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