Transcript for CDC Telebriefing: Zika

OPERATOR: Welcome, and thank you for standing by.  You are in a listen only mode until the question and answer mode of today's call.  If you would like to ask a question, please press star one.  Today’s conference is being recorded.  I would now like to turn the meeting over to Tom Skinner. 

TOM SKINNER: Thank you will for joining us today for this update on Zika virus.  Today’s CDC is releasing a couple of sets of interim guidelines on Zika.  one pertaining to a guidelines for health care providers, who are caring for pregnant women, and women of reproductive age with possible Zika virus exposure another set of the guidelines for sexual transmission of Zika virus.  Today we have the Director of the Centers for Disease Control and Prevention Dr. Tom Frieden and then he'll answer your questions. 

TOM FRIEDEN: Thanks very much for joining us.  Good morning.  Today I’ll discuss updated interim guidelines for health providers caring for pregnant women and describe new interim guidelines for the prevention ever sexual transmission of Zika virus.  But first, I want to step back and reflect.  It’s been exactly two weeks since CDC released our first travel alert notice on Zika virus in the Americas.  That was the same week CDC first identified Zika in brain tissue from infants who tragically had died from Zika.  I wish we knew more about Zika today.  I wish we could do more about Zika today.  I understand that this is a stressful situation for women and families, and particularly, for women who are pregnant.  And what we're doing in our efforts is prioritizing all of the work that we can do to protect pregnant women.  Zika associated Microcephaly and other fetal harm are new phenomenon.

 It has been more than 70 years since Rubella was a cause of fetal malformations.  We’re not aware of any mosquito disease associated with such a potential devastating birth outcome on a scale anything like what appears to be occurring with Zika in Brazil.  Because this phenomenon is so new, we are quite literally discovering more about it each and every day.  With each passing day, the linkage between Zika and microcephaly becomes stronger.  In addition, the linkage between Zika and syndrome becomes stronger the more we learn.  Because it's new and can be so severe, it's scary, especially for women who are pregnant or considering pregnant.  At CDC, we work 24/7 to protect people from health threats.  Key things.  Finding out all we can as fast as we can.  Second, being open and transparent about what we know and what we don't know.  We tell it like it is.  Third, doing all we can to protect people, both with the tools we have today, and by working both ourselves and with partners to develop tools for tomorrow. 

Two weeks ago, we issued a notice that pregnant women should not travel to areas where Zika virus transmission is ongoing.  That’s still the bottom line.  In addition, women who are pregnant and are in one of these areas should strictly follow steps to prevent mosquito bites.  In fact, everyone living in areas where Zika is spreading should avoid mosquito bites.  Over the past two weeks CDC and our partners have discovered a lot about it, but still much more to learn.  All but one case in the United States are either among returning travelers or in the U.S. territories of Puerto Rico, U.S. Virgin Islands and America Samoa.  Sexual transmission of Zika reported by Dallas.  There is no doubt that over the coming months, many more travelers will return to the U.S. with Zika infection.  Some of them will be pregnant women and already one, a woman in Hawaii, unfortunately, did give birth to an affected infant.  We expect that there could be local transmission in some parts of the United States, particularly in areas where the primary mosquito species that spreads Zika is present.  We hope and expect that local transmission will not become widespread.  But we'll have to change our guidance as we learn.  We’re working with state and local health departments to prevent local transmission, and we're also working intensively with Puerto Rico, U.S. Virgin Islands, America Samoa where local transmission is already occurring. 

Now, let me turn to today's release of interim guidelines.  The first of them is an update.  We’re updating our guidance for health care providers who are caring for pregnant women during this ongoing Zika virus transmission time.  Testing for Zika virus is improving.  I can say that over the past two weeks, we've learned several things.  First, the serological test, which is an IGM test, which tests for an acute infection, is performing better than we had hoped.  So we have more confidence in this test than we did even two weeks ago.  It is not perfect.  There is no perfect test for Zika.  But we need to roll out this test and that's exactly what we're doing.  that's why the new guidance recommends that not only should pregnant women who have had symptoms have testing for Zika virus, but also, to the extent possible, pregnant women without symptoms of Zika virus who did travel to a place where Zika was spreading, be offered testing between two and 12 weeks after returning from areas with ongoing Zika virus transmission.  As in the original guidance, pregnant women with a history of travel who live in Zika endemic areas and who have had Zika like symptoms should be prioritized for testing for Zika virus.  The best way to predict whether Zika virus is present is the presence of Zika like symptoms in people who may have been exposed to mosquito which carry the Zika virus. 

Women should discuss testing options with their health care provider, a full set of our recommendations is available on CDC.gov. We also heard from the providers community that serial ultrasounds were challenging.  Listening to women, their providers, families, we've adjusted and refined the guidelines and rolling out the availability of serological testing.  We wish more tests were available.  Our laboratories are literally working around the clock to get test kits out.  We’re fortunate that we have test kits at all.  That’s a reflection of many years of work done by scientists in CDC laboratories around the country, who have developed this test.  And were in active conversations with many companies to offer them.  Our technology, our materials, so that they can develop these, and they can be more widely available.  But we’re aware that it will be frustrating for some period of time.  Not everyone who wants to get a test will be able to get it and working as fast as we can to increase the availability of testing. 

Next, I’ll discuss CDC's interim guidelines for the prevention of sexual transmission of Zika virus.  Earlier this week, a Dallas county health department investigation revealed that a person who recently traveled to an area with Zika virus returned to the U.S. and developed Zika like symptoms.  That person later tested positive for Zika.  Subsequently, their sexual partner, who by report had not traveled, also developed Zika like symptoms.  Both of their infections with Zika virus were confirmed in the CDC laboratory.  These Zika virus continues to be spread primarily through the bite of an infected mosquito.  But we know that it can on occasion be spread by sexual contact, we're also aware of rare examples of transmission through blood transfusion.  Because it's possible that it can be transmitted through sex and because our primary concern and priority here is the protection of pregnant women, we're recommending the following.  Men with a pregnant sex partner, sorry.  Men who either live in or have traveled to an area of active Zika virus transmission and who have a pregnant sex partner should either consistently and correctly use condoms during sex, or abstain from sexual activity during the duration of pregnancy.  Consistent and correct use of latex condoms reduces the risk of many infections.  It’s also worth remembering that Zika virus illness is usually mild.  Approximately four out of five people who are infected never know they have it.  They don't appear to have symptoms.  When symptoms do occur, they generally last a few days or at most a week.  it's also very important to remember that the risk of Zika infection depends on how long and how much a person has been exposed to mosquito and the steps they've taken to prevent mosquito bites while in an infected area and how much Zika was spread anything that area. 

Our close today is talking about where we go from here.  Unfortunately, in places that have had a lot of the dengue virus, it could be many cases of infection, including some in women who are pregnant.  Whether and how many microcephaly cases there may be is not possible to know it.  There will continue to be many travelers with Zika coming back to the U.S., and some of these may be pregnant.  That’s why our bottom line again is that women who are pregnant should not travel to areas that have Zika virus. 

Finally, Zika reminds us that over and over, nature is a formidable enemy.  That’s why we have to invest in laboratories, disease detectives, tracking systems, mosquito surveillance and control programs, in the U.S.  And around the world.  Again, we wish we knew more.  We wish we could do more.  We know that this is anxiety provoking for women who are pregnant, and their families.  But there is something everyone can do.  Pregnant women can take steps to protect themselves.  Either by not traveling to an area with Zika infection, spreading or if they're in such an area by rigorously using mosquito protection.  That means repellant, clothing with repellant in it, long sleeves, and long pants.  If possible, air-conditioning, or at least screens.  Men who have traveled to areas where Zika is spreading and who have pregnant sexual partners should use a condom or abstain.  communities where Zika is spreading can reduce breeding sites by removing standing water and states localities, territories to implement effective mosquito pro cams to kill mosquito larvae and to control mosquito populations.  We at the federal government are working around the clock across the federal government to respond with the tools we have today while we try to optimize those and establish tools for tomorrow.  Thank you very much.  I’ll take questions now. 

TOM SKINNER: We’re ready for questions, please. 

OPERATOR: Thank you.  We will now begin the question and answer session.  If you would like to ask a question, please press star 1.  Make sure your phone is unmuted and record your information.  To withdraw, you may press star two.  Limit yourself to one question and one follow-up question.  Please stand by for the first question.  Our first question is from Helen Branswell with Stat News.  The line is open. 

HELEN BRANSWELL: Hi, my question, Dr. Frieden, you mentioned that things are evolving pretty rapidly.  The scientists announced that they had found active virus, so I presume that means viral was in saliva and our urine, do you think that is something the CDC will have to address going forward in the sexual transmission prevention guidance? 

DR FRIEDEN: We’re still learning more about Zika virus and how it works in the body.  Right you know, there are a total of three cases in the world literature of Zika virus being threatened in male genital urinary secretions.  As we learn more, we will adapt.  I think it's important to step back and emphasize that Zika is a mosquito borne virus, and the overwhelming majority of cases are spread by mosquitos.  There are unknowns.  We don't know how long the Zika virus may persist in semen, but it will be, we to months before we know more.  What we try to do is give people what we know when we know it, so you can decide based on the best available information. 

HELEN BRANSWELL could I follow up please. 

TOM FRIEDEN:  Yes, go ahead. 

HELEN BRANSWELL Thank you.  I see from the guidance here from what you said that priority is being placed on preventing transmission in women who are pregnant.  The guidance doesn't say anything about men who have sex with men.  Is there a message for them from the CDC preventing Zika transmission? 

TOM FRIEDEN: Our priority here is to prevent the pregnant women from being infected with Zika for that reason spread by other routes or among other populations is a much less concern, because again, four to five Zika infections are asymptomatic and those that are generally mild.  The real problem here is the effect on the developing brain of the fetus.  That is what has to be the priority for protection.  Next question, Carolyn. 

OPERATOR: Our next question is from Caleb Hellerman from CBS News Hour.  Your line is open. 

CALEB HELLERMAN: Thank you.  I was curious, the report yesterday about from the AP that some of the problems with serum samples here in brazil, I’m wondering, has that slowed down sort of lush or fast scientific inquiry in any way?  How are you dealing with that?  Are you making any kind of impact at the speed at which you're trying to get answers? 

TOM FRIEDEN: That has not been our experience at all.  We have found that the Brazilian government and scientists to be open, transparent and excellent partners.  We have had a team in Brazil working side by side doing studies on Guillain-Barre syndrome.  We have had specimens from our laboratories, when i said at the outset that we identified Zika virus in brain tissue of affected infants. That was a Brazilian specimen that had been sent to the U.S.  So i understand that the media have written about this, but that is not the reality that we have.  Right now.  There are challenges with specimen sharing that need to be worked out.  Issues that have gone on for many years, but have not undermined our response.  We already have positive samples from Puerto Rico not U.S. that we're able to grow in the laboratories.  as we work to develop better diagnostic tests, we do that in collaboration with other countries and we make sure that each country does it in consistency with its -- consistent with its own laws and regulations.  Next question, please. 

OPERATOR:  Thank you. Our next question or comment comes from Maggie Fox from NBC News. Your line is open. 

MAGGIE FOX: Thanks very much.  I’ll have a follow-up as well.  But Dr. Frieden, how do we know for sure that mosquito are the main route of transmission?  The reason i ask this is that most people are infected with any mosquito-borne virus within close proximity with other people. In case in Dallas, I’m wondering if there is any line of inquiry to make sure that the who transmitted the virus, that the semen was tested and perhaps even the saliva, to answer the question, not to raise the question, but just to be sure that we know it was sexual transmission, and that we know a bit more about assumptions that are made about what the vector is. 

TOM FRIEDEN:  Thank you.  Of course, we keep an open mind, but let's just go back to the basics here about Zika and mosquitos. The Aedes Aegypti is an aggressive mosquito.  It bites four or five people at one blood meal.  It bites relatively painlessly, so you don't swat it and kill it.  And it is ideally suited to the crowded urban environment, where there is standing water that can be a small as a drop of water in a bottle cap where it can breed.  And where it is challenging to get rid of or avoid, because it bites all day long.  Not just at dawn and dusk.  So everything that we've seen about not just Zika, but dengue and chikungunya suggests that this is the overwhelming cause of transmission.  Any time there are lots of cases, you'll see rare or occasional phenomenon happening sometimes.  And we think that is what is happening here.  As i indicated at the outset, we will be doing studies of how long the virus can persist in semen.  It goes away from the blood within about a week.  So we wouldn't be surprised to see, for example, occasional transfusion associated cases if someone gave blood when the virus was in their blood, and that's why on February 1st, the American association of blood banks issued the guidance to defer blood donations for all individuals who had traveled to an area with Zika transmission for 28 days.  That was a margin of safety for blood transfusion.  And because we don't know how long Zika is spread in semen, and because our concern is for that great vulnerability of the developing fetus, that's why we're saying that for men who may be infected may have been infected, whose partner is pregnant, they should wear a condom or abstain until the completion of the pregnancy. Pregnancy comes to term. 

MAGGIE FOX:  My follow-up was the semen involved in Dallas, Texas tested and if it wasn't, why didn't the Dallas County Health Department do that? 

TOM FRIEDEN: follow that investigation active and ongoing, and we're collaborating with the Dallas County Health Department on that.  As soon as more information is available, we'll make that public. 

TOM SKINNER: Next question. 

OPERATOR: From Mike Stobbe from the Associated press.  Your line is open. 

MIKE STOBBE: Hi, thank you for taking my question.  Just a couple.  First of all, in the Dallas case, was that male transmission to female?  Also, just so it's crystal clear, the guidance today on sexual transmission does not speak to kissing, and it does not speak to male to male transmission.  Is that correct? 

TOM FRIEDEN: In terms of your second question, we're specifically looking at all forms of insertive sex, including oral anal and vaginal from men who may have had Zika to women who are pregnant.  In terms of the Dallas case, we've released the details of those that we're going to release. 

MIKE STOBBE:  Okay, and my follow-up, thank you, is doctor, you said during your prepared comments that something about with each passing day, the more we learn, the linkage between Zika and microcephaly becomes stronger.  We have had reported cases outside of Brazil of Zika and microcephaly.  Is that correct?  Could you say more about what you're learning with each passing day that is helping you in your mind this link? 

TOM FRIEDEN: Well, in fact, there is a case of microcephaly in Hawaii, that we also mentioned two weeks ago all in the same day when we issued the response. That woman had been in Brazil early in her pregnancy, delivered an infant with microcephaly in Hawaii.  So we have seen cases outside of Brazil. We also have looked at the time course of Zika infection in different countries we don't expect to see infants born yet in other countries.  That’s why we're concerned that if the link is there, and again, we're not certain. There may be co factors.  There is still a lot that we don't know about Zika. But the association is looking stronger and stronger, and we're not surprised not to see cases of microcephaly in other countries because of the time frame between infection and delivery. 

TOM SKINNER:  Next question, Carolyn. 

OPERATOR: Our next question is from Kat Long from the wall street journal.  Your line is open. 

KAT LONG: Hi, thanks for taking my question.  Do you concur with the Brazil health officials advising pregnant women to avoid exposure to avoid saliva that it can be transmitted that way?  And I also have a follow-up. 

TOM FRIEDEN:  Sorry. I was on mute.  What we do in public health is to provide the best available information so that women can decide for themselves what they want to do. We know that semen may have large quantities of viable virus for at least a short period of time after Zika virus infection.  The data on saliva and on urine is less clear, but what we would do is provide that information and allow people to make their own choices. 

KAT LONG:  And how likely do you think it is that it can be transmitted through saliva or urine. 

TOM FRIEDEN: We just have no data to inform that, and we try to stick to the science here at CDC. The science says that we know that viruses can be transmitted through sex, relatively efficiently. That’s why there are so many sexually transmitted infections in the U.S. and around the world. And although other modes of transmission may occur, they tend to be much less common. 

TOM SKINNER: next question, Carolyn. 

OPERATOR: Thank you.  Our next question is from Dan Childs from ABC news.  Your line is open. 

DAN CHILDS: Thank you very much for taking my question. When will we know whether there is a key risk window during pregnancy when it comes to the possible connection between Zika and microcephaly?  And I have one follow-up question. 

TOM FRIEDEN:  Well, Zika behaves as many other infectious and other toxic causes of fetal malformations.  The first trimester and early part of the second trimester would be the highest risk time.  however, if Zika has as we fear what's called a neurotropic, where it's targeting the developing brain, then adverse consequences could occur at any time in pregnancy, and that's why our advice is specifically that regardless of the trimester of pregnancy, women who are pregnant should not travel to areas with Zika spreading and for women living in areas where Zika is spreading, they should protect themselves against mosquitos for the duration of pregnancy. 

DAN CHILDS:  Thank you.  and the follow-up question is are we getting any better at knowing whether there is actually a spectrum of developmental consequences, i, microcephaly that may be occurring or perhaps less physical? 

TOM FRIEDEN: This is one of the key questions that we'll be investigating in the coming days, weeks and months.  Because either possibility is there.  On the one hand, it may be that many of the children who don't have obvious microcephaly have significant health effects.  On the other hand, it may be that if there isn't microcephaly that children will have normal neural development.  We just don't know at this point.  We’re always going to err on the side of safety. 

TOM SKINNER: Next question, Carolyn. 

OPERATOR: Thank you. Our next comes from Sandee Lamotte from CNN.  Your line is open. 

SANDEE LAMOTTE: thank you so much for taking my q you indicated tests going on to test the semen of individuals.  Can you give us more specifics on that?  is that at the epicenter?  is that with the husbands of the women who have given birth to babies with microcephaly?  What exactly is being tested? 

TOM FRIEDEN:  really, the studies of viral persistence in semen will occur in many parts of the world including U.S. with traveler whose have come back and Puerto Rico where we have some sites where we have a he been monitoring other viral disease.  This is going to take time.  They’re not simple.  Essentially two ways to test for virus in semen.  One of them is a real time PCR or polymerase chain reaction, that's a very sensitive test, so that will be positive, even when the individual is not infectious.  Because it will measure or find even tiny parts of the virus, even if the virus is dead.  Nonviable.  The other test is what's called a culture or growing the virus, and though that's more specific, it's much less sensitive, and it may miss some people who are infectious, but the virus doesn't grow.  So these are studies that will take weeks to months to come up with reliable information, and they're underway. 

TOP SKINNER Next question, Carolyn. 

OPERATOR: thank you.  Next question is from Rob Stein from National Public Radio. 

ROB STEIN:   Thanks very much for taking my question.  I was just hoping you could talk a little bit more about the reports out today about the active virus being found in saliva and urine.  How worried should people be about that?  Should pregnant women not kiss men who have traveled or partners that have traveled what Zika is present?  I was hoping to get guidance on what this report means and how -- where people should be about it and what if any precautions they should take as a result. 

TOM FRIEDEN: We take all reports seriously.  We would need more information about that report, including the methodology of it.  But I think we have to go back to the bottom line here.  The bottom line here is this is a mosquito-borne disease, and that means in areas where Zika is spreading, women should protect themselves against mosquitos.  And for women who are pregnant, they shouldn't travel to an area where Zika is spreading.  The new guidelines we've issued this morning have to do with all forms of insertive sex between men who may have Zika and pregnant partners. 

ROB STEIN: That includes kissing, then? 

TOM FRIEDEN:  No.  We have not issued guidance on that. 

TOM SKINNER: Next question, Carolyn. 

OPERATOR: Thank you.  Our next question or comment is from Maryn Mckenna from National Geographic.  Your line is open. 

MARYN MCKENNA: thanks so much for taking my question.  Dr. Frieden, you said the CDC expects local transmission of Zika in the United States.  Is there anything you can say at this point about the robustness of state and local mosquito control programs? 

TOM FRIEDEN: Mosquito control in the U.S.  Is often done by what are called mosquito abatement or abatement districts and quite variable.  Some of them do a suuperb job, some of them less so.  That’s why it's so important that we invest in the systems to track and find mosquitos.  This is not easy work.  And I can -- although the mosquitos did spread Zika spread West Nile having worked on that for many years, the different aspects of mosquito control can be quite complex, labor intensive, and really when it comes to both Zika in general and mosquito control specifically, it is not easy, and it is not quick.  For mosquito control, you need to have monitoring of both mosquito larvae and adult mosquito.  That’s a labor intensive complex undertaking, and then you need to control mosquito larvae and adult mosquitos, and that's a labor intensive and challenging area.  We know from the experience with dengue, you have to get to very high levels of mosquito control to drive down the risk of dengue in the community. 

MARYN MCKENNA: My follow-up question this sounds like something you're concerned about. 

TOM FRIEDEN:  Yes, I think it is concerning because of the pregnant women and the developing fetus and because there is such an important need for us to learn more and do more in the U.S., in Puerto Rico and the other territories of the U.S., which have had lots of dengue cases in the past, and that's a marker for the risk of Zika and around the world. So that we can learn more and partner to address Zika as effectively as possible. 

TOM SKINNER: next question, Carolyn. 

OPERATOR: thank you.  In the Lisa Schnirring from CIDRAP news. 

LISA SCHNIRRING: Hi, Dr. Frieden, a real quick question here.  You said that there have been 35 imported cases in the United States and then you have some in territories.  I’m wondering if there has been any syndrome cases in any of those that people have picked up. Thanks so much. 

TOM FRIEDEN: Yes.  So let me just clarify a bit about the reporting of Zika cases.  We have worked with what's called CSTE, Territorial Epidemiologists.  It is a reportable disease throughout the U.S. and the territories.  We will be updating on our website, as we did today the number of officially traveled cases, 35 Zika cases, within the U.S. states, as well as locally acquired cases in Puerto Rico, the U.S. Virgin Islands.  We have heard reports by today of 51 cases in the continental U.S. 50 of them from travel and one of them in Dallas from apparent sexual transmission.  We’ve heard of 21 cases in Puerto Rico, 20 locally acquired and one from travel elsewhere.  Among all of those cases, there have been six pregnant women [NOTE: updated by CDC after the telebriefing to 7 pregnant women: 6 in continental US, one in Puerto Rico, a US territory].   One affected child.  And one individual with Guillain-Barre syndrome.  I have to say on Guillain-Barre syndrome in an individual case.  So there is a fair amount of Guillain-Barre syndrome in the U.S.  a real illness, influenza infection, a range of other infections.  And so in any individual case, it can be difficult to say it's associated, but there does appear to be one case.  as we look at numbers going forward, we'll be looking particularly not just at the number of cases, because we do expect there to be many more travel associated cases in the weeks to months to come because there is a lot of travel to places with Zika spreading, particularly at the number of pregnant women, the number of affected children and also the number of individuals with Guillain-Barre. 

TOM SKINNER: Next question, Carolyn. 

OPERATOR: our next question or comment is from Lena Sun from "Washington Post."  Your line is open. 

LENA SUN: Hi, Dr. Frieden, can you follow-up on that information, is there any kind of monitoring or additional surveillance that you're doing for these six pregnant women, and the one case with Guillain-Barre syndrome, and is there any more you can share or elaborate about those cases? 

TOM FRIEDEN:  Because of medical confidentiality, i can't go into any details.  We’re working closely with the patients and their physicians.  And it's obviously a very challenging situation for them.  And we respect their privacy. 

LENA SUN I have a follow-up.  It’s more about the science.  How significant do you think it is that they were able, the Brazilians were able to find antibodies in the spinal fluids of those babies with microcephaly. 

TOM FRIEDEN:   Again, we have not seen the details of which tests were done. We’ve worked with the Brazilians collaboratively and in fact, they're one of 14 countries which we have provided training and materials to so that they can do the test that was developed in the CDC laboratories.  That information is certainly of interest, and is one of the things which if confirmed would increase our level of suspicion really that microcephaly is causal. 

TOM SKINNER: Next question, Carolyn. 

OPERATOR Thank you.  Next question is from Kerry Sheridan from AFP.  Your line is open. 

KERRY SHERIDAN: Great.  Thanks for taking my question.  Dr. Frieden, i was point you made earlier about other cases of microcephaly outside of Brazil.  You weren't surprised not to see them, because of the time frame between infection and delivery.  I was wondering, i would imagine that health officials are anticipating cases in other areas.  Can you say anything more about when those cases might start to arrive? 

TOM FRIEDEN:  Our scientists are looking at that, and though we don't have a crystal ball, we do have some of the best scientists and modelers and laboratory experts in the world.  It will depend on a series of unknowns.  The first is how much Zika was there.  And that's hard to know.  The second is how likely is it that a case that an infection with Zika in pregnancy at different stages symptomatic or not resulted in an infected infant. we just don't know that.  There are lots of unknowns here.  We have teams on the ground and heading out today, tomorrow next week to partner with countries around the continent so that we can learn more in Latin America, Caribbean and elsewhere. 

KERRY SHERIDAN: Thank you. 

TOM SKINNER: Next question, please. 

OPERATOR: Our next question is from Nicholas St. Fleur from the New York Times.  Your line is open. 

NICHOLAS ST. FLEUR: Hi there. Thank you for taking my question.  My question is looking at the CDC's advice.  the CDC have any advice for women who are currently not pregnant but are thinking about becoming pregnant who have sexual partners, male partners who have been to one of these affected areas?  What is your advice to them to prevent sexual transmission? 

TOM FRIEDEN: I think the key there is to talk with your doctor.  We encourage women to discuss this with their doctor and with their sexual partner, and to remember that the risk of Zika infection depends on how long someone was in a Zika affected area, how much Zika there was at the time.  How many mosquito bites the person got.  We wish we had a perfect test to determine if someone was potentially infectious, but we don't have that today.  And with the limited test capacity that we're rolling out, we're prioritizing women who are pregnant.  It may be then several weeks or several months.  We have a much more widely available, much more accurate test, and we are working around the clock ourselves, and with the number of companies to try to make that available to people.  But it's not available today. 

TOM SKINNER Carolyn, we'll take two more questions. 

OPERATOR: Thank you. Our next question or comment is from Julie Steenhuysen from Reuters the line is open. 

JULIE STEENHUYSEN: I wonder if you could tell us about the protocols for the studies that you're going to be running in Brazil to, you know, sort of make that causal link between Zika and microcephaly. 

TOM FRIEDEN: So one of the key methodologies here is what is called a case controlled study, where we identify infants who definitely have microcephaly and identify controls who definitely don't have microcephaly, and then we compare both their characteristics of the mothers, the infants, the environment and most importantly, we got laboratory tests.  There are really three classes of tests here.  One test for active infection, and that looks for the actual virus itself, with PCR second looks for the body's reaction to infection.  Looking at both IGG and IGM, antibodies, and the third, plaque reduction neutralization, PRNT, which looks at whether it's likely to be from that particular virus. None of these tests are perfect and is some cross reactivity of the latter two with dengue and chikungunya which may be common in these areas.  So these study also take weeks to months to complete but we'll continue to keep people updated on our progress as we move forward. 

JULIE STEENHUYSEN: Okay, and also, given that, you know, concerns, are you going to be at -- soon adding any other country to the travel restriction? 

TOM FRIEDEN: As every time we -- there is Zika reported and confirmed in a country, we add it to the travel advisory, the best place, best way to look is to look on our website. 

TOM SKINNER: Carolyn, we'll take one last question, please. 

OPERATOR: Thank you.  Our final question comes from Lynn Peterson from trend medicine.  Your line is open. 

LYNN PETERSON: Thank you. The question is if it's in semen, then in someone gets pregnant from that semen, is that fetus that newly formed fetus at risk? 

TOM FRIEDEN: We have no information on that.  This a new phenomenon that we still don't know about. 

LYNN PETERSON So doesn't that mean that men should be tested, and people are basically at risk?  Fetuses are at risk, they get created? 

TOM FRIEDEN: You're asking questions that we don't have scientific answers to.  And what we do know is that for many different infections and other toxins or things that cause problems in pregnancy, the highest risk is in the first trimester.  We also don't know for example the likelihood that there would be transmission in the way that you're outlining. 

But the key here, i would like to just close, by reminding people of four key things.  First, the bottom line for most people in the U.S. is that pregnant women should postpone travel to Zika affected areas.  Second, our new guidance is that pregnant women should use protection during sex with condoms or abstain.  If their partner has traveled to an area where Zika is spreading.  Third, that pregnant women who themselves traveled to an area where Zika has been spreading should be tested for the virus between two and 12 weeks after return.  And finally, that this is a new phenomenon.  It has been more than 50 years since a viral cause of a significant birth abnormality has been identified.  We’re learning more about it every day.  We wish we knew more.  We wish we could do more and we understand that pregnant women and their families are anxious. That’s why we emphasize that there is something that everyone can do. Pregnant women can defer travel or if they're in Zika affected area, can rigorously prevent mosquito bites, communities can reduce mosquito populations by mosquito control and invest in effective mosquito control.  We at CDC and throughout the federal government are working 24/7 to scale up testing for Zika, track the virus, implement the best ways we have to protect people today, while we figure out better ways to kill mosquitos, and encourage people to make informed decisions by providing all of the information that we know when we know it.  the situation that you've all been rapidly and as we learn more will share more, so that Americans can decide how best to protect their own health.  Thank you very much. 

TOM SKINNER: Carolyn, this concludes our telebriefing transcript of this call will be posted to the CDC newsroom as soon as possible. If reporters need additional information, or have other questions, they can call the CDC press office at 404-639-3286, or e-mail media@CDC.gov. 

OPERATOR: That concludes. You may disconnect it.  

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES