ECTOPARASITES
Lice
Order: Phthiraptera (LICE)
Two Orders (head width, mouthparts differentiate)
(1) Mallophaga – (Chewing Lice)
i. Chewing parasites with mandibulate mouthparts.
ii. Feed: sloughed epidermis, feathers and sebaceous
secretions.
iii. Hosts: birds (most) and mammals.
iv. No species are parasites of man.
(2) Anoplura – (Sucking Lice)
i. Bloodsucking parasites of mammals
ii. Haustellum mouthpart
iii. Solenophagus (all lice)
iv. Hosts: mammal (humans have 3 species)
Biology
(1) Dorso-ventrally flattened body.
(2) Claws adapted to grasp the host
(3) All lice are wingless
(4) Hemimetabolous Life Cycle
Egg  Nymph  Adult
Family: Pthiridae (crab louse)
(1) Species: Phithirus pubis
(2) Morphology
(3) Location on Host
(4) Size
(5) Eggs attached to coarser body hairs.
(6) Habits
(7) Spread
(8) Transfer
(9) Diseases
Family: Pediculidae (head louse)
(1) Species: Pediculus humanus capitis
(2) Location on Host
(3) Size
(4) Eggs attached to the hairs (glued).
(5) Habits
(6) Spread
(7) Transfer
(8) Diseases
(9) Treatment
Family: Pediculidae (Body louse)
(1) Species: Pediculus humanus humanus
(2) Location on Host
(3) Size
(4) Eggs on clothing seams (glued).
(5) Habits
(6) Spread
(7) Transfer
Louse Borne Diseases
(1) Vagabond’s Disease
(a) Pediculosis
(b) Vector
(c) Saliva (toxic effects)
(d) Distribution
(e) Diagnosis
Louse Borne Diseases
(2) Trench Fever
(a) Vector
(b) Pathogen
(c) Reservoir
(d) Distribution
(e) Transmission
(f) Diagnosis
(g) Non pathogenic to louse
Louse Borne Diseases
(3) Epidemic Relapsing Fever
(a) Vector
(b) Pathogen
(c) Reservoir
(d) Distribution
(e) Transmission
(f) Diagnosis
Louse Borne Diseases
(4) Epidemic Typhus
(a) Vector
(b) Pathogen
(c) Reservoir
(d) Distribution
(e) Transmission
(f) Symptoms and Diagnosis
Louse Control
Body Lice – change and wash clothing in water hotter than
60C. In epidemic situations, 10% DDT in talc dusted on
between body and underclothes (other insecticides – 1%
malathion, 2% temephos, 1% propoxur, 0.5% permethrin).
Protect from future infestation with insecticide treated
clothing.
Head Lice – soap and water washing for adults and
nymphs. Combing to remove nits or shaving head.
Insecticides, but resistance in many areas of the world.
Pubic Lice – insecticidal emulsions and lotions. Resistance
not as much of a problem. 1% permethrin – reapply
because eggs not killed. 0.5% malathion – kills eggs too.