[Investigation on food contamination with parasites in Shanghai market].

OBJECTIVE: To understand the contamination status of food with parasites in Shanghai market, so as to provide the evidence for formulating the surveillance strategy in parasitic diseases and provide the technical support in the food safety. METHODS: The freshwater fish products, marine products, vegetables, snails and frogs were sampled with the cluster random method in the farmer-trades and supermarkets of the 18 districts in Shanghai City during 2005-2010 period, and all the specimen were screened by the digestion method, or crushing method or dissection method or saline floatation method to check the parasite metacercaria or larvae or eggs. RESULTS: A total of 5 185 specimen in 23 species of fishes were screened in fresh-water products, with parasite infection rate of 1.93%. About 4 033 specimens of 20 species of fishes and shrimps were screened and 1.76% of samples were infected with Clonorchis sinensis. Among all kind of fishes, the highest infection rate was 7.83% (48/613) in Pseudorasbora parve. No any infected specimen was found among 1 152 specimen of fresh water crustacean screened. Anisakis spp. were found in 12.7% of 433 specimens of 23 species of seawater products, among them, the higher infection rate of Anisakis spp. was found in Pneumatophorus japonicas and Trichiurus haumela with their infection rates of 50.00% (13/26) and 23.46% (42/179), respectively, which much higher than those found in other seawater products (P < 0.01). In 37 kinds of vegetables, the parasite eggs were found in one of 428 specimens with its infection rate of 0.47%, while no any parasite egg was found in 103 specimens of 10 kinds of fruits. No any Angiostrongylus cantonensis larvae were found in 330 snails, 31.37% of 102 frogs were found infected with Spirometra mansoni spargana. No any contamination with parasites was found in 116 meat specimens of pigs and cattle. In the same time, the intestinal parasite infection rate of residents was 0.42% (131/31 239). CONCLUSIONS: It is found that some of foods in Shanghai markets are contaminated with parasites. Therefore, it is necessary to enforce the activities in health education as well as to take integrated prevention measures in order to ensure the food safety.

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

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

[Prevention and control of intestinal nematode infection in Shanghai].

OBJECTIVE: To evaluate the current status of intestinal nematode infection in Shanghai and make recommendations for further control activities. METHODS: Retrospective review of the control program was made based on the change of nematode prevalence in Shanghai area since the 1950s, and challenges under the current situation were analysed. RESULTS: The intervention measures included chemotherapy, health education, sanitary disposal of human excreta and safe water supply. With the control strategy, socio-economical development and the change of farming patterns, the prevalence of intestinal nematode infection in population was reduced by 88.5%, from 62.6% in 1955 to 8.2% in 2000. Among them, ascaris infection decreased by 89.0%, from 52.1% to 6.3%, hookworm infection decreased by 99.0%, from 12.9% to 0.1%, but pinworm infection was still as high as 18.9% in 1999. CONCLUSION: Prevalence of nematode infection in Shanghai was considerably reduced. To match it with the current socio-economical development in the Municipality, however, more needs to be done. Sustainable control activities and surveillance are recommended.