Diagnosis of the nervous form of Maedi-Visna infection with a high frequency in sheep in Castilla y Leon, Spain.
Between 1997 and March 2004, the nervous form, or visna, of maedi-visna infection was diagnosed in 71 of 1631 sheep (4.35 per cent) examined in the Castilla y León region of Spain, of which 634 had shown nervous signs. The presence of the virus was confirmed by immunohistochemistry and in some cases by pcr on frozen-thawed or paraffin-embedded tissue samples. The main clinical signs were hindleg ataxia and paresis, but blindness or nystagmus were also observed. Thirty-three of the affected sheep (46.5 per cent) were two years old or younger. The affected sheep showed variable degrees of a non-suppurative meningoencephalitis, and immunohistochemistry identified positive cells in all cases, with no relation to the intensity of the inflammatory lesion.
Departamento de Patología Animal, Medicina Animal (Anatomía Patológica), Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain.
J
J
Benavides
N
N
Gómez
D
D
Gelmetti
M C
MC
Ferreras
C
C
García-Pariente
M
M
Fuertes
J F
JF
García-Marín
V
V
Pérez
D000375:Aging; D000818:Animals; D001921:Brain / Q000473:pathology / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay; D007150:Immunohistochemistry; D016133:Polymerase Chain Reaction; D012756:Sheep / Q000821:virology*; D013030:Spain / Q000453:epidemiology; D016182:Visna / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology