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

2. 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.

3. 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

4. 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

5. Image of life cycle Louse Life Cycle

6. Mallophagan (Chewing) Lice Ex. Trichodectes, Felicola, Bovicola

7. 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

8. Control Mainly Topicals Sprays Dips Pour-ons Shampoos Mallophagan (Chewing) Lice

9. Anopluran (Sucking) Lice Ex. Haematopinus, Lignonanthus, Solenopotes Solenopotes sp.

10. 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

11. Control Topicals Sprays, Dips, Pour-ons, Shampoos Systemics (Why do these work?) Ex. Subcutaneous Ivermectin Anopluran (Sucking) Lice

12. 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?