Climate Change Means A Rise In Mosquito-Borne Illness

Jan 17, 2019

The sunlight coming through the picture window of Debbie Casey’s room at a nursing home in Daytona Beach falls on a message board covered with pictures from her life. 

In most, she’s smiling wearing the trademark blonde bob her son Brian has tried to keep up even though she’s in a coma in a hospital bed. He says just a few months ago his spunky 68 year-old mother was doing fine.

“Working full-time. She had just built a little home that was going to be her retirement home, Brain Casey said.”

But then Debbie Casey ended up in an emergency room in Gainesville with what doctors thought was a stroke.

“It took about ten days to finally identify what was causing her problem,” her son said. “Because it’s just so extremely rare.”

Debbie Casey was one of only five people hospitalized nationwide with Eastern Equine Encephalitis this year.

University of Florida entomologist Dr. Jonathan Day estimates about five times that many got infected with the disease, but they got only mild flu-like symptoms that went away after a few weeks. He says shifting climate patterns make Florida more vulnerable to the disease.

“During years where we have an exceptionally wet winter and early spring, that sets the stage for Eastern transmission and that’s exactly what we had this year,” Day said.

The number of people who got sick in the United States from an infected mosquito, tick, or flea tripled between 2004 and 2016. More than 640,000 cases over that time, according to the Centers For Disease Control and Prevention.

In Florida, changing climate and a lack of good diagnostic tools, make it easier for insect-borne diseases like Eastern Equine Encephalitis to spread. The personal and financial costs of even one case of this disease can be catastrophic.

In Florida, the dry season between mid-November to mid-May is actually getting wetter. The rise in humidity makes it easier for mosquitoes to fly farther outside the swamps where they normally live. From there, they can end up in people’s backyards.

“And that’s what we saw this year,” Day said. “Very wet winter, very wet conditions that allowed those mosquitos that were infected to disperse, carry the virus with them, and infect horses and humans.”

University of Florida’s Dr. Kartik Cherabuddi said in the case of patients like Casey, where the infection moved to her brain, long-term care costs can be in the hundreds of thousands of dollars.

“It amounts to a huge monetary burden,” Cherabudi said. “From the initial bill, rehab and therapy and trying to have people who can be around them and help with daily function.”

Most of Casey’s costs have been picked up by Medicare and Social Security, but her son Brian says he’s already had to pay $20,000 in out-of-pocket costs. And he might have to sell Debbie’s home to pay the rest of her bills.

Cherabuddi, who who treats people with Eastern Equine Encephalitis at UF Health Shands Hospital in Gainesville says most people will never even known if they’ve gotten the virus.

“Most people would have a syndrome that’s very similar to a flu-like illness,” she said.

Cherabuddi says only five percent of patients land in the hospital with the severest symptoms including one of the worst headaches of their lives, a high fever, slurred speech and blurry vision.

“This is when it causes infection in the brain lining and the brain itself,” she said. “And when that happens about a third to a half of patients will succumb to the illness.”

And testing for Eastern Equine Encephalitis isn’t easy. There’s a spinal fluid test that often comes back with false negatives if it’s administered too soon and a standard blood test can be slow.

“Most often people are not thinking of sending the test and two when they do send it it takes a week or so to come back,” Cherabuddi said.

The patient’s condition can get much worse waiting for results. And that increases the chances of long-term disabilities. The cost of care for speech and memory problems or even paralysis resulting from the illness can be in the hundreds of thousands of dollars. There’s no medication or vaccine for Eastern Equine Encephalitis and with a lack of research funding, doctors don’t expect this will change anytime soon.

Debbie Casey’s doctors won’t know the extent of her brain damage until she wakes up. And that makes it hard for her son Brian Casey to plan for her care. He’s been working from home part-time so that he can be at his mom’s bedside.  

“It gets frustrating after a while because I’m a thinker and a planner,” he said. “And there’s not much I can plan beyond a certain amount of time.”