Syn: Mycoplasmal pneumonia

Diagnosis

Identification of Mycoplasma hyopneumoniae infection in a herd by ELISA serology, or in individual animals by PCR on affected lung.

ELISA serology can provide a profile of the M. hyopneumoniae infection status of the herd. Blood samples may be collected from the abattoir or from a subpopulation of animals in the piggery. Seroconversion after natural challenge can take 9 weeks, so targeting older pigs for serological profiling is more cost-efficient.

Carriage in the live animal can be detected by PCR from nasal swabs. However, nasal excretion is variable, so a negative swab PCR on a single occasion is of limited diagnostic value.

Specimens required

Live pigs:

1. Serum (or heparin plasma) samples from affected pigs and their cohorts for ELISA. Since this is a herd disease, the results should be looked at in this light rather than on an individual animal basis. For this reason, it is recommended that about 30-40 sera be submitted on each occasion.
2. Nasal swab material collected into sterile PBS for PCR (if required; may be cost prohibitive)

Slaughter pigs:

1. Fresh lung samples submitted chilled or frozen for PCR. For PCR, samples taken from the affected site and measuring 1 cm³ is sufficient.
2. Fixed affected lung for histopathology
3. Culture is expensive and not routinely available. For samples where an isolate is required (e.g. for intensive investigation or research), these must be fresh and reach the laboratory within a few hrs of slaughter, and preferably come from well developed lesions.