Often such a big outbreak starts with a couple of cases.

"This is the first big E. coli outbreak that we have had here," he added.

It was rewarded with the biggest outbreak of fires since 1986, as the number reached 182, almost triple the level in 1993.

But there was a big outbreak in the Midwest following a very dry summer.

- Union leaders have announced plans for what could be the biggest outbreak of industrial action since the 1926 General Strike.

Then effective vaccines largely eliminated big outbreaks, driving the national caseload down to an average of 265 in recent years.

The probability of a big outbreak is low.

Vets are having to deal with the biggest outbreak of distemper in ten years.

It's the biggest outbreak in the city in more than a decade.

Flu hunters are expected to forestall any big outbreak.