Table 3 National criteria for control and elimination of schistosomiasis in P.R. China

Stage I.

1. The infection rate in residents should be less than 5%.

Morbidity control of schistosomiasis

2. The infection rate in domestic animals should be less than 5%.

3. No outbreak of acute schistosomiasis cases.

Stage II.

1. The infection rate in residents or domestic animals should be less than 1%.

Transmission control of schistosomiasis

2. No acute schistosomiasis case infected locality.

3. No infected Oncomelania snail should be detected for at least 2 successive years.

4. Data reflecting the changes in human and domestic animal infections and in snail examinations at administrative village level should be available.

Stage III.

1. No new infection should be found either in human or in domestic animals for 5 successive years.

Transmission interruption of schistosomiasis

2. No Oncomelania snail should be found after careful surveys for at least 2 years.

3. Data and documents, and plans and measures for surveillance and consolidation of the control work should also be available.

Stage IV.

If no new infection in human and domestic animals has been detected for 5 successive years after reaching the criteria of transmission interruption, the area can be declared as an area of elimination for schistosomiasis, whereas consolidation and surveillance of the control work should be continued.

Elimination of schistosomiasis