By Wally Kennedy
Globe Staff Writer
JOPLIN, Mo. —
Steven Weersing survived Joplin’s 2011 tornado, but the battle to recover from a fungus that nearly killed him continues 20 months later.
Weersing has a crater-like scar on the right side of his chest. To save him from the mold that was eating his skin and muscle, doctors cut away four ribs and part of his chest wall.
He makes regular trips to Children’s Mercy Hospital in Kansas City, where he is viewed as a miracle patient. When he arrived there shortly after the tornado, his chances for survival were placed at 5 to 10 percent. The trips now are for surgeries that will cover the scar.
“I’m doing pretty good,’’ the 17-year-old said. “They put balloons under my skin to stretch it out. They’ll stretch the skin from the sides to pull over the scar.
“I still have a long way to go. But things are looking good otherwise. I’m about to have a baby.’’
His girlfriend’s due date is May 22.
Weersing, who was in a vehicle near 20th Street and Rex Avenue when the tornado hit, was probably the last person to contract the aerosolized fungus that affected 13 of the storm’s victims.
Ellen Freeman, who lived at 2515 Picher Ave., was probably the first.
Freeman now lives at Spring River Christian Village. At age 77, she is the oldest person to survive the fungus, which has left her with a deep impression in her right thigh. She was hospitalized for nearly four months with a fractured neck and hip, and a laceration to her head.
“I get pain medicine every few hours and I take a pill for the itching,’’ she said. “Mentally, I’m doing pretty good. I am so thankful to have this place to live. I still miss being on my own, but I’ve come to the realization that this is my home.’’
The worst part for Freeman ended five months ago.
“They dressed the wound three times a day. It hurt so bad,’’ she said. “But that stopped in September.’’
Like Weersing, she will look at the possibility of having skin grafts or plastic surgery to minimize the scar that remains.
And, like Weersing, she has something to look forward to in her life.
“That’s my 1-year-old grandson, Julian. He’s the joy of my life,’’ she said.
Freeman and Weersing are among eight survivors who developed a rare fungal infection after coming into contact with aerosolized spores of apophysomyces trapeziformis. Five other people with the fungus died within two weeks of exposure.
Using whole genome sequencing, which decoded the chemical letters in the fungus’s DNA, scientists at the Transitional Genomics Research Institute (TGen) in Flagstaff, Ariz., concluded the Joplin infections represent the largest documented cluster of apophysomyces infections.
The development of this type of infection is not unprecedented after a natural disaster, but it is extremely rare. Eight cases were reported after a 1985 volcanic eruption in Colombia. The fungus also was identified as the agent of soft-tissue infections in two people who were injured during the 2004 Indian Ocean tsunami.
Because of this cluster of cases in Joplin, health providers responding to future tornadoes or other natural disasters now know that such clusters are possible, and that timely diagnosis of the fungus and early intervention with appropriate medication can improve outcomes.
The fungus grows in soil, wood and water. It’s harmless to humans unless it penetrates the skin. When it does, it spreads aggressively — growing within a matter of hours.
“What is remarkable is that this is not a human disease,’’ said David Engelthaler, the TGen scientist who helped unravel the 34 million chemical letters that make up the fungus’s DNA. “It does not know how to interact with a human host and the human body does not know how to react to it.
“It enters the capillary system and just takes off, branching out and growing really fast. It ends up blocking off the blood flow to the tissue. That causes the necrosis. It kills off large areas of tissue,’’ he said.
To stop it, the tissue ahead of the fungus must be cut away.
“The medical folks learned that this fungus grows within a matter of hours. They could visibly see the fungus growing back.’’
The technology that led to the whole genome sequencing of the fungus is so new that identifying the fungus would not have been possible five years ago, Engelthaler said.
The DNA analysis established that several strains of the fungus were involved in the Joplin cases. The scientists interpret that to mean that the fungus has gone through a large number of mutations and has become well established in the area, and probably has been for a long time.
The scientists checked with health officials in Alabama and Massachusetts where tornadoes occurred in 2011 before the Joplin tornado. There were no fungal infections among the people who were seriously injured in those tornadoes.
A study by the federal Centers for Disease Control and Prevention, published Dec. 6 in The New England Journal of Medicine, suggests that the source of those spores might be some “small bodies of water’’ that were early in the tornado’s destructive path.
But that’s only speculation. Dr. Benjamin Park, who led the CDC’s probe into the fungal cases, readily admits: “The source of the fungus is still not known.’’
It is believed the spores, which may have come from a single source because of their genetic similarity, were inoculated into the skin of Freeman and Weersing and other victims when they were injured by flying debris. They and all of the other fungal cases sustained serious and life-threatening injuries. Most had at least five or more wounds or fractures. That degree of injury, more than anything else, put them at greater risk for infection, the CDC study concluded.
“We conducted a case control study to look for reasons why some people got infected and others did not. We found that the severity of injury was tightly associated with risk of infection,’’ Park said.
Engelthaler said epidemiologists on the ground in Joplin identified the bodies of water and noted that they had gathered a lot of water from storms before the tornado.
“We don’t know much about this fungus, but we know it grows pretty well in water,’’ he said. “It’s quite likely this water was swirling around in the tornado. The people with the most injuries in the middle of the most destructive swath ended up getting the fungus.’’
The CDC’s look at the cases shows that Weersing might be the luckiest of them all. His fungal infection was the first to be confirmed just six days after the tornado. He was one of two to receive surgical debridement just one day after the tornado, referring to the process where sections of dead, damaged or infected tissue are removed. And most importantly for Weersing, he received the appropriate antifungal medication for the type of fungus he had at the beginning of his treatment.
That compares with six fungal patients who were not prescribed the appropriate antifungal medication at the beginning of their treatment. Freeman was among those, according to the CDC analysis. Her fungus culture tests provided confirming evidence 16 days after her injury.
Four of the six died. For three of them, the fungal infection was listed as the primary cause of death, though no autopsies were performed to conclusively prove that.
Weersing’s case underscores the principal findings of the CDC study about the cases of mucormycosis, which is a rare infection caused by organisms that belong to a group of fungi called mucoromycotina.
Said Park: “Mucormycosis can often be difficult to recognize and diagnose, so we encourage clinicians to consider this infection particularly when treating patients who have had a history of trauma.
“Early recognition and treatment with antifungals that are active against these organisms may improve the chances of survival,’’ he said in an email statement.
The research also showed that two medications — posaconazole and amphotericin B — were the best at controlling the fungus.
“These fungi are naturally difficult to treat — many antifungals are just not effective against them,’’ he said. “Antibacterial antibiotics would have no effect.
“I can’t comment on any particular case, but I can say that these fungal infections do take a long time to eradicate. Many people need months of antifungal therapy.’’
All 13 fungal patients were located in a three-milelong zone within the area with the most catastrophic damage. There were no cases on the periphery of the damage zone. Nine had been in single-family homes, two were in vehicles, and one was in a public building. The location of one patient at the time of the tornado is not known.
The tornado claimed 161 lives and injured at least 1,150 people. Many of the injured suffered penetrating trauma and deep lacerations, yet they did not develop fungal infections.
Engelthaler said it is possible that many of the injured were exposed to the fungus but did not develop an infection.
“A scratch is not enough for it to set up shop,’’ he said. “It needs to be deeply implanted. That’s why the people with the most injuries and most severe injuries developed infections. There was no evidence of mild cases and there were not many that were missed.’’
Another factor could be the structure of the tornado.
“There is an alternative hypothesis that has to do with the structure of the tornado and how the winds in a tornado move in different directions,’’ he said. “It is possible the fungus was circulating in the middle of the tornado as it moved through.’’
For Park, that environmental component touches on the random nature of why 13 people became infected with the fungus and others did not.
“There is also likely to be an environmental component, whereby some injured patients were unlucky and had these spores inoculated into their skin during their injury,’’ he said.