West Nile Virus: History, Symptoms, Diagnosis, Transmission, And Treatment

For most of us, getting a mosquito bite is not unusual. Whether you are camping, hiking, or spending an extended amount of time outdoors— a bite is not unusual. Most of the time, we complain about the itchiness and move on. However mosquitoes have the ability to spread diseases through these bites, and occasionally, these infections can become lethal. Hi, my name is Paige, and today I am going to introduce you to a mosquito-borne disease known as the West Nile virus. I will discuss what the virus is, the symptoms, how it is diagnosed, means of transmission, means of prevention, and a potential cure for the disease.

First, I will discuss the history of West Nile virus and how it is transmitted. West Nile virus originated in Africa, and in 1999, a case was appeared on the east coast of the United States.

Since then, West Nile Virus has been detected in nearly every state. Other than the North America and Africa, cases have been reported in a variety of countries in Asia, Europe and the Middle East. Infection most often occurs through mosquito bites from mosquitoes who have fed off of disease ridden birds. Only certain types of mosquitos (the genera Culex, for example) have the potential to become infected. This is why not every mosquito bite you receive poses a threat. However the ones who can infect are healthy carriers; rather than dying, they spread the disease to other living things that they feed on (such as humans). A person can also contract West Nile Virus through transfusions or transplants, however this is rare because blood is always checked for such diseases. It can also be transferred from mother to child, but it is very unlikely. Good news — it cannot be spread by physical contact!

Transition Statement

1. When West Nile Virus is contracted, 8 of 10 people infected do not establish symptoms and do not know that they have contracted the virus. Yes this means you may have contracted West Nile Virus at some point in time, because this virus is quite viral in all of California! 1 out of 5 people develop flu-like symptoms, such as aches, pains, fever, fatigue, headaches, vomiting and diarrhea; this is called West Nile Fever. These individuals will become sick, and then develop immunity that will last a lifetime. 1 out of 150 people who acquire West Nile Virus will contract illnesses that damage the central nervous system, otherwise known as neuroinvasive diseases. This is when the virus can become truly dangerous; neuroinvasive diseases cause inflammation of the spinal cord and brain and can cause permanent neurological injury (Centers for Disease Control and Prevention).
2. If the virus has become a neuroinvasive disease, then laboratory analysis must be done to determine that the root cause is West Nile Virus. First, a laboratory technician takes a sample of cerebrospinal fluid or blood. Then, he or she will test for an antibody known as Immunoglobulin M. Antibodies are blood proteins that are produced to counteract a disease causing antigen that appears in the body. IgM is found specifically in the lymphatic fluid and in the blood and is the first antibody made when a person is fighting an infection in the lymphatic system. This test must also prove that the IgM antibodies are West-Nile Virus specific. If the antibodies are not WNV specific, it does not rule out West Nile Virus as the cause because the antibodies take 3 to 8 days to develop after the patient contracts the virus and can last in the body for a few years after. Therefore, multiple tests will be done after a few days to see if those particular antibodies begin to appear. If the WNV specific antibodies are present, the patient may have contracted the virus. Because of the longevity of the antibodies, and the ability to contract the infection without realizing it, more tests must be done to prove that the results are not from a past infection, but the infection at hand.

These evaluations test for microorganisms such as viruses, protozoans, parasites, and fungi that cause disease. A common evaluation is the Plaque-Reduction Neutralization Test, in which a dilution is performed (much like the one performed in class) to isolate the antibody. It is then tested on a plate to see whether the antibody can successfully neutralize the virus and prevent the formation of plaque, or whether a change in the antibody is indicated. If prevented, then the patient is sure to have contracted West Nile Virus from a mosquito. This test is also commonly used to test for the Zika virus, however it is not the first method of diagnoses because it is timely and expensive. Another methods includes using specific cultures to grow RNA from a persons tissue using an indicator. If this comes out positive, it can also confirm infection. The only true way to prevent yourself from contracting West Nile Virus is to protect yourselves from mosquitos altogether. I will now share how you can protect yourselves from mosquitoes indoors and outdoors.

Prevention

1. If you are spending a significant amount of time outside in the evening, or in an area with a surplus of mosquitoes, wearing insect repellent is the best way to protect yourself. To ensure the repellant you are using is safe, ensure that is is registered by the Environmental Protection Agency. To ensure it is effective, make sure it has a high percentage of one of the following ingredients (DEET, etc. ). In the United States, DEET is the most commonly used active ingredient in repellent. The EPA also suggests that these chemicals can be harmful to children, and the repellent should be applied to clothes rather than directly to skin. If you are also wearing sunscreen, it is also recommended that you apply the sunscreen first and the repellent second. The other key method of protection is wearing the proper clothing. If it is possible to wear long pants and shirts, this will durastically reduce the mosquitos ability to reach your skin. In addition, the chemical permethrin is an insecticide and mosquito repellent that that is safe to put on clothing, which adds an extra layer of resistance. If a person is sleeping outside, they can use a mosquito bed net to sleep under.
2. Individuals who live in environment where mosquitos are found indoors must follow another series of recommendations to protect themselves. For one, screens should be used on all doors and windows to prevent mosquitoes from coming inside. If it is possible to use air conditioning rather than leaving windows open, this is also ideal. To prevent mosquitos from laying eggs, which they do in moist environments, ensure that anything holding water in the house is regularly emptied and cleaned.
3. There is not yet an approved vaccine for West Nile virus. However, a vaccine has been approved and is used on horses. The National Institute of Health also funded West Nile Virus vaccine trials on humans in 2015, and work is still being done to develop a safe and effective vaccine.