PROSPECTIVE CHARACTERIZATION OF THE CLINICOPATHOLOGICAL AND IMMUNOLOGICAL FEATURES OF AN IMMUNODEFICIENCY SYNDROME AFFECTING JUVENILE LLAMAS

The clinicopathologic and immunologic features of 15 llamas affected w ith juvenile llama immunodeficiency syndrome (JLIDS) are described. He althy adult (n = 10) and juvenile (n = 10) llamas served as controls. JLIDS llamas were characterized by wasting, and clinically apparent, r epeated infections were frequently observed. The median age at which a health problem was first perceived was 11.6 months. All 15 affected l lamas died or were killed, and JLIDS was confirmed at necropsy. The me dian duration of illness was 3.5 months. Lymphocyte blastogenesis assa ys showed suppressed responses (particularly to Staphylococcus sp. Pro tein A) in JLIDS llamas. No evidence of retroviral infection was detec ted. Mild, normocytic, normochromic, non-regenerative anemia, low seru m albumin concentration and low to low-normal globulin concentrations were typically found on initial clinical evaluation. Lymph node biopsi es showed areas of paracortical depletion, All l llamas affected with JLIDS had low serum IgG concentrations, pre-vaccination titers against Clostridium perfringens C and D toxoids of less than or equal to 1:10 0, and no titer increase following vaccination.