Comparison of clinical, hematological, and virological findings in alpacas (Lama pacos) inoculated with bovine viral diarrhea virus isolates of alpaca or bovine origin

Clinical evidence demonstrates that alpacas may contract and propagate bovine viral diarrhea virus (BVDV). The objective of this research was to compare and characterize clinical signs, hematological findings, viremia, and seroconversion resulting from intranasal inoculation of alpacas with BVDV 1b and BVDV 2 isolates from cattle and a BVDV 1b isolate of alpaca origin. Three groups of six alpacas were intranasally inoculated with a different isolate (Group 1: BVDV 1b of bovine origin; Group 2: BVDV 2 of bovine origin; Group 3: BVDV 1b of alpaca origin). Following inoculation, all three genotypes induced viremia, nasal shedding and seroconversion in naïve alpacas. The onset of viral detection in serum was significantly different among groups; the median onset was 4, 2, and 7 days for Groups 1, 2, and 3, respectively. Onset of viral detection in white blood cells was significantly different with median onset at 3, 2, and 4 days, and median cessation at 13, 9, and 13 days, respectively. The median onset of viral nasal shedding was 8 days and was not significantly different between groups. Virus was detected after inoculation until a median of 8 days in nasal secretions, 10 days in serum, and 12 days in white blood cells. A reduction in mean total leukocytes was observed in all three groups when compared to pre-inoculation leukograms. Results demonstrate that BVDV 1b and 2 strains cause alpacas to exhibit viremia and nasal shedding of virus in a temporal pattern that is similar to the outcome of acute infection of cattle.