December 16, 2012
Joplin Tornado Caused Fungal Infection Which Claimed 5 Lives
April Flowers for redOrbit.com - Your Universe Online
Following the massive tornado that devastated Joplin, Missouri, in 2011, a fast growing, flesh eating fungus killed five people according to two new studies. The studies were based on genomic sequencing by the Translational Genomics Research Institute (TGen) and the U.S. Centers for Disease Control and Prevention (CDC).
Usually, this common fungus that lives in soil, wood or water has no effect on humans. Once it is introduced deep into the body through a blunt trauma puncture wound, however, it can grow quickly if the proper medical response is not immediate. Five of the 13 subjects infected through injuries suffered during the tornado died within two weeks. The results of these studies were published in the New England Journal of Medicine (NEJM) and PLOS One.
"Increased awareness of fungi as a cause of necrotizing soft-tissue infections after a natural disaster is warranted “¦ since early treatment may improve outcomes," concluded the NEJM study published in early December.
TGen scientists, using whole genome sequencing, which decoded the billions of chemical letters in the fungus' DNA, concluded that the Joplin infections represented the largest documented cluster of Apophysomyces infections, according to the PLOS One study published in November.
"This is one of the most severe fungal infections that anyone's ever seen," said David Engelthaler, Director of Programs and Operations for TGen's Pathogen Genomics Division. Engelthaler was the senior author of the PLOS One study, and a contributing author of the NEJM study.
"We're able to apply the latest in science and technology to explore these strange and dangerous pathogens, like we've never been able to before," said Engelthaler, adding that this is the latest in a series of collaborations between CDC and TGen. "This is the first peek into the genome of this dangerous fungus."
The victims were infected when their injuries from the tornado were contaminated with debris from the storm, said Dr. Benjamin Park, chief of the Epidemiology Team at the CDC's Mycotic Diseases Branch. This debris includes gravel, wood and soil, as well as the aerosolized fungus. Park was the lead author on the NEJM study and contributed to the PLOS One study.
Fungal infections are rare without the multiple and deep wounds caused by the storm. Dr. Park says the typical hospital might see one a year.
Apophysomyces infections seal off capillaries, shutting down the blood supply and leaving tissue to rot, quickly ravaging the entire body. In a process called debridement, doctors try to get ahead of the infection by surgically removing sections of dead, damaged or infected tissue.
Engelthaler said one example of this process was a patient who required a new titanium rib cage because the fungus rapidly destroyed skin and bones in a deep wound to the upper right chest.
"It's unlike anything you've ever seen before," said Engelthaler, a former State of Arizona Epidemiologist and former Arizona Biodefense Coordinator. "It's unreal. It looks like there is no way this person can be alive."
There are only two drugs – amphotericin B and posaconazole – approved by the FDA for use against mucormycetes, the group of molds that includes Apophysomyces and causes mucormycosis, making it of utmost importance that the exact mold causing an infection is identified rapidly and accurately.
"It is not known whether the outcomes for these case patients would have been different if mucormycete-active agents had been used initially," said the NEJM study. "The timely diagnosis of mucormycosis is essential for guiding therapy, because the early initiation of appropriate anti-fungal medication and aggressive surgical debridement are associated with improved outcomes."
Both studies recommended complete genomic studies, stating that it could lead to better diagnosis and a better understanding of this pathogen. The sequencing done by TGen identified Apophysomyces in all 13 cases in Joplin, as well as establishing that several strains were involved in the outbreak. This alerted scientists that the fungus was well established in the area and probably had been for a long time.
"These disasters put us at risk for exposure to organisms that are around us, but don't normally cause disease," Engelthaler said. "There's clearly an entire world out there that we're not seeing on a regular basis. It takes a severe event like this tornado for us to come face-to-face with some of the more dangerous pathogens out there."