sante.roperto@unina.it
(SR)
Abstract – Highly pathogenic bovine Deltapapillomaviruses (δPVs) were detected and quantified for the first time
using digital droplet polymerase chain reaction (ddPCR) by liquid biopsy
in 103 clinically healthy sheep. Overall, ddPCR detected bovine δPVs in
68 blood samples (66%). Bovine papillomavirus (BPV) infection by a
single genotype was revealed in 59% of the blood samples, and BPV
coinfection by double, triple or quadruple genotypes was observed in
41% of liquid biopsies. The BPV-2 genotype was most frequently seen in
sheep, whereas BPV-1 was the least common. Furthermore, ddPCR was very
useful for detection and quantification; the BPV-14 genotype was
observed for the first time in ovine species, displaying the highest
prevalence in some geographical areas (Apulia). In 42 of the positive
samples (61.8%), a single BPV infection was observed, 26 of which were
caused by BPV-2 (61.9%) and 7 by BPV-13 (16.7%). BPV-14 was
responsible for 7 single infections (16.7%) and BPV-1 for 2 single
infections (4.7%). Multiple BPV coinfections were observed in the
remaining 26 positive samples (38.2%), with dual BPV-2/BPV-13 infection
being the most prevalent (84.6%). BPV infection by triple and quadruple
genotypes was also observed in 11.5% and 3.8% of cases, respectively.
The present study showed that ddPCR, a biotechnological refinement of
conventional PCR, is by far the most sensitive and accurate assay for
BPV detection. Therefore, ddPCR displayed diagnostic and epidemiological
value resulting in the identification of otherwise undetectable BPV
genotypes as well as their geographical distributions and suggesting
that animal husbandry practices contribute to cross-species transmission
of BPVs.
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Keywords: bovine papillomavirus (BPV) DNA; digital droplet PCR( ddPCR); liquid biopsy; peripheral blood; viral load.