UH aims to understand how the Zika virus is spread through sex

University of Hawaiʻi at Mānoa
Tina Shelton, (808) 554-2586
Director of Communications, Office of Dean of Medicine
Saguna Verma, PhD, (808) 692-1662
Associate Professor, Tropical Medicine, Med Microbiology, Pharmacology
Posted: Dec 2, 2016

Dr. Saguna Verma
Dr. Saguna Verma

If you began to let your guard down a little with recent reports that the World Health Organization no longer considers the Zika epidemic a public health emergency – don’t.

The “emergency” status was adopted at a time when little was known about the various ways in which the Zika virus is transmitted. Now more is understood, including how Zika virus in pregnancy can lead to devastating brain damage in newborns. Dropping the term “emergency” does not change the fact that Zika virus is expected to continue to spread and requires a long-term solution.

This month, public health officials reported that mosquitoes in Palau, 4,700 miles from Hawai’i, are infected with Zika virus and are spreading it to people.

Now, a UH Mānoa scientist has received funding to explore one of the newest and potentially most worrisome ways the Zika virus can spread: through unprotected sex.

Dr. Saguna Verma, an associate professor of tropical medicine with the John A. Burns School of Medicine (JABSOM), wants to understand how Zika virus infection in men makes them susceptible to transmit the virus to their sexual partners, even though they may appear symptom-free.

“Clinical data shows that infectious Zika virus can be sexually transmitted by men long after the virus is cleared from their blood,” said Dr. Verma. She believes Zika virus hides within specific cells unique to the testes, silently prolonging the infection.

Dr. Verma and her partners will work with human cells that form a blood-testes barrier. Normally, a blood-testes barrier protects the delicate germ cells from infection and resulting “immune attack” by the immune cells from the blood. They intend to demonstrate the extraordinary way by which the virus penetrates this barrier.

“We believe the Zika virus infects cells of the blood-testes barrier and induces inflammation. This response may trigger the disruption of the blood-testes barrier and allow the virus to eventually enter the inner compartment of the testes and establish persistent infection in the germ cells. We have standardized an in vitro blood-testes barrier model that will be used as an innovative tool to address this study," she said.

Ultimately if the mechanism by which Zika virus enters and remains persistent in the testes for several months is discovered, Dr. Verma wants to unlock a way for antiviral medicines to be used to clear Zika virus from the testes and being spread through sex. It is something that motivates her work in infectious disease.

“This tug of war between the mankind vs. pathogen inspires me," she said.  "The idea that new host or virus players continue to evolve in the microscopic battle between re-emerging viruses and human immune system fascinates me."

Additional information:

The UH-JABSOM Zika virus research group is uniquely positioned for this study, because its members have spent a decade studying how West Nile virus enters into the brain, a process that also confounds a usually protective barrier between the brain and blood. The multidisciplinary collaborative team has expertise in the in vitro blood-tissue barrier, flavivirus pathogenesis, non-human primate models, and clinical pathology. In addition to Dr. Verma, the team includes Dr. Vivek R Nerurkar, Department of Tropical Medicine, Medical Microbiology and Pharmacology, Dr. Karen Thompson, Department of Pathology, JABSOM, and Dr. Hanne Anderson, Research Director, at the Rockville, Maryland-based Bioqual Inc. http://www.bioqual.com/contact.html

About the grant:

The special Zika virus response grant (1R21AI129465-01) of $471,000 over two years is funded by the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.

Title: Under attack: Modulation of the blood-testes barrier by Zika virus

Summary: The ongoing epidemic of Zika virus (ZIKV) has caused severe unexpected clinical outcomes including increased risk of sexual transmission. Currently, there is no vaccine or specific therapeutic measures available to combat viral infection and has therefore brought an urgent need for models to understand the associated mechanisms. Understanding how ZIKV gains entry into the immune privileged site of the testes and the role of inflammatory mediators in facilitating this process will fill the fundamental gap of the mechanism of testicular infection of ZIKV and facilitate development of strategies to prevent virus-testes entry.

For more information, visit: http://jabsom.hawaii.edu/news-media/uh-med-now/