Common Mosquito-Borne Diseases that Affect Animals

We have covered quite a lot of topic related to human mosquito-borne diseases no this blog, because those are ones that can affect us the most. However, there are a ton of mosquito-diseases that our pets and horses can get and suffer from, which is why I dedicate this article to those, who care about their animals and want to find out more about the illnesses that they can catch from little, pesky insects called mosquitoes.


Although human mosquito-borne diseases like West Nile Virus can infect dogs and cats, too, for them these diseases aren’t half as harmful than they are to us. In fact, something like West Nile virus wouldn’t usually make your cat or don sick, therefore most likely they won’t ever exhibit any signs of this virus. But an illness called Heartworm disease is a different story.


It is a mosquito-borne disease that can affect your pet and even cause death. Unlike other mosquito-borne diseases, where the mosquitoes carry the bacteria or virus of these diseases, for heartworm disease they carry the actual heartworm larval, that once is injected into our pets by the mosquito biting them, will live in your pet’s large blood vessels that are located around the lungs. The usual symptoms for Heartworm disease in dogs are cough, intolerance to exercise, fatigue, labored breathing, rapid heat beat, decreased appetite and weight loss, and even 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, appetite decrease and weight loss, with difficulty walking, fainting and swollen belly in later stages of this disease.

On top of that sometimes your pets can also be infected with Lyme disease through a mosquito bite. Then you will see sings of lethargy, loss of appetite and depression. However, Lyme disease is rarer in pets than Heartworm disease, which is why you should give your pets heartworm preventives all year around.


Unfortunately, there are more mosquito-borne diseases that can affect horses that there are those, that affects cats and dogs, which is why it is important to take mosquito control measures around your horses, so there is less of a chance, that they get infected with one of these diseases.

The best known mosquito-borne disease that affect humans as well as horses is West Nile Virus, that can cause spinal cord and brain inflammation, and horses can also get the previously mentioned heartworm diseases, although it is quite rare for them to get this illness. Other than these two mosquito-borne diseases, there are four more, that I want to talk about, because all of them can sauce severe symptoms to horses.

One disease, that although is exclusive to Africa, is known to be found other parts of the world too, like Middle East, Spain and India is the African Horse Sickness. You need to watch for this sickness, because more severe forms of it causes death is 95% of all acute cases and can do it in less than a day. The symptoms for 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 as well as treatment available for this disease.


Another illness, that is more often transmitted by horsefly, but also is known to be transmitted by mosquitoes is Equine Infectious Anemia. The symptoms for this one are fever, lethargy and loss of appetite. Unfortunately, if your horse has this disease in an acute form, it might cause death, because 33% of all horses of severe Equine Infectious Anemia cases die within a month. And even though there is a vaccine that is used in China to combat this disease, a U.S. vaccine is only in development, so we might need to wait some time to be able to properly threat this disease.

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

And lastly there is the Venezuelan Equine Encephalitis, which is similar to the two previously mentioned types of Encephalitis, therefore has similar symptoms as well as severe case outcomes. There also is a vaccine and treatment for this disease, but the bad news is that, this disease can be transmitted from horses to humans, and it can be especially dangerous to humans.

 What to do to make sure your pets or horses don’t get these diseases?

Well the main thing is to make sure that there are no mosquitoes in the first place, that can bite your animals, because if there are no mosquitoes, there are no mosquito-borne diseases to transmit. You can do this not only by dumping and draining all your standing water reservoirs, to make sure mosquitoes don’t have anywhere to breed and you can also use a mosquito fogger to fog the area where you know your animals will be staying. Just make sure that the insecticide you use is labeled as animal friendly, because you don’t want to cause more 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!


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