Zika Virus Q&A: What you need to know about sex, blood donations

The mosquito-borne Zika virus, linked to an epidemic of birth defects in Brazil, is spreading quickly throughout the Americas. A case of sexually transmitted Zika in the United States and the possibility of getting the virus through blood transfusions are creating the latest concerns.
The World Health Organization declared the outbreak a "public health emergency of international concern." Here is the latest on what you need to know:

Q: Can you get Zika through a blood transfusion?  

A: Yes. Brazil has reported that two people have gotten Zika through a blood transfusion. Blood suppliers can't screen the blood supply for Zika because there's no commercial test for it. However, the risk of contracting Zika from a blood transfusion in the continental USA is extremely low because the virus is not spreading among local mosquitoes.

Q: Are blood banks taking precautions?

A: Yes. The American Red Cross is asking people to avoid donating blood if they've traveled to Zika-affected areas in the past 28 days. The American Association of Blood Banks issued a similar recommendation. Canadian Blood Services is barring people from giving blood within 21 days of traveling outside Canada, the continental USA and Europe.

Q. How serious is the risk of sexual transmission?

A. Scientists have known since 2008 Zika can be transmitted through sex, but they say such transmission is extremely rare. Doctors aren't sure if a person needs to be sick with obvious symptoms in order to spread the virus through semen.
Health officials in Texas on Tuesday  confirmed a case of sexually transmitted Zika. The WHO said the case is cause for concern and requires further investigation, but said mosquitoes are the most common means of transmission and should be the primary focus for disease control.

The Dallas County health department has confirmed two people in the Texas county have tested positive for the Zika virus. One patient had sexual contact with another infected individual; the other patient contracted the virus while in Venezuela. WFAA-TV

Q: How can people reduce the risk of sexual transmission?

A: Using condoms and practicing safe sex reduces the risk of sexual transmission of Zika.

Q: How long does Zika last in blood or semen?

A: Zika stays in the blood for about a week. Mosquitoes can only pick up the virus if they bite someone during this time. Scientists don't know how long Zika can live in semen.

Q: What is the Zika virus?

A: Zika virus appeared for the first time in 1947 in Uganda. For decades, health experts considered it a minor-league virus that, until recently, was limited to a narrow belt of equatorial Africa and Asia.

Q: How does it spread?

A: The Aedes mosquito spreads Zika. Unlike the flu, it does not spread from person to person. Mosquitoes that bite an infected person can spread it to future victims.

Q: When and where did this current outbreak begin? 

A: Zika was first detected in Brazil in May. ​Researchers suspect the virus may have arrived in South America during the 2014 World Cup Games that drew millions of fans to Brazil. Zika usually causes no symptoms, which could explain why the first cases of illness weren't reported the country until the following year.

Q: Where is the virus currently spreading?

A: Zika is now in at least 25 countries and territories in Latin America and the Caribbean.

Q. Has Zika reached the continental USA yet? 

A. Yes and no. More than 30 Americans have been diagnosed with Zika after returning from visits to countries with Zika outbreaks. These travel-related cases pose a very low risk for spreading. In one case, a resident of the Dallas area contracted Zika virus from a sexual partner who had visited Venezuela. Health officials aren't including the continental USA in their list of outbreak countries because the virus is not entrenched in local mosquito populations.

Q: Are there concerns this summer's Olympics could spread the virus wider?

A: Brazil's hosting of the Games could give mosquitoes a chance to infect people from around the world. Public health officials in Rio de Janeiro downplay the risk, saying there will be fewer mosquitoes when the sporting event opens during the cool month of August. City workers are already destroying mosquito-breeding grounds.

Q. What are the symptoms of Zika?

A. Four out of five people infected by Zika have no symptoms. Those who do usually have mild symptoms lasting two to seven days, such as fever, rash, headaches, joint pain, muscle pain, lack of energy, weakness and pink eye. It typically takes three to 12 days for illness to develop after a mosquito bite.

Q: Is it deadly?

A: Not usually, but people with pre-existing health problems can develop fatal complications.

Q: Why are people concerned?

A: The virus is linked to serious birth defects. In October, Brazil's Ministry of Health recorded an unusually high number of cases of microcephaly, in which babies are born with small heads and incomplete brain development. Brazil is investigating 3,500 cases of microcephaly. It usually has 100 to 200 such cases per year, a number that may have missed some infants with the condition.
Children with microcephaly may have facial distortions, developmental disabilities, short stature, difficulties with balance and coordination, speech problems and seizures.

Q. Could American women experience the same birth defects if Zika spreads within the USA?

A. No one knows for sure. Doctors don't know why the virus is only now associated with birth defects. It's possible that a second factor beyond Zika virus influences the risk of microcephaly.

Q: How is microcephaly treated?

A: There's no treatment for microcephaly. At least 38 Brazilian babies have died. Although some children have normal intelligence and development, their heads remain small, according to the Mayo Clinic.

Q: Why did some nations advise women to postpone pregnancy?

A: The spike in birth defects in Brazil prompted Colombia, Ecuador, El Salvador and Jamaica to recommend women delay pregnancy until doctors understand more about the virus. El Salvador issued the strongest warning, urging women not to conceive for two years.
However, scientists have no idea how long the Zika virus will pose a risk to pregnant women. Health officials in El Salvador believe that people could develop immunity to the virus over time.
Many public health officials have criticized the advice to postpone pregnancy, saying it's unrealistic to tell women when to conceive. About half of pregnancies are unplanned.

Q. What other warnings have been issued about the virus? 

A. The Centers for Disease Control and Prevention warned pregnant women to avoid traveling to areas with Zika outbreaks. Women who cannot avoid traveling should consult their doctors and take steps to avoid mosquito bites, such as wearing long sleeves and pants. Women thinking of becoming pregnant should also consult their doctors before traveling to outbreak zones. Neither the CDC nor the World Health Organization have issued any statements about postponing pregnancy.

Q: What other ailments is Zika linked to? 

A: Zika is linked to cases of Guillain-Barre, a rare immune system disorder that can cause temporary paralysis.

Q: What treatments or vaccines are available for Zika virus?

A: There are no approved treatments or vaccines for Zika.

Q: How is Zika diagnosed?

A: Diagnosing Zika is difficult because its symptoms can mimic those of other mosquito-borne diseases, and there are no approved commercially available tests. Only a few labs can perform the tests that detect Zika virus in blood samples.

Q: What populations are at greatest risk of Zika?

A: People who live in poverty are at greatest risk because they live in environments where mosquitoes thrive: trash-strewn neighborhoods with lots of standing water, where mosquitoes breed, in homes without air conditioning or even window screens to keep the mosquitoes out. Although cities in Latin America and the Caribbean often meet these conditions, many impoverished communities along the Gulf Coast in the USA are also at risk, said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston.

Q: How can the risk of Zika be reduced?

A: The only way to prevent infection is to avoid mosquito bites by staying indoors when visiting an area where the virus is present, wearing long pants and long-sleeved shirts, and using mosquito repellent. Communities can reduce their risk of Zika by eradicating mosquitoes and by removing trash that collects standing water.