3 Things You Need to Know About West Nile Virus

For many children, summer means two things:  bed time is extended and friends come over to play all day. Unfortunately, your child’s playtime invitation may extend to one particular uninvited guest – the mosquito. As this pesky arthropod flies into your neighborhood, it may bring along more than just a bite.

Several cases of West Nile have been confirmed this year. Here are three things you need to know when your child plays outside:

What is West Nile Virus?

West Nile Virus (WNV) is an arthropod-borne virus most commonly spread by the bite of infected mosquitoes. This disease is rare in the United States, but several cases have been confirmed.

Mosquitos become infected with WNV when they feed on infected birds and spread the disease to humans. In a very small amount of cases, WNV has been spread through blood transfusion, organ transplants and from mother to baby during pregnancy, delivery and breastfeeding. The disease is not transmitted from person-to-person through casual contact.

What are the symptoms?

Many children (approximately 80 percent) who become infected with WNV will not show any symptoms at all and will fully recover as their immune system kills the virus, causing no harm. However, there is no way to know in advance whether or not your child has been infected and, if infected, whether he or she will develop WNV-associated illness.

If your child does develop symptoms, typically these would occur 2-6 days after infection (ranging from 2-14 days in normal hosts or up to 21 days in immunocompromised individuals) and would most typically include flu-like symptoms like fever, mild to moderate headache, nausea, fatigue and a transient blanching rash. These symptoms usually last a few days and then go away on their own.

For less than one percent of those infected, severe illness can occur as the virus affects the membranes of the brain or spinal cord (meninges), causing meningitis, or the brain itself, causing encephalitis. About one in 150 people infected with WNV will develop severe symptoms, including sudden high fever, severe headache, stiff neck, confusion, muscle jerks, tremors, seizure or nausea and vomiting. Call your child’s doctor right away if you notice any of these symptoms. Hospitalization may need to occur for supportive treatment including intravenous fluids, pain medication and nursing care.

How can I prevent it?

There is no vaccine or specific antiviral treatment for WNV at this time. However, the easiest and best way to avoid infection by WNV is to prevent mosquito bites. There are several things parents can do:

Protect your child’s skin. Using a protective barrier on skin such as an insect repellant with 30 percent DEET (American Academy of Pediatrics) can help to repel mosquitoes. This strong protective barrier requires extra precautions. Avoid application of DEET on children younger than two months of age, in a combination product with sunscreen, or over cuts or wounds or on clothing. Bathe your child with soap and water and rinse with clean water to remove repellent before he or she goes to bed.

Encourage your child to wear protective clothing to prevent mosquito bites while playing outside. An additional protection is application of permethrin to clothes, effective through multiple washes (avoid application to skin).

Both DEET and permethrin have been proven to repel ticks (and to kill ticks in the case of permethrin). If weather permits, wearing long sleeves, long pants and socks can add an additional barrier of protection.

Take extra care during peak hours.The mosquitoes that spread WNV are most active from dusk to dawn, especially 1-2 hours before sunset. During these times, parents should take extra precautions and consider keeping children indoors if possible.

Mosquito proof your home. Be mindful of mosquitoes around your home. Use screens in windows to keep mosquitoes out and empty any standing water from flowerpots, wading pools, buckets and other water sources since these are potential breeding grounds for mosquitoes.

For additional bug repellent tips, click here or to learn more about mosquito-borne diseases, click here.


W. Garrett Hunt, MD
W. Garrett Hunt, MD, is a member of the Section of Infectious Diseases at Nationwide Children’s Hospital and an Associate Professor of Clinical Pediatrics at The Ohio State University College of Medicine. His clinical interests include education of medical students and residents, and the management of children and adolescents with infectious diseases, particularly tuberculosis and infections in the immunocompromised host. His research interests are primarily associated with clinical trials dealing with the treatment of neonatal herpes simplex virus and congenital cytomegalovirus. He is local principal investigator of protocols contracted with the Collaborative Antiviral Study Group sponsored by the National Institute of Allergy and Immunology.

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