Vicious Viruses: Readiness is Job Number One

By Lt. Col. Eric Halsey, head of Virology Department at NAMRU-6, Peru

* Editor’s note: This is blog number four out of six in a series of blogs from NAMRU-6.

Aedes aegyptiMosquitoes can do more than spoil your picnic. They can ruin your day, your week, or even your life. Mosquitoes are the main insects that carry arboviruses—Arthropod-borne viruses—a group of pathogens threatening an ever increasing number of countries and people. Some of the more well-known arboviruses include West Nile virus, dengue virus, and yellow fever virus. The Virology Department of the Naval Medical Research Unit No. 6 (NAMRU-6) in Peru concentrates much of their research effort into studying this dangerous category of menacing microbes.

Of all the arboviruses, the dengue virus poses the greatest threat to the readiness of the United States soldier. In the past, dengue fever was a major cause of non-battle related illness in both the Pacific theater of World War II and the Vietnam War. In addition to these Southeast Asian and south Pacific locations, dengue disease is now present throughout much of Latin America, the Caribbean, Africa and Central Asia. Over three billion people live in regions experiencing dengue disease, many of which are of a strategic interest to the United States. And not even the United States is safe from this pesky pathogen. In 2009, Key West, Fla., suffered a dengue outbreak and the virus is currently thought to be present in some border regions with Mexico.

Dengue fever carries the nickname “breakbone fever” because of the intense bone pain that accompanies infection. Other common symptoms include headache, nausea, and overwhelming fatigue. In its most severe forms, dengue hemorrhagic fever or dengue shock syndrome, infection may lead to life-threatening bleeding, organ failure, and death. Of the more than 50 million people infected worldwide annually with the dengue virus, approximately 15,000 die. Both numbers have steadily increased over the past two decades.

Insecticide-treated curtains in an Iquitos, Peru, home. (Photo courtesy of NAMRU-6 public affairs).
Insecticide-treated curtains in an Iquitos, Peru, home. (Photo courtesy of NAMRU-6 public affairs).

The Virology Department at NAMRU-6 has a long-standing history of dengue research that has continued to the present day, many taking place in the Amazon city of Iquitos, Peru. Recent projects include two novel strategies to kill the mosquito that transmit the virus. One strategy involves curtains pre-treated with insecticide that are hung in people’s houses. The other strategy utilizes a trap with a color, shape, and size that lures the female mosquito to lay her eggs in a substance that is toxic to both her and her offspring.

A black and red mosquito trap (foreground) being prepared by Amy Morrison, PhD, study coordinator in Iquitos, Peru. (Photo courtesy of NAMRU-6)
A black and red mosquito trap (foreground) being prepared by Amy Morrison, PhD, study coordinator in Iquitos, Peru. (Photo courtesy of NAMRU-6)

In addition to mosquito-focused interventions, other NAMRU-6 research focuses on tests that can rapidly diagnose infection within minutes at the bedside and other assays that can distinguish who will develop severe disease days before it manifests. Moreover, a recent departmental study identified that human movement, much more than that of the mosquito, was a main determinant in the spread of disease throughout a community. NAMRU-6 Virology’s vast surveillance network that assesses people with fever of unknown cause boasts sites in six Latin American countries and routinely identifies emerging and dangerous strains of dengue virus, sharing this information with ministries of health. All of the aforementioned projects leverage the joint initiatives of safeguarding public health in the host country as well as the US soldier.

 No vaccine or medication currently exists to treat infection with the dengue virus. Until that goal is realized, NAMRU-6 Virology will continue to research ways to combat the mosquito, decrease transmission, and, ultimately, eliminate this vicious virus from the many locations it currently threatens. The value of a preventive approach today may be measured in money and lives saved in the future.

Click on the following links to see the series of blogs from NAMRU-6: 1 (NAMRU-6 overview), 2 (bacteriology) and 3 (entomology).