There are times when the clinical signs of disease become too great to handle and therefore a radical rethink of disease control needs to be considered.

There are four routes to consider:

1. Mass medication
2. Change in pig flow - which could be to a completely different batching system (For example: Three week batching)
3. Partial depopulation
4. Full depopulation and repopulation

In any attempt to control a major disease problem, on-farm biosecurity and excellent health management must be combined with a medication program.