Colostrum and milk can transmit jaagsiekte retrovirus to lambs.
Ovine pulmonary adenocarcinoma (OPA) is a contagious disease caused by jaagsiekte sheep retrovirus (JSRV). In the three studies performed, we have obtained data of the importance of colostrum/milk (C/M) in the transmission of JSRV. In the first study, a group of sheep from a flock with a long history of OPA, samples from colostrum and peripheral blood leucocytes (PBLs) were collected. Two specific PCRs (U3-LTR and env of the JSRV) were carried out. Using U3PCR 8/34 sheep were positive in colostrum whereas with envPCR 7/34 were positive. From these animals only one was positive with U3PCR in the PBLs. Evidence of the transmission of JSRV infection by C/M was obtained in two more separate studies. In the second study, PBLs from five lambs from JSRV+ ewes and two from JSRV-ewes were tested by the U3PCR. They were fed C/M by their mothers during 3 months and slaughtered 7 months after birth. Three out of five lambs from the JSRV+ sheep become PBL positive at 3-4 months old and the other two were also positive at 4-6 months of age. One lamb of the JSRV-sheep became also PBL positive at an age of 3 months. In the third study, a group of lambs from JSRV negative mothers were fed with C/M from JSRV+ sheep and housed in separate unit. For comparison, another group of the same origin and maintained in another different unit, were fed with C/M containing a JSRV virus preparation. All lambs were blood sampled monthly and JSRV infection was detected as early as 15 days and several times onwards in both groups. Control groups fed with C/M from JSRV free flock and JSRV blood test negative sheep were always negative. Together these results indicate that suckling is an important natural transmission route for JSRV.
Grego
Elena
E
Dipartimento di Produzioni Animali Epidemiologia ed Ecologia, Facoltà di Medicina Veterinaria, Università degli Studi di Torino, Grugliasco, Italy.
De Meneghi
Daniele
D
Alvarez
Vega
V
Benito
Alfredo A
AA
Minguijón
Esmeralda
E
Ortín
Aurora
A
Mattoni
Mario
M
Moreno
Bernardino
B
Pérez de Villarreal
Maider
M
Alberti
Alberto
A
Capucchio
Maria Teresa
MT
Caporale
Marco
M
Juste
Ramón
R
Rosati
Sergio
S
De las Heras
Marcelo
M
D000821:Animal Feed; D000818:Animals; D003126:Colostrum / Q000821:virology*; D004032:Diet / Q000662:veterinary; D005260:Female; D041943:Infant Formula; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary*; D022141:Jaagsiekte sheep retrovirus; D008892:Milk / Q000821:virology*; D011648:Pulmonary Adenomatosis, Ovine / Q000635:transmission* / Q000821:virology; D012756:Sheep