Hunting down the H5N1 virus

What is the root cause of the outbreak?

Although the infected processing plant reopened last week, government investigators are still trying to root out the cause of H5N1 virus outbreak in Suffolk, which led to the culling of 160 000 birds earlier this month.

Initially, the finger of blame had pointed to the infected droppings of migrating wild birds. There had been an outbreak of H5N1 among captive geese in the Csongrád region of Hungary in January, but there was no obvious link to the outbreak at the Holton farm, which is owned by UK poultry tycoon Bernard Matthews.

By the eighth day of the outbreak, genetic tests confirmed that the Suffolk virus was the same pathogenic Asian strain found in Hungary. That in itself didn't prove that there was a direct link; the infection still may have come from a third country. But it had also become clear that Matthews not only had a processing plant in Hungary but that a consignment of partly processed turkeys, originating 30 miles from the source of the Csongrád outbreak, had been delivered to the Suffolk plant days before birds there had started getting sick.

The key question asked in the …