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.
Benavides
J
J
Departamento de Patología Animal, Medicina Animal (Anatomía Patológica), Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain.
Gómez
N
N
Gelmetti
D
D
Ferreras
M C
MC
García-Pariente
C
C
Fuertes
M
M
García-Marín
J F
JF
Pérez
V
V
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