The BBC's Tim Luard presents China's fight against the Sars virus as

a Maoist-style "patriotic extermination campaign" against civet cats, badgers, raccoon dogs, rats and cockroaches.

Then he goes on to compare it to Mao's "four pests" campaign, in particular the anti-sparrow campaign:

Villagers were told to rush out to the fields, banging on pots and pans and screaming at the tops of their voices.

The sparrows took to the air, and as the pandemonium continued, stayed there, too terrified to land, until they dropped dead from exhaustion.

The only trouble was that sparrows are a vital link in the food chain and are particularly fond of locusts. With no sparrows left to eat them, there was a plague of locusts, the crops were ruined and millions of people died in the ensuing famine.

That's not right; other factors were also involved, like collectivization:

In October 1955, Mao ordered Chinese peasants to be organized into collectives of 100-300 families. He would later order even larger collectives to be organized. As a result, in 1956 grain yields fell by up to 40 percent. Not satisfied, Mao ordered farmers to put into practice several Lysenko-ist practices, which combined with the collectivization, decimated Chinese agriculture.

Not to defend the current sillines, but the anti-sparrow campaign was only one factor.