Lice General information VMP 920 Infection & Immunity II Veterinary Parasitology.

LiceGeneral information

VMP 920Infection & Immunity II

Veterinary Parasitology

Lice Groups

MALLOPHAGAN LICE Broad head to accommodate

Chewing mouth parts (mandibles & muscles).

Feed on fur, feathers and epidermal debris.

ANOPLURAN LICE Narrow head w/ piercing /

sucking mouth parts. Feed entirely on blood.

Eggs, called “nits”, cemented to hair or feathers, hatch in 1 to 1.5 weeks. Nits not affected by insecticides

Thus retreatment required, usually 1-2 weeks apart.

Nits hatch & go through a series of nymphal stages, before becoming adults.

Louse Life Cycle

Transmitted by: close contact grooming tools horse tack, pet collars & clothes

Usually more common in winter than summer due to crowded barn, longer hair coat and poor (stressed) condition of host

Louse Life Cycle

Image of life cycle

Louse Life Cycle

Mallophagan (Chewing) Lice

Ex. Trichodectes, Felicola, Bovicola

Pathology Feed on fur, feathers, & epidermal

debris Irritation

Restless, stressed animals Bite / scratch => skin, fur, wool, feather

damage Decrease productivity

Egg and milk production decline. Decreased Feed conversion.

Mallophagan (Chewing) Lice

Control Mainly Topicals

Sprays Dips Pour-ons Shampoos

Mallophagan (Chewing) Lice

Anopluran (Sucking) Lice

Ex. Haematopinus, Lignonanthus, Solenopotes

Solenopotes sp.

Pathology Feed entirely on blood

Heavy infestations = anemia; even death Irritation

Restless, stressed animals Bite or scratch => fur, wool, or skin

damage Decrease productivity

Milk production decline Decreased Feed conversion.

Anopluran (Sucking) Lice

Control Topicals

Sprays, Dips, Pour-ons, ShampoosSystemics (Why do these work?)

Ex. Subcutaneous Ivermectin

Anopluran (Sucking) Lice

Important Points

Know the lice life stages Know how lice are transmitted Know importance of “nits” as related to need

for retreatment. Which season are lice more prevalent? Why? Know morphologic differences in Mallophagan &

Anopluran Lice Know pathology caused by Mallophagan &

Anopluran Lice Which group(s) of lice are treated with topical

insecticides; which are treated with systemics? Why the difference?