When the Pennsylvania Department of Health issued its first warning a little more than a month ago about a new virus with a strange name, it may not have seemed like cause for much concern.
The sometimes-disabling virus, called chikungunya (pronounced chik-en-gun-ye), is transmitted via mosquito bite, but only three people in Pennsylvania had it, and all of them had gotten bitten during overseas travels.
Public health experts, however, knew that with the vector — or means of transmission — present in Pennsylvania, chikungunya eventually would make its presence known in a bigger way.
"If you have the vector, you'll have the disease," said Dr. Jeffrey Jahre, section chief of infectious diseases at St. Luke's University Health Network.
And indeed, in only a month, the virus has started to take off in Pennsylvania. The state last week reported 12 confirmed cases, but the actual number likely is higher. St. Luke's has treated two patients with it, and Lehigh Valley Health Network last week had four confirmed and four suspected cases.
Chikungunya also is landing at an inopportune time. The state has cut spending on its mosquito eradication program, and hasn't sprayed in public areas in the Lehigh Valley at all this year. While that indicates another mosquito-borne disease, West Nile virus, is at a low level now, it does leave the door open to the new virus.
At least it's new here.
Chikungunya was first described in 1952 in Tanzania, according to the World Health Organization. It is a term in the Kimakonde language roughly translated as "to become contorted," which describes the posture of those afflicted with the virus from the joint pain they feel.
Symptoms usually develop three to seven days after the person is bitten. While chikungunya is not a fatal disease, it often results in fever, rash, muscle aches and joint pain. The pain can be disabling, and it can last for years, according to WHO.
There is no vaccine to prevent chikungunya, nor is there a treatment for it, so doctors can only recommend rest, fluids and over-the-counter medicine to treat the pain and fever.
The virus is carried by two types of mosquitoes: Aedes aegypti and Aedes albopictus. Both species are found in the southeastern United States and some parts of the Southwest. But Aedes albopictus also is found in the mid-Atlantic states, including Pennsylvania.
Chikungunya was endemic largely to Africa and Southeast Asia, until it jumped the ocean to the Caribbean islands. It was discovered on the island of St. Maarten late last year. Public health officials found that the cases soon were locally transmitted — when a mosquito bites someone who is infected with the virus and then bites another person.
In no time, the virus exploded across the islands, including Puerto Rico. Residents who had been bitten and suffered nothing more than a welt and an itch now were finding themselves feverish and, in some cases, in great pain.
That's when public health authorities started counting the days until chikungunya showed up here.
"We also knew when it occurred that way in the Caribbean that it would only be a matter of time … before there were locally transmitted cases in the United States," Jahre said.
In a matter of months, nearly 500 people across the United States have confirmed travel-related cases of the illness, according to the U.S. Centers for Disease Control and Prevention. However, four cases in Florida have been confirmed in people who did not travel to areas where chikungunya is endemic.
The big question for the rest of the country is how far chikungunya will spread via local transmission.
"Who's to say?" Jahre said.
In a briefing July 17, the CDC said it thinks chikungunya will behave like dengue virus in the United States, where imported cases have resulted in sporadic local transmissions but have not caused widespread outbreaks. It said that none of the more than 200 imported chikungunya cases between 2006 and 2013 triggered a local outbreak, but as more infected travelers return to areas where the virus is not local, the likelihood of local transmission grows.
Public health officials have relatively recent experience with the West Nile virus that teaches them to be wary about predicting the next steps.
"I think that is the poster child for what can happen," Jahre said.
Also spread by mosquitoes, West Nile was first found in New York state in 1999. By 2012, it was in every one of the continental states except Oregon, CDC records show.
"Nobody predicted what West Nile would do," said Dr. Luther Rhodes, chief of infectious diseases at Lehigh Valley Health Network.
A contributor to the spread of chikungunya is travelers, including people who regularly visit family and friends in places like Puerto Rico and the Dominican Republic, Rhodes said. People who are used to visiting the Caribbean but not using mosquito repellent "often take less precaution because they're going home," he said.
Travel agents at AAA East Central in Allentown recommend that vacationers check the CDC site to get the latest on precautions to take before leaving, said Sally S. McCorrisson, director of travel services. There is no restriction on travel to places where chikungunya is present.
But Rhodes said he'd think twice about going to the Caribbean now if he suffered from arthritis or had another condition that could be exacerbated by the virus.
For those who do travel, the best advice is to take steps to prevent mosquito bites, health authorities say. Use repellent with DEET; wear long sleeves and pants, especially in the daytime, which is when the two Aedes mosquitoes usually bite, CDC says.
Locally, Valley residents can help by making sure containers that pool water are emptied to prevent mosquito breeding areas.
"The junk that people leave around — small containers, tires, trash — if people clean up their space, that will go a long way in helping us keep things under control," said Louise Bugbee of the Lehigh County Extension office.
She acknowledged that budget pressures have cut into the state's program for spraying for mosquitoes. Since the 2010-11 fiscal year, spending on mosquito spraying by the Department of Environmental Protection is down 26 percent, to $3.8 million.
There has been no public spraying in the Lehigh Valley this year, although Bugbee said that also is determined by the amount of West Nile samples collected.
"We have to have numbers that warrant a spray, and so far we haven't gotten to that threshold," she said.
On Friday, Pennsylvania officials announced the state has detected its first probable human case of West Nile infection this year. A Philadelphia County man was hospitalized due to the virus, but he has since recovered, the Department of Environmental Protection said.
When mosquitoes are involved, public health officials know, the insects usually find a way to survive and thrive.
"We think we know a lot about viruses," Rhodes said. "You can see how humbling it is."
• What: A virus transmitted to people by mosquitoes.
• Symptoms: Fever and joint pain, headache, muscle pain, joint swelling or rash.
• Risk here: The virus can be imported to new areas by infected travelers who visited the Caribbean.
• Treatment: There is no vaccine to prevent the virus or medicine to treat it.
• Travel: When traveling to countries that have the virus, use insect repellent, wear long sleeves and pants.
Source: Centers for Disease Control and PreventionCopyright © 2015, The Baltimore Sun