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Carrion Fly and Disease Vector Activity Associated with a Decomposing Corpse LTJG David England,MSC,USN Medicolegal Entomology Navy Entomology Center of Excellence Naval Air Station Jacksonville, FL. Objectives. Basic Methods For Estimating Postmortem Interval - PowerPoint PPT Presentation
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Carrion Fly and Disease Vector Activity Associated with a Decomposing Corpse
LTJG David England,MSC,USN LTJG David England,MSC,USN Medicolegal Entomology Medicolegal Entomology
Navy Entomology Center of ExcellenceNavy Entomology Center of ExcellenceNaval Air StationNaval Air StationJacksonville, FLJacksonville, FL
ObjectivesObjectives
1.1. Basic Methods For Estimating Basic Methods For Estimating Postmortem IntervalPostmortem Interval
2.2. Oregon Decomposition And Insect Oregon Decomposition And Insect Succession ModelSuccession Model
3.3. Current Forensic Entomology Current Forensic Entomology EndeavorsEndeavors
AccumulatedAccumulated
DegreeDegree
DayDay
HoursHours
Post MortemPost Mortem
IntervalInterval
(PMI)(PMI)
Estimation of PMIEstimation of PMI Insect succession Insect succession
patternspatterns Insect life cyclesInsect life cycles Influential Influential
variablesvariablesLife Cycle
Variables
Succession
PMIPMI
Variables that influence Variables that influence PMIPMI
TemperatureTemperature SeasonSeason SpeciesSpecies Death ScenarioDeath Scenario ToxicologyToxicology Parasitoids & PredatorsParasitoids & Predators
Insect SuccessionInsect Succession
Succession of insects generally follows a similar Succession of insects generally follows a similar pattern at the family level, but there are pattern at the family level, but there are variations at the genus and species levels with variations at the genus and species levels with respect to differing geographical locations respect to differing geographical locations
Forensic entomology ‘works’ because succession Forensic entomology ‘works’ because succession is a very predictable and consistent eventis a very predictable and consistent event
Site LocationSite Location
Soap Creek Soap Creek Ranch,Ranch,
18km NW of 18km NW of CorvallisCorvallis
Animal ModelAnimal Model
36 kg domestic pigs36 kg domestic pigs Euthanasia methodEuthanasia method ClothedClothed CagedCaged Human homicide Human homicide
scenarioscenario
Sampling Methods: Sampling Methods: Onsite & LaboratoryOnsite & Laboratory
Temperature readings: ambient, carcass and Temperature readings: ambient, carcass and maggot mass maggot mass
Insect SamplingInsect Sampling
Sticky, Pitfall, Hand Sample and NetSticky, Pitfall, Hand Sample and Net One Pig Weighed Daily (Change in Mass)One Pig Weighed Daily (Change in Mass) Growth ChambersGrowth Chambers
22°C and 12 hours controlled light22°C and 12 hours controlled light Identifications - OSU Insect CollectionIdentifications - OSU Insect Collection
Stages Of Stages Of Decomposition*Decomposition*
FreshFresh BloatedBloated Active DecayActive Decay Advanced DecayAdvanced Decay Dry RemainsDry Remains
**Catts and Haskell, 1990Catts and Haskell, 1990
Fresh StageFresh Stage
10 minutes PMI 10 minutes PMI Calliphoridae, Calliphoridae,
species species Lucilia Lucilia illustrisillustris (Meigen) (Meigen)
Egg clusters: Egg clusters: six hours PMIsix hours PMI
Reared and Reared and identifiedidentified
CalliphoridaeCalliphoridaeGreen bottle fly (Green bottle fly (Lucillia illustrisLucillia illustris))
Photo: http://bugguide.netPhoto: http://bugguide.net
Bloated Stage Bloated Stage
Eight hours - BloatingEight hours - Bloating 12 hours, bald-faced 12 hours, bald-faced
hornets hornets ((Dolichovespula Dolichovespula maculata) maculata) (Linnaeus)(Linnaeus)
33 hours PMI: the 33 hours PMI: the green bottle fly eggs green bottle fly eggs hatched hatched
48 hrs: Staphylinidae 48 hrs: Staphylinidae appearappear
Staphylinidae Staphylinidae
Brown and gold roveBrown and gold rove(Ontholestes cingulatus)(Ontholestes cingulatus)
Hairy roveHairy rove(Creopilus maxillosus(Creopilus maxillosus
Photo: http://bugguide.netPhoto: http://bugguide.net
Active Decay Stage Active Decay Stage
72 hour PMI72 hour PMI Red-tailed flesh flyRed-tailed flesh fly
((Sarcophaga Sarcophaga haemorrhoidalis)haemorrhoidalis)
Terrestrial isopodsTerrestrial isopods Adult green bottle fly Adult green bottle fly
decreasing decreasing Dermestidae, Dermestidae,
Silphidae, Histeridae Silphidae, Histeridae
Advanced Decay Stage Advanced Decay Stage
120 hours: carcass 120 hours: carcass began to desiccatebegan to desiccate
132 hours: third 132 hours: third instar/post feeding instar/post feeding maggotsmaggots
147 hours: maggot 147 hours: maggot mass exited carcassmass exited carcass
Large Large predator/scavenger predator/scavenger activity activity
Post Feeding ActivitiesPost Feeding Activities
Green bottle fly pupaeGreen bottle fly pupae
Dry Remains Stage Dry Remains Stage
288 hrs PMI288 hrs PMI DesiccatedDesiccated Beetle ActivityBeetle Activity No odorNo odor Seasonal rain mid- Seasonal rain mid-
OctoberOctober 25 days: scavengers 25 days: scavengers November: cages November: cages
removedremoved
November, 2005 November, 2005
Cage removedCage removed
April, 2006April, 20066 months 6 months after cage after cage removalremoval
6 months 6 months after cage after cage removalremoval
Decomposition SummaryDecomposition Summary
Green bottle fly within 10 minGreen bottle fly within 10 min Ovipositing/egg cluster 6 hrsOvipositing/egg cluster 6 hrs 33 hrs: first hatch33 hrs: first hatch 12 hrs: predators (hornet)12 hrs: predators (hornet) 72 hrs: predators (beetles)72 hrs: predators (beetles) 168 hrs: green bottle maggots left carcass168 hrs: green bottle maggots left carcass Jan. 1Jan. 1stst little evidence left; dead vegetation little evidence left; dead vegetation
Temperature SummaryTemperature Summary
Ambient temperatures (°C):Ambient temperatures (°C):
Mean 20.8; Min. 9.03; Max. 34.9Mean 20.8; Min. 9.03; Max. 34.9 Maggot mass temperature (°C):Maggot mass temperature (°C):
Mean 30.9; Max. 50.7 (128 hrs.PMI)Mean 30.9; Max. 50.7 (128 hrs.PMI) Mean RH: 50%Mean RH: 50% Precipitation: none until Oct.Precipitation: none until Oct.
Rate of DecompositionRate of Decomposition
Percentage of Mass Loss
0
20
40
60
80
100
1 2 3 4 5 6 7 8 9 10
Days
Mas
s %
mas
s
Decomposition RatesDecomposition Rates
Decomposition
0
1
2
3
4
5
0 5 10 15 20 25 30 35 40
Time
Mas
sLo
g of
% m
ass
Linearized Regression Analysis_______________________________________________________________Studies R² Slope (estimated) _______________________________________________________________
Grassberger: European Urban Habitat 1) May 0.907 -0.0786 2) Aug. 0.9677 -0.0586
Richards: Hawaiian Islands1) 1877 m 0.9338 -0.10752) 1169 m 0.8651 -0.1104
3) 646 m 0.8834 -0.1204
Anderson: SW British Columbia1) Carcass 1 0.9253 -0.0372
2) Carcass 2 0.9781 -0.0303
England: Corvallis, Oregon 1) Carcass 1 0.9517 -0.2378
SummarySummary
Regional ModelRegional Model Standardized AnalysisStandardized Analysis
* * All slope values produced consistent results*Exponential decomposition rate that can be evaluated with linearization
Utilized In Further Research (geography, Utilized In Further Research (geography, seasons, scenarios, etc.)seasons, scenarios, etc.)
Current Forensic Current Forensic Entomology EndeavorsEntomology Endeavors
Provide Entomological Training For Provide Entomological Training For Naval Criminal Investigation ServiceNaval Criminal Investigation Service
Georgia Research With Naval Criminal Georgia Research With Naval Criminal Investigation ServiceInvestigation Service
Iraq Fly SamplesIraq Fly Samples
AcknowledgementsAcknowledgements
Dr. Phil RossignolDr. Phil Rossignol
Dr. Anne RossignolDr. Anne Rossignol
Dr. Brian CroftDr. Brian Croft
Dr. Paul JespersenDr. Paul Jespersen
CDR SzumlasCDR Szumlas
Joyce TakyasuJoyce Takyasu
Clint SextonClint Sexton
Questions and
Discussion