[Potential risks for transmission of schistosomiasis caused by mobile population in Shanghai]

To understand the potential risk for schistosomiasis transmission caused by introduction of infection source from mobile population in Shanghai.

Field investigation was conducted in the suburb of Shanghai City by screening the mobile population living in Shanghai for more than 1 month and over 1 years old in a procedure of interviewing, serum indirect hemagglutination (IHA) test, and then fecal examination to detect the eggs with nylon sedimentation approach for those IHA positives.

Among 2,931 mobile people investigated, 1,575 were male (53.74%) and 1356 were female(46.26%); 138 out of 2931 were positive in IHA test (4.71%). 1938 (66.12%) out of 2 931 came from Schistosoma japonicum-endemic provinces and its positive rate in mobile population (5.99%) was significantly higher than those from the transmission-interrupted provinces (2.6%) (chi2=10.28, P<0.01), and those from non-endemic provinces (1.68%) (chi2=12.86, P<0.01). The 138 IHA positives all showed negative in fecal examination. In accordance with the serum positive rate and egg-infection rate in the national reporting system in 2004, it was estimated that there would be about 13 356 and 1 699 potential serum positive cases respectively from endemic area and transmission controlled area, and about 2,168 and 255 egg-positive cases from the two kind areas respectively, majority of the cases were from Anhui Province.

Schistosomiasis transmission risks potentially exist in Shanghai suburb due to the introduction of infected mobile people from other endemic provinces, and a surveillance system and quick response are needed for the possible re-emergence of the disease.