Interspecific transmission of small ruminant lentiviruses from goats to sheep

Abstract

This study was conducted in order to evaluate the transmission of caprine lentivirus to sheep using different experimental groups. The first one (colostrum group) was formed by nine lambs receiving colostrum from goats positive for small ruminant lentiviruses (SRLV). The second group (milk group) was established by nine lambs that received milk of these goats. Third was a control group, consisting of lambs that suckled colostrum and milk of negative mothers. Another experimental group (contact group) was formed by eight adult sheep, confined with two naturally infected goats. The groups were monitored by immunoblotting (IB), enzyme-linked immunosorbent assay (ELISA), agar gel immunodiffusion (AGID) and nested polymerase chain reaction (nPCR). All lambs that suckled colostrum and milk of infected goats and six sheep of the contact group had positive results in the nPCR, although seroconversion was detected only in three of the exposed animals, with no clinical lentiviruses manifestation, in 720 days of observation. There was a close relationship between viral sequences obtained from infected animals and the prototype CAEV-Cork. Thus, it was concluded that SRLV can be transmitted from goats to sheep, however, the degree of adaptation of the virus strain to the host species probably interferes with the infection persistence and seroconversion rate.

Keywords: cross-infection; goats; lambs; small ruminant lentivirus.

Figure 1. Results of nPCR for small ruminant lentiviruses, in peripheral blood leukocytes from nine lambs that received colostrum from infected goats within the first 24 hours of life

Figure 2. Results of nPCR for small ruminant lentiviruses, in the peripheral blood leukocytes of nine lambs that received milk from infected goats during 15 days

Figure 3. Results of nPCR for small ruminant lentiviruses, in peripheral blood leukocytes from eight sheep raised confined together with infected goats, during 720 days