Abstract :
Caprine arthritis-encephalitis (CAE) is a multi-systemic viral syndrome in goats caused by
small ruminant lentivirus (CAEV). The control measures prescribed for CAEV control are
based on the identification of infected animals through a suitable serological test. The aim of
thisworkwas to improve the CAE control measures through the association of indirect (agar
gel immunodiffusion—AGID) and direct (PCR) assays to CAEV diagnosis. Thirty-nine kids
born to AGID-seropositive dairy goats were separated from their dams immediately after
birth, fed heat-treated colostrum from AGID-seronegative goats and then after pasteurized
goat milk. AGID was performed at birth before colostrum, at 9 and 12 months, and the
AGID-seropositive animalswere segregated. Seronegative goatswere also submitted to PCR
to detect proviral DNA in blood, and the positives were isolated. A study of accumulated
residual negativity was performed using a 95% confidence limit rate. During the 12 month
experimental period no clinical signs of CAEV were observed. At the end of that period 34
animals remained AGID-seronegative to CAEV, corresponding to 87% accumulated residual
negativity. When submitted to PCR, 4 of the 34 AGID-seronegative animals showed positive
results, leading to a 77% final accumulated negativity rate with 64–90% confidence limits.
We conclude that the classical management practices recommended for CAEV control are
insufficient in CAEV eradication programs and that PCR may be a useful tool for decreasing
the risk of breeding AGID false negative animals (CAEV carriers).
