Ectoparasites

Dr.DARLAN DJALI CHANParasitology DepartmentMedical Faculty of UISU

EctoparasitesGeneral

Definition: parasites which live on the

surface of a host and are dependent on at least one gene or its product from that host to complete their own life cycle

(Dr.Clive Bennet 1998)

EctoparasitesGeneral

Ectoparasite infestations are often seen in pediatric patients

Typical infestations result from arthropods such as: S.scabiei, Pediculus humanus corporis and Pediculus humanus capitis

EctoparasitesScabies

Due to Sarcoptes scabieiBelongs to order Astigmata,

Class Arachnida

ScabiesfeaturesAdult female: ± 0.4mm longIt burrows into stratum corneum layer

of skinEggs: laid in burrows, glossy, white

and smooth, lays2-3 eggs/day; hatch in 3-4 days

Larvae grise to skin surface and mature in 14 to 17 days.

Adult females: life span 30 daysAdult male: dies shortly after mating

Scabieslife cycle

Scabiesfeatures

Gravid female scabies mite Gravid female scabies mite

Burrow of Burrow of SarcoptesSarcoptes consisting adult female consisting adult female and eggsand eggs

ScabiesEpidemiology

Transmissions:Close contact;

holding hands, sharing towel, clothing or bedding

Personal contact: sleeping together, sexual

Breeding environments:

In overcrowded living conditions

Elderly nursing homes

In school children playing together

RoommatesSexual patrners

Human scabies on the handHuman scabies on the hand

ScabiesPreventionAvoid sharing personal stuffCheck family membersClothing and underwear

should changed regularlyHave regular bathingKeep all bedding well

laundered

LiceFeaturesOrdo pthiraptera;

subordo: anopluraDorso-ventrally flattened bodieswingless Permanent

ectoparasites of mammals: sucking blood

Nocturnal feeding

Body LiceGeneralDue to: Pediculus humanus

corporisDefenition: parasitic insects that live on the

body and clothing or bedding of infected humans

Body lice are found on the body and clothing or bedding used by infested people. Occasionally eggs are attached to body hair

Body LiceGeneralAdult female louse her can lay up

to 150 eggs a day during 20-day adult life span.

Eggs hatch in 7-10 days, and the larvae mature into adults in 9 days

Lives and lays eggs in the seams (layers) of clothing

The adult louse emerges from clothing to take a blood meal, usually at night.

Body LiceEpidemiologyLives and lays eggs in the

seams (layers) of clothingThe adult louse emerges from

clothing to take a blood meal, usually at night.

Body LiceMedical importantDermatitisVector of

diseases:o Trench Fever:o Louse borne

epidemic typhuso Louse borne

relapsing fever

Transmission:o Fecal

contaminationo Body crushingo Physical

contact

Body LicePrevention and controlPersonal hygieneChanging and washing the

clothing in water hotter than 60ºC, preferably followed by ironing

Permethrin in lotion, shampoo, emulsion, and powder

Head LiceGeneralDue to: Pediculus humanus

capitisDefinition: parasitic insectsm

found on the heads of peopleCommonly found on the scalp,

behind the ears and near the neckline at the back of the neck.

Children 3-10 years are commonly affected

Head LiceGeneralThe adult female louse lays 7

to 10 eggs daily in egg casings (nits) that are cemented to the base of hair shafts

Eggs hatch in 8 to 10 days, mature in 8 to 15 days, and live 9 to 30 days as adult

Head LiceepidemiologyTransmission: head to head

contact is common during play at school and at home;– Wearing clothing, such as hat,

scarves, coats etc– Using infested combs, brushes,

or towels– Lying on a bed, couch, pillow,

carpet that has recently been in contact with an infested person

Head LiceMedical importanto ItchyoErythemaoDiscomfortoSecondary infection:

oVagabond’d disease: darkened, thickened skin (hyperceratination)

oPlica polonica: exudate, fungus grow, a fetid odor

Head LicePrevention and controloPersonal hygieneoRegularly washing with soap

and warm wateroRegularly combing with

ordinary combo Permethrin in lotion, shampoo,

emulsion, and powder

Pthrirus Pubis (Crab Louse)

Pubic LouseCrablike appearanceLife in pubic hair and

body hairLife cycle: 3-4 weeksDirect transmission:

Body contact (STD)EctoparasiteCrawling

Pthrirus Pubis (Crab Louse)PREVENTION & CONTROL

Personal hygienePermethrin in

lotion, shampoo, emulsion, and powder