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What causes heartworm in dogs and how do mosquitoes spread it?

Updated On September 23rd, 2025

Hello, I am a student at Ohio State and I am currently enrolled in a veterinary entomology class and have a research project. (a)What is your job position/title? Where is your workplace (city, state, country)? How long have you been in clinical practice for? (b) Please describe a problem/disease you have encountered in a patient or a public/veterinary health situation you experienced that was directly caused by an insect or arachnid?

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Answered By Ana M, DVM

Veterinarian

Published on April 10th, 2019

Thank you for submitting your question regarding your school project. I am an associate veterinarian in Colorado Springs, CO. I have been in practice for 12 years. I recently saw. a case of heartworm disease. The dog was a 5 year old spayed female mixed breed dog. She was rescued from a group in southern Colorado. Thankfully she was not symptomatic for the disease and responded well to treatment. Heartworm disease is transmitted to dogs by mosquito bites. I hope this information helps!

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    Answered By Laura Johnson VMD

    Veterinarian

    Published on June 14th, 2018

    Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Heart worm is transmitted by mosquitoes only. The larva completes it's life cycle with in the mosquito. The tick is not part of it's life cycle. Ticks carry many other diseases though. I recommend preventing heart worm and flea and ticks with preventatives, then your dog will be protected. Have a great day!

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Related Questions

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As said that heartworms disease is only cause by mosquito bite so suppose a dog is having heartworm and one tick from that infected dog pass to my dog through my clothes and that tick of heartworm i fected dog bite my dog so will my dog is also going
Hi, thanks for using Boop by Petco! Heart worm is transmitted by mosquitoes only. The larva completes it's life cycle with in the mosquito. The tick is not part of it's life cycle. Ticks carry many other diseases though. I recommend preventing heart worm and flea and ticks with preventatives, then your dog will be protected. Have a great day!
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
What blood test are available to detect heartworms inside the dog? Also i feed stray dog outside my office and he is xoughing since february i started giving him antibitoic and give him for month he got okay as soon as i stop giving him and he sits i
Heart worms can be detected through a blood test that can be done at a veterinarian’s office. Heart worms are transmitted by mosquitoes...a mosquito harboring a life stage of the heartworm will transmit it to a dog by biting it. It is not passed from dog to dog through casual contact. Heartworm disease is easily prevented, so if your veterinarian can test your dog and he is negative....there are a number of heartworm preventative products available through your veterinarian. Thank you for using Boop by Petco
Updated on September 24th, 2025
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Can dogs get diseases transmitted by mosquitoes? West Nile Virus, etc.
Heart worm disease is transmitted by mosquitos. This is by far the biggest concern for diseases spread by mosquitos that we see in dogs. Dogs are quite resistant to developing disease from west nile virus, so while they can technically become infected, they don't get sick. Dogs do not get malaria from mosquitos. There is another form of malaria that affects dogs that is spread by ticks. Ticks can also transmit a number of other diseases to dogs, including lyme disease, and many other diseases. Here is a website with a lot of great information on what diseases your pets can get from mosquitos and ticks: http://www.cvbd.org/en/mosquito-borne-diseases/ Talk to your veterinarian about a monthly heart worm prevention, as well as flea/tick control measures. These are important parts of your pet's healthcare! I hope that helps you! thanks for asking Boop by Petco!
Updated on September 24th, 2025
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Health & Wellbeing
I took my dog too the vet yesterday they told me he has heart worms. He has a few other things wrong too but I heard from other people heart worms in very dangerous i'm just wondering if you by any chance know how a dog gets heart worms. I've very wo
Hi, I'm Dr. Johnson. Thanks for using Boop by Petco. Poor Midnight Yes, heartworm disease is serious. Dogs get heartworm from being bitten by an infected mosquito. The mosquito injects microfilaria (baby heartworm) in to the skin when they bite the dog. It can then take 6 months to travel from the skin to the pulmonary artery. If they get a lot of heartworm they back up in to the heart (Caval syndrome). That is very serious because the adult worms have to be extracted from the heart via the jugular vein. Your other dogs can not get it from Midnight, only from a mosquito. You should have all your dogs tested then started on heartworm prevention. The gold standard of treatment is injectable adulticide as 3 injections. One is given then the other 2 a month later 24 hours apart. During treatment and 2 months after the 3rd injection the dog has to be strictly cage rested. The major risk of treating and HAVING heart worm is sudden death from clots to the lungs. Talk to your Vet about tre
Updated on September 24th, 2025
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How do dogs get heartworms?
Great question! Heartworms are transmitted via mosquitos. I've attached a link to a Pet Coach article with tons of information. I hope this helps! https://www.petcoach.co/article/all-you-need-to-know-about-heartworm-disease/
Updated on September 24th, 2025
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Stray dog has severe cough since February 2018 I given him medicine in May whole month it become okay as soon as I stop giving medicine knowing that he is ok now he started to cough again so what possible reason it could be bronchitis or something el
I am sorry to hear that your dog is coughing. There are so many reasons for chronic cough such as allergic bronchitis, pulmonary hypertension, heartworm disease, enlarged heart, fungal infection, parasites, and cancer. To answer your question heartworm is transmitted by mosquitoes only and can not pass through people. Also, there is no answer to how long it takes for a cough to resolve. It completely depends on what is causing the cough. I would highly encourage you to consider a follow up appointment with your veterinarian soon. X-rays, bloodwork, and a fecal exam may be recommended to help determine the diagnosis and best treatment plan. Best of luck and thank you for using Pet Coach.
Updated on September 24th, 2025
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Health & Wellbeing
if the dog im about to adopt has heart worms (treatment will start as soon as the adoption process is completed), is it possible for them to spread to my other dog if the two come in contact with each other?
The dogs cannot directly spread heartworm disease between each other. However, mosquitoes can bite your newly adopted dog and if they bite your other two dogs, they could transmit heartworm disease. Make sure your other two dogs have been heartworm tested recently and are receiving heartworm prevention every month without fail. If you do those things, there should not be an issue. :-)
Updated on September 24th, 2025
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Health & Wellbeing
Do mosquitoes always give dogs heart worm? What are the symptoms of heart worm?
Only infected mosquitoes have the potential to pass along heartworm disease to your dog. Symptoms may include a persistent cough, exercise intolerance, decreased appetite and weight loss. https://www.heartwormsociety.org/heartworms-in-dogs
Updated on September 24th, 2025
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Health & Wellbeing
I had my dog spayed about 2 weeks ago & the animal shelter asked me if my dog takes heart worm medicine & I said no So they tested my dog & the results were negative So do I have to give my dog heart worm medicine?
Yes, if you live in an area with mosquitos. Heartworms are spread by mosquitoes, not by dog to dog contact. The mosquito injects larva into the blood when they bite the dog and over six months they grow into adult heartworms that live in the heart and surrounding blood vessels. Infected dogs have many worms in their heart and they eventually die of heart failure if not treated. The treatment is expensive and can be hard on the dog. Heartworm prevention is given monthly for life and protects your dog from heartworms and intestinal parasites. There are many different safe products some that include flea prevention also. Please talk with your veterinarian about getting prevention for Sophie soon. Thanks for using Boop by Petco to help you care for Sophie.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Can a kitten or cat contract heartworm if they infest a dead mosquito?
Hi there. No, heartworm disease is only transmitted through mosquito bites - meaning that the mosquito bites the pet, and transfers microscopic heartworm larvae directly into the tiny blood vessels under the skin. Eating a dead mosquito cannot transmit the disease.
Updated on September 24th, 2025
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