At least seven species of exotic animals found in Guangdong province are known to carry the corona virus that causes Sars. More than a few of them, including the civet cat, are also favourites of gourmets and are popular fare during the winter months. Now that the suspected case in Guangzhou has been confirmed and similarities between the patient's infection and those seen in civets has been established, it makes sense for the local authorities to turn their attention to stopping the sale and consumption of these animals.
Wild animal markets have been shut and the slaughter of more than 10,000 civets - plus badgers and raccoons, which are of the same animal family - has been ordered. These steps may be necessary - although we suspect they are designed to make it look as though the authorities are doing all they can to stop Sars. But stopping the disease is not so simple. In any case, caution has to be used in the slaughter process, and other measures will be required if the threat of Sars moving to humans is to be contained.
One World Health Organisation expert has said it is possible that transmission happens during slaughtering. Often, the animals are killed in the markets while customers watch. Blood and other debris are allowed to drop to the floor, and the areas are cleaned up by hosing them down with water. The process may not be too different at hotels and restaurants, except that the slaughter happens in an area away from where the customer dines.
A WHO study found that more than one-third of those who fell ill with the Sars virus before February last year were workers who handled, killed or sold such animals. Many such workers have also tested positive for Sars antibodies, indicating they have been exposed to Sars and built up immunity. While researchers are not certain about the exact method of transmission or under what circumstances it is likely to occur, almost everyone agrees that the wild animal markets and the restaurants where these delicacies are consumed are places where those conditions could come together again to produce another outbreak.
But if the risk of infection during slaughter is high, adequate controls should be in place as Guangdong follows through with its mass cull.
After the cull, there will still be an unquantified risk from other reservoirs of the Sars virus, on farms and in the wild - and there will still be demand for such game. Lessons can be drawn from last year's ban on the sale and consumption of 56 species, which lasted until August. Stiff fines and spot checks did not prevent a thriving underground trade. Some restaurants still served the animals - they simply did not put them on the menu.
