Contagious ecthyma, diagnosed in three lambs, was transmitted to two researchers having direct contact with oral secretions from these lambs. Intracytoplasmic viral particles were demonstrated by electron microscopy in gingival biopsies from one lamb. Lamb to lamb transmission was most likely caused by use of a contaminated gavage feeding tube. Concern for the effects of this disease and Q fever on patients having contact with contaminated medical researchers prompted the formulation of safety guidelines to prevent potentially disastrous zoonotic disease.