Human Cadaver Fungi Identified

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Human Cadaver Fungi Identified

By Viegas, Discovery News

http://dsc.discovery.com/news/briefs/20060522/corpsefungi_hum.html

May 22, 2006 — Deceased individuals supposedly " push up daisies, "

but a forthcoming study suggests human cadavers are more likely to

support several species of white and yellow fungi.

The study is the first to describe in detail species of fungi

obtained from human corpses. In the future, forensics experts may

use the information during criminal investigations to determine an

individual's time of death.

Fungi, which are parasitic plants that lack chlorophyll, leaves, and

true roots and stems, often form part of the natural decomposition

process that recycles nutrients back into the food chain.

In this case, as lead author Kiyoshi Ishii told Discovery News, " The

fungi feed on the dead. "

Ishii and his colleagues analyzed two humans whose bodies were found

decomposing in very different environments. The first was a corpse

discovered lying face down on a concrete floor in an abandoned

house. Police determined the body belonged to a 72-year-old man who

had been missing for 10 months. The scientists observed yellow and

white fungi on the deceased's chest, abdomen and thighs, but little

insect infestation, probably because the house was dry and isolated.

The second case study involved skeletal remains clad in a shirt and

pants, which all were found in a forest next to a rope hanging from

a tree branch. Forensics specialists determined the body belonged to

a 50-60-year-old man who had hung himself at least 6 months before

the body's discovery. The scientists once again detected yellow and

white fungi growing on the corpse.

Ishii, a biologist at Dokkyo University School of Medicine in Japan,

and his team collected the fungi and incubated them in a laboratory.

They identified several species including Gliocladium sp., a slimy

counterpart to penicillin; Eurotium chevalieri, a fungus that can be

bright yellow; and Eurotium repens, which is commonly found in soil.

The Eurotium species dominated the collected samples.

Ishii explained that the white and yellow coloration is associated

with the sexual stages for Eurotium fungi. The parasite produces

threadlike filaments that terminate with circular, colorful

structures called ascomata that are involved in reproduction. The

fungi also produce colorful conidia, or asexual spores, which tend

to form in the morning and germinate in the afternoon and evening

hours.

Ishii said the environment in which a body lies, rather than the

biochemistry of the individual or the manner of death, tends to

dictate how much or how little fungi will colonize a cadaver. The

team's findings have been accepted for publication in the journal

Legal Medicine.

Yuichi Chigusa, a medical parasitologist and entomologist at Dokkyo

Medical University's School of Medicine in Soka City, Japan, told

Discovery News that fly larvae usually infest corpses within an hour

to a half-day after the victims' death, followed by Coleoptera

(beetles) infestation and then fungal colonization. He is excited

about the potential of fungi for further aiding detective work.

" I am surprised that fungus is a potential tool for determining post

mortem intervals in cadavers without infestation of dipteran larvae

and/or beetles, " Chigusa said. " Therefore, I think it is very

important that forensic pathologists, forensic entomologists and

forensic mycologists cooperate in determining post mortem intervals

during forensic analysis. "