(1) Myiasis
(2) Post-Mortem Artifacts
…
Myiasis
Myiasis is an infestation of a living organism
by developing larvae (maggots) of a variety
of fly species (Myia is Greek for fly).
l  May be relatively benign, cause serious
health concerns, and even death.
l  Under some conditions, can be used to treat
disease and infection.
l
Types of Myiasis
l
Cutaneous myiasis,
l
l
l
l
l
l
wound myiasis
Furuncular myiasis.
Nasopharyngeal myiasis, the nose, sinuses, and
pharynx are involved.
Ophthalmomyiasis - eyes, orbits, and periorbital
tissue
Intestinal – alimentry tract
Urogenital myiasis – invasion of urogenital system
Parasitic and Opportunistic
Species
l
Obligate (primary) parasites
l
l
l
l
l
Colonize living hosts
Dermatobia hominis (human botfly)
Cordylobia anthropophaga (tumbu fly)
Cochliomyia homnivorax (screwworm)
Facultative (secondary) parasites
l
l
Obligate human
parasites
Primarily cattle
but will attack
humans
Opportunists, usually associated with carrion or
cadavers, will colonize living flesh under some
conditions
Some blowflies (Lucilia species, Phormia,
Cochliomyia macellaria), some sarcophagids
(fleshflies), some muscids (housefly relatives)
Botflies and Screwworms
(Domain of Medical Entomology)
l
Dermatobia – Central/South America
l
l
Cordylobia – Sub-Saharan Africa
l
l
l
Capture another insect, lay their eggs on it, and when that insect
(mosquito or fly) lands to feed, the eggs hatch and burrow into our
skin
Attracted to human feces/urine and to wet clothing where the
females lay their eggs.
Emerged maggots sit in the soil and wait for a disturbance, then
rapidly move to the surface and burrow into the feet or legs of the
person. Eggs also hatch when people wear clothing with eggs
New World Screwworm (Cochliomyia) – Texas*, Mexico,
Caribbean, C. and S. America, Old World Screwworm,
Chrysomyia bezziana (Africa)
l
Females lay eggs in wounds, sores, or healthy mucous membranes
Botflies
l
O
Tumbu Flies
Screwworms
Secondary Myiasis and the Law
l
l
l
Myiasis of healthy individuals in temperate-zone,
developed countries is rare.
When it occurs, often associated with homeless
indigents, substance abusers, and those with
compromised immune systems.
May also be associated with elderly, bedridden or
incapacitated patients in long-term facilities, or
infants
l
In these cases, myiasis can be utilized in criminal cases
focusing on neglect or unsanitary conditions
l
Wound Myiasis
l
l
Mostly opportunistic
species usually
associated with cadavers
L. sericata is the most
frequent species
Cases involving neglect
l
l
l
The faunal composition of cadavers can reveal
information about the conditions preceding death as
well as those post-mortem
Especially useful is the presence or absence of
certain species
l  Muscidae - houseflies and their relatives generally
associated with excrement
l  Fannia, Muscina, Musca,
Until relatively recently, the potential utility of this
information was routinely ignored by medical
examiners and other crime scene investigators
Foot maggots
l
l
l
Elderly woman found dead in
filthy apartment (blocked
toilet, rotting food)
Her foot was in a plastic bag
and was badly infested with
large blowfly ( L. sericata)
maggots but the rest of her
body and face was intact
with no colonization and
little decomposition
What might you conclude?
Colonization Patterns
l
l
l
l
l
Elderly woman found in an urban
apartment that was cluttered and
untidy but not filthy
Cadaver exhibited bleeding pressure
ulcers (b) on the buttocks, back, and
(c) chin, and chest.
Eyes and face were intact
Maggots of lesser house fly Fannia
canicularis and stable fly Muscina
stabulens, and adult larder beetles
(Dermestes lardarius) were
collected on and under the body.
What might you conclude?
Child neglect
l
l
l
l
l
Dead child found in an apartment.
Mother was addict and street prostitute and could not
recall when last at the apartment
Social service agency accused of neglect
Calliphora and Fannia
larvae were found on the
face and body – 5-7 day
PMI
However, Fannia larvae
estimated to be 14 days
old in uro-genital area
Maggots for Good!
l
Maggots have long been recognized for their
ability to clean wounds
l
l
l
l
Civil War - amputations
World War I – compound fractures
With the advent of MRSA and other antibiotic
resistant bacteria, maggot debridement therapy
is gaining in popularity
Lucilia sericata cultures are now commercially
available for health care industry
Myiasis and Medicine
l
Maggots secrete a potent cocktail of
products that function as antibiotics as
well as directly remove necrotic tissue
Behold, the
mighty maggot
9 Days
l
Fun with Orzo…
Post-Mortem Artifacts
l
Altered appearance
l
Insects impart changes to the cadaver that
could be interpreted as ante-mortem
l
l
l
Larval movement
l
l
Wounding
Sexual assault
Maggot movement produces artifacts
Adult activity
l
l
Blood spatter versus fly specks
DNA acquisition / contamination
Ant feeding damage
Altered Appearance
l
Activity by a variety of organisms including
insects can alter the appearance of a cadaver.
l
l
Can hide or remove forensically valuable evidence
Can create the post-mortem illusion of antemortem trauma
Vulture feeding
Cockroach feeding patterns
Rat feeding on fingers
l
Ants
l
Especially problematic –
can significantly change
rates of decomposition
Can significantly alter
the appearance and
remove / hide forensic
information
Maggot Activity
l
l
The undulating movement of maggots in
masses can be sufficient to alter the
position of clothing.
Changes in the position of undergarments
can present the illusion of a sexually
motivated crime
l
Maggot Movement
Maggot movement
Maggots can track blood through their
movement
l  Can create the illusion of ante-mortem
movement by the decedent
l  Can mask or destroy other trace evidence
l