Pregnancy and West Nile Virus

A J Woldman

What Is West Nile Virus?
West Nile virus is a mosquito-borne virus that can, in rare cases, cause encephalitis, an inflammation to the brain. West Nile is spread to humans through the bite of an infected mosquito. Researchers believe the most likely explanation for its appearance here is that the virus was introduced by an infected imported bird or an infected person returning from a country where the virus is more prevalent. Before making its way to the US in 1999, West Nile virus was more commonly found in birds and humans in Africa, Eastern Europe, West Asia and the Middle East.

What are the odds of pregnant women getting West Nile Virus?
According to the Centers for Disease Control and Prevention (CDC), the chances of pregnant women becoming severely ill from any one mosquito bite are extremely small. Even if a mosquito is infected, less than 1 percent of people (pregnant and non-pregnant alike) who are bitten and become infected will become severely ill.

If you do become infected, the symptoms are usually mild and may or may not include headache, low-grade fever, slight body aches and occasionally, a skin rash accompanied by swollen lymph glands. In more severe infections the individual could suffer the onset of high fever with profound head and body aches, disorientation, tremors, convulsions and in the most severe cases, paralysis, coma or death. However, the latter is more likely to appear in individuals who are aged 50 years and older, says a CDC representative, who also notes, "Being pregnant does not present a greater risk of infection, nor is there any documented evidence that a woman's pregnancy is at risk due to infection with West Nile virus."

What about breastfeeding moms? Can they pass West Nile on to their babies? The CDC reports there has been no documented evidence of the virus being passed on to breastfed babies through breastmilk. Also, the virus cannot be transmitted from person-to-person, (e.g. through kissing or touching a person who is infected with the disease). The best thing to do if you think you may be experiencing symptoms of the virus is to call your doctor, the CDC recommends.

Reducing your chances of infection
Many pregnant and nursing women are reluctant to use any form of mosquito repellent because they are worried about harming their children. According to the CDC, both pregnant and breastfeeding women can and should use a repellent containing N,N-diethyl-m-toluamide, or N,N-diethly-3-methylbenamide, the chemical names for DEET. This will help guard against the chances of being bitten by an infected mosquito if they are going to be outdoors during peak mosquito biting times (dusk, early evening and dawn). The CDC recommends using a repellent containing DEET of 35 percent sparingly, taking care to apply it only to exposed body parts with your hands instead of spraying it directly onto your skin. The CDC states there have been no reported adverse events following the use of these repellents in pregnant or breastfeeding women.

Adelaide Nardone, MD, board certified OB/GYN working in Providence, Rhode Island with an affiliate of Women and Infants Hospital, says pregnant women may use DEET but should take precautions to use it carefully. "It should never be ingested, and eye and lip contact must be avoided," she says. "Too, it should never be used on open wounds, cuts or sunburned skin." Dr Nardone also notes that products containing DEET should be washed off clothes and the body as soon as possible.

Adrienne Rencic, MD, PhD, a clinical dermatologist at Mercy Medical Center in Baltimore Maryland, agrees, adding, "DEET is an extremely safe medication when used wisely. A recent study found that pregnant women who used DEET to prevent mosquito bites with an application of 1.7 grams per day, suffered no adverse effects and neither did their babies." She notes that the study was performed on women in their second and third trimesters, and concluded by saying, "As with all medications used in pregnancy, the final determination to use or not to use DEET should be made by your own obstetrician, who is most familiar with your specific case."

For your baby and child
Infants and children should also be protected when outdoors during peak mosquito biting times. Keeping them attired in long pants, long sleeved shirts, with socks and shoes that cover their feet is best. Also, research has shown that mosquitoes are more likely to be attracted to dark-colored clothing, so wearing lighter colors while outdoors is advisable.

The American Academy of Pediatrics has recommended parents take a cautious approach and use products with a low concentration of DEET, 10 percent or less, on children, and to always follow the recommendations appearing on the product label for proper application. There are some guidelines that cite it is acceptable to use products containing DEET on children who are over 2 years of age. Dr Nardone advises using a lower concentration of DEET on smaller children, (usually less than 30 percent). Another precaution parents can take is to cover their infant carriers with a protective netting to help guard against mosquito bites.

In addition to the above precautions, for the safety of your children, the CDC suggests that when using repellents on children, you should first apply them to your own hands and then rub them on your child. Be careful to avoid your child's eyes and mouth and use sparingly around their ears. Do not under any circumstances apply repellent to your child's hands because children often put their hands in their mouths or touch their eyes, and never apply repellents to wounds or irritated skin. You should also not allow your children to apply repellents themselves, and they should be stored out of reach with other medications and toxic chemicals. Finally, parents should bathe their children after use of repellents, and if a repellent has been applied to a child's clothing, the article of clothing should be washed before allowing the child to wear it again.

Reducing exposure around your home
Since most mosquitoes need standing water to lay their eggs, there is a lot that can be done around the home to keep mosquitoes at bay. Besides spraying, here are some useful tips that will help reduce the number of mosquitoes around your home, and hopefully, ease your nerves a bit.

1. Be sure to always turn over plastic wading pools when not in use.
2. Change the water in bird baths every three to four days.
3. Dispose of any tin cans, plastic containers, ceramic pots or similar water-holding containers, and eliminate any standing water that collects on your property.
4. Drill holes in the bottoms of all recycling containers that are kept outdoors.
5. Clean and chlorinate swimming pools, outdoor saunas, hot tubs and drain water from pool covers.
6. Make sure roof gutters aren't clogged and can drain properly, and be sure to clean your gutters every spring and fall.
7. Remove any and all discarded tires from your property. Used tires have become the most common mosquito breeding site in the country.
8. Make sure that all the doors and windows around your home have tight fitting screens, and repair or replace all screens that have tears or holes in them.
9. Remind or offer to help your neighbors eliminate mosquito breeding sites on their property.
10. Report any sightings of dead birds in your area to your state health department.

It is important to remember that contracting the disease is not very likely and if we all take the precautionary measures to protect our children and ourselves from the chances of being bitten by a mosquito, then we have relatively nothing to worry about. Children need to experience the outdoors, it's a big part of growing up. Being armed with information about what we can do to protect them and ourselves against West Nile virus is our best form of defense.