Today, the Centers for Disease Control and Prevention (CDC) issued additional travel warnings for pregnant women as the Zika virus outbreak continues. Initially, the CDC listed 14 countries, but they just added eight more countries in South America, the Caribbean and Polynesia.

These precautions come after the CDC announced about a dozen cases of Zika virus confirmed in the United States — Florida, Illinois, New Jersey, Texas and Hawaii. All of the confirmed cases in the U.S. have been in residents who had recently traveled to countries where mosquitoes have tested positive for the Zika virus. There have been no cases of locally transmitted Zika in the U.S.

What is Zika virus?

According to the World Health Administration (WHO), the Zika virus disease is caused by a virus that is transmitted by Aedes mosquitos. Incidentally, these are the same mosquitoes implicated in the transmission of dengue and chikungunya viruses.

The virus was first identified in the Zika forest of Uganda in 1947 in rhesus monkeys. However, it was not identified in humans until 1952 in Uganda and the United Republic of Tanzania. The virus remained relatively benign until 2007 when it arrived on the Yap Island in the southwestern Pacific Ocean where is quickly infected most of the island's 11,000 inhabitants. It resurfaced again in Tahiti and other areas of the French Polynesia where it continued to spread through other South Pacific locations.

By May of 2015, Zika had arrived in Brazil, where it has taken hold.


The Zika virus is transmitted to people through the bite of an infected mosquito that previously bit another infected person. The mosquitoes lay their eggs in and near standing water and are aggressive daytime biters that prefer to bite people. They can be found living near people, both indoors and outdoors.

Of recent concern is the suspected transmission from mother to baby. Although rare, an infected mother can pass the virus to her newborn around the time of birth. Growing concerns have mounted that it is possible for the Zika virus to pass from mother to fetus during pregnancy, however it continues to be investigated.

Signs and symptoms

The symptoms of the Zika virus include fever, skin rashes, conjunctivitis (redness of the eyes), muscle and joint pain, malaise and headache. The symptoms are usually mild and can last from 2-7 days. Hospitalization is uncommon and deaths are rare.

Considering the similar symptoms to many other mosquito-transmitted illnesses, it is imperative to notify healthcare providers of recent travel. There are blood tests to diagnose the virus, although diagnosis by serology can be difficult due to its similarity to dengue, West Nile and yellow fever.


Typically no specific treatment is required. However, those sick with Zika virus should obtain plenty of rest and fluids and treat pain and fever with common medications. However, should the symptoms worsen, they should see medical advise.


The goal of prevention is to minimize exposure and protecting oneself from bites by using insect repellants, wearing long-sleeved shirts and long pants, use air conditioning or window/door screens to keep mosquitoes outside and empty standing water from containers that promote breeding.

Unlike other mosquito-transmitted illnesses, there is no vaccine.

Special precautions for pregnant women

Recently in Brazil, health officials have observed an increase in Zika virus infections and an increase in babies born with microcephaly (small head) and other poor pregnancy outcomes. Although the CDC and WHO have not definitively established a connections between the Zika virus and microcephaly, there is a growing body of evidence that they may be associated.

Until further information is known, the CDC has issued a Level 2 Practice Enhanced Precautions alert for all travelers to countries where Zika virus transmission is ongoing. Due to the lack of either a vaccine or prophylactic medications, the CDC is recommending that all pregnant women consider postponing travel to areas currently experiencing transmissions. However, should travel be necessary, the CDC are urging travelers to strictly follow steps to avoid mosquito bites.

For updates on travel advisories and developing information, please visit the CDC Zika virus site or the WHO Zika virus site.