, then use imaging and blood tests to assess heart and lung function and the infection status.

Physical examination

listening to the heart and lungs, and assessing pulse quality and gum colour

Chest X-rays

assessing heart size and changes in the lungs

Echocardiography

checking heart structure and blood flow

Blood antigen test

screening for heartworm infection

Blood tests and biochemistry

assessing overall organ function and complications

Advanced imaging, such as CT, or hospital monitoring may be arranged if needed

04How is it treated and managed after diagnosis? Medication, diet adjustments, and care guidance

Treatment may require hospital care for acute signs and long-term follow-up. Recheck visits and imaging are important for assessing recovery and complications.

During an acute episode, hospitalisation with oxygen and supportive care may be needed
Parasite treatment, supportive care, and monitoring are planned according to disease severity
Activity must be restricted during treatment, with exercise tolerance rebuilt gradually
Follow your vet's advice for regular rechecks, echocardiography, and blood tests
Diet and weight management can help reduce strain on the heart
Long-term follow-up at a referral or specialist clinic with echocardiography is recommended

05What should I prepare before seeing the vet? Key details that help identify the cause quickly

Record videos of coughing, wheezing, or laboured breathing for your vet to review

Note when symptoms started, how they have changed, and how often they occur

Test and record how your dog tolerates short periods of exercise

If your dog has fainted, write down how long it lasted and what was happening at the time

Bring recent weight records and a list of all medications and supplements

Before the visit, you can phone ahead to ask whether specialist tests should be arranged

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.