Nav: Home

New insight into course and transmission of Zika infection

October 06, 2016

BOSTON - Though first documented 70 years ago, the Zika virus was poorly understood when it burst onto the scene in the Americas in 2015. In one of the first and largest studies of its kind, a research team lead by virologists at Beth Israel Deaconess Medical Center (BIDMC) has characterized the progression of two strains of the viral infection. The study, published online this week in Nature Medicine, revealed Zika's rapid infection of the brain and nervous tissues, and provided evidence of risk for person-to-person transmission.

"We found, initially, that the virus replicated very rapidly and was cleared from the blood in most animals within ten days," said corresponding author James B. Whitney, PhD, a principal investigator at the Center for Virology and Vaccine Research (CVVR) at BIDMC. "Nevertheless, we observed viral shedding in other bodily fluids such as spinal fluid, saliva, urine and semen, up to three weeks after the initial infection was already cleared."

Whitney and colleagues infected 36 rhesus and cynomolgus macaques with strains of the Zika virus derived from Puerto Rico and Thailand. Over the next four weeks, the scientists tested blood, tissues, cerebrospinal fluid (CSF) and mucosal secretions for the presence of Zika virus, as well as monitored the immune response during early infection. Their data shed new light on the previously little-studied virus, and might help explain how Zika causes the devastating neurological complications seen in adults and unborn babies.

"Of particular concern, we saw extraordinarily high levels of Zika virus in the brain of some of the animals - the cerebellum, specifically - soon after infection," said Whitney, who is also assistant professor of medicine at Harvard Medical School and an associate member of the Ragon Institute of MGH, MIT, and Harvard. "Only one in five adults has noticeable symptoms of infection. However, if our data translate to humans, there may be need for enhanced clinical vigilance for any persons presenting with unusual neurological symptoms, and they should be tested for Zika infection."

Like in humans, Zika infection in the experimental primates appeared relatively mild, producing fever and an increase in blood cells associated with the immune response. All recovered without intervention. But while the virus was cleared from the blood stream within ten days, the researchers observed Zika virus in urine as soon as two days after infection in some subjects. By the third day after infection, Zika was detectable in the saliva of up to half of the subjects, where it remained until the study ended at 28 days after infection.

"This underscores the need to understand what's happening in anatomic reservoirs where the virus may hide for a long time," said Whitney.

Early in infection, the researchers found high levels of Zika in the genital tracts of both sexes. Zika remained detectable in semen and in uterine tissues until the end of the study. The first sexually transmitted case of Zika in humans was documented in 2007, but these new findings suggest transmission may occur long after Zika symptoms - if they ever appeared - resolve. Because the researchers found high levels of the virus in semen and uterus, but little in vaginal secretions, the findings may also illuminate sexual transmission of Zika.

"We found that male-to-female transmission may be easier, while female-to-male may be less likely," said Whitney. "Nonetheless, the high levels of Zika we observed in the uterus underscore the danger to a developing fetus."

The new study also highlights the need for the rapid development of vaccines and therapies against the virus. Zika infection in pregnant women has been shown to lead to fetal microcephaly and other major birth defects. The World Health Organization declared the virus epidemic a global public health emergency on February 1, 2016.
-end-
Study coauthors include: (co-first authors) Christa E. Osuna and So-Yon Lim, both of the CVVR at BIDMC; Claire Deleage of Leidos Biomedical Research at Frederick National Laboratory for Cancer Research,; Bryan D. Griffin, Derek Stein, Lukas T. Schroeder, Robert Omage, Ma Luo and (co-first author) David Safronetz of the National Microbiology Laboratory, Canada; Katharine Best, Peter T. Hraber, Erwing Fabian Cardozo Ojeda and Alan S. Perelson of Los Alamos National Laboratory; Hanne Andersen-Elyard and (co-first author) Mark G. Lewis of Bioqual; Scott Huang, Dana L. Vanlandingham and Stephen Higgs of Biosecurity Research Institute, Kansas State University.

About Beth Israel Deaconess Medical Center

Beth Israel Deaconess Medical Center is a patient care, teaching and research affiliate of Harvard Medical School and consistently ranks as a national leader among independent hospitals in National Institutes of Health funding.

BIDMC is in the community with Beth Israel Deaconess Hospital-Milton, Beth Israel Deaconess Hospital-Needham, Beth Israel Deaconess Hospital-Plymouth, Anna Jaques Hospital, Cambridge Health Alliance, Lawrence General Hospital, Signature Healthcare, Beth Israel Deaconess HealthCare, Community Care Alliance and Atrius Health. BIDMC is also clinically affiliated with the Joslin Diabetes Center and Hebrew Rehabilitation Center and is a research partner of Dana-Farber/Harvard Cancer Center and the Jackson Laboratory. BIDMC is the official hospital of the Boston Red Sox. For more information, visit http://www.bidmc.org.

Beth Israel Deaconess Medical Center

Related Immune Response Articles:

How to boost immune response to vaccines in older people
Identifying interventions that improve vaccine efficacy in older persons is vital to deliver healthy ageing for an ageing population.
Unveiling how lymph nodes regulate immune response
The Hippo pathway keeps lymph nodes' development healthy. If impaired, lymph nodes become full of fat cells or fibrosis develops.
Early immune response may improve cancer immunotherapies
Researchers report a new mechanism for detecting foreign material during early immune responses.
Researchers decode the immune response to Ebola vaccine
The vaccine rVSV-EBOV is currently used in the fight against Ebola virus.
Immune response depends on mathematics of narrow escapes
The way immune cells pick friends from foes can be described by a classic maths puzzle known as the 'narrow escape problem'.
Signature of an ineffective immune response to cancer revealed
Our immune system is programmed to destroy cancer cells. Sometimes it has trouble slowing disease progression because it doesn't act quickly or strongly enough.
Putting the break on our immune system's response
Researchers have discovered how a tiny molecule known as miR-132 acts as a 'handbrake' on our immune system -- helping us fight infection.
Having stressed out ancestors improves immune response to stress
Having ancestors who were frequently exposed to stressors can improve one's own immune response to stressors, according to Penn State researchers.
Researchers discovered new immune response regulators
The research groups of Academy Professor Riitta Lahesmaa and Research Director Laura Elo from Turku Centre for Biotechnology have discovered new proteins that regulate T cells in the human immune system.
Blueprint for plant immune response found
Washington State University researchers have discovered the way plants respond to disease-causing organisms, and how they protect themselves, leading the way to potential breakthroughs in breeding resistance to diseases or pests.
More Immune Response News and Immune Response Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.