This document discusses insects of medical importance. It describes how some insects directly damage human tissue or act as vectors for disease. Additionally, it explains how some insects provide useful medical services through substances like venom or maggots used for debridement. Key disease vectors discussed are mosquitoes transmitting malaria, fleas transmitting plague, and kissing bugs transmitting Chagas disease. The model organism Drosophila melanogaster is also described as useful for genetic studies.

1. Medical Entomology

2. Insects of Medical Importance
 Directly cause damage to human tissue
 Act as Vectors for disease-causing
organisms
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 Provide useful medical services/drugs
 Are useful model systems in genetic
studies

3. Stinging Insects
 Belong to the order Hymenoptera
 Includes Paper wasps, Yellow Jackets, Honey
bees and Fire Ants
 Have specialized venom glands attached to
“sting”

4. •Insect venom
causes local
pain, redness,
and swelling in
people who are
not allergic.
Envenomation Symptoms

5. Envenomation Symptoms
 Allergic reactions
 Happen on the second (or later) sting
 Antibodies to venom over-react and produce chemicals
(like histamines) that can damage neighboring cells.
 Severe allergies can lead to anaphylactic shock, a
potentially deadly swelling of the airways and other
tissues.
 If you’ve been allergic once, you’ve got a 60% chance of
being even more allergic next time. Carry an EpiPen!

6. Africanized Honey
Bee and Feral Bees

7. Red Imported
Fire Ant

8. Biting Insects
 Saliva from several biting insects acts as an
allergen in many people
 This can lead to intense itching when bites
are numerous:

10. Insects As Vectors
 Several Biting Flies and Reduviid Bugs
carry infective stages of disease causing
pathogens. They are responsible for
spreading diseases like:
 Malaria (Mosquitoes in genus Anopholes)
 Plague (Rodent Fleas)
 West Nile Virus (Mosquitoes)
 Typhoid/Cholera/Dysentary (Muscid Flies)

11. Malaria
 Caused by 4 species of protists in the genus
Plasmodium
 Anopholes sp. Mosquitoes transmit the infective
stage of Plasmodium to people.
 Active Plasmodium destroy large quantities of red
blood cells
 There are 300-500 million infections/yr world-
wide, with 1 million deaths/yr.
 Malaria has been virtually eradicated in the United
States (US citizens with malaria have contracted
it in other parts of the world)

12. Life cycle
of Plasmodium

13. Trypanasomiasis (Sleeping Sickness)
 Caused by two subspecies of protists in the genus
Trypanosoma
 Carried from host to host blood-sucking tsetse flies
 Trypanosome infection is characterized by a series of
progressive symptoms:
 Swelling at bite
 Immune rxn (swelling of lymph nodes,etc)
 Infection and swelling of CNS
 Possible heart failure
 These flies are found throughout middle Africa, where the
disease affects 66 million people in 36 countries

14. Trypanosoma and
the Tsetse Fly

15. Chaga’s Disease
 Caused by an American trypanosome,
Trypansoma cruzi
 Spread by blood feeding kissing bugs
 Occurs throughout Central and South America,
with some cases reported in the Southern US
 Use “reservoir animals” like raccoons and
armadillos to keep population present
 Heart and blood vessel damage is a common
symptom due to chemicals released by the
parasites in the blood

16. Trypanosoma cruzi
and the Kissing Bug

17. Pharmaceutically Important Insects
Venom is
extracted from
insects that
sting in order to
test people for
allergies and to
treat allergies
in a series of
small
injections.

18. Apitherapy
 One of the major peptides
in bee venom, called
Melittin, is used to treat
inflammation in sufferers
of Rheumatoid Arthritis
and Multiple Sclerosis.
 Melittin blocks the
expression of inflammatory
genes, thus reducing
swelling and pain.
 It is administered by direct
insect sting, or
intramuscular injections.

19. Maggot Debridement Therapy
 Recognized as useful by WWI surgeons
 Used for
 removing dead tissue from wound
 Preventing infection
 Speeding healing process
 An extract, Allontoin, is used for treating the
infectious bone disease, Osteomyelitis

20. “Beetle Juice” Therapies
 Cantharidin – the blister-
causing oil found in several
families of beetles (most
notably, Meloidae)
 Historical use by Greeks and
Romans
 Aphrodisiac????
 Currently accepted by FDA in
2004 for treatment of warts and
other skin problems

21. Insect Genetics
 The model organism,
Drosophila
melanogaster

22. What Can We Learn From a Fly?
 How genes work
By using mutation studies and gene mapping:
 Organization/Location
 What genes code for which proteins
 Development
 Which cells become what body part, when and
HOW!
 Proteins, enzymes, and neurotransmitters
involved.

23. Other Insect Models
 Currently, We have sequenced the
following genomes:
 Several species of Drosophila
 Several species of disease-carrying mosquito
(Anopholes gambaei, Aedes, and Culex)
 The Silkworm, Bombix mori
 The Honey Bee, Apis mellifera
 A Flour Beetle, Tribolium casteneus

24. The End