WASHINGTON - State health officials across the USA report a surge of suspected cases of a painful mosquito-borne illness that can leave those infected with severe joint pain that can make walking or even shaking hands unbearable.
All but one American suspected of contracting the disease known as chikungunya had recently traveled to the Caribbean. The first case of the disease being transmitted on U.S. soil was confirmed in Puerto Rico late last month.
Infectious disease experts say conditions are ripe for the illness to explode in a large swath of the USA where two mosquito species known to spread the disease are in abundance.
"It's not a matter of if but when," said James Crowe, a pediatric infectious disease expert at Vanderbilt University School of Medicine.
The disease was discovered in Africa more than 60 years ago and was detected in the Caribbean late last year. About 135,000 people have been suspected or confirmed infected in the Western Hemisphere — mostly in the Caribbean — since last year, according to the Pan American Health Organization.
The symptoms of chikungunya — which is derived from the Kimakonde language and roughly translates as "to become contorted" — include fever, muscle pain, headache, nausea, fatigue and rash. The disease shares some clinical symptoms with dengue and is often misdiagnosed in areas where dengue is common.
The disease, which has no known cure, is less lethal than mosquito-borne illness West Nile virus. The joint pain can be excruciating, and debilitating symptoms usually last days and sometimes weeks.
In recent weeks, state health officials have reported that American travelers to the Caribbean from Arkansas, California, Connecticut, Florida, Indiana, Maryland, Nebraska, New York, Nevada, North Carolina, Tennessee, Texas and Virginia have been stricken with symptoms consistent with chikungunya. Wednesday, officials in the U.S. Virgin Islands reported a locally transmitted case of the disease.
"Thankfully, deaths from the disease are rare, but the pain can be severe and debilitating," said Joseph Acierno, chief medical officer at Nebraska's Department of Health and Human Services, which this week confirmed the first case of a Nebraskan contracting the disease.
The infected woman had traveled to Haiti, where she may have contracted it.
The warm and wet summer season on its way in the continental USA provides optimal conditions for the disease to spread through the country. Mosquitoes transmit the disease by biting an infected traveler, then biting another person. The disease cannot be spread person-to-person.
Two species of mosquitoes, aedes albopictus and aedes aegypti, carry the disease. The Centers for Disease Control and Prevention says the albopictus, commonly known as the Asian tiger mosquito, is "more likely to play a larger role in transmission in the United States due to its wide distribution."
That species can be found from Florida to the mid-Atlantic region and in large swaths of the Midwest. The aegypti, also known as the yellow fever mosquito, is mostly found in the Southeast.
CDC studies showed an average of 28 people per year tested positive for chikungunya in the USA from 2006-2013. All were travelers visiting or returning to the USA from affected areas.
In 2014, the number of suspected infected people has exceeded the U.S. yearly average. Florida and Tennessee have counted a total of 37 suspected cases in recent weeks.
Of the 14 suspected cases involving Tennesseans, 13 had returned from mission trips from Haiti, said Abelardo Moncayo of the Tennessee Department of Health.
Missy Henriksen, vice president of public affairs at the National Pest Management Association, said federal and state health officials began anticipating that the disease could become an issue in the USA when the first cases were identified in the Caribbean late last year.
She said there is concern among health officials that chikungunya could be spread farther globally as tens of thousands of soccer fans and athletes visit Brazil for the World Cup. One of the species of mosquitoes is common there.
Americans should watch for symptoms to help prevent the disease from spreading, she said.
"It's critical that people who are traveling to some of these countries where it is endemic are extra cautious and sensitive if they return home and are not well," Henriksen said. "They should immediately consult with a medical professional."