K15 Ectoparasites 1

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Questions and Answers

What is the typical length of a Pediculus humanus capitis (Head Lice)?

2.3-3.6 mm

1.1-1.8 mm

5-6 mm

2-3 mm (correct)

What is the main mode of transmission of body lice infestations?

Through contact with infected animals

Through airborne transmission

Through contaminated food and water

Through close person-to-person contact (correct)

What is a common symptom of body lice infestation?

Fever and chills

Vomiting and diarrhea

Intense itching and rash (correct)

Headache and fatigue

What is the primary characteristic of ectoparasites?

They remain on the skin for relatively long periods. Signup and view all the answers

Which of the following statements about head lice is true?

Head lice are known to cause intense itching Signup and view all the answers

Which class does Fleas, Lice, and Bedbugs belong to?

Insecta Signup and view all the answers

What is the primary habitat of body lice?

On clothing Signup and view all the answers

What is the order of Lice?

Phthiraptera Signup and view all the answers

What is a potential complication of body lice infestation?

Secondary bacterial infection of the skin Signup and view all the answers

What is the main difference between head lice and body lice?

Their habitat Signup and view all the answers

What is a characteristic of insects?

Chitinous exoskeleton and three pairs of legs Signup and view all the answers

How long does it take for itching to appear after a person gets head lice for the first time?

4-6 weeks Signup and view all the answers

What is the body structure of insects?

Three-part body Signup and view all the answers

Why are body lice infestations more common in certain populations?

Due to poor hygiene Signup and view all the answers

What is the primary way head lice infestation is spread?

Through close person-to-person contact Signup and view all the answers

How long can head lice survive if they fall off a person and cannot feed?

Less than 1-2 days Signup and view all the answers

What is a characteristic of Arachnida?

Four pairs of legs Signup and view all the answers

What is the classification of Lice?

Kingdom: Animalia Signup and view all the answers

What is the nickname of pubic lice?

Crabs Signup and view all the answers

How are pubic lice typically spread?

Through close personal contact Signup and view all the answers

What is a characteristic of Lice?

Small and wingless Signup and view all the answers

What is the typical symptom of pubic lice infestation?

Itching in the pubic and groin area Signup and view all the answers

What is unique about the front legs of pubic lice?

They are very large and resemble pincher claws Signup and view all the answers

What is NOT a way that head lice can be spread?

Through contaminated food and water Signup and view all the answers

What is the primary method of treating body lice?

Improving the personal hygiene of the infested person Signup and view all the answers

What is the minimum temperature required to kill lice and eggs when washing clothes?

130°F Signup and view all the answers

What is the purpose of using a magnifying lens when checking for lice?

To distinguish lice eggs from other particles found in hair Signup and view all the answers

What is the function of some pediculicides?

To kill both lice and eggs Signup and view all the answers

What is a characteristic of adult bed bugs that have recently fed?

They are balloon-like and reddish-brown. Signup and view all the answers

Why is it important to wash and dry hats, scarves, pillowcases, bedding, clothing, and towels?

To destroy lice and eggs Signup and view all the answers

What is unique about the antennae of true bugs?

They have four parts. Signup and view all the answers

What is the recommended frequency for changing clean clothes worn by the infested person?

Weekly Signup and view all the answers

What is the name of the medicinal ingredient used in some lice-killing lotions?

Permethrin Signup and view all the answers

What is the purpose of Integrated Pest Management (IPM)?

To use pesticides judiciously and carefully. Signup and view all the answers

What is the recommended action after vacuuming to reduce bed bug populations?

Immediately seal and dispose of the vacuum bag. Signup and view all the answers

What is the name of the FDA-approved medicinal ingredient for treating lice?

Ivermectin lotion Signup and view all the answers

What is the characteristic of young bed bugs (nymphs) when they have not fed recently?

They are smaller and nearly invisible. Signup and view all the answers

What is the purpose of installing bed bug interceptors?

To prevent bed bugs from climbing up furniture legs. Signup and view all the answers

What is a characteristic of bed bug eggs?

They are pearl-white in color. Signup and view all the answers

What is essential for all stages of Cimex spp.?

Blood meals from warm-blooded hosts. Signup and view all the answers

Study Notes

Ectoparasites

Ectoparasites are pathogens that infect only the superficial layers of the skin, attaching or burrowing into the skin and remaining there for relatively long periods of time.

Classification of Ectoparasites

Class: Insecta (Fleas, Lice, and Bedbugs)
Class: Arachnida (Ticks and Mites)

Characteristics of Insecta

Chitinous exoskeletons
Three-part bodies (divided into head, thorax, and abdomen)
Three pairs of legs
Two antennae

Lice

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Phthiraptera

Biology of Lice

Small, wingless, blood-sucking ectoparasites of mammals and birds
Prevalence: Low standard hygiene
Infestation: Pediculosis
Have humans as their only host
Have similar life cycles
Morphology: Body Dorso-ventrally flattened, 3 parts: Head - Thorax - Abdomen

Types of Lice

Head lice: Pediculus humanus capitis (2-3 mm long)
Body lice: Pediculus humanus corporis (2.3-3.6 mm long)
Pubic lice (crabs): Pthirus pubis (1.1-1.8 mm long)

Body Lice

Also known as Pediculus humanus humanus
Adult body lice are 2.3–3.6 mm in length
Live and lay eggs on clothing and only move to the skin to feed
Symptoms: Intense itching and rash caused by an allergic reaction to louse bites
Can transmit disease (epidemic typhus, Bartonella quintana infection, and epidemic relapsing fever)

Head Lice

Not known to transmit any disease
Symptoms: Itching (“pruritus”) - caused by an allergic reaction to louse bites
Infestation: Pediculosis
Spread: Close person-to-person contact
Not transmitted by animals

Pubic Lice

Pubic (“crab”) lice: Dorsoventrally-flattened
Adults are much broader in comparison to head and body lice
Second and third legs have a large modified claw with a thumb-like projection, used for grasping on to hair shafts
Symptoms: Itching (“pruritus”) in the pubic and groin area
Spread: Through sexual contact, close personal contact, or contact with materials used by an infested person

Treatment of Lice

Body Lice: Improve personal hygiene, assure regular change of clean clothes
Head Lice: Use pediculicides (medicines that kill lice), routine retreatment recommended
Pubic Lice: Use lice-killing lotion containing 1% permethrin or a mousse containing pyrethrins and piperonyl butoxide

Bedbugs

Adult bed bugs: About the size of an apple seed (5-7 mm or 3/16 - 1/4 inch long), brown, with a flat, oval-shaped body
Young bed bugs (nymphs): Smaller, translucent or whitish-yellow in color
Bed bug eggs: Tiny, pearl-white in color, marked by an eye spot if more than five days old

Life Cycle of Bedbugs

Two species of bed bugs (Insecta: Hemiptera: Cimicidae) implicated in human infestations: Cimex lectularius and C. hemipterus
Adults and all nymphal stages need to take blood meals from warm-blooded hosts, typically humans

Control Measures for Bedbugs

Integrated Pest Management (IPM): Environmentally sensitive approach to pest management that relies on knowledge of the pest and a combination of common-sense practices
Environmental Modification: Vacuuming, sealing cracks, using barriers, and judicious use of pesticides if needed

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Description

Learn about ectoparasites, including lice, fleas, and bedbugs, and their impact on human health. This quiz covers the general introduction to ectoparasites and their types.