ANSC 315 Ectoparasites

Fleas

• insects (arthropods)

• Ctenocephaladies felis (“cat flea”)

  • most common flea of dogs and cats

• Causes:

  • itching

  • anemia (from blood loss)

  • flea bite allergic dermatitis

• Carry & Spread:

  • tapeworms (Dipylidium caninum — flea tapeworm)

  • plague (cats)

  • haemobartonellosis (cats) — disease of red blood cells

Life Cycle of Fleas

Eggs hatch in 1-2 days → Larvae feed for 4-8 days on debris → An adult flea MAYBE begin to emerge in as little as 5 days → ***An adult flea may live without feeding for as long as 125 days. Adult flea finds a new host and jumps from pet to pet. Unless controlled, it is possible for a flea to live on a host for as long as 2 years. The life cycle may be completed as quickly as 3 weeks.*** → Adult female flea finds a host → Adult female feeds for 2-3 days, then lays eggs.

What is the Life Cycle of Fleas?

2-3 weeks

Eggs can Hatch up to ______ After being Laid.

1 year

____ ____ is Very Resistant to Treatment.

pupa stage

Majority of the Flea Life Cycle is Spent _____ the Animal in the Environment.

off

Flea Treatment

• environment

• animal

Environmental Control of Fleas

• access to other animals

• removal of adults, eggs, larva, and pupa

• vacuuming

• launder bedding

• flea “bomb” or spray

• boric acid or mineral salts — kill larva and eggs, not adults

• flea growth regulators applied to the dog — interrupt flea life cycle

Selected Tick-Born Disease

• lyme disease

• ehrlichia

• rocky mountain spotted fever

Animal Applied Flea and Tick Products

• sprays

• powders

• collars

• spot on

• oral

Compounds

• insecticides

• insect growth regulators

• natural

• mechanical

Most to Least Toxic Compounds

MOST

Insecticides

Organo-Phosphates

Carbamates

Pyrethrins

Newer Insecticides

LEAST

Insecticides

• most act on nervous system of the insect (some can affect nervous system of mammals)

• organo-phosphates

• carbamates

• monamine oxidase inhibitors (Amitraz)

• pyrethrins/synthetic pyrethroids

• insect-specific topicals (newer)

Organo-Phosphates

• quite toxic

• Primary Target: Nervous System

• Toxicity:

  • increased heart rate, shortness of breath, skin flushing, irritation, tremors, nausea, vomiting, blurred vision increased salivation

  • Chlorpyrifos (dursban), dichlorvos, phosmet, naled, diazinon, malathion, tetrachlorviaphos

Carbamates

• Primary Target: Nervous System

• toxicity is similar to O-P but generally NOT as severe

• carbaryl, propoxur

Pyrethrins

• chrysanthemum derivatives

• pyrethrins short acting, fairly safe

• synthetic pyrethroids — permethrins

  • last longer

  • toxic to cats

• low toxicity in humans

  • more commonly — skin irritation, upper respiratory tract irritation

Newer Insecticides

• more specific to insect nervous sytem

• don’t seem to have same effect on mammalian nervous system

Insect Growth Regulators

• interfere with egg hatching or development of adult insect to prevent further breeding and egg laying

• not insecticides — do not kill adults

Mange

SCABIES — Sarcoptic Mangw

• contagious

• very pruritic

• zoonotic (don’t live on human for longer than a few hours but can cause itchiness)

• burrow into epidermic

• common in wild animals

Demodicosis

• young animals (usually)

• demodex mites (entire life cycle on host)

• immunosuppressed animals

• local to system signs

Treatment of Mange

• wash collars, leaashes, bedding

• bathe with antibacterial or antipruritic shampoo

• paramite dip (organo-phosphate)

• mitaban — demodex, sarcoptes

• ivermectin — scabies, some demodex

• selamectin — scabies

Cheyletiella

• “walking dandruff”

• parasitizes keratin layer on skin surface

• severe seborrhea sicca — flaking along back

• sticky tape prep for diagnosis

• zoonotic

• dogs, cats, rabbits

Lice

• species specific (humans don’t get from animals, vice versa)

• pruritic

• clean environment to prevent return

Warbles

• cuterebra

• lays eggs in soil

• larval stage in animals

  • opening to allow larva to breath

  • leaves animal when becomes a fly

Myiasis (Maggots)

• flies deposit eggs on warm, wet, damaged skin

• larvae very destructive

• “punched out” areas of skin — can group together to cause large areas of decay

• disease of neglect

  • check outdoor pets frequently

  • avoid matting of hair

  • minimize flies in outdoor environment