Lecture 24 (Fleas and Lice)

Created by Harley Chase and Kylee Wood

Control and treatment of what is the single largest small animal health issue?

Fleas

T or F: Fleas are an irritating and embarrassing household nuisance.

True

What accounts for approximately $1 billion in annual sales in the U.S. alone?

Flea control products

What is Ctenocephalides felis known as?

The “Cat Flea”

What are the following describing?

• Laterally compressed body

• Adults are parasitic on the host

• Larvae feed on defecated blood & organic debris in environment

“Cat Flea” - Ctenocephalides felis

What are the flea species of minor importance?

Ctenocephalides canis & Pulex simulans

What is Ctenocephalides canis known as?

The “Dog Flea”

What is the comparison of Ctenocephalides canis and C. felis on a dog infested with fleas?

• C. canis → 12 to 20%

• C. felis → ~80%

What is Pulex simulans known as?

The “False Human Flea”

What are Pulex simulans typically found on?

Wild canids (particularly coyotes), Rodents, Opossums, other wildlife

What is seen in the following image?

C. felis

What is seen in the following image?

C. felis

What is seen in the following image?

C. canis

What is seen in the following image?

Pulex simulans

What accounts for over 50% of all dermatologic cases seen in the South East?

Flea related health problems

T or F: Fleas are a significant source of discomfort for animals and humans.

True

What are Fleas biologic vectors and intermediate hosts for?

Parasites, Viruses and Bacteria

Fleas are biologic vectors and intermediate hosts for parasites, viruses, and bacteria such as what?

• Dipylidium caninum

• Acanthocheilonema reconditum

• Plague (Yersinia pestis)

• Bartonella henselae (cat scratch)

• Suspected vector competence for transmission of FeLV

  • Transmission by blood meal

  • Transmission through feces

Adults fleas are what, which is required for maturation and reproduction?

Obligate Blood Suckers

Will adult fleas feed on any warm-blooded host?

Yes

What do larval stages of fleas feed on?

Digested blood and organic debris (dander, dried feces, etc.)

What is true for newly hatched adult fleas?

They are able to survive long periods of starvation

How long does it take for the life cycle of a flea to be complete under optimal conditions?

3 weeks

What is the primary source of flea egg and flea larvae infesting companion animals?

Wildlife visiting yards of pet owners

What may be the primary vector for introducing fleas to the hyper sensitive dog?

The asymptomatic cat

What is adverse to flea survival outdoors?

Cooler weather (< 40*F) — (5 days at 34*F)

What must successful control of flea infestations be directed at?

All stages of life cycle

• Fleas on primary host, fleas on secondary (asymptomatic) hosts, larval/pupal stages off of the host in residential environment

What is failure to treat any stage the basis of?

Perceived treatment failure

Products that kill fleas on the host, prevent re-infestation of the host (repellent properties) and prevent eggs from hatching or larvae from developing (growth regulators) are key for what?

Successful control of flea infestations

Successful mitigation of all Flea related infestations are based on what 4 activities?

1. Killing fleas on the primary host (Dog affected by flea bite dermatitis)

2. Killing adult fleas on reservoir hosts (Asymptomatic cohorts of the affected animal)

3. Preventing fleas from immediate re-infestation

4. Elimination of larval stages in the environment (Bedding, Carpets, Habitual Hangouts)

Failure to follow-thru on any single activity results in a perception of treatment failure

What type of life cycle do chewing and sucking lice have?

Direct Life Cycle

Chewing and Sucking Lice are dorso-ventrally flattened - do they have wings?

No - wingless

Chewing and Sucking Lice are poorly adapted for life off the host and are what?

Highly host specific

How can chewing and sucking lice be controlled?

By Tx and nit removal

When comparing lice - what is the following describing?

• Head wider than thorax

• Bites skin, chews feather, & feeds on sloughed dermis, oozing blood/serum

• Host specific, only lice on birds and cats

Chewing Lice

When comparing lice - what is the following describing?

• Head more narrow than thorax

• Pierces skin, sucks blood, hypoprotinemia

• Host specific, dogs, goats, horses, cows, etc.

Sucking Lice

What is seen in the following image?

Sucking Louse b/c head is smaller than thorax

What is seen in the following image?

Chewing Louse b/c head is larger than thorax

What is the general term for louse infestation?

Pediculosis

Who is Pediculosis (louse infestation) often associated with?

Young animals

Human Pediculosis is exclusively host specific - what 3 species infest people?

• Pediculus humanus capitis

• P. humanus humanus

• Pthiris pubis

What is the treatment/control for Pediculosis in companion animals?

• Fipronil

• Imidacloprid

• Selamectin

What is the treatment/control for Pediculosis in Livestock?

• Macrocyclic lactones (Pour-on & oral formulations)

• Attention to other factors affecting herd health

What are considered True Bugs (Hemiptera)?

Reduviid bugs and Bedbugs (Cimex lectularius)

What are Reduviid bugs also known as?

Kissing Bugs or Assassin Bugs

What are Reduviid Bugs the intermediate host for?

Trypanosoma cruzi

Who are hosts for Reduviid Bugs?

Dogs and Cats

What is the common name for Cimex lectularius?

Bedbugs

Who are hosts for Bedbugs?

Rabbits, Poultry, and Pigeon Colonies — exsanguination of young & neonates

What is the clinical significance and pathogenic potential of fleas and lice?

• Source of discomfort

• Dermatologic issues

• Vector potential