Intrauterine and transmammary transmission of Mycobacterium avium subsp paratuberculosis in sheep.
OBJECTIVE
To investigate intrauterine infection of foetuses with Mycobacterium avium subsp paratuberculosis and the presence of infection in mammary secretions of sheep.


METHODS
A study of 142 late-pregnant ewes and their foetuses from two heavily infected flocks.


METHODS
Infection of ewes was determined at necropsy by histopathology and culture of tissues and mammary secretions. Antemortem tests (clinical assessment, faecal culture and serology) were also applied. Foetuses from 59 infected ewes and 47 apparently uninfected ewes were examined by culture and histopathology.


RESULTS
Five of five ewes with clinical ovine Johne's disease had infected foetuses. Only one of 54 subclinically affected ewes, and none of 47 uninfected ewes had an infected foetus. M a paratuberculosis was cultured from mammary secretions or mammary glands of only two of 76 ewes, both of which were clinical cases and had infected foetuses.


CONCLUSIONS
Although intrauterine or transmammary transmission of Mycobacterium avium subsp paratuberculosis may occur frequently in clinically affected sheep, these are less common in subclinically infected ewes. Therefore these modes of transmission are unlikely to compromise existing control programs for ovine Johne's disease on most farms, especially if programs include the immediate culling of clinically affected sheep.
Lambeth
C
C
Faculty of Veterinary Science, University of Sydney, Private Bag 3, Camden, New South Wales 2570.
Reddacliff
L A
LA
Windsor
P
P
Abbott
K A
KA
McGregor
H
H
Whittington
R J
RJ
D000818:Animals; D005260:Female; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary*; D008321:Mammary Glands, Animal / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000472:pathogenicity*; D009517:New South Wales; D010283:Paratuberculosis / Q000517:prevention & control* / Q000635:transmission*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000517:prevention & control / Q000635:transmission