University of South Florida

Zika Virus UPDATE #1: Q&A

Written by · April 8, 2016 @ 3:00 pm · Filed under Uncategorized

The Zika virus pandemic continues to expand. As of March 23, 2016 there were 39 countries included on the CDC’s Travel Alerts (http://wwwnc.cdc.gov/travel/notices). In a remarkably short span of time, research focusing on the mosquitos that spread Zika, its pathogenesis (the virus’ effects on the body), clinical consequences, and available diagnostic testing has made rapid progress and provided new insights. This information is already being translated into guidelines and algorithms being used by the medical community to help patients, especially in the clinical management of women who are or want to become pregnant. On March 25, 2016 the Centers for Disease Control and Prevention (CDC) released updated guidance about caring for women of reproductive age with possible Zika exposure and the prevention of sexual transmission. USF Health is committed to meet the needs of our patients, through research initiatives undertaken both globally and locally. Dr. Douglas Holt’s update to the Zika virus question-and-answer document has been posted to the USF Health News site below,  including USF Health’s efforts to contribute to scientific discoveries and advancements associated with the Zika virus pandemic.

Sincerely,

Charles Lockwood, MD, MHCM
Senior Vice President, USF Health
Dean, USF Health Morsani College of Medicine

Zika Virus Update: Q&A

By Douglas A. Holt, MD
Andor Szentivanyi Professor of Medicine
Director, Division of Infectious Diseases and International Medicine
USF Health Morsani College of Medicine (MCOM)

(Updated April 8, 2016)

How is USF Health responding to the research efforts targeting Zika?
  • USF Health is building on a strong foundation of basic science expertise that Dean Donna Petersen, ScD, established within the College of Public Health (COPH) under the leadership of Dr. Tom Unnasch, chair of the Department of Global Health. Dr. Unnasch and his faculty, including Dr. John Adams and Dr. Dennis Kyle, are internationally recognized as leaders in malaria, leishmania and arboviral diseases.
  • In response to the call by Dr. Charles Lockwood, senior vice president of USF Health and dean, Morsani College of Medicine, to expand research even before the Zika outbreak, Drs. Unnasch and Holt began a joint recruitment effort for National Institutes of Health-funded researchers in infectious diseases.
  • USF Health has longstanding partnerships with academic institutions, ministries of health, science and technology, and nongovernmental organizations in Panama through the USF Health International Education Foundation Office established in the City of Knowledge. Faculty from the COPH Department of Global Health and the MCOM Division of Infectious Diseases are working with scientists from the Gorgas Memorial Health Institute in Panama to respond to the Zika outbreak in that country.
  • These efforts include medical students Key Yan Tsoi and Michelle Lippincott as well as their faculty advisors, Dr. Lynette Menezes from MCOM Infectious Diseases, Dr. Nestor Sosa, director general of the Gorgas Institute, and Dr. Dimelza Arauz, a Gorgas scientist, who are conducting an epidemiological study of current Zika cases in Panama.
  • Drs. Adams, Holt, Anthony Odibo (Ob/Gyn) and Unnasch are working with Dr. Sosa to submit grant proposals to the NIH for Zika research.
  • As part of National Public Health Week and World Health Day, the USF COPH hosted a panel discussion on Emerging Vector-Born Diseases, including Zika virus. Speakers included Dr. Robert Novak, professor of global health, infectious disease ecology and medical entomology, COPH; Dr. Sarah Obican assistant professor of obstetrics and gynecology and Dr. Douglas Holt, director of the Division of Infectious Disease, MCOM.
Does Zika virus cause microcephaly and other birth defects?
  • On April 1, 2016 the CDC declared that  strong evidencence now exists that Zika virus causes fetal birth defects, including microcephaly, incomplete brain development, eye problems, and impaired fetal growth.  Studies are being done to better understand how Zika virus affects pregnancy.
  • A retrospective review of a Zika outbreak in French Polynesia from October, 2013 to April, 2014 suggests that if a mother is infected during the first trimester, the risk of microcephaly is about 1%. This is a 20-fold increase in the syndrome compared with rates observed before the Zika outbreak.
  • The risk of symptomatic congenital disease from Zika virus may be less in comparison to rubella and cytomegalovirus (CMV). When mothers are infected in the first trimester with rubella there is a 34-90% risk that the baby will have symptomatic congenital rubella syndrome. The fetal risk associated with CMV is 13%. However, up to 70% of the population will be infected during a Zika outbreak, far more than occurs with rubella and CMV infections. This explains the large number of microcephaly cases now being reported in Brazil.
What happens when a pregnant woman becomes infected with Zika virus?
  • Most babies whose mothers had Zika during pregnancy are not born with major birth defects. However, researchers cannot rule out widespread though more subtle neurodevelopmental abnormalities. Researchers are working to better understand how often  Zika during pregnancy causes problems and precisely what those problems entail.
  • Initially, there is a brief period when the virus circulates in the mother’s bloodstream and spreads throughout the body.
  • The virus can be passed from a woman to her fetus during pregnancy or around the time of birth.
  • The fetus becomes infected as the Zika virus passes from the mother’s bloodstream across the placenta.
  • Early evidence from Brazil suggests that the greatest risk of Zika infection to the baby occurs when the mother is infected during the first trimester of pregnancy. This is also similar to what is known about other viruses associated with congenital conditions such as rubella and CMV. However, third trimester fetal deaths have been reported.
  • The fetus is also less able to immunologically contain and control a Zika infection resulting in a prolonged and more profound infection. Zika virus from the infected fetus has been detected in the mother’s blood for up to two months.
  • Zika virus appears to have a predilection for infecting and damaging developing neural cells, resulting in a potentially profound impact on brain growth and development. The pathophysiology and clinical findings of congenital Zika syndrome are very reminiscent of that seen with congenital rubella infection.
  • What is still unknown about Zika infection during pregnancy:
  1. We don’t know if sexual transmission of Zika virus poses a different risk of birth defects than mosquito-borne transmission.
  2. We don’t know whether the risk to the fetus is different if the mother shows signs of Zika infection or is asymptomatic.
  3. We don’t know how often the fetus becomes infected by the mother.
  4. We don’t know which infected fetuses will develop birth defects.
I am pregnant and am worried I may have been infected by Zika virus. What will my doctor do?
  • They will first ask questions to determine whether you might have been exposed to the Zika virus. Have you traveled to any area with Zika transmission at any time when you might have been pregnant? Has your partner?
  • If so, the doctor will try to determine the most likely time you could have been infected.  When did you travel? What did you do?  Do you recall being bitten by mosquitoes, or having any of the following signs or symptoms suggestive of Zika infection: fever, rash, muscles aches or conjunctivitis?
  • If your partner traveled without you, have you had unprotected sex since his return, and does he recall a “Zika-like” illness?
  • If you are at risk, contact your local health department to arrange Zika testing.
What are the recommendations if I am pregnant and a blood test indicates I am positive for Zika?
  • An initial fetal ultrasound will be performed around the 16th week of gestation. Even if the results show no abnormalities, your obstetrician will recommend serial ultrasounds.
  • Unfortunately, ultrasounds may not always detect abnormalities associated with congenital Zika syndrome. This is especially true for an ultrasound done early in pregnancy or soon after the fetus is infected with Zika.
  • In some cases, a fetal brain MRI might be used to better assess the risk, but even this test cannot completely exclude congenital Zika syndrome.
  • Amniocentesis can also be used to screen for the presence of Zika virus RNA.
What should couples do before attempting to become pregnant?
  • Consult with your physician.
  • If neither of you has traveled to any area with Zika transmission in the last six months, there is no need to delay.
  • At this time couples who want to become pregnant cannot get tested for Zika virus to determine if they were infected. It is unknown what the test results would mean, and the CDC does not have enough tests to be used for this purpose.
  • Men who become infected with Zika can spread the the virus to their partners during sex. There are six cases of this happening in the United States so far.  All the men recalled being sick and had sex within a few weeks of being ill. We know that live Zika virus can be found in semen beyond two weeks. Semen has also tested positive for viral particles using RT-PCR for up to 62 days.
  • A man who has traveled to a area of Zika transmission could have been exposed to the virus, so the following precautions are recommended:
  1. If the man did NOT show any symptoms of Zika disease, the couple should wait at least eight weeks before attempting to become pregnant.
  2. If the man did show symptoms of Zika, the couple should wait at least six months before attempting to conceive.
  • A woman who has traveled to a Zika area should delay attempts to become pregnant for at least eight weeks, whether she developed symptoms of Zika or not.
Did the CDC report that Zika will come to Florida?
  • On April 1, 2016, the CDC released recommendations that states prepare to manage cases of Zika virus. The Florida Department of Health has been doing this since October, 2015.
  • Health care providers and the general public have been educated about how Zika is spread, where you might get infected, and the symptoms of Zika.
  • The Hillsborough County Health Department has investigated and arranged for testing of anyone suspected to have been infected with Zika virus, including pregnant women who had traveled to a Zika infected area.
  • Any person who tests positive for Zika virus is interviewed about their risk of exposure to Zika and for any possibility that they were infected in the United States. To date, all acquired the infection while traveling in an area affected by Zika, except for  six cases involving sexual transmission by men infected outside the continental United States.
  • If someone is identified as infected but has not traveled to, or had sex with a man who has visited, a Zika infected area, then they will be the first person infected in the United States by a mosquito.
  • The Florida Health Department initiates investigations to identify anyone who might have been bitten by an infected mosquito.
  • These potentially exposed people would be asked if they had any recent illness and to report the onset of any illness suggesting Zika infection.
  • Mosquito control efforts would target affected neighborhoods.
  • Quarantines would not be used and are ineffective, since, other than by sexual transmission, Zika does not spread from person to person.
Will the Zika pandemic end?
  • A time will come when most of the population will have been infected with Zika. In the French Polynesia outbreak an estimated 70% of the population became infected.
  • Zika infection results in lifelong immunity. Eventually a community develops “herd immunity” whereby the virus does not have enough people who are susceptible, so its spread becomes limited.
  • Zika virus then becomes endemic to that area. This means that Zika will join other diseases like dengue that are regularly found in certain areas.
  • Travelers to Zika areas  are advised to avoid mosquitoes. Women of childbearing age should take steps to prevent pregnancy.
  • A Zika vaccine would be very useful, especially for women in his situation. 
Where can I get more information?

 

 

 

No related posts.

Tags: , ,

Network-wide options by YD - Freelance Wordpress Developer