Abstract:
The objectives of this work were to determine the site of persistence of lumpy skin disease virus (LSDV) in bulls
shedding the virus in semen for a period longer than 28 days,
to determine if the virus is present in all fractions of semen and
to study lesions that developed in the genital tract. Six
serologically negative postpubertal bulls were experimentally
infected with a virulent field isolate of LSDV. The polymerase
chain reaction (PCR) was performed on sheath washes,
vesicular fluid, supernatant and cell-rich fractions of semen
from day 10 to day 26 postinfection (p.i.). Bulls that were
positive by PCR on the whole semen sample collected on day
28 p.i. were slaughtered and tissue samples from their genital
tracts submitted for histopathological evaluation, immunoperoxidase
staining, virus isolation and PCR. Two of the bulls
developed severe lumpy skin disease (LSD) and were found to
be shedding viral DNA in their semen on day 28 p.i. Viral
DNA was identified in all semen fractions from all bulls, but
mostly from the cell-rich fraction and from the severely
affected bulls. The PCR assay was positive on postmortem
samples of testes and epididymides from the two severely
affected bulls. Virus could be recovered from the testes of these
two bulls and from the epididymis of one of them. Immunoperoxidase
staining was positive for LSDV staining in
sections of testes and epididymides exhibiting necrosis. This
study suggests that the testis and epididymis are sites of
persistence of LSDV in bulls shedding virus in semen for
prolonged periods and revealed that viral DNA is present in all
fractions of the ejaculate.
