No Small Threat

If you’re traveling this summer, remember that one little bite from a mosquito carrying the Zika virus can lead to illness. For women who are pregnant or trying to become pregnant, symptoms of the virus include fetal birth defects.

While it normally would have been the powerful, razor-toothed jaws of a shark I’d be afraid of on a recent scuba-diving vacation to the Caribbean, I was instead fearful of a creature that could rest on the tip of my fingernail. Killing more humans than any other animal in the world, mosquitoes have infected millions over the course of centuries. Malaria, dengue and yellow fever are the most serious, but let's not forget the U.S. epidemic of West Nile virus and now a major concern, the Zika virus.

What Is It? Zika virus disease is primarily spread through the bite of an infected Aedes species mosquito. Sexual transmission of the Zika virus from a man is possible. Fever, rash, joint pain and conjunctivitis are the most common symptoms after being bitten. Usually mild in most cases, the symptoms last up to a week with people rarely becoming sick enough to visit the hospital. For this reason, many people might not realize they have been infected.

The real threat is for women who become infected with the Zika virus during pregnancy. Symptoms include a serious birth defect called microcephaly, where babies are born with abnormally small heads and other severe fetal brain abnormalities.

Once a person has been infected, he or she is likely to be protected from future infections. The Zika virus usually remains in the blood of an infected individual for about a week but can be found longer in some people. There is no vaccine or anti-viral treatment for Zika.

This isn’t a new disease. Discovered in 1947 in Uganda, the first human cases of Zika were detected in 1952. Outbreaks have been reported in tropical Africa, Southeast Asia and the Pacific Islands. In 2015, the Pan American Health Organization issued an alert regarding the first confirmed Zika virus infection in Brazil. On Feb. 1, 2016, the World Health Organization declared it a Public Health Emergency of International Concern. Local transmission has been reported in many other countries and territories, and it will likely continue to spread to new areas.

Where Is It? These areas have active mosquito-borne transmission of the Zika virus:

  • Cape Verde
  • Mexico
  • Aruba
  • Barbados 
  • Bonaire 
  • Cuba 
  • Curaçao
  • Dominica
  • Dominican Republic
  • Grenada
  • Guadeloupe
  • Haiti
  • Jamaica
  • Martinique
  • The Commonwealth of Puerto Rico, a U.S. territory
  • Saint Barthelemy
  • Saint Lucia
  • Saint Martin
  • Saint Vincent and the Grenadines
  • Sint Maarten
  • Trinidad and Tobago
  • U.S. Virgin Islands
  • Belize
  • Costa Rica 
  • El Salvador
  • Guatemala
  • Honduras
  • Nicaragua
  • Panama
  • American Samoa 
  • Fiji
  • Kosrae (Federated States of Micronesia)
  • Marshall Islands 
  • New Caledonia
  • Papua New Guinea
  • Samoa
  • Tonga
  • Bolivia 
  • Brazil
  • Colombia
  • Ecuador
  • French Guiana
  • Guyana
  • Paraguay
  • Peru
  • Suriname
  • Venezuela

How To Protect Yourself

  • Cover skin by wearing long-sleeved shirts and long pants.
  • Use insect repellents containing DEET, picaridin, oil of lemon eucalyptus or IR3535.
  • Stay in places with air conditioning and window and door screens to keep mosquitoes outside.
  • Use permethrin-treated clothing and gear (such as boots, pants, socks, and tents). You can buy pre-treated clothing and gear or treat them yourself.
  • Sleep under a mosquito bed net if air-conditioned or screened rooms are not available or if sleeping outdoors. Also use mosquito netting to cover babies in carriers, strollers or cribs.

Zika Virus in the U.S. 2015 – 2016 (as of May)
By the Numbers
503 travel-associated Zika virus disease cases reported
0 acquired vector-borne cases reported
48 of those cases were found in pregnant women
10 of those cases were transmitted sexually
44 states have reported at least one case of the Zika virus