Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

1The screen versions of these slides have full details of copyright and acknowledgements

Vector-borne Diseases:Myiasis in Humans and Other Animals,

Including Applied Applications in Larval Therapy & Forensic Entomology

1

Dr. Jamie StevensAssociate Professor of Molecular Systematics

School of BiosciencesUniversity of Exeter

email: j.r.stevens@ex.ac.uk

Myiasis - lecture plan• Introduction

• Defining myiasis– What is and what is not myiasis

– Dermal and subdermal myiasis

– Wound or traumatic myiasis

– Accidental myiasis

• Agents of myiasis− Biology and life-histories of the main groups

of myiasis flies

CalliphoridaeBlowflies

Screwworm flies

Bird blowflies

Calliphorids

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• Evolution of parasitism

• Control and intervention strategies− Chemical control

− Models of fly development Climate mapping

Predictors of risk of fly strike, e.g. Strikewise

− Sterile insect technique

• Larval therapy

• Forensic entomology

SarcophagidaeSarcophagids

Wohlfahrtia sp.

OestridaeOestrids

Gasterophilids

Hypodermids

Cuetrebrids

− Others

3Courtesy of Dr M. Hall, NHM

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

2The screen versions of these slides have full details of copyright and acknowledgements

Key texts…

Key texts

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Key texts…

The importance of myiasis-causing flies

• As pests of livestock (and occasionally humans), i.e. as agents of myiasis

• As pests of wild animals

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– Myiasis-causing flies can significantly effect condition, fecundity, grazing behaviour, and survival of wild animal populations

• As forensic indicators of time of death

• In medical applications - larval therapy

Defining myiasis

• Agents of myiasis include:

– Bot and warble flies - Oestridae

– Flesh flies - Sarcophagidae

– Blowflies - Calliphoridae

Other Diptera Muscidae Syrphidae etc

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– Other Diptera - Muscidae, Syrphidae, etc.

• Infestation of a living animal by dipterous larvae (Hope, 1840; Zumpt, 1965)

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

3The screen versions of these slides have full details of copyright and acknowledgements

Classification of myiasis 1:according to the anatomical position

in or on the host

7Note: the division of myiasis into five rows is based on the grouping of Zumpt (1965) in the first column; The second and third columns show the comparable groupings of Bishopp (see Patton, 1922) and the modification of these by James (1947); Re-drawn from Hall http://www.fao.org/DOCREP/U4220T/U4220T07.HTM

Classification of myiasis 2:according to the parasitic relationship

of the Diptera with the host

8Sources: Patton (1922); Smart (1943); Zumpt (1965); Kettle (1984); Re-drawn from Hall, see: http://www.fao.org/DOCREP/U4220T/U4220T07.HTM

Myiasis-causing fliesBlowflies - Calliphoridae

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http://www-naweb.iaea.org/nafa/ipc/screwworm-flies.htmlCSIRO

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

4The screen versions of these slides have full details of copyright and acknowledgements

Myiasis-causing flies: Lucilia bufonivora

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Photo courtesy of Mr Michael Porter

Myiasis-causing flies: blowflies & screwworm flies

11Courtesy of Dr M. Hall, NHM

From ‘A Manual for the Diagnosis of Screw-worm Fly’, J.P. Spradbery, 1991, CSIRO, Canberra, Australia

Blowflies and screwworm flies: economic impact

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• Up to 80% of all British sheep farms have been documented as being affected by myiasis caused by the blowfly Lucilia sericata, with a mortality rate of around 2%

• In some other areas of Europe, mortality rates of up to 20-30% have also been reported

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

5The screen versions of these slides have full details of copyright and acknowledgements

O h t

Typical blowfly lifecycleOne complete lifecycle of all stages of the parasite

L1

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Adult phase

Soil phase

On-host phase

L2

Myiasis-causing flies: furuncular larvae

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2nd stage larva

Éric Dehecqab et al., 2005

Myiasis-causing flies: sanguinivorous larvae

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Courtesy of Prof T. Whitworth, Washington State University

Courtesy of Prof T. Whitworth, Washington State University

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

6The screen versions of these slides have full details of copyright and acknowledgements

Myiasis-causing fliesFlesh flies - Sarcophagidae

16Courtesy of Dr M. Hall, NHM

Courtesy of Dr M. Hall, NHM

http://commons.wikimedia.org/wiki/File:Sarcophagidae_2009.JPG

Myiasis-causing flies (2)Flesh flies - Sarcophagidae

17Courtesy of Dr M. Hall, NHM

Courtesy of Dr M. Hall, NHM Courtesy of Dr M. Hall, NHM

http://commons.wikimedia.org/wiki/File:Sarcophagidae_2009.JPG

MyiasisBot and warble flies - Oestridae

18Courtesy of Dr D. Colwell, Agriculture

and Agri-Food Canada, Lethbridge

Hypoderma bovis

Hypoderma lineatum

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

7The screen versions of these slides have full details of copyright and acknowledgements

Oestridae warble fly - Hypoderma lineatum

Courtesy of Prof D. Otranto, University of Bari

19Courtesy of Dr D. Colwell, Agriculture and Agri-Food Canada, Lethbridge

Oestridae - various

20Photographs courtesy of Prof D. Otranto, University of Bari

Przhevalskiana silenus

Myiasis

Other flies - e.g. Syrphidae Eristalis tenax (Linnaeus-the rat-tailed maggot

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entnemdept.ufl.eduhttp://commons.wikimedia.org/wiki/File:Insect_20060830.jpg

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

8The screen versions of these slides have full details of copyright and acknowledgements

Evolution of parasitism in myiasis-causing flies

22From Otranto & Stevens 2002, Intl. J. Parastol.From Stevens 2003, Intl. J. Parastol.

Evolution of myiasis

23Wikipedia

Contrasting breeding strategies can influence myiasis control strategies

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Somerset, England

New South Wales, Australia

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

9The screen versions of these slides have full details of copyright and acknowledgements

Myiasis control:traps, targets and insecticides

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Myiasis control:docking, crotching and mulesing

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Control: disease ecology• Strike, coupled with worm damage, notably dehydration and blood loss,

can be particularly severe in young lambs

27Courtesy of Prof R. Wall, Univ of Bristol

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

10The screen versions of these slides have full details of copyright and acknowledgements

Distribution of New World screwworm fly Cochliomyia hominivorax

28Reproduced from ‘A Manual for the Diagnosis of Screw-worm Fly’, J.P. Spradbery, 1991, CSIRO, Canberra, Australia

• SIT relies on the widespread release of huge numbers of sterile males of the target pest species

• The sterile males then find and mate with fertile females in the field and the resulting egg batches are non-viable

Progressive shift of eradication zones in the screwworm SIT programme

in North and Central America

1957 - 1959

1962 1966

29Courtesy of Dr A. S. Robinson, FAO/IAEA, Vienna

1982

1962 - 1966

1986 - 1991

1983

19841999

1994

1996

1998

1981

1972 - 1980

1998-2001

Climate modelling to predict potential spread of Old World screwworm fly

(Chrysomya bezziana) in Australia

Reproduced from Sutherst et al., (1989) Med.Vet. Ent., 3: 273–280

30From Wall & Stevens (1990), New Scientist

Aerial release trial, Safia, Papua New Guinea, 1989

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

11The screen versions of these slides have full details of copyright and acknowledgements

Climate data, models and control

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• Temperate regions:Flies re-emerge in spring after winter diapause; Successive generations breed in discrete cohorts giving rise to cycles in fly numbers

• Subtropical/tropical regions:No cold weather, no diapause; Little fluctuation in fly numbers

From Wall et al., (1993), J. Appl. Ecology

• Reports of blowfly larvae cleansing wounds span many cultures over several centuries

• The modes of action of ‘wound-healing’ larvae may be broadly categorized into three main areas:

– Debridement

Di i f ti

Larval therapy

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– Disinfection

– Stimulation of wound granulation and repair

Wikipedia

Comparison of blowfly lifecycles

• The relatively well defined succession of insects occurring on a dead body can be exploited to estimate a measure of time since death –often referred to as the minimum post mortem interval or simply ‘minimum PMI’

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Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

12The screen versions of these slides have full details of copyright and acknowledgements

Acknowledgements

I am grateful to numerous friends and colleagues for granting me permission to use some truly exceptional images, without which this seminar would havebeen a very dull affair; In particular, thanks go to:

• Dr Martin Hall Dept of Entomology The Natural History Museum London UK

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• Dr Martin Hall, Dept. of Entomology, The Natural History Museum, London, UK

• Dr Doug Colwell, Agriculture and Agri-Food Canada, Lethbridge, Canada

• Professor Domenico Otranto, Faculty of Veterinary Medicine, University of Bari, Italy

• Professor Richard Wall, School of Biological Sciences, University of Bristol, UK

• Professor Terry L. Whitworth, Washington State University, USA

• Dr James Wallman, School of Biological Sciences, University of Wollongong, Australia

• Dr Allen Robinson, FAO/IAEA, Wagramerstrasse, Vienna, Austria

Additional reading: general myiasis• Aubertin, D. (1933) Revision of the genus Lucilia R.-D. (Diptera, Calliphoridae); Linn. Soc. J. Zool. 38: 389-463

• Colwell, D.D., M.J.R. Hall & P.J. Scholl (Eds.) (2006) The Oestrid Flies: Biology, Host-Parasite Relationships, Impact and Management; CABI Publishing, Oxford, ISBN 0 85199 6841

• Colwell, D. D., Otranto, D. and Stevens, J.R. (2009) Oestrid flies: eradication and extinction versus biodiversity; Trends in Parasitology, 25: 500-504

• Hall, M.J.R. and Wall, R. (1995) Myiasis of human and domestic animals; Advances in Parasitology, 35: 258-334

• Hall, D.G. (1948) The blowflies of North America; Thomas Say Foundation, Lafayette, Indiana

• James, M.T. (1947) The flies that cause myiasis in man; US Dept Agric Misc Publ 631, Washington

• Otranto, D. (2001) The immunology of myiasis: parasite survival and host defense strategies; Trends in Parasitology, 17: 176-182

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gy,

• Papavero, N. (1977) The world Oestridae (Diptera), mammals and continental drift; W. Junk, The Hague, ISBN 9061931231

• Pape, T. (1987) The Sarcophagidae (Diptera) of Fennoscandia and Denmark; Fauna Entomologica Scandinavica, Vol. 19, E.J. Brill, Copenhagen

• Rognes, K. (1991) Blowflies (Diptera, Calliphoridae) of Fennoscandia and Denmark;Fauna Entomologica Scandinavica, Vol. 24, E.J. Brill, Copenhagen

• Sabrosky, C.W., G.F. Bennett and T.L. Whitworth (1989) Bird blow flies (Protocalliphora) in North America (Diptera: Calliphoridae), with notes on Palearctic species; Smithsonian, Washington

• Stevens, J. & Wall, R. (1996) Classification of the genus Lucilia (Diptera: Calliphoridae): a preliminary parsimony analysis; Journal of Natural History, 30: 1087-1094

• Wall and Shearer (2001) Veterinary Ectoparasites, 2nd Edn., Chapter 5, Myiasis pp. 114-142

• Zumpt, F. (1965) Myiasis in Man and Animals in the Old World; Butterworths, London

Additional reading: control and intervention strategies

• Dyck, V.A., Hendrichs, J., Robinson, A.S. (Eds.) (2005) Sterile Insect Technique. Principles and Practice in Area-Wide Integrated Pest Management. Springer, Dordrecht. ISBN: 978-1-402040504

• French N.P., Wall, R., Cripps, P.J. and Morgan, K.L. (1992) Prevalence, regional distribution and control of blowfly strike in England and Wales; Veterinary Record, 131: 337-342

• Otranto, D. & Stevens, J. R. (2002) Molecular approaches to the study of myiasis-causing larvae; International Journal for Parasitology 32: 1345-1360

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International Journal for Parasitology, 32: 1345-1360

• Robinson, A.S. and Stevens, J.R. (Eds.) (2009) Proceedings of an FAO/IAEA Coordinated Research Project on Enabling Technologies for the Expansion of Screwworm SIT Programmes; Medical and Veterinary Entomology, Vol. 23 (Supplement 1, June)

• Knipling, E.F. (1955) Possibilities of insect control or eradication through the use of sexually sterile males; Journal of Economic Entomology, 48: 902-904

• Spradbery, J.P. (1991) A Manual for the Diagnosis of Screw-Worm Fly; CSIRO, Australian Government Publishing Service, Canberra

• Sutherst R.W., Spradbery J.P. & Maywald G.F. (1989) The potential geographical distribution of the Old World screwworm fly, Chrysomya bezziana; Medical and Veterinary Entomology, 3: 273–280

Vector-borne Diseases: Myiasis in Humans and Other Animals, Including Applied Applications

in Larval Therapy & Forensic EntomologyDr. Jamie Stevens

13The screen versions of these slides have full details of copyright and acknowledgements

Additional reading: evolution

• Erzinclioglu, Y.Z. (1989) The origin of parasitism in blowflies; Brit. J. Ent. Nat. Hist. 2: 125-127

• Stevens, J.R. (2003) The evolution of myiasis in blowflies (Calliphoridae); International Journal for Parasitology, 33: 1105-1113

• Stevens, J.R. and Wallman, J.F. (2006) The evolution of myiasis in humans and other animals in the Old and New Worlds (part I): phylogenetic analyses;

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(p ) p y g y ;Trends in Parasitology, 22: 129-136

• Stevens, J.R., Wallman, J.F., Otranto, D., Wall, R. and Pape, T. (2006) The evolution of myiasis in humans and other animals in the Old and New Worlds (part II): biological and life-history studies; Trends in Parasitology, 22: 181-188

Additional reading: larval therapy and forensic entomology

• Byrd, J.H. and Castner, J.L (Eds.) (2009) Forensic Entomology: The Utility of Arthropods in Legal Investigations, 2nd Edition. CRC Press, Boca Raton, FL, USA; ISBN 978-0-8493-9215-3

• Erzinçlioglu, Z. (2000) Maggots, Murder and Men; Harley Books, England; ISBN 0-946589-65-8

K id A L i S tt H d St J R (2005) A tib t i l ti

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• Kerridge, A., Lappin-Scott, H. and Stevens, J.R. (2005) Antibacterial properties of larval secretions of the blowfly, Lucilia sericata; Medical and Veterinary Entomology, 19: 333–337

• Sherman, R.A., Hall, M.J.R. and Thomas, S. (2000) Medicinal maggots: an ancient remedy for some contemporary afflictions; Annual Review of Entomology, 45: 55-81

• Stevens J. & Wall, R. (2001) Genetic relationships between blowflies (Calliphoridae) of forensic importance; Forensic Science International 120 (1-2): 116–123

• Wells, J.D. and Stevens, J.R. (2008) Application of DNA-Based Methods in Forensic Entomology; Annual Review of Entomology, 53: 103-120

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