Furnished by the Iowa Dept. of Agriculture
International SheepLetter
Vol. 18 No. 5, August 1998

"Club Lamb Fungus” is a highly contagious fungal infection of the skin of sheep. It was first diagnosed in 1989 and is now widespread in the sheep industry. It is an especially severe problem in show lambs. This is thought to be due to the close clipping and washing of show animals, although the disease, caused by a Trichophyton sp., also occurs in commercial and purebred sheep flocks.

The club fungus lesions appear as expanding spots that last for several weeks. The fungus is in the skin and roots of the wool follicles. Active lesions are small, crusty, circular or rectangular, brown-colored and are closely attached to the skin. The lesions are almost impossible to detect except in sheep that are closely shorn, such as for shows and expositions. Sheep must be examined very closely for the infection. The chances of detecting the lesions in unshorn sheep are almost zero. This causes a major problem for veterinarians who inspect sheep and lambs for 4-H and FFA shows.

The fungal spores are easily transmitted by contact with contaminated clippers, blankets, combs, bedding, bunks, and pens. The frequent contact of lambs such as at weigh-ins and “jackpot” shows, along with loss of natural protection because of close clipping, washing, and covering with blankets, probably contributes significantly to the incidence and severity of the disease in show lambs.

Club lamb fungus causes a nasty “ringworm” infection in people. It causes acute inflamed areas that may result in scarring. The infection is more severe in young people than adults. Infection of the hands and arms is common in youth and adults who work with infected lambs. The potential for human infection raises concerns about contact with the public at shows and expositions. For this reason, shows and expositions must develop rigorous inspection programs to keep infected sheep off the premises.

The fungal infection is responsive to intensive treatment with antifungal agents such as a topical captan paste. Treatment with 7% iodine is effective but staining of the wool is a problem. Treatment should be intensive and repeated until all signs of infection are gone.

Last year at the Iowa State Fair, all 4-H lambs were reinspected after arrival and before penning. Sixteen were found to have club lamb fungus infection and were removed from the grounds. In order to keep infected lambs out of fairs and expositions, it is necessary to do several things:

1. Educate 4-H and FFA leaders about club lamb fungus and its prevention by avoiding contact with infected lambs, disinfecting clippers, blankets and other potential fomites.
2. Rigorously inspect all sheep for evidence of infection prior to signing health papers.
3. Reinspect all lambs at the fair after close clipping. All infected lambs should be removed from the premises.

Iowa State University Extension will provide educational materials about club lamb fungus to 4-H and FFA leaders, regulatory veterinarians, fair and exposition managers, and others who may be impacted by this growing problem.