Josepha DeLay

Animal Health Laboratory, University of Guelph, Guelph, ON

AHL Newsletter 2023; 27:14.

The CanSpot ASF program remains open for African swine fever (ASF) surveillance testing of eligible swine cases submitted to the AHL.  The eligibility criteria for testing include a broad range of clinical and pathologic scenarios (Table 1).  To date in 2023, these criteria have been met for an average of 54% of swine pathology submissions to the AHL.  Unfortunately, only 35% of eligible cases included appropriate tissue samples (fresh spleen) for ASF PCR testing.  Surveillance testing could not be pursued on the remaining 65% of eligible cases due to the lack of appropriate samples.

A proactive surveillance program is only as successful as the quality and magnitude of sampling.  More robust ASF surveillance testing in Ontario swine could be accomplished if fresh spleen were included with every field postmortem case submitted to the AHL.  In many cases, eligibility for ASF surveillance testing is not suspected based on the clinical scenario, although subsequent histopathology findings often do meet eligibility criteria.  For example, nursery pigs may have clinical pneumonia without a significant increase in mortality, in which case the group would not be eligible for CanSpot ASF testing.  However, the same group may have histologic evidence of septicemia or fibrinous pleuritis that would qualify for testing.  Sampling spleen at the time of field necropsy in every case would allow ASF surveillance testing to proceed for all eligible cases, including those in which eligibility was not expected based on clinical findings.  

Please remember to include pertinent clinical history and gross postmortem findings on the submission form, such as increased mortality, fibrinous pleuritis or pericarditis, or splenic torsion.  These findings will influence eligibility for ASF surveillance testing.

Trace-back information (PID, or the physical address of the herd) must also be available in order to proceed with CanSpot ASF surveillance testing. 

Thank you to all swine practitioners who have submitted samples and agreed to ASF surveillance testing. Please continue to include fresh spleen with all field necropsy cases.   AHL

Table 1. Clinicopathological presentations eligible for CanSpot ASF testing in swine.