Bluetongue, which can kill up to 50 percent of the sheep in infected flocks, has not appeared on mainland Spain in more than 40 years.

Under the Zoonoses Order 1989, the ministry can slaughter any infected flock.

It also called for a plan to protect workers with vaccines and flu drugs if infected flocks needed to be culled.

Virus-bearing material can be picked up on shoes and clothing and carried from an infected flock to a healthy one.

It is true that, during the 1980s, the number of newly reported infected flocks per year did increase.

Would anyone be willing to say that the program is finally beginning to work because the reported number of newly infected flocks has declined?

Culling of infected birds is normally performed in infected commercial flocks.

These cause diarrhoea with progressive emaciation and there may be high mortality in heavily infected flocks.

Vietnam has scaled back its culling of potentially infected flocks, mostly because there is no money to compensate farmers.

(Vietnam stopped killing potentially infected flocks when money ran out.)