Introduction
Infection with Mycoplasma iowae is seen in turkeys, and can occur in other poultry and wild bird species. Infection occurs via the conjunctiva or upper respiratory tract and transmission among poults may be vertical, venereal or horizontal.
Signs
- Embryonic mortality.
- Reduced hatchability.
Post-mortem lesions
- Stunted embryos with hepatitis and enlarged spleens, some with down abnormality. Leg lesions can be shown in inoculated birds but do not seem to occur naturally, perhaps because all affected embryos fail to hatch.
Diagnosis
Isolation and identification of the causative organism from dead-in-shell embryos.
Treatment
Pressure differential dipping has been used where breeder flocks are infected. Specialised dip tanks are subjected to negative pressure which partially collapses the air cell of the submerged eggs. When the vacuum is released the eggs draw in antibiotic solution which is subsequently absorbed through the shell membranes. This can increase hatchability by 5-10% in this situation. Antibiotics that have been used are tylosin and enrofloxacin.
Prevention
Eradication of the infection from breeding stock, purchase of M.i.-free stock, maintenance of this status by good biosecurity. For eradication purposes egg injection provides more consistent dosing per egg than does egg dipping.