ECTOPARASITES Lice. Two Orders (head width, mouthparts differentiate) (1) Mallophaga – (Chewing...

ECTOPARASITESECTOPARASITES

LiceLice

Two Orders (head width, mouthparts differentiate)Two Orders (head width, mouthparts differentiate)

(1)(1) Mallophaga – (Chewing Lice)Mallophaga – (Chewing Lice) i.i. Chewing parasites with mandibulate mouthparts.Chewing parasites with mandibulate mouthparts. ii. Feed: sloughed epidermis, feathers and sebaceous ii. Feed: sloughed epidermis, feathers and sebaceous secretions.secretions. iii. Hosts: birds (most) and mammals.iii. Hosts: birds (most) and mammals. iv. No species are parasites of man.iv. No species are parasites of man.

(2) Anoplura – (Sucking Lice)(2) Anoplura – (Sucking Lice) i.i. Bloodsucking parasites of mammalsBloodsucking parasites of mammals ii.ii. Haustellum mouthpartHaustellum mouthpart iii. Solenophagus (all lice)iii. Solenophagus (all lice) iv. Hosts: mammal (humans have 3 species)iv. Hosts: mammal (humans have 3 species)

Order: Phthiraptera (Order: Phthiraptera (LICE)LICE)

Biology

(1) Dorso-ventrally flattened body.

(2) Claws adapted to grasp the host

(3) All lice are wingless

(4) Hemimetabolous Life CycleEgg 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 ControlLouse ControlBody 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.