BEIJING -- The Chinese Ministry of Health on Thursday issued an emergency response plan for dealing with mass illness of unknown origin.

Mass illness of unknown origin is defined as at least three cases with the same clinical symptoms occurring in one place in a period of two weeks. The cases might be severe or fatal and the symptoms cannot be explained by doctors above county hospital level.

The place could be a medical institution, village, community, construction site or school, and the illness may be an infectious disease, poisoning or other unknown illnesses.

The plan classifies incidents according to three levels of severity, and requires local governments to work out graded emergency response measures.

Any individual or organization is entitled to report a mass illness of unknown origin to health departments under the State Council or local health authorities.

"Local medical institutions or medical practitioners must report incidents by phone or fax to local health authorities within two hours, and those able to make on-line reports must do so immediately," the plan states.

It notes that medical staff who reach the scene where infectious illness is reported must take protective measures, quarantine patients and if necessary suggest that the area be cordoned off.

Schools or factories where the incident happened should suspend classes or production if necessary, and relatives of the patients or those in close contact with them should be placed under medical observation.

The bodies of patients or animals must be disinfected strictly and samples should be collected in accordance with relevant regulations.

Items, places, environment, animals and plants at the scene must be disinfected, and poultry and livestock in the area must be kept in enclosed places.

If necessary, wild animals or poultry which might be infected should be controlled or slaughtered after approval from the local government.

The plan recommends raising public awareness by education, and requires that medical waste and quarantined items be properly dealt with when at-scene treatment is complete.