title: Clinical evaluation of immunity following experimental or natural infection of ewes with Chlamydia psittaci (var. ovis).
abstract: The immunity conferred by a primary infection either experimental or natural was challenged at 70 days of pregnancy by intradermal inoculation of 8 X 10(7) virulent yolk sac propagated chlamydiae. The experimental primary infection was carried out, 19 months before at 70 days of pregnancy by intravenous inoculation (PI ewes). The natural primary infection was obtained 14 months before the challenge when the ewes (PCC ewes) were placed in contact with experimentally infected ewes. The response to challenge inoculation was followed by recording rectal temperature. CF antibody titer, lambing performance and by chlamydial isolation from vaginal swabs. The experimental primary infection protect against the challenge: none of the four ewes aborted or shedded chlamydiae. The immunity following a field exposure seems less reliable: the four ewes have a normal duration of pregnancy, three of them have at least a live lamb, but all of them shedded chlamydiae.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D002691:Chlamydophila psittaci / Q000276:immunology; D005260:Female; D007109:Immunity; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000662:veterinary*; D009956:Psittacosis / Q000276:immunology / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial