Dr. Metzger reviews the most current literature and guidelines, as of March, 2016, for the Zika Virus.
St. David’s Healthcare CME program recognized the significance of ongoing clinical changes in medicine and how often new techniques and outcomes are introduced. We are proud to offer the library of courses available to you, however, cannot guarantee that all courses are presented with the most current information. The course shown above is no longer available for CME credit. SPEAKER 1: Doctor Brian Metzger earned his Master of Public Health from Emory University and his medical degree from Medical College of Georgia. He's board certified in both infectious diseases and internal medicine, and his postgraduate training was that Mount Sinai School of Medicine and Albert Einstein College of Medicine. Doctor Metzger has won many scholarly awards and has written several publications in epidemiology allergy and infectious disease. As the medical director of infectious diseases Saint David's, we often look to him for his guidance and expertise when faced with public health issues and infection prevention opportunities. Please join me in welcoming Doctor Brian Metzger, who is here to present Zika-- a virus finding a new home. BRIAN METZGER: Thank you everyone. Thanks for coming. Really, it's great to have you here this afternoon. I thought this was an appropriate little cartoon here. It's essentially a virus-- Zika virus is finding a new home. Its home was Africa, Southeast Asia, and through a little bit of travel has found a large new home. So I thought that was very appropriate. So Zika virus itself is a member of the family of viruses called Flaviviridae, so it's often referred to as a Flavivirus. That group of viruses, that family of viruses includes Dengue, Yellow Fever, Japanese Encephalitis, and West Nile virus that we here in Texas had a little run in with a few years ago. It's an enveloped RNA virus. It's transmitted by several species of Aedes mosquitoes around the world, including ones that we have here locally, which are Aedes Egypti and Aedes Elba Albopictus. Here's the distribution of that Aedes Egypti mosquito. So you can see a nice band there through Central Africa and Southeast Asia, which was its original home, the virus' original home, but we'll see kind of migrated its way to South America. And as far as US distribution, mainly southeast and little pockets in the southwest. Here's the distribution in the US of the Aedes Egypti and Albopictus. Egypti, as you saw just the slide before, is mainly southeast. But Albopictus really extends into some major metropolitan areas in the Northeast, including DC and Philadelphia. Clinical factors of Zika include an incubation period of approximately 2 to 14 days after a mosquito bite. Overall, Zika virus illness itself is not severe. It's a very mild illness. The symptoms resolve typically in about two to seven days. Zika virus is detectable in blood via PCR for a few days to a week after the initial symptoms. The infection does appear to confer immunity to the person that was infected. So those symptoms that are mild include Maculopapular rash, typically starting in the head and neck and descending. Also includes Conjunctivitis, the nonpurulent type. Fever, which is pretty mild and low grade. And Arthralgias, small joints of the hands and feet. So we just touched on this a minute ago, how they primary route is the Aedes mosquito. One important point still to point out that still holds today is that Zeke has not been spread by mosquitoes in the continental US. There are other modes of spread which we've come to find out are maternal-fetal, as well sexual. Zika virus RNA has been detected in many different bodily fluids that you see there, including blood, urine, semen, saliva, CSF, amniotic fluid, and breast milk. Now it's unknown whether the presence of virus in some of the above fluids really translates into transmissibility. There's a difference between detecting the viral DNA, which can just be really a few copies of virus. There's a difference between that kind of detection and actual transmissibility. Now onto Zika's origins. It was named from the Zika forest of Uganda where the virus was first isolated in 1947. What happened was fever developed in a rhesus monkey in an area where they were, I believe, studying Yellow Fever. That monkey's serum was then inoculated into mice. All the mice then became ill quote unquote transmissible agent was later named Zeke virus. It was isolated from the mouse brains. In 1948, Zika virus was isolated from Aedes Africanus mosquitoes that were trapped in that same forest. This is what Zika looks like under an electron micrograph. You see the arrow pointing to the viral particles. In 1952, serological surveys in Uganda and Nigeria showed a high prevalence of antibodies, really showing that that virus was already present, was endemic in that area of the world at least for a few years prior, and probably a lot longer. A lab in 1956 artificially fed mosquitoes that transmitted Zika virus to mice and a monkey. So they fed the virus to these mosquitoes that then was able to transmit Zika to mice and a monkey, sort of sealing that vector relationship. In 1968 the virus was isolated from people in Nigeria. Subsequent serologic studies found evidence of Zika in other nations of Africa and Asia. So really from 1947 to 2007, this is the way the Zika map looked. Again, mean mainly that band across Central Africa and Southeast Asia. There's a list of countries where the virus was known to exist, and mainly it caused sporadic infections. So it was endemic to the area, really just sporadic infections, typically in younger persons since there was really constant exposure in these areas, so children were mainly the ones getting infected. Then Zika takes a journey east. In 2007, in the first major documented outbreak occurred on Yap Island in Micronesia. And there you can see-- so this is the area where it was endemic to already and jumped over to Micronesia. This was published in New England Journal of Medicine in 2009. There were no hospitalizations or deaths, and it was estimated about 73% of the population more than three years of age were recently infected. Zika continued to head east, this time in 2013 to 2014. Created a larger outbreak in the French Polynesia before spreading throughout the Pacific. This affected about 32,000 people in this area, and there's your French Polynesia. And here was Micronesia, so it was really spreading throughout the Pacific Islands. So here's one of the little tangents. I'm going to try to take this-- not only tell you the latest recommendations, but how we got there. One little tangent here that they actually found during this French Polynesia outbreak was that they were concerned about their blood supply in their blood transfusions since they had this massive outbreak of Zika cases. So what they did was they implemented a program of looking for specific nucleic acid testing of blood donors. And from November 2013 to February 2014 they found that 42 or 3% of 1,500 blood donors were PCR positive for Zika virus, and all these folks were asymptomatic at the time of donation. Currently the FDA does not have a licensed blood donor lab screening test available to detect Zika virus here in the US. So here right at this moment we're really relying on using questionnaires and screening donor histories to ask about recent travel, really asking, have you been in any of these affected countries within the past four weeks? OK, back to the original program. So Zika continues its spread to the east. In February of 2014, Zika appeared for the first time in the Western hemisphere on Chile's Easter Island. I learned a lot of things putting this together, but one thing I learned is that Easter Island is a part of Chile. I didn't realize that. So here's Easter Island, I want to say right off the coast of South America. It's pretty far. Now moving on to Brazil. In the summer of 2014 there was-- my phrase, Dengue light, that was appearing in Natal. Patients with a rash, bloodshot eyes, fever, and joint pains begin appearing in local clinics and ERs, and no one could really figure out what this was. It sure seemed like Dengue, but when they tested it, when they tested these patients, they were negative for Dengue, for Chickungunya Virus, and for West Nile Virus. So they kind of scratched their heads for a bit. In the meantime, Dengue light was headed south through Recife. This was really the epicenter, this Northeast area of Brazil. That has been the hardest hit throughout the epidemic. Here's Natal, here's Recife. And then by March 2015, it was continuing south down to Salvador. On March 26, 2015 there were a group of ER physicians that really noted a large number of patients now that were presenting with this dengue-like illness, and it was a hospital in the state of Bahia in Brazil at this particular hospital, Santa Helena hospital in the ER. So serum samples were sent from 24 patients and they were tested using ELISA specific for dengue, IgG IgM. Of course they were negative. Then the samples were sent to the Federal University of Bahia where they were analyzed using PCR to try to detect, again, Dengue, Chickungunya, West Nile Virus, Mayaro virus, and Zika virus. All were negative for Dengue, Mayaro and West Nile virus, but samples from 7 or 29% of the patients were positive by PCR for Zika and 3 were positive for Chickungunya. And so that was really the beginning of detection of the virus in Brazil. But by the end of 2015, the Brazilian ministry of health had estimated that about 440,000 to 1.3 million cases of Zika virus had occurred. Circulation of Zika continued onward to Columbia and then Suriname in October and November 2015, respectively. So it landed in Brazil-- at least thought to have landed in Brazil initially, and then was spreading already throughout the South American continent. Another little side note here. They performed phylogenetic analysis on these viruses, and what they found was that the Brazil and Suriname strains belong to the Asian genotype, again confirming that the same virus that was migrating eastward from Asia, it was moving in an eastward direction rather than coming from Africa. It most closely related to the strains circulating in French Polynesia, the one that was circulating in that epidemic in 2013 and shared over 99% of its nucleotide and amino acid identity, respectively. Subsequently, Zika virus was isolated from Guatemala and Puerto Rico and also was sequenced as the Asian genotype. So how did it get there? There's a lot of speculation about this, obviously. Two main competing theories, I would say, are that it arrived during the 2014 World Cup. Natal was a host city, that was the epicenter of the first cases. And that city happened to be a host city for that World Cup. And cases really began to appear just a few weeks after the World Cup in that summer of 2014. The other competing theory is that arrived during the Va'a World Sprint, which was a canoe race in Rio where there were teams from several Polynesian islands that competed there. That one, I think, a little bit weaker, personally, just because this didn't all start in Rio. If it started in Rio I think it would've been recognized in Rio very quickly. Now to Zika complications. There's really two main complications, or groups of complications and intrauterine or congenital infection. So we'll start with Guillain-Barre syndrome. In December 2013, again, during that epidemic in French Polynesia, they really did a good job of investigating that outbreak. But there were first published cases of Guillain-Barre syndrome occurring immediately after Zika virus infections in patients during that outbreak. Neurologic deficits began about seven days after myalgia, fever, rash, and conjunctivitis was appearing in these patients. Between October 2013 in April of 2014, French Polynesia experienced that largest Zika virus outbreak ever. And during that same time period an increase in Guillain-Barre was reported, suggesting that possible association between Zika and Guillain-Barre. So this author here along with some others actually just came out in Lancet, just, I believe, last week-- is online only at this point. Which, a few of the articles that I present here are online only. This is evolving so rapidly in new data are coming in all the time. So this particular study, they really aim to assess the role of Zika virus and Dengue virus infection in developing Guillain-Barre. So they performed a case-control study. The cases were patients with Guillain-Barre diagnosed at a hospital I'm not even try to pronounce, but was in Tahiti in French Polynesia during that outbreak period. Controls were age matched, sex matched, and resonance matched patients who presented to the hospital a non-febrile illness, that was control group number one, comprised of 98 patients. And then the control group two of 70 patients was age matched with acute Zika virus disease and no neurologic symptoms. 42 patients were diagnosed with Guillain-Barre during the study period. 41 of them, or 98% with GBS had anti-Zika virus IgM or IgG. All of them had neutralizing antibodies against Zika, compared with only 54, or 56% of the 98 in control group number one. And that was a very significant difference between those two groups. 39, or 93 percent of patients with Guillain-Barre had Zika virus IgM present, and 37, or 88% had experienced the transient illness-- a median of about six days with of range of about 4 to 10 days before the onset of neurological symptoms, suggesting that recent Zika infection. 12 patients required respiratory assistance. No patients died-- they all recovered. Another important point was that past Dengue virus history did not differ significantly between the three groups, between the case group and the two control groups. You can see 95%, 89%, and 83%, respectively. The incidence of Guillain-Barre during the outbreak was estimated to be a chilling 0.24 cases per thousand Zika virus cases. So we typically think of Guillain-Barre in terms of-- in the US, it's usually 1 or 2 per 100,000 population-- not infected patients, but 1 or 2 per 100,000-- so if you put that in terms of 100,000 cases, that's 24 cases per 100,000. Now moving on to Intrauterine infection. The Zika virus has been associated with various malformations like microcephaly, brain atrophy, ventricular enlargement, intracranial calcifications, and even, quite often, unfortunately, fetal loss. Now what is microcephaly? It's a condition in which the neonate's head is smaller than expected compared with neonates of similar gestational age and sex. It's associated with the other infectious illnesses, including Rubella, Cytomegalovirus, Lymphoctytic choriomeningitis virus, as well as toxoplasmosis, and, very rarely, other flaviviruses viruses like Dengue or West Nile virus. It's also associated with non-infectious agents, such as alcohol and mercury. And here' just a little picture of what a neonate's skull appearance is like in microcephaly. Congenital microcephaly can be detected prenatally, but commonly it's detected after birth. I think in the US that would likely be different. No definition of microcephaly has been universally accepted. It ranges from head circumference three or more or two or more standard deviations below the mean, or less than the third or fifth percentiles. Because of varying definitions, the birth prevalence of congenital microcephaly is difficult to monitor in a population. But the case was being built that the Zika virus was related to these cases of microcephaly that began appearing in Brazil. Initial epidemiologic investigations found an association between microcephaly and a maternal rash-like illness. Then in another set of cases, amniotic fluid was obtained from two pregnancies that were affected by microcephaly that were positive for Zika virus RNA by PCR. Then laboratory testing demonstrated Zika virus infection in tissue from three neonates with microcephaly, and two were-- fetal loss had occurred. Here investigators, again, from French Polynesia-- again, learned a lot from that outbreak. On November 24th, 2015 the authorities of French Polynesia reported an increase of microcephaly from an average of one reported case annually that they would see in that population to 17 cases of CNS malformations in fetuses and infants during that 2014-2015 period. CNS malformations were observed in 12 cases, and findings lead to termination in nine instances. Three remaining cases were born at term with normal body measurements but presented with poly-malformations and brain lesions. So heading back to Brazil, in September and October of 2015, at this point an unusual increase was noted in Brazil with the number of newborns with microcephaly, mainly in that state of Pernambuco, Brazil. And by the end of 2015, more than 3,500 newborns with microcephaly we were being reported in Brazil. Of course, it wasn't known how many of these cases were associated with Zika virus infection. Stepping aside a little bit, in the US, estimates range from-- or at least published estimates are 2 to 12 affected newborns per 10,000 live births in the US. But there were really no population-based estimates of congenital microcephaly available in Brazil at the time before these observed cases appeared in 2015. There were some hospitals that kept their own data, like hospital-based data, and so in some cases they were able to find a difference, but there were no population-based estimates. And what those local hospital-based comparisons found was an estimated 20-fold increase in the number of newborns with microcephaly reported in Brazil during that time period compared to prior years. So this was from February 5th, 2016, which is now so old. This is really-- again, the epicenter here is in Northeast Brazil, and this salmon area here were suspected areas, states in Brazil with suspected cases as of January 2016. And these had confirmed cases of microcephaly in these areas here, and you can see these rings get larger as there's more cases in each state. And again, Pernambuco is hit hard, as well as the state of Bahia. And down here you have suspected microcephaly cases, typically in the mid 100s from 2010 through 2014, and then a huge spike in 2015 with 3,670 cases reported. The Brazil ministry of health recently released an updated report on March 1st, and now they're up to 5,909 cases that were suspected. With 641 of them now being confirmed, a thousand, approximately, were discarded, and 4,200 were still under investigation even at this point. In the US, in January of 2016, the first case of Zika-related congenital microcephaly was encountered. It was in Hawaii. A baby was born to a woman who had traveled to Brazil during her pregnancy. It was believed to be, I think, in May of 2015. The baby and mother both tested positive for past Zika infection. Talk a little bit about Zika's brain cell target. This was just published on March 4th-- again, online only-- in the journal Cell Stem Cell, where these investigators looked for the direct target cells for Zika virus in the developing human fetus. They weren't clear at the time, so they took a strain of Zika and serially passaged it through a monkey and mosquito cells, efficiently infecting human neural progenitor cells derived from induced pluripotent stem cells. So what they've found was that infected human neural progenitor cells release infectious Zika virus particles, and significantly more than any other cell line, even other neural cell lines. It's this one in particular that was pumping out virus. Importantly, Zika virus infection increased the cell death and disregulated cell-cycle cycle progression in their study, and it resulted in attenuated neural progenitor cell growth. And here's a figure from that study. Top bars show Zika-infected cells and it's immuno-stained with this green denoting Zika virus particles. So you can see the Zika-infected cells lighting up green that are infected, and non-Zika exposed, this was the normal look. And down here you have, again, those neural progenitor cells having high infection rates, similar 70%, 80% of the cells being infected, whereas other neurons and other neural cells were infected 10%, 20% of the time. So that particular cell line was really what's likely driving these cerebral malformations. Now here's the big one. This was just released on March 4th, as well. This was the ever expanding presentation here today because new data just kept pouring in. And this is published in the New England Journal of Medicine, entitled, "Zika Virus Infection in Pregnant Women in Rio de Janeiro-- Preliminary Report." So they really just had some of their data to release at this point. And in that study they attempted to characterize that spectrum of Zika virus disease in pregnancy. They followed patients in Rio de Janeiro to describe clinical manifestations in mothers and the repercussions of acute Zika virus infection in their fetuses. From September 2015 to February 2016, they enrolled pregnant women in whom a rash had developed within the previous five days. They tested their blood and urine for Zika virus by reverse transcriptase PCR-- we'll just call it RT-PCR, or PCR-- followed the women prospectively and collected clinical and ultrasound data. 88 pregnant women with rash were enrolled from that September 2015 to February 2016, and of those 88 women, 72, or 82% tested positive via the PCR method for Zika virus in blood, urine, or both. Timing of acute infection range from 5 to 38 weeks gestation, so it was a whole spectrum of where these women were at in their pregnancy. Predominant clinical features included-- in the mothers-- included pruritic descending macular or maculopapular rash, as well arthralgias, conjunctival injection, and headaches. So all of what we've previously seen published before. Interestingly, only 28% had fever, and it was short term and low grade. Here's a figure of pictures from some of these women. They make it hard to make out. That's supposed to show that maculopapular rash on the face. There's your conjunctival injection. This one here's supposed to denote-- [AUDIO OUT] --and then more rash, rash, and then blanching rash here on the abdomen. What they found was that women that were positive for Zika virus were more likely than those who were negative for Zika to have one, maculopapular rash-- 44% versus 12%, which was significant, as well as conjunctival involvement, 58% versus 13%. And lymphadenopathy, 40% percent versus 7%. Fetal ultrasound was performed in 42 Zika-positive positive women, which was 58% of their cohort. 28 of the patients declined, either because the center was too far for them to travel, they want to travel that far, or they were afraid of what they might what they might find in the ultrasound. Ultrasound was performed also in all Zika-negative women that these women were compared to. So fetal abnormalities were detected by ultrasound in 12 of the 42 Zika-positive women, or 29%, and none of the 16 Zika-virus negative women. Here's a graph looking at the number of cases, one to four, really. And then the week of gestation at the time of infection. And then the lighter bars have normal findings on ultrasound and the darker bars have abnormal findings. And so this is a little bit different than the usual narrative that we had heard, which was this is likely a phenomenon of the first trimester, maybe early second trimester. There were women that we infected out well into their second or even third trimester. Adverse findings included in the study were fetal deaths at 36 and 38 weeks gestation. There were two. In utero growth restriction with or without microcephaly in five, ventricular calcifications or other central nervous system lesions in seven, and abnormal amniotic fluid volume or cerebral umbilical artery flow in seven. To date, 8 of the 42 women in whom the fetal ultrasound was performed have delivered their babies and the findings have been confirmed. So now moving on to another big story in this epidemic, and that has to do with the Dallas case, sexual transmission of this virus. So this was the report from the Dallas County Health and Human Services, where they had, on February 2nd, released this press release that stated that the first Zika virus case acquired through sexual transmission in Dallas County in 2016. So this was a case of a male traveler that had gone to Venezuela and subsequently came back and he was having Zika-like symptoms and then transmitted to his sexual partner. And so that was reported. So CDC released interim guidance for prevention of sexual transmission of Zika on February 5th, so shortly thereafter that that case was released. However, there were other cases they had previously been reported that were described in the literature of sexual transmission. There was a transmission from a scientist to his wife. The scientist had been out in Senegal in 2008, returned to Colorado, and his partner became-- his female partner became infected. There was a second report of a male traveler who had gone to Thailand and returned to Florence, Italy in 2014 and subsequently infected his girlfriend. After the Dallas case, the CDC received reports of 14 instances of suspected sexual transmission. On February 26th, CDC published six cases from male travelers of transmission from male travelers to female non-travelers. Two of these cases were confirmed and four were probable. There were two instances that were excluded-- didn't really seem likely, I suppose-- and six others that are still under investigation, so could still be more cases. So this went from being the Dallas case and these other couple of cases reported in the literature, to now six total cases with six others under investigation. Now the mode of spread is condom-less vaginal intercourse in all these cases when a male partner was symptomatic or shortly thereafter that their symptoms had resolved. Transmission from an infected women to their partner has not yet been reported, neither has transmission been reported from persons with asymptomatic infection. At this time, the length of time at the virus persists in semen is really unknown-- still a question, still remains a question. Though a recent report had described detection of Zika virus RNA by PCR as long as 62 days after illness onset. However, infectious virus wasn't cultured from that sample. So again, that difference between detection and actual transmissibility that they have to work through. So the recommendations were that health care providers should now consider any person who has condom-less sex with a male partner, who has traveled to an area of ongoing Zika virus transmission, and who has had symptoms of Zika disease during travel or within two weeks of return, as potentially exposed. I know it's a mouthful. And here are those areas of active transmission. Can you all see that? They're supposed to be a contrast. Kind of goes along here and goes right up to our doorstep and includes a lot of the Caribbean. Further recommendations-- men who reside in or have traveled to an area of ongoing Zika virus transmission who have a pregnant partner should abstain from sexual activity or consistently and correctly use condoms during sex with their pregnant partner for the duration of pregnancy. Pregnant women should discuss their male partner's recent travel history and any illness consistent with Zika with their health care provider. So those are the current recommendations. Travel associated cases-- so, a travel-associated associated case means that a person with Zika became infected due to someone traveling to an area with active Zika transmission. That includes travelers becoming infected and anyone infected by that particular traveler. That's the distinction there, so that includes that case in Dallas of sexual transmission. It's travel associated. It's not from local spread, it's travel associated, as are cases of vertical transmission. That's also travel associated. As of February 17th of this year, the US states had reported a total of 82 travel associated Zika cases to the CDC. 18 of these were in Texas, including the one sexual transmission, and like I said, it's two cases. But also two cases in Travis County which were both in returning travelers. Also of the 82 travel-associated cases were nine pregnant travelers with Zika infection identified after returning to the US. Among these women-- so it was a nice little cohort of nine pregnant travelers with Zika virus infection here in the US-- and among those women there were no Zika virus related hospitalizations or deaths reported. Two experienced early pregnancy losses, two chose to undergo elective terminations of pregnancy, three infants were born-- two healthy, and one with severe microcephaly-- and two pregnancies continue without known complications at this time. So you can see even with those nine cases here in the US, very high percentage of either fetal loss or microcephaly. Now reporting of Zika. Health care providers are required to report suspected cases to state or local health departments to facilitate diagnosis and reduce the risk of local transmission. CDC established a registry to learn more about pregnant women in the US with confirmed Zika virus infection and their infants. And this is important here locally. To discuss testing, you should call the Austin/Travis County Health Department epidemiology division, and the number is 512-972-5555. Really, all this is supposed to funnel up through the local health department and onto the state, and potentially, to the CDC. Will active transmission spread to the US? That's the million dollar question right now, it's unknown. There are cases, obviously in returning travelers. The same mosquito vectors present here in the US is present in the other endemic and epidemic areas, and that mosquito vector can become infected with Zika and can transmit Zika. But other flavivirus virus experience, with Chickungunya and Dengue, is that it's spread by the same mosquito, but US outbreaks have really been small and very limited, so it's very difficult to tell whether Zika will spread very far into the US. I think it's expected-- there may be little pockets of outbreaks here and there, kind of like Dengue and Chickungunya have had. But it's difficult to say, just don't really know. Now what's needed for a US outbreak are people infected with Zika to enter the US-- check. An Aedes mosquito in the US-- yes. Bites the infected person, and then during that relatively short time period where virus is present in the blood, that's that critical period where that bite needs to occur. So you can see why returning traveler comes back but that person would have to be bitten by a mosquito within a relatively short amount of time. And then also, that infected mosquito would have to live-- that bit that person-- would have to live long enough for the virus to multiply in the mosquito to bite another person. So on to laboratory testing. Zika virus testing is performed at the CDC and a few local state health departments. Texas' lab is creating capacity at this time. They're trying to create a capacity where they can test about 135 cases or specimens a week. From what I've heard I think counties up in Dallas are also trying to get their own testing locally. Health care providers, again, should contact state and local health departments to facilitate testing. Again, there is that number. In the US there's no commercially available FDA-cleared test for diagnostic purposes. There's still no FDA cleared test, that obviously takes some time to develop. CDC is working to expand the diagnostic testing capacity, but it's still ongoing at this point. During the first week of illnesses, Zika virus disease can often be diagnosed with PCR serum. A negative PCR doesn't always rule out Zika infection, however, because the further you are away from your initial symptoms, the less likely you're going to be positive by PCR because that viral load is waning. During the first seven days of symptom onset the viral RNA can be identified in serum and PCR is that preferred test. So patients coming in with Zika-like symptoms within seven days, PCR is the preferred test. Again, like I pointed out, Viremia decreases over time, and that specimen collected on the fifth to seventh day after symptom onset doesn't really preclude Zika virus infection and serologic testing should be performed. And those serologic assays are virus-specific IgM and neutralizing antibodies, which typically start to develop late in that first week of illness. There are some problems with this assay as well, because-- and it can sometimes be difficult to interpret because there's some cross-reactivity of Zika virus testing with other related flaviviruses. So it's sometimes difficult to interpret. So we have the PCR testing, then we have IgM testing, and then the third piece is a plaque-reduction neutralization testing. And that measures virus-specific neutralizing antibodies to confirm primary flavivirus infections and try to differentiate them from each other. So this is a test that is used to help differentiate Zika from other flavivirus infections in patients, And health care providers really should consider all available information when ordering a test for Zika, and that includes their travel history, history of flavivirus infection, vaccination history, vaccination mainly for other flavivirus infections, ultrasound findings, and presence of symptoms. And these-- we're usually not going to test these patients on our own, so we're typically working with state and local health departments to assist in interpreting these results. Some guidance for pregnant women. Postpone travel to Zika areas or where there's active transmission. Unfortunately, that includes the 2016 summer Olympics in Rio. If travel is a must, they're advised to strictly follow steps to prevent mosquito bites during the trip-- using repellents, covering exposed skin by wearing long sleeved shirts, long pants, and hats-- which is, I hear, very comfortable in Brazil-- and sleep in screen or air-conditioned rooms, and use a bed net if the area where you're sleeping is exposed to the outdoors. If a male partner who lives in or has traveled to the area where Zika is active, use condoms or do not have sex during pregnancy. This is an actual recommendation. See a doctor if they develop fever, rash, joint pain, conjunctivitis during their trip or within two weeks after traveling to a country where z has been reported, that two week cut-off. Guidance for OBs-- test pregnant women who have a clinical illness consistently with Zika during or within two weeks of travel to areas with ongoing Zika virus transmission. PCR for symptomatic patients should be used in that for seven days, like we talked about. And then the IgM and plaque-reduction neutralizing antibody testing should both be performed on specimens on the fourth day or beyond the onset of symptoms. For pregnant women with no relevant exposure, and that includes women who haven't traveled to these places of active transmission-- and they've traveled within the United States-- laboratory testing for Zika is not indicated, at least at the time of this talk. Hopefully that doesn't change. Test asymptomatic pregnant women with recent travel to an area where Zika is active. This was a leader recommendation about a month or so ago, the recommendation to test asymptomatic pregnant women that had recently traveled to an area of active transmission. And those women should be tested with IgM antibodies and that plaque-reduction neutralization testing. And that IgM test should be performed about 2 to 12 weeks after the known exposure, and that would suggest that a recent Zika virus infection did not occur if there was a negative result in that time frame, and so that may obviate the need for serial ultrasounds, which would have ordinarily been recommended in those patients. Also for OB, MMWR. Then CDC publication has some nice algorithms. This one, for instance, is pregnant women with a history of travel to an area with ongoing Zika transmission. So you test using those tests just mentioned, and then it tells you whether routine prenatal care is indicated or considering amniocentesis in certain situations, and just takes you through that algorithm. And then this one is for pregnant women residing in an area with ongoing Zika virus transmission, and that one is whether the woman reports clinical illness or does not report clinical illness and takes you through things to think about or do. Now in summary, currently there's an ongoing Zika virus outbreak in the Americas. It's unclear to what degrees Zika will spread to the continental US. Clinical manifestations include acute onset of low grade fever with maculopapular rash, arthralgia, or conjunctivitis. Zika virus infection has been associated with congenital microcephaly, fetal loss, and Guillain-Barre syndrome. The diagnosis of Zika virus infection is established using PCR or serology testing. Pregnant women should postpone travel to areas with ongoing mosquito transmission of Zika and strictly adhere to mosquito protective measures when traveling to these areas. Pregnant women with Zika virus exposure should undergo lab testing and ultrasound to evaluate for presence of fetal microcephaly or intracranial calcifications. And finally, sexual transmission of Zika has been described, and individuals with infection and exposure should abstain from sexual activity or use condoms for the duration of their pregnancy. Thanks for listening. I'll take some questions. All right, so this is a question about testing here locally. So it's basically if you have someone that you are suspecting Zika or you have an asymptomatic pregnant woman that has traveled to an endemic area, then yes, you would call that Austin/Travis County Health Department number and tell them the situation and then they would tell you how to collect the sample or get the sample to them, which they would then forward on to CDC to get tested. Yeah, that's how it is right now. Hopefully, I would think in the next month, testing would be available at the state lab here in Austin. They're in the process of making that happen, it's unclear how long that'll take. The question's about women who aren't pregnant traveling to epidemic areas or areas with active transmission, and basically those women are not-- so they'll have typical Zika disease, which is relatively mild and will only last a few days. So the thinking there is that if they're not pregnant at that point, the virus is only present in their system for a few days and so would be gone by any subsequent pregnancy. I suppose, theoretically, if a woman just happens to become pregnant at that moment of Zika infection, there would probably be spontaneous loss of that fertilized egg, I would imagine. The question's about the IgM serology assay and whether it's very sensitive or specific. Honestly, I don't think anyone knows. I don't think it's really been studied, what the sensitivity and specificity is of that test. Now that being said, I would think it's very high, just because our experience with previous serology assays, with IgM testing, and even other flaviviruses, the sensitivity and specificity are very high in those cases. I should say the sensitivity. The specificity is a whole other issue that we talked about briefly, where it could have it could be a positive due to another type of flavivirus that's cross-reacting. Thank you all so much for coming. Appreciate it. [APPLAUSE]