Bovine Viral Diarrhea Virus in North American Alpaca Herds

Principal investigators:

Topliff CL, Smith DR, Clowser SL, Steffen DJ, Henningson JN, Brodersen BW, Bedenice D, Callan RJ, Reggiardo C, Kurth KL, Kelling CL.
Department of Veterinary and Biomedical Sciences, Institute of Agriculture and Natural Resources, University of Nebraska, Lincoln, NE 68583-0905, USA
J Am Vet Med Assoc. 2009 Feb 15;234(4):519-29.

OBJECTIVE: To determine the prevalence of bovine viral diarrhea virus (BVDV)-infected alpaca herds in the United States and investigate factors associated with seropositive herd status and, subsequently, determine the proportion of animals within seropositive alpaca herds that are persistently infected (PI) carriers for BVDV, obtain information regarding previous herd exposure to BVDV, determine titers of anti-BVDV antibodies of dams, and ascertain whether individual seropositive crias had received supplemental colostrum at birth. DESIGN: Prevalence study. ANIMALS: 63 alpaca herds with >or= 12 registered female alpacas. PROCEDURES: 250 alpaca breeders were randomly selected from 562 eligible herds listed in the Alpaca Owner and Breeders Association membership directory and mailed a voluntary participation request. Sixty-three alpaca breeders participated in the study. From each herd, blood samples from >or= 4 crias were tested for BVDV, BVDV RNA, and serum neutralizing antibodies against BVDV. A region of the genome of BVDV recovered from PI crias was sequenced to determine genetic homology. RESULTS: Among the 63 herds, 16 (25.4%) had seropositive crias and 4 (6.3%) had PI crias. Infections in 3 of the 4 herds with PI crias were linked as evidence by the genetic homologies of viruses. In addition to PI crias, feeding supplemental colostrum was associated with herd seropositivity. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirmed the importance of BVDV infections in alpacas in the United States and highlighted the importance of determining the BVDV infection status of animals before they are commingled to limit exposure of herds to BVDV infection.