Despite being hit with the largest dengue fever outbreak in the United States since World War II, Hawaii residents are fortunate in that there’s only one strain of the virus in the state.

But health professionals say the virus that is here is especially risky to people who have been previously exposed to a different strain elsewhere.

Dengue fever is a severe, flu-like illness that affects all ages, but is rarely fatal. Since September, as of Sunday, there have been 181 cases confirmed on the Big Island.

Department of Health Microbiologist Becky Kanenaka demonstrates testing processes in hood at the State of Hawaii Department of Health Laboratory Facility on the top of Waimano Home Road. 12 dec 2015. photograph Cory Lum/Civil Beat
Department of Health microbiologist Becky Kanenaka demonstrates dengue fever testing processes at the state Department of Health Laboratory on Oahu. Cory Lum/Civil Beat

According to the state Health Department, only a handful of those people are potentially infectious at the moment, meaning that if a mosquito bit them, it might become a carrier (the virus is not transmitted directly from one human to another).

There are four types of dengue virus – DENV-1, DENV-2, DENV-3 and DENV-4. So far, DENV-1 is the only type seen in the three outbreaks in Hawaii since 2001, while DENV-2 is more common throughout Asia.

Those who get dengue can develop a partial immunity to that specific strain. But studies show people are at a much higher risk for developing severe dengue if they’ve been exposed to another type previously.

“If somebody let’s say had been traveling in Asia… where they had been exposed to dengue type 2, then they would be at a greater risk living in Hawaii (which has dengue type 1),” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston.

Nicknamed “breakbone fever,”  the dengue virus can develop into severe forms known as dengue hemorrhagic fever and dengue shock syndrome, which can be fatal.

Sarah Park, the chief of the disease outbreak division for the state Health Department, said regardless of whether someone has been exposed to the virus once or multiple times, they’re still at risk for developing severe forms of the virus and should seek immediate medical attention.

“Frankly, anyone who gets dengue infection, whether it’s your first time, second time, third time, is at risk of severe dengue,” Park said. “Especially with people with underlying medical conditions … for instance a pregnant woman, could be more at risk for severe dengue.”

She worries that if people only think they can develop severe dengue after acquiring the virus more than once, they won’t seek medical care. That’s why the DOH doesn’t have information about the increased risk on their website, she said.

For severe dengue cases, medical care can lower mortality rates from more than 20 percent to less than 1 percent.

There are two types of mosquitoes in Hawaii – Aedes aegypti and Aedes albopictus – that can transmit the viruses that cause dengue fever. Wikipedia

Health officials say the Big Island outbreak could last for months —through the peak of tourist season. Hotez thinks there could be more cases than previously documented.

“Anytime you diagnose a case you have to assume there’s several that you’re not diagnosing,” said Hotez.

Health professionals say the Big Island’s outbreak isn’t a widespread threat to Aloha State residents, but it is evidence of an increase in outbreaks across the globe.

Before 1970, dengue epidemics had only happened in nine countries. Now, the virus, which is spread by mosquitoes, is present in 125 countries, and infects as many as 400 million people each year, according to the U.S. Center for Disease Control and Prevention.

Hotez thinks dengue outbreaks could spread to the mainland U.S. in states such as Texas, Florida and California, which are home to the type of mosquito capable of transmitting the virus.

“I think (Hawaii) is a part of a bigger problem that we’re starting to see,” said Hotez. “(For) the next few years, we’re going to be in for a rocky road.”

Here are the things you can do to help prevent dengue fever:

  • Apply mosquito repellant on exposed skin and clothing
  • Wear long sleeves and pants, and light-colored clothing, to limit exposure to mosquitoes
  • Eliminate standing water around residences to reduce mosquito breeding
  • Repair damaged screens and jalousie windows

About the Author