MTAP 1 PARASITOLOGY (ARTHROPODS)

ARTHROPODS

Bilaterally symmetrical

Segmented body

Several pairs of jointed appendages

Rigid chitinous exoskeleton (molting)

Sexes are separate

GRADUAL METAMORPHOSIS

COMPLETE METAMORPHOSIS

STAGES OF ARTHROPODS

egg, nymph, adult

GRADUAL METAMORPHOSIS:

egg, larva, pupa, adult

COMPLETE METAMORPHOSIS:

INFESTATION

invasion of superficial tissues

INFECTION

invasion of deeper body tissues and cavities

ENVENOMATION

Injecting saliva or venom with their bites/stings.

– Ants, bees, wasps, scorpions, spiders

VESICATION

Capable of spraying a vesicating (blister-causing) chemical substance from glands located on each body segment.

– Large tropical millipedes, blister beetles

BLOOD LOSS

Responsible for producing significant irritation or blood loss to humans & domestic animals

– Bedbugs, kissing bugs, lice, fleas, flies, mosquitoes, biting midges, ticks, mites

TRANSMISSION OF INFECTIOUS AGENTS

Biological or mechanical transmission of infectious disease agents

HYPERSENSITIVITY REACTIONS

Results from allergic hypersensitivities: most serious reactions to arthropod bites and stings

Entomophobia

unreasonable or excessive fear of seeing or touching arthropods.

Delusory parasitosis

emotional disorder in which a person is convinced that he is infected with parasites or arthropods despite objective evidence to the contrary.

humanus corporis

Human body louse

h. capitis

head louse

Phthirus pubis

A.k.a crab lice, infest widely-spaced coarse hair in the pubic area in adults or eye lashes in children.

sexual contact

Phthirus pubis Transmission in adults is usually by

Erythematous lesions

______ can be seen in the pubic region of the patient in response to the bites of the crab lice arthropods

Tunga penetrans

Both sexes feed on blood. The female flea, after insemination, burrows itself in the skin of the toes and the sole of the foot. The female swells to the size of a pea, produces eggs and dies in the tissue. There is local reaction to the bite and the eggs and dead flea produce reaction. The infested tissue can get infected and gangrenous.

-Jigger flea or chigoe

-Americas and Africa.

(Tunga penetrans)______ or______, a serious pest in the tropical and subtropical regions of the _____ and _____

Pulex irritans (human flea)

Body of adult is short, deep, flattened from side to side, 2-3 mm long, 3 pairs of legs, last pair very long. Head has no ctenidia (“combs”) as do dog & cat fleas which may bite man.

2-3 mm

3 pairs of legs

Pulex irritans (human flea)

Body of adult is short, deep, flattened from side to side,_____long, ________, last pair very long.

body or clothing

SOURCE OF MATERIAL for Pulex irritans (human flea)

Sarcoptes scabei (scabies mites)

Common at all times in very poor communities with inadequate washing facilities.

1% malathion or benzene hexachloride (crotamiton for infants).

treatment for Sarcoptes scabei (scabies mites)

hot water

Sarcoptes scabei (scabies mites) clothes should be washed in __________