Common Mosquito-Borne Diseases that Affect Animals

Home » How To Get Rid Of Mosquitoes » Mosquitoes » Mosquito Diseases » Common Mosquito-Borne Diseases that Affect Animals

We’ve covered quite a lot of mosquito-borne diseases that affect humans on this blog. These are obviously the ones that can affect us most.

However, there are a ton of mosquito-borne diseases that our pets and horses can catch and suffer from. This is why we’ve decided to dedicate this article to those who care about their animals and want to find out more about the illnesses that they can catch from those little, pesky insects called mosquitoes.

Mosquito-Borne Diseases That Affect Pets

dog and cat

Tehmasip Khan/

Although dogs and cats can catch diseases like the West Nile virus, for them, these diseases aren’t half as harmful as they are to us. In fact, something like the West Nile virus wouldn’t usually make your cat or dog sick. They most likely wouldn’t even exhibit any signs of this virus. But there’s an illness called heartworm that’s a different story.


This is a mosquito-borne disease that can affect your pet and even cause death. In many other mosquito-borne diseases, the mosquitoes carry the bacteria or virus. This isn’t the case with heartworm. Here, they carry the actual heartworm larva, which, once injected into our pets by the mosquito biting them, will live the large blood vessels located around your pet’s lungs.

The usual symptoms of heartworm in dogs include cough, intolerance to exercise, fatigue, labored breathing, rapid heartbeat, decreased appetite, and weight loss. They can even have a swollen belly, sudden labored breathing, and pale gums in more severe cases.

For cats, the symptoms of heartworm disease are coughing, asthma-like attacks, vomiting, decreased appetite, and weight loss. Difficulty walking, fainting, and swollen belly show up in the later stages of this disease.

Lyme Disease

On top of that, your pets can sometimes become infected with Lyme disease through a mosquito bite. You’ll then see signs of lethargy, loss of appetite, and depression.

However, Lyme disease is rarer in pets than heartworm. This is why you should give your pets heartworm prevention medication all year round.

Mosquito-Borne Diseases That Affect Horses

Unfortunately, more mosquito-borne diseases can affect horses than cats or dogs. This is why it’s important to take mosquito control measures around your horses. You want to make sure there’s less of a chance that they could get infected with one of these diseases.

West Nile Virus and Heartworm

The most well-known mosquito-borne disease that affects humans and horses is the West Nile virus. It can cause spinal cord and brain inflammation. Horses can also get the previously mentioned heartworm, although it’s quite rare for them to get this illness.

Other than these two mosquito-borne diseases, there are four more that we want to talk about because all of them can cause severe symptoms in horses.

African Horse Sickness

One disease that is exclusive to Africa but has been found in other parts of the world, like the Middle East, Spain, and India, is African horse sickness. You need to keep an eye out for this disease because more severe forms cause death in 95% of all acute cases. It can do so in less than a day.

horses surrounded by mosquitoes

Milena de Narvaez Ayllon/

The symptoms of this disease are heavy breathing, fever, sweating, edema on the face and inside the mouth as well as heart failure. The good thing is that there is a vaccine and treatment available for this disease.

Equine Infectious Anemia

Another illness to watch out for is equine infectious anemia. While it’s more often transmitted by horseflies, mosquitoes can also transmit it. The symptoms of this are fever, lethargy, and loss of appetite. Unfortunately, if your horse has this disease in an acute form, it might cause death.

Sadly, 33% of all horses with severe equine infectious anemia die within a month. Even though there’s a vaccine used in China to combat this disease, the U.S. vaccine is still in development. So, we might need to wait before we can properly treat this disease.

Eastern and Western Encephalomyelitis

Then there are Eastern and Western equine encephalomyelitis, which are caused by viruses. The symptoms include stiffness, fever, decrease in appetite, and confusion as well as seizures and stupor in some cases. If the virus isn’t detected early enough and it has a chance to progress, there might be brain inflammation, dysfunction, and even death. Luckily, there is a treatment available and a preventive vaccine that’s highly encouraged.

Venezuelan Equine Encephalitis

Lastly, there’s the Venezuelan equine encephalitis. It’s similar to the two previously mentioned types of encephalomyelitis and has similar symptoms and severe case outcomes. There’s also a vaccine and treatment for this disease. The bad news is that this disease can be transmitted from horses to humans and can be especially dangerous to humans.

How to Make Sure Your Animals Don’t Get These Diseases

The main thing to do is to make sure that there are no mosquitoes that can bite your animals in the first place. If there are no mosquitoes, there are no mosquito-borne diseases to transmit.

You can do this by dumping and draining all your standing water reservoirs to make sure mosquitoes don’t have anywhere to breed. Use a mosquito fogger to fog the areas where you know your animals will be staying.

Just make sure that the insecticide you use has a label that states that it’s animal friendly because you don’t want to cause any accidental damage to your animals.


Rebecca Hill

Hello to you, Ms. Karen!! Thanks so much for sharing your information about foggers and Mosquitos!

Are there any cases of that Venezulan type of Mosquito caused illness in the U.S.A. as of yet?.. :(((


    Hello Rebecca,

    I am glad you find my articles helpful. That is why I created this Blog!
    Venezuelan Equine Encephalitis is a mosquito-borne disease that affect horses and unfortunately can affect humans too. It is very common in the Americas, and although it mostly affects South and Central America regions, there have been cases of this virus in the U.S. Luckily cases of this virus in the U.S. are pretty rare nowadays, because there is an effective vaccine for horses.
    Hope this answered your question!


Submit a comment

Your email address will not be published*