1. Pests, Plagues & Politics Lecture 7
BUGS ON YOU

2. Key Points Bugs Living on You
Historical Perspective
Obligate Parasites
3 Types of Lice
Biology and control
Facultative Parasites
Human Flea, Bot Fly, Sand Fleas
Bed Bugs

3. Bugs On You
Demodex follicularum
the human follicle mite

4. BUGS ON YOU “Even a superficial survey of the evolution of
human cleanliness reveals that its development
has lagged far behind the intellectual, aesthetic,
and moral progress of man.
Cleanliness has not been akin to godliness.”
H. Zinsser, RATS, LICE & HISTORY

5. Bugs On You Saint Benedict (6th century) Saint Francis of Assisi
“Bathing shall seldom be permitted.”
Saint Francis of Assisi
“an unwashed body is the stinking badge of piety.”
Queen Isabelle of Castile
boasted of two baths in her life
Napoleon, in a letter to Josephine
“Be home in two weeks. Don’t bathe.”

6. Bugs On You Colonial America Why?? Pennsylvania & Virginia
laws which either banned or limited bathing
Philadelphia
bathing more than one a month prohibited
Why??
Bathing meant nudity which could only promote promiscuity

7. The Strongest Bond

8. Bugs On You OBLIGATE Insect Parasites of Humans LICE
parasitism (Gr. Parasitos = eating with another)
LICE
Order Anoplura (“unarmed tail”)
The Sucking Lice
parasitic on mammals & birds
15 families & ca. 500 species worldwide
Haemophagic with piercing/sucking mouthparts.
Wingless with flattened bodies
Hemimetabolous (incomplete metamorphosis)

9. Human Lice Three “types” - Two species Pediculus humanus capitus
The Head Louse
Pediculus humanus humanus
The Body Louse
Pthirus pubis
The Crab Louse

10. Head Lice Pre-WWI: head lice a familiar feature in American homes.
Now making a come back
est. 12,000,000 cases in the U.S.
Female Louse
50 to 150 eggs (egg = NIT) in her life time
lays them at the base of hairs
eggs hatch in 5 to 10 days - three molts
three weeks “egg to egg”
Adult louse
Louse about to hatch from the egg.
Louse egg on a human hair
The NIT

11. First The Biology Head lice
(Pediculus humanus capitis) are tiny insects about two millimeters long which live on the scalp and neck of humans.
They feed from human blood and must eat at least twice a day; they cannot survive for more than one day at room temperature off a human body.

12. Head Lice Transmission Slang close physical contact
exchange of combs &/or hats
Slang
WWI & II
“motorized dandruff”

13. Common Chemical Treatments
Nix
Rid
Pronto
Clear

14. One other problem… RESISTANCE: SAFER ALTERNATIVES:
Overuse of pediculicidal products has lead to decreased effectiveness
These survivors are breeding a new super race of lice, resistant to our chemicals
SAFER ALTERNATIVES:
Head Lice to Dead Lice
Incorporates a“5 step battle plan”
Promotes use of olive oil to kill resistant adult lice
PART 1 -
PART 2 -

15. Body Louse P.h. humanus Latin: Pedis - louse; Pediculus = small louse
English: Pedicular, an adj. = lousy
“A dozen white louses do become an old coat well;
It’s a familiar beat to man and signifies love.”
Wm. Shakespeare; Merry Wives of Windsor

16. Body Louse Normally found on clothing
Louse is on you only during feeding
usually when you’re sleeping
Spends most of time in the seams of your clothing (ergo common name “seam squirrel”)
Eggs deposited on clothing
Transmitted via exchanged clothing
Average # lice per host = dozen
A known vector of typhus

17. Body Louse Control Allogrooming
vignette: Richard the Lion Hearted & his ‘permitted’ washer women
Chemical
DDT saved millions
The Whirlpool washing machine and a dramatic increase in personal hygiene.

18. Lice tell us when humans began to wear clothes!!!
Recent molecular DNA studies of head lice & body lice show:
Body lice diverged from head lice about 72,000  42,000 years ago
Body lice live in the clothing
Ergo humans ran around naked for longer than we thought.
Study also supports African origin for Homo.

19. Crab Louse Also known as the pubic louse (& other nomens)
Infests the pubic regions
requires well spaced hair
stationary beast & spends long amounts of time feeding (quite irritating)
up to 30 eggs per female louse

20. Crab Louse Transmission Frequency Only one other species in the genus
Venereal (from Venus, Roman Goddess of Love) – an STD
Frequency
OSU Student Health Center
2.4% of student population
Only one other species in the genus
Pthirus gorillae

21. Facultative Parasites of Humans
These are parasites that normally utilize non-human hosts, but can use humans as an alternative.

22. The “Human” Flea Numerous species of fleas will feed on human blood.
Cat flea
Dog flea
Ground squirrel flea (which is a known vector of plague)
Human flea: Pulex irritans
cosmopolitan & normally a parasite of swine

23. The “Human” Flea
“It was often said that women were attacked by fleas more often than men were. The cause may conceivable have been a response to ovarian hormones.”
Miriam Rothschild, Scientific American (1965)

24. Human Bot Fly Order Diptera Dermatobia hominus
South & Central American distribution
Female fly lays her eggs on mosquito & other “bugs”
Mosquito bites human
fly larvae “pop” out of eggs and penetrate human
develop within the human and bore out to pupate

25. Human Bot Fly Also known as the “torsalo”
3 - 4 weeks in the larval stage undergoing three instars

26. Sand Flea A true flea (Order Siphonaptera)
family Tungidae
Tunga penetrans
New World tropical & sub-tropical
Common names
jigger - chigger - chigoe
Minute: 1 mm in length
Female borrows into skin & feeds & grows
Larval fleas crawl out of host & spend their pupal phase in the ground/soil/sand

27. Sand Fleas
&
You

28. Sand fleas are well known to human civilizations.
Chimu (pre-Incan) pottery from Peru depicting feet
with punch holes, a result of sand flea infestation.

29. Bed Bugs Order Hemiptera Cimex lectularius
Haematophagous - a blood meal between each molt
Closest relative is the BAT bed bug
a’ha, where were we living 30,000 years ago??

30. “Night-night, dear, sleep tight…and don’t let the bedbugs bite.”

31. Corvallis G.T. – 28 November 2003

32. Key Points Bugs Living on You
Historical Perspective
Obligate Parasites
3 Types of Lice
Biology and control
Facultative Parasites
Human Flea, Bot Fly, Sand Fleas
Bed Bugs