Signs and Symptoms

While West Nile Virus most commonly affects birds, it can also infect humans and other animals, including dogs. Generally, however, dogs do not seem to be particularly susceptible to this disease, as their immune systems are able to effectively fight off the virus. Yet, to be safe, it’s always a good idea to be aware of the potential risks that your pet faces and to know how to best prevent and avoid them. This is especially true if your dog is elderly, weak, or has a compromised immune system, as such animals will be more susceptible to all illnesses, including West Nile Virus.

Most dogs that have this disease transmitted to them through a mosquito bite will simply carry the virus without showing any symptoms or suffering from any form of ill health. However, for those dogs that do become ill, there are a number of symptoms that will likely be displayed. Fever and weakness are two warning signs that will likely arise in a case of canine West Nile Virus. Muscle spasms and a loss of muscle coordination may also occur. A number of neurological signs can also be indicative of West Nile Virus, including behaviors such as head tilting, circling, and trouble with walking. Depression, a loss of appetite, and other neurological disorders including seizures or an apparent personality change can also occur when a dog is suffering from this mosquito-transmitted disease.

If your dog is displaying any of the above symptoms, contact a veterinarian immediately. These warning signs and behaviors can be indicative of other serious illnesses as well. Either way, the sooner your dog can receive treatment, the better. A veterinary doctor will be able to determine whether your pet’s symptoms are being caused by West Nile Virus or another medical condition, and will be able to administer treatment accordingly.

Diagnosis

If your dog is exhibiting signs and behaviors consistent with an infection of West Nile Virus, your veterinarian will begin by taking a complete medical history of your pet and conducting a thorough physical examination. At this point, the doctor will look for clinical signs as well as any indication that your pet’s symptoms could be caused by another illness or medical condition. It’s important to carefully describe the symptoms and behaviors that you have observed at home in order to assist the veterinarian. Furthermore, if your dog has recently been exposed to mosquitoes, it’s important to mention this to the veterinary doctor, as this may help with respect to reaching a prompt and accurate diagnosis.

In order to rule out other causes of a canine patient’s illness and to identify West Nile Virus if it is indeed present, a variety of tests may be performed. Most likely, blood test will be conducted in order to check for the presence of such an infection in the dog’s bloodstream. Once a dog has been diagnosed with this illness, an appropriate treatment plan can be developed and implemented, hopefully saving the animal’s life and restoring its health.

Pathophysiology

Found in both tropical and temperate climates, West Nile Virus was first isolated in Uganda in 1937 from the blood of a human female. The first fever epidemic caused by this disease on record occurred in Israel during the early 1950’s. In 1999, West Nile Virus made its first appearance in the Western Hemisphere, causing the deaths of birds, horses, and humans in New York City and other areas in the northeastern United States. In recent years, this disease has spread quite quickly through Europe and North America and has become one of the fastest growing health threats in North America. Even so, the risk to canines is still very low; birds, horses, and humans seem to be far more susceptible to this virus than dogs.

West Nile Virus is one of a family of viruses known as Flaviviridae. This family of viruses includes several other major diseases such as dengue fever and yellow fever. These viruses are predominantly spread through mosquito bites, and the role of the mosquito in the transmission of West Nile Virus was clearly observed and recorded during studies conducted in Egypt during the 1950’s. Since mosquitoes are the transmitting vehicle of this disease, West Nile Virus is a greater threat in areas where there are large mosquito populations. Furthermore, most cases of illness caused by West Nile Virus arise between the months of July and October, when mosquito activity is at its height.

Perhaps the most frightening aspect of this mosquito-transmitted virus is the fact that it can cause encephalitis (inflammation of the brain). This condition is extremely dangerous, and is responsible for neurological symptoms such as head tilting, loss of muscle coordination, and seizures. Viral encephalitis can cause severe damage to the nervous system and can even cause death. This is why the best way to deal with West Nile Virus is to prevent transmission and infection from occurring in the first place.

Causes

As mentioned previously, contraction of West Nile Virus usually occurs as a result of a mosquito bite. Mosquitoes carry this disease and bite birds, transmitting the virus to these feathered animals. The birds then unwittingly act as “amplifying hosts,” which means that the viral levels that develop within them are high enough that the birds can infect other mosquitoes that bite them. These mosquitoes then go on to infect other birds, humans, and a number of other animals, including dogs. In Africa, the most common species of mosquito to transmit this disease is Culex univittatus, while in North America the most common species are Culex pipiens and Culex restvans.

Treatment

When a dog becomes infected with West Nile Virus, there is no specific treatment available to cure the animal of this disease. However, generalized viral treatment and treatments for encephalitis may be effective, especially when the illness is caught in its earlier stages. This is why it’s vitally important to have your dog examined by a veterinarian as soon as possible if you notice unusual symptoms and behaviors such as those caused by West Nile Virus. When trying to protect your pet against this disease, the best method is prevention, and there are a number of ways that you can safeguard your canine companion against mosquitoes and the diseases that they carry.

The best thing to do with respect to protecting your dog from West Nile Virus is to limit your pet’s exposure to mosquitoes. Avoid having your dog outdoors during the evenings or at dawn, as these are the times when these insects are most active. It’s also important to ensure that the environment surrounding your home is not providing any sort of haven for breeding mosquitoes. Make sure that areas of standing water are eliminated if at all possible, including ponds and birdbaths. Also, outdoor water bowls should be emptied and refilled daily to ensure that mosquitoes cannot lay their eggs in the water.

When attempting to keep your pet mosquito free, keep in mind that many insect repellents that are safe for humans are extremely harmful for animals such as dogs. There are insect repellents available that have been specifically designed for dogs, including homeopathic and natural options. If you wish to use such a product on your dog, it’s always best to consult with a veterinarian first in order to ensure that the product is safe for your individual pet.

Another important step that can help to protect your dog from West Nile Virus is to make sure that he or she has a strong and healthy immune system. This will help your dog to combat the virus if it is bitten by a disease-carrying mosquito. Supplements are particularly beneficial with regards to bolstering an animal’s immune system, especially omega-3 fatty acids and antioxidants. By providing your dog with immune support, you will be increasing its chances of fighting off West Nile Virus as well as many other illnesses that could potentially harm your beloved pet’s health.