Rom J Leg Med [22] 253-256 [2014]
DOI: 10.4323/rjlm.2014.253
© 2014 Romanian Society of Legal Medicine The importance of collecting live fly larvae from a severely decomposed
human cadaver in winter. Case report
Masahito Hitosugi1,*, Masashi Kirinoki2, Kanto Ishii3, Satomu Morita1, Satoshi Furukawa1, Yuichi Chigusa2
_________________________________________________________________________________________
Abstract: A severely decomposed cadaver was found in a snow-covered mountain forest on January 31, 2010. The
cadaver, later identified as a 24-year-old Japanese man, was hanging from under a tree and consisted mainly of skeletal remains.
At autopsy, dozens of larvae were observed around the inner cavity of the knee joint, and entomologically they were identified as
the third instar larvae of the family Piophilidae (Diptera). It is interesting that the larvae were found alive at the autopsy in January
when snow is present. The entomological information supports the information that the man had died around September 8 with
the following reason: the location where the victim was found was too cold for the flies to have deposited their eggs; at the man’s
death, the ambient temperature was enough high for flies to deposit their eggs; according to the gradual decrease of the ambient
temperature, the larvae penetrated into deep lesion with feeding. This is a valuable case demonstrating that live larvae can be
obtained from a severely decomposed cadaver found in winter and can support the information about the time of death. This
report also validated the importance of collecting Piophilidae flies of severely decomposed cadavers in winter.
Key Words: fly larvae, winter, severely decomposed cadaver, forensic entomology, postmortem interval, autopsy.
E
ntomological information can often be
useful in determining both the manner of
death (insect activity can sometimes be concentrated
around wound sites) and the post mortem interval (PMI)
when medical parameters are no longer of value [13]. Collecting insect larvae, and rearing them to adults
for species and instar identification, can provide useful
entomological evidence [4].
For cadavers with short PMI, detailed information
about the species and instars of collected larvae may
provide entomological evidence for PMI estimation.
Even if the cadavers had been restored for the
long time, flies are often observed and provide useful
information [5].
We report a case in which a victim was found in
a snow-covered forest. Although the cadaver consisted
mostly of skeletal remains due to postmortem changes,
live fly larvae could be collected. As this entomological
evidence was well accordance with the information
obtained from police investigation, we suggest the
importance of collecting live insects even in the severely
decomposed cadavers in winter.
1) Department of Legal Medicine, Shiga University of Medical Science, Shiga 520-2192, Japan
* Corresponding author: MD, PhD, Professor, Department of Legal Medicine, Shiga University of Medical Science, Tsukinowa,
Seta, Otsu, Shiga 520-2192, Japan, Tel. +81-77-548-2200, Fax +81-77-548-2200, E-mail: hitosugi@belle; Shiga-med.ac.jp
2) Department of Tropical Medicine and Parasitology, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan
3) Department of Legal Medicine, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan
253
Hitosugi M. et al
The importance of collecting live fly larvae from a severely decomposed human cadaver in winter
Case report
Case history
A body was found in a mountain forest in the
northern part of Tochigi Prefecture (lat. 36.96°N; long.
139.70°E), Japan, on 31st of
January, 2010 (Fig. 1). As
the season was winter, the
forest was covered with
snow. The victim, found
hanging from under a
tree, was later identified
through dental analyses
and his belongings as
a 24-year-old Japanese
man. Reportedly, he had
been worried about his
relationship with his
girlfriend. He was last
seen by his friend on the
morning of September 8,
2009, and was reported
to the police as missing
on September 12 by
his family. The police
investigation revealed that
the victim’s vehicle was
captured by a road-side
camera near the location
where he was found on 1
pm, September 8. Later,
his vehicle was found at
the parking area located
in the forest.
The
climatological
Figure 1. The body of a data obtained from the
24-year-old man, comprising government
weather
mostly skeletal remains, found station located a short
hanging from under a tree in a distance from where the
snow-covered mountain forest.
body was found is shown in Fig. 2. The mean temperature
from the time of the man’s disappearance to the body’s
discovery had ranged from -5.8–16.3°C with a daytime
maximum temperature of -3.3–24.9°C and a daytime
minimum temperature of -11.1–15.3°C.
Autopsy findings
An autopsy performed the day after the body was
found revealed that most of the body (the head, face, chest
and upper extremities) consisted of skeletal remains. The
lumbar region and lower extremities were mummified,
which caused them to be dry and leathery with no moist
putrefaction. The skin and underlying tissues were hard.
No marked injuries were found on the cadaver except for
post-mortem changes. When the skin and soft tissues of
the lower extremities were cut to examine the injuries,
dozens of larvae were observed around the inner cavity
of the knee joint (Fig. 3).
Figure 3. Dozens of larvae of the family Piophilidae found in
the inner space of the victim’s knee joint.
Entomological examination
From discovery until autopsy, the body was
stored in the morgue at the temperature of 5.0°C. At
autopsy, some larvae were collected from the cadaver,
treated in 70°C ethanol and preserved in 70% of ethanol.
Following rearing to adults, the larvae were identified as
the third instar larvae of the family Piophilidae (Diptera).
Discussion
Figure 2. Changes in maximum and minimum ambient
temperature between the time when the victim went missing in
September 2009 to when the body was found in January 2010,
in the northern part of Tochigi Prefecture, Japan.
254
Because insects use decomposing cadaver tissues
both as a source of food and as a place to rear their young,
they can be used to determine the postmortem interval
in concert with information of species, instar, growth rate
and ambient temperature [1-3, 6]. For this reason, forensic
entomology, which identifies the species and stages of
insects, has become increasingly important for criminal
investigation [4, 7]. Sarcophagid, calliphorid and muscid
Romanian Journal of Legal Medicine flies, which are the first insects to colonize decomposing
remains, usually arrive from minutes to hours after
death and begin to lay eggs or larvae. Therefore, larvae
are helpful for estimating PMI in relative short duration
after death [1-3]. In this case, the victim was found in
January when snow is often present. It is interesting that
the larvae were alive at the autopsy. According to the
police investigation, the man had died around September
8. The climatological data indicated that the maximum
ambient temperature was over 10°C around September
and October, enough condition that the flies deposit eggs.
The Piophilid flies shown in this case are
commonly found in a variety of protein rich animal
matter, and their presence has been typically associated
with advanced stages of cadavers [8]. Furthermore, it has
been assumed that larvae do not develop in a cadaver
until 3–6 months postmortem, when fatty acids and
caseic products are present [9]. There have been some
reports of Piophilidae larvae found in forensic cases [1012]. In this case, as the postmortem duration longer, the
ambient temperature gradually decreased. Subsequently,
around January 31 when the cadaver was discovered, the
maximum ambient temperature was 6.6°C and minimum
was -3.7°C. To avoid the low ambient temperature the
larvae had migrated into the deep lesion of the cadaver,
crawled into the inner space of the knee joint to avoid
the cold conditions and to seek soft tissue for feeding.
Generally, at the temperature varying from 0 to 10°C, as
the deceleration of metabolic activity of larvae,
development mainly stops like under anesthetic
condition. However, because the larval aggregation
produces the heat and contributes to the larval activity,
larvae can feed human cadaver’s tissue even in the low
temperature around 4°C like refrigeration [13, 14].
In this case, because the larvae have powerful
proteolytic enzymes including collagenase that aid
Vol. XXII, No 4(2014)
dissolution of the tissues and facilitate penetration, they
could penetrate deep into the body where they successfully
grew and survived [15, 16]. In addition to the insulating
ability of the inner space of the knee joint, an increase in
temperature caused by the feeding activity of the larvae
was considered as a factor influencing their survival.
However, although they were alive, most larvae had not
developed into adults because of the low environmental
temperature at the site of death.
In this case, the entomological information
supports the information that the man had died around
September 8. To develop live larvae at the autopsy lead
to the following considerations: the location where
the victim was found was too cold for the flies to have
deposited their eggs; at the man’s death, the ambient
temperature was enough high for flies to deposit their
eggs; according to the gradual decrease of the ambient
temperature, the larvae penetrated into deep lesion with
feeding.
In the field of forensic entomology,
sarcosaprophagous families of Diptera such as
Calliphoridae or Sarcophagidae are useful for
determining PMI in the early phase of decomposition. In
this case, Piophilidae also provides valuable information
about cadavers in advanced stages of decomposition in
winter. This case is valuable in that live larvae could be
found from a severely decomposed human cadaver in
winter. The entomological information can support the
information obtained by the police. This report validated
the importance of collecting Piophilidae flies of severely
decomposed cadavers in winter.
Acknowledgement. The authors greatly acknowledge to Yumie Tsunoda, for her technical assistance
of this study.
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