Saturday, July 23, 2016

Mysterious Zika transmission

Health officials said Monday that they are investigating the case of a man in Utah who has contracted Zika virus locally through unknown means, one of the more mysterious cases of transmission yet involving the virus.

The individual, who has not been identified, recently helped care for his father, who had contracted Zika and died earlier this month. The second case had not recently traveled outside the country.

That shifts the focus of the investigation to mosquitoes and the possibility that the new case became infected while caring for his dying father. The older man had a serious illness when he contracted Zika while traveling outside the US.

Though most commonly transmitted through the bite of an infected mosquito, Zika virus can be spread through contact with body fluids from an infected person including semen and blood. The virus is also found in urine and saliva…

The man who died had exceptionally high levels of the Zika virus in his system at the end of his life. Health officials acknowledged the younger man was related to the man who died earlier this month but declined to provide further details; they were father and son, according to a person who was familiar with the case but who was not authorized to speak for attribution.

A statement from the CDC said the older man’s blood contained 100,000 times more virus than is normally seen in Zika infection.

It’s too soon to say whether that fact allowed for a type of transmission that hasn’t yet been seen, said Dr. Michael Bell, deputy director of the CDC’s division of health-care quality promotion.

“Currently there’s nothing specific we can say other than recognizing that a high viral load could be a different situation than we would ordinarily see,” said Bell.

“From the infection control perspective, I think it’s early to make a clear statement about what we think could have happened.”

 State officials are working with the CDC to try to interview and test other people who came in contact with the man who died — additional relatives, health-care workers — to see if there were other, undetected secondary cases.

With Zika infection, as many as four out of five cases develop no symptoms; most would go undetected…

“There is a lot of uncertainty around this investigation and we’re currently exploring all avenues for possible transmission,” Dr. Angela Dunn, deputy state epidemiologist, told STAT.

“We’re exploring contact with the deceased patient [as a transmission route] as well as our mosquito trapping and testing for Aedes, the species of mosquito that is known to carry the mosquito virus as well as testing other mosquito species for the Zika virus.”

Dunn said Aedes mosquitoes are not thought to be established in Utah. Trapping efforts are underway around the residences of the man who died and his relative to try to see what types of the insect are present and whether any of them are infected with Zika.

Courtesy of Doximity


  1. Which came first: high Zika viral load or a diminished immune system? This is a question that epidemiologists and medical experts from the Centers for Disease Control and Prevention are pondering in regards to the recent case of Zika identified in Salt Lake City, Utah that may have resulted in the individual's death.

    Just last week a Utah resident was reported to have died with a Zika infection in June. The CDC confirmed that the male patient presented with a “unique situation”: an unusually elevated Zika blood viral load (100,000 times higher than any other sampled Zika patients). In what CDC experts called a “chicken or egg” investigation, it was noted that it is still unclear whether the elderly patient died from the Zika infection or from other underlying comorbidities. Thus, the CDC is conducting a “thorough review” to understand the clinical course of the deceased patient’s underlying comorbidities to uncover whether the high viral load contributed to the patient’s death, or if the patient’s comorbidities left him immunocompromised, which lead to the high viral load.

    Now, a family member of the deceased patient has tested positive for the Zika virus. The individual experienced mild symptoms associated with a Zika infection, and a rapid recovery, as is the “typical clinical course” of the virus. At the moment there is no clear evidence as to how the patient became infected.

    Although the primary mode of transmission of the Zika virus remains the bite of an infected female Aedes aegypti mosquito, the virus has also been identified in contaminated saliva, blood, semen, and urine.

    The CDC has dispatched an Emergency Response Team (CERT), including infection control, virology, mosquito control, disease investigation and health communications experts, to work in conjunction with the Utah Department of Health to help investigate this “unusual” case of Zika transmission. CERT will be conducting interviews with other family members of the deceased patient as well as healthcare workers who may have come in contact with him. In addition, although Utah does not harbor any of the Zika mosquito vectors (Ae. aegypti and Aedes albopictus), the team will be collecting local mosquitos for viral testing.

    During a briefing, CDC experts confirmed that nothing can be truly ruled out in terms of modes of viral transmission. However, they believe that two scenarios are “extremely unlikely”: Zika is an airborne virus; other mosquito populations within this particular area have become Zika vectors. It was confirmed that, thus far, there has been no clinical evidence of Zika transmission through casual contact, sneezing, or coughing. Nonetheless, Michael Bell, MD, deputy director of the Division of Healthcare Quality Promotion, confirmed that the CDC is currently meticulously assessing the situation to see if any other mode of transmission is possible. Although the recently identified patient is a family member of the deceased, it is not impossible that this patient could have acquired a Zika infection through other means.

  2. The Centers for Disease Control and Prevention (CDC) has been working alongside the Florida Department of Health (DOH) to investigate two possible non–travel-related cases of Zika virus infection in two separate counties. Now, health officials are confirming two new non–travel-related Zika cases identified in Florida, bringing the total to four cases.

    The first case had been confirmed in Miami-Dade County, Florida, on July 19, 2016. The individual had no recent history of travel to Zika-endemic countries. Just two days later, a second, unrelated case was reported in Broward County, Florida. These cases were reported shortly after an elderly patient in Salt Lake City, Utah, died with an unusually high viral load of Zika. The patient had recently returned from a trip to a country with active Zika transmission. What has baffled health officials in Utah is that one of the decedent's family members, who had no travel-history to a Zika-endemic country, had contracted the virus while caring for the patient. The Florida DOH has confirmed that the third and fourth newly diagnosed non–travel-related Zika cases are in pregnant women.

    A rise in the number of Zika infections in individuals who have no history of travel to Zika-endemic areas gives way to the question: is Florida experiencing active Zika transmission? The answer to this question remains to be seen; meanwhile, the Florida DOH and the CDC are currently investigating other possible modes of infection transmission through which these individuals may have contracted the virus. In the meantime, the US Food and Drug Administration is urging that blood establishments stop blood collection in the infected counties "until the blood establishments implement testing of each individual unit of blood collected in the two counties with an available investigational donor screening test for Zika virus RNA or until the blood establishments implement the use of an approved or investigational pathogen inactivation technology." Furthermore, the FDA also recommends that Florida counties in close proximity to those with possible active Zika transmission implement similar precautions.

    - See more at:

  3. Mosquitos probably are spreading the Zika virus in southern Florida, the state's health department announced today.

    The Florida Department of Health (DPH) said there is a "high likelihood" that four individuals with the virus probably acquired it through mosquito bites in an area of active transmission north of downtown Miami. These cases — representing three men and one woman — are the first known instances of local transmission of the virus, which causes microcephaly and other birth defects, in the continental United States. The DPH acknowledged, though, that no trapped mosquitos in Florida have yet to test positive for the virus.

    In contrast, the 1658 cases of Zika infection reported by the US Centers for Disease Control and Prevention (CDC) as of July 28, with one exception, occurred because someone became infected while traveling to another country in which local transmission was occurring, or else the virus was acquired via sex from an infected individual. In a single case, someone became infected in a laboratory...

    As of July 21, 13 women infected with Zika in the United States have delivered babies with birth defects, according to the CDC. For another six women with the virus, a pregnancy was lost with evidence of birth defects.

    The CDC said today that it expects to see more cases of locally transmitted Zika infections in the continental United States. The agency has sent a medical epidemiologist to Florida to help the state investigate its outbreak.

    "All the evidence we have seen indicates that this is mosquito-borne transmission that occurred several weeks ago in several blocks in Miami," said CDC Director Tom Frieden, MD, MPH, in a news release. "We continue to recommend that everyone in areas where Aedes aegypti mosquitoes are present — and especially pregnant women — take steps to avoid mosquito bites. We will continue to support Florida's efforts to investigate and respond to Zika and will reassess the situation and our recommendations on a daily basis."

  4. The Centers for Disease Control and Prevention (CDC) confirmed that the four previously reported non–travel-related cases of Zika infection in Miami-Dade County, Florida, were locally acquired. In a teleconference, Tom Frieden, MD, MPH, director of the CDC, confirmed that “Zika is here.” The four cases are the first locally acquired cases of Zika in the United States. The CDC is working closely with the Florida Department of Health (DOH) to investigate an area north of downtown Miami where the infected individuals are suspected to have contracted Zika, based on epidemiological analysis and investigation. Zika is confirmed to cause microcephaly and other neurological complications in developing fetuses. However, the CDC is not advising women residing in Florida to postpone pregnancy; the CDC calls it a “highly personal decision.” Nonetheless, the CDC recommends that all pregnant women, including those who do not present with Zika-like symptoms, be tested for the Zika virus, “even if the odds [of infection] are low.” Because Aedes aegypti mosquitoes, which transmit Zika, only travel around 150 meters in a lifetime, active Zika transmission in these areas is a “focal problem that needs to be addressed locally.” Based on past transmission of mosquito-borne viruses in Florida, Dr. Frieden notes that local Zika transmission within the state is “not unexpected.” According to the CDC, active Zika transmission has been ongoing in the Florida since early July. However, efforts to confirm local Zika transmission require extensive investigation through testing of the Zika vector, Ae. aegypti, which is difficult. Dr. Frieden described the process as “looking for a needle in a haystack.” Thus far, there have been approximately 1,657 travel-related cases of Zika in the United States and now four locally acquired cases of Zika-infected individuals in Florida, two of whom are pregnant women. Upon reports of Zika diagnosis, Florida health officials took measures to reduce the mosquito population within the areas where infected individuals reside. Furthermore, the DOH investigated possible routes of transmission, including travel and sexual intercourse with infected individuals. Once these possibilities were ruled out, the DOH began to suspect local transmission. The Florida DOH has been aggressive in its efforts to minimize the Ae. aegypti population in Miami. According to the CDC, Zika is not a concern unless there continue to be more cases of locally acquired Zika after mosquito control efforts have been taken.

    - See more at:

  5. Florida Governor Rick Scott today said that 10 more individuals in the Miami area have been infected with Zika, likely through mosquito bites, which has quickly brought the total to 14 since the first four cases were announced on July 29.

    Florida is the first state to report local transmission of the virus, which causes birth defects, most notably, microcephaly.

    In a sign of a rapidly developing outbreak, Scott said that the Centers for Disease Control and Prevention (CDC) has issued a travel advisory cautioning women who are pregnant or are thinking about becoming pregnant to avoid unnecessary travel to the 1-square-mile neighborhood just north of downtown Miami that is experiencing local Zika transmission. Otherwise, "Florida remains safe and open for tourism," Scott said in a news release.

    The CDC is expected to issue the travel advisory later today. CDC Director Tom Frieden, MD, MPH, said in a news conference on August 29 that the outbreak in southern Florida was not yet widespread enough to warrant a travel advisory.

  6. The risk of Zika virus infections at the Olympic Games in Rio de Janeiro is low and has been overcome, health officials in Brazil said on Sunday, five days before South America's first Games are due to begin.

    Rio de Janeiro's health secretary, Daniel Soranz, said Zika should not deter travelers from coming to the Games, as cases of the virus had dipped significantly in recent months.

    The mosquito-borne virus has been linked to microcephaly, a birth defect among babies of pregnant mothers infected by Zika, and its discovery in Brazil last year led to concern over the Games, which are expected to attract some 500,000 visitors.

    However, with dry and cooler weather in Rio amid the southern hemisphere winter, the incidence of Zika and other mosquito-borne diseases such as dengue and Chikungunya has declined sharply in recent months.

    "Since November of last year, we have already been showing projections and scientific studies that show this won't be an issue during the Olympics," Soranz told a news conference.

    "Since two weeks before the Games, the number of cases were almost non-existent. In the city, cases are very rare and for us it is an issue that we have more than overcome," he said.

  7. For women thinking about getting pregnant who are having unprotected sex, I would say that when Zika reaches your part of the United States, it's time to advise women to use contraception or be abstinent. I'd rather bet on contraception than abstinence, because we fail at abstinence and I'm not afraid to advise contraception. But if you're of childbearing age and Zika is around, it is important to remember that it's associated with some very bad birth defects. We've seen them in South America, including microcephaly, among other problems. You don't want to be pregnant with this virus being present. So, putting off childbirth, deciding to be careful, and asking men to wear condoms—as well as the various protection methods I mentioned earlier—are very important if we are going to try to minimize the threat to babies that Zika poses.

    I also think there's going to have to be some discussion about being pregnant with the possibility of being infected with the Zika virus. We've had this huge ongoing debate in our society about abortion. Is abortion something that a woman should be told about, be aware of, if she is pregnant and gets a positive test for Zika or if she thinks she's been exposed?

    I think that option does have to be presented. It's difficult to say and to offer, but some women are going to say, "I can't take that chance," or "If this baby's going to have a very burdensome birth defect, I don't want to bear it."

    Zika is not only going to challenge us in terms of how we try to keep distance between us and the mosquitos that carry it, but it's also going to challenge our views about contraception and abortion, as well as some of our views about how we talk to our patients about their sexual activity.

  8. On August 5, 2016, the FDA announced its approval of a field trial in which genetically modified Aedes aegypti would be released in Florida to target the population of the Zika-carrying mosquitos in the area, as Puerto Rico reported its second Zika-related death...

    In response to the Zika epidemic, the British company, Oxitec Ltd., genetically engineered an Aedes aegypti mosquito (OX513A) that would transmit a modified gene to its offspring to cause their premature death. In March 2016, the US Food and Drug Administration (FDA) started reviewing the possible environmental impacts of conducting a field trial in which the OX513A would be released in Key Haven, Florida. Since male mosquitos do not spread Zika, the company believes that OX513A will not pose additional harm to the trial area.

    Nonetheless, the trial earned much backlash from Key Haven residents; that is not to say that the FDA did not take public opinion into consideration. In March, when the FDA announced that it was reviewing the field trial proposal, it also opened the doors for public commentary. In addition, in an exclusive interview with Contagion, FDA spokesperson Siobhan DeLancey addressed concerns regarding the release of OX513A.

    According to an update on the environmental review, the FDA considered thousands of comments from the public prior to publishing its final environmental assessment (EA). In the EA, the FDA announced the “finding of no significant impact (FONSI) that agrees with the EA’s conclusion that the proposed field trial will not have significant impacts on the environment.” Nonetheless, the FDA clearly states that the decision to approve the field trial does not denote approval for commercial use of OX513A.

  9. In his briefing, Pestorius also updated reporters on the investigation into the puzzling case of nonsexual Zika transmission in Utah, where a dying man apparently passed the virus to a son who was taking care of him.

    Pestorius said the case was “an outlier” because the older man had such high amounts of virus in his body. He said investigators have assessed the various ways the son might have come into contact with his father’s bodily fluids, and it appears that the son may have caught the virus as he wiped his father’s tears.

    He said the CDC is considering whether it needs to revise its guidelines for medical professionals and others who may care for people infected with Zika.

  10. A case of the Zika virus in Utah is now the only one in the continental U.S. that’s still puzzling researchers on exactly how it spread, health officials said Tuesday.

    The man caught the illness after caring for his infected father, who had an extremely high level of the virus in his blood when he died in June, according to a report released by the U.S. Centers for Disease Control and Prevention. One possibility is that he transmitted the virus to his son through a bodily fluid in a way that hasn’t been recognized with Zika yet, officials said. The son kissed and hugged his dying father and helped care for him in a hospital, according to the report.

    Investigators couldn’t test the unidentified Salt Lake County man because he had already been cremated by the time he was diagnosed, said Angela Dunn with the Utah Department of Health. Signs of Zika​ have been found in blood, urine, semen and saliva, and the case could direct new research into whether it can also be carried in things like tears or stools, she said.

    No other cases have yet been found among the family or health workers. It’s unclear whether the case points to a potentially common mode of transmission, said Alex Kallen with the CDC. “I don’t think we know the answer to that right now,” he said.

    The father caught the mosquito-borne virus abroad, but the son didn’t travel to an affected area or have sex with anyone who did, the report said.

    The son has since recovered. The virus causes only a mild illness in most people. But during recent outbreaks in Latin America, scientists discovered that infection during pregnancy has led to severe brain-related birth defects​.

    Health officials also haven’t found any of the tropical mosquitoes that mainly spread the virus in the area or evidence that local mosquitoes are carrying the virus, according to the report released by the CDC.

    The son didn’t report touching any bodily fluids, and other family members had similar interactions with the father without getting sick, Dunn said. “We weren’t able to identify anything he did that was different,” she said.

    It’s not uncommon to be unable to identify a key thing a patient did or didn’t do before catching an illness like Zika, Kallen said. Small, even unremembered, factors can often make a big difference, he said.

    The investigation is ongoing, and more information is expected later this year.