Experimental Exposure of Naive Alpacas to Bovine Viral Diarrhea Virus 1a, 1b, and 2

J. W. Johnson1; M. A. Edmonson1; P.H. Walz1; M.D. Givens2
1 Department of Clinical Sciences, Auburn University, 36849, Auburn, AL, USA
2 Animal Health Research, Auburn University, 36849, Auburn, AL, USA

Introduction

Authors previously speculated that viremia seldom developed in camelids following infection with BVDV. However, confirmed persistent infections of New World camelids indicates that viremias have occurred with genotype lb strains of BVDV. This research compares and characterizes clinical signs, viremia, and seroconversion resulting from intranasal inoculation of alpacas with genotype 1 b and 2 strains of BVDV isolated from cattle and genotype 1b of alpaca origin.

Methods

Three groups of six alpacas were inoculated with a different genotype of BVDV (1b [Group 1], 2 [Group 21, and lb alpaca-strain [Group3]). Virus isolation was performed on serial serum, white blood cell, and nasal swab samples. Daily physical examinations and serial leukocyte counts were evaluated. Virus neutralization was performed on serum.

Results

All three genotypes of BVDV induced viremia in naive alpacas. No clinical illness was detected in any group. The onset of viral detection in serum was significantly different among groups; the mean onset was 4.0, 2.3, 7.5 d for Groups 1, 2, and 3 respectively. Onset and duration of viral detection in white blood cells was significantly different among groups with respective values for onset of 3.0, 2.3, and 4.7 d and cessation of 13.0, 10.0, and 12.3 d. The mean onset of viral nasal shedding was 6.9 d. Virus was detected for an average of 8.9 d in nasal secretions and 9.4 d in serum. A significant leucopenia was observed in all three groups but magnitude was not affected by viral strain. Group 3 took significantly longer to reach the nadir of leucopenia. All animals in the study seroconverted

Conclusions

All evaluated strains of BVDV induced viremia in alpacas. The presence of virus in white blood cells indicates active replication in all three study groups. Furthermore, all three evaluated strains induced nasal shedding of infectious virions.

Funding

Alpaca Research Foundation
PO Box 1043
Siler City, NC 27344