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DoD adds funding to enhance Zika surveillance

  • Published
  • By Cheryl Pellerin

The Defense Department is providing $1.76 million in extra funding to military laboratories to expand Zika virus surveillance worldwide and assess the virus’s impact on deployed service members’ health and readiness, Navy Cmdr. Franca Jones said in a recent interview.

Jones, who holds a doctorate, is chief of the Global Emerging Infections Surveillance and Response, or GEIS, section of the Armed Forces Health Surveillance Branch in the Defense Health Agency’s Public Health Division.

The enhanced Zika virus surveillance will involve 10 projects in 18 countries and territories by four lab partners based in the United States and five located overseas.

Jones said the labs receiving more Zika virus funds are part of the GEIS integrated worldwide emerging infectious disease surveillance network that includes core Army or Navy medical research labs in Egypt, Georgia, Kenya, Peru, Thailand, Cambodia and Singapore, and Army, Navy and Air Force labs in the United States, working in more than 60 countries around the world.

In the current fiscal year, she added, GEIS already has provided its network partners with more than $51 million to support a range of emerging infectious disease surveillance programs.

Mosquito-Borne Zika

Zika virus disease spread to people through the bites of Aedes aegypti mosquitoes, usually shows mild symptoms -- fever, rash, joint pain and red eyes -- that last several days or a week, according to the CDC. But Zika virus infection during pregnancy can cause a serious birth defect called microcephaly and other severe fetal brain defects, the CDC says.

In May 2015, the Pan American Health Organization issued an alert about the first confirmed Zika virus infection in Brazil. Three months ago, the WHO declared Zika virus a public health emergency of international concern. Local transmission has been reported in many other countries and territories.

Zika virus likely will continue to spread to new areas, CDC says. Some 4,905 confirmed and 194,633 suspected cases had been reported in 33 countries and territories in the Western Hemisphere, according to an April 6 Armed Forces Health Surveillance Branch summary.

Jones said the DoD labs will use the Zika money provided by the branch’s GEIS section for three kinds of surveillance studies. One will look retrospectively for Zika virus exposure among DoD personnel through serum repository samples. A retrospective study looks backward in time, in this case using serum samples of patients who had been deployed in areas with high rates of Zika virus infection.

The other surveillance studies will leverage existing work in the GEIS lab network in different parts of the world to expand clinic-based surveillance for Zika virus disease among DoD and civilian populations, and expand testing for Zika virus in mosquitoes.

DoD Serum Repository

The Defense Department collects a range of blood serum samples from all service members before, during and after their military service, and maintains the samples in the Armed Forces Health Surveillance Branch’s Department of Defense Serum Repository. Serum is a clear fluid that’s part of a person’s blood. It’s used in many medical diagnostic tests and in blood typing. The repository is the world’s largest of its kind, with more than 60 million serial serum samples from more than 10 million service members.

For the retrospective Zika virus surveillance study, military virologists -- scientists who study viruses -- and public health officials will check the serum samples of service members stationed in the United States and in high-risk regions in the Caribbean and other places overseas. The scientists will be looking for prior exposure to Zika, dengue and chikungunya viruses, all of which are transmitted by Aedes aegypti mosquitoes. In recent years, according to CDC, dengue and chikungunya cases have begun to appear in the United States, most of them brought in from tropical urban areas of the world.

Understanding Risk

“For the service members, I can talk from personal experience,” Jones said. “Our blood is drawn when we enter active duty, prior to and following all deployments, and occasionally during acute illness for the purpose of storing in the serum repository, allowing for [later] analyses of a service member's serum over his or her time in service.  So the serum repository keeps a history of a service member's serum on tap.”

She added, “When looking to understand exposure to our service members, the repository provides a unique resource for helping to determine if, when and where there was any exposure to a variety of pathogens.”

This serum surveillance effort will examine 500 samples from service members stationed in Puerto Rico during a time when some of the viruses were transmitted, and 500 from service members deployed to West Africa, Jones said.

“We’re trying to understand the baseline risk for service members,” she added.

Lines of Effort

Other lines of effort for surveillance for the labs include looking for Zika virus in mosquitoes in the Caribbean, East Africa and Southeast Asia, Jones said, and also looking for Zika virus in service members and in military beneficiary and civilian populations who go to medical facilities with a fever, medically known as a febrile illness.

The febrile surveillance will be done in the southwestern United States -- California, Arizona and Texas -- and in the Caribbean, Central and South America, East and West Africa and Southeast Asia, she said.

In mosquito surveillance, scientists capture mosquitoes in traps and take them to the DoD labs to be processed to get their genetic material for testing.

“By testing the genetic material, we can understand where mosquitoes are carrying the virus,” Jones explained. “We won't necessarily be able to tell quantitatively the percentage of mosquitoes carrying the virus, but in relative terms we’ll learn about the population that's carrying the virus, in what parts of the world, and the risk to DoD populations.”

Febrile Illnesses

Human surveillance focuses on service members and military beneficiary and civilian populations who go to the hospital with febrile illnesses.

“Most of these are efforts where we are already conducting surveillance for other febrile pathogens,” Jones said.

“For example we have a study in Peru, where they’re already doing clinic-based febrile surveillance activities in South America. These are people in the population who come to the clinic with a febrile illness. Their blood will be drawn and sent to the [Naval Medical Research Unit No. 6 in Lima] for testing for Zika virus, along with other pathogens the scientists there have been looking for,” she added.

Protecting the Global Force

Jones said officials don’t know what they’re going to find in the GEIS-funded effort. “It's very possible that the actual [number] of mosquitoes that are carrying the virus or the number of patients that we get is so small that the chance of finding something could be small,” she acknowledged. But she said GEIS still wants to do the work, because the lack of Zika virus in the samples is also valuable information and helps to determine the risk to service members.

“For us in GEIS, because [infectious diseases can emerge anywhere], it's very important to us to understand what diseases are currently in what geographic locations in the world, and understand what disease may emerge and spread rapidly,” Jones explained. “Our forces are present globally, and we need to make sure that they are able to complete their mission. Infectious diseases are one of the things that can impede their ability to do their mission.”

(Follow Cheryl Pellerin on Twitter: @PellerinDoDNews)