West Nile virus (WNV) is most typically spread to people by the mosquito vector. Wearing insect repellents and protective clothing reduce the risk of being infected. There are no drug treatments or vaccinations that work against WNV infection. Thankfully, most people who become infected with WNV show no signs or symptoms. About 20% of infections lead to fever or other symptoms, and only about 1% of those infected will develop more severe, and sometimes fatal illness of the neurological system.
WNV is an arbovirus that is usually spread by infected mosquitoes. Transmission of the virus has been seen across the globe in Africa, Asia, Australia, Europe, India, and the Middle East. It was first discovered in North America in 1999 but is now across the lower 48 states of the United States and Canada alike with outbreaks every summer since (Centers for Disease Control and Prevention, 2016).
Mosquitos become infected with WNV with they take a blood meal from an infected bird. As they take another blood meal from other mammals or humans, they spread the virus to the new host. Therefore, people who work or participate in outdoor activities are the most at risk for infection. In rare cases, blood transfusions, pregnancy, delivery, and breastfeeding, as well as organ transplant, can be the source of infection (Centers for Disease Control and Prevention, 2016).
WNV incubates in the new host from 2 to 6 days but can be as long as 14 days. Between 70 and 80% of people who are infected with WNV show no symptoms at all. About 20% of those infected with WNV will experience more severe symptoms such as fever, joint pains, vomiting, or rash. These symptoms can last weeks or even months. About 1% of patients will experience more serious neurological symptoms, and these can even lead to death. High fever, tremors, paralysis and even death can be part of neurological issue. Approximately 10% of people who develop neurological symptoms from WNV will die. Elderly people or patients with coexisting complications such as cancer, kidney disease, organ transplant are more likely to show symptoms from a WNV infection (Centers for Disease Control and Prevention, 2016).
There is no specific treatment for WNV nor is there a vaccine to prevent the illness. Over-the-counter pain medications can be used to reduce fever and inflammation in patients that not so severe that they require hospitalization. Those who do need hospitalization will be given stronger pain medications, intravenous fluid support and nursing care (Centers for Disease Control and Prevention, 2016).
Because there is no specific treatment or vaccine, it is important to prevent mosquito bites. Following the “four Ds” has been recommended to prevent mosquito bites. Mosquitoes are most active at Dusk. Avoiding being outside during this time will help to prevent mosquito bites. Dressing appropriately for being outside is important as well. Wearing long sleeve and pants and thicker clothing that mosquitoes cannot penetrate will avoid bites to your skill. Using a deterrent such as DEET is also important. Chemicals such as DEET should be used to repel mosquitoes from being attracted to a taking a blood meal. While the chemical has been tested and deemed safe for use on humans since 1957 many people are not comfortable putting it directly on their skin. This also makes the concept of dressing in long pants and sleeves even more appropriate because the DEET can be applied to clothing instead of skin. The last D, drainage, is important for keeping the environment mosquito free. Removing all locations of standing water will prevent mosquitoes from being able to breed. Reducing the amount of mosquitoes that are born ultimately reduces the number that are carrying WNV and reduces that chance that an individual will become infected with the illness (Olin, 2012).
WNV incubates in the patient typically from 2 to 6 days but could be as long as 14 days. Most laboratory tests show no specific indications when looking for WNV. MRI of the brain shows no abnormalities except in cases of encephalitis which shows changes in the thalamus, brainstem, and basal ganglia. Testing the blood serum and cerebrospinal fluid can be done to detect IgM antibodies for WNV. These antibodies are visible between 3 and 8 days of symptom onset and typically last in the body between 30 and 90 days. Viral cultures have also been shown to detect RNA of the virus in serum, tissues and cerebrospinal fluid (Centers for Disease Control and Prevention, 2016).
Nursing protocols are important to support the WNV patient. Because there is no specific treatment, supporting the body is imperative. Patients that have severe meningeal illness will require pain management for headaches and as nausea and vomiting is often comorbid, antiemetics and rehydration will be needed as well. Encephalitis is often associate with seizures due to increased intracranial pressure and close monitoring by the nurse is important. People with either encephalitis or poliomyelitis could also have compromised airways and should be monitored for ensure they are able to breath on their own. Due to neurological changes respiratory failure could occur quickly and ventilation support might be necessary (Schweon, 2003).
