The production of Mycoplasma iowae infection of turkey poults suitable for monitoring antimicrobials.

In an attempt to produce a persistent infection with M. iowae (Mi) three separate trials were conducted using strain B 11/80, a virulent strain, strain M 012-118, a recent isolate of unknown virulence, and strain Iowae 695 (I 695), the type strain. In each trial groups of 2-day-old poults were infected via the oesophagus, trachea, cloaca and directly into the lungs. Isolation during life was attempted from the oropharynx and the cloaca, and at necropsy at the end of the experiment (21 days after infection) from the trachea, lungs and airsacs, and the brain. The highest proportion of isolations were made at necropsy from the lungs and air sacs, and trachea, from birds infected with B 11/80 or M 012-118 via the lungs or B 11/80 given via the trachea. During life the proportion of isolations was lower than at necropsy but highest, overall, with B 11/80 given via the lungs or trachea and isolated from the oropharynx, or administered via the cloaca and isolated form this site. Strain I 695 was rarely isolated whatever the route of infection. There were few recoveries following infection via the oesophagus with any strain and no mycoplasmas were isolated from the brain. For the production of MI infection suitable for monitoring antimicrobials in young poults we would recommend infection with a pathogenic strain of the organism directly into the lungs.