Search

Objective: To evaluate the effectiveness of Oncomelania snails control following the implementation of integrated schistosomiasis control measures in river channels connecting the Yangtze River in endemic areas of Nanjing City., Methods: The river channels connecting the Yangtze River with snails in Nanjing City were selected as the study pilots. The integrated schistosomiasis control measures implemented in the study pilots were investigated by means of retrospective analyses and field surveys from 1998 to 2019, and the effectiveness of snail control was evaluated., Results: Integrated control measures with emphases on environmental improvements including water resource projects for schistosomiasis control were implemented in the study pilots during the period from 1998 to 2019, including river bank concretion with 84.51 km in length, marshland cutting and dredging with 50.41 km in length, building 2 sluices and 3 overflow dams, digging one floodway and snail control with chemical treatment that covered an area of 3 370.80 hm 2 . No Schistosoma japonicum infection had been detected in snails since the completion of the integrated control measures. In addition, snails had been eliminated in 6 river channels connecting the Yangtze River until 2019, with the snail habitats reducing from 214.33 hm 2 to 52.22 hm 2 in 10 river channels connecting the Yangtze River and the snail density reducing to below 0.1 snails/0.1 m 2 in snail-breeding river channels connecting the Yangtze River., Conclusions: The integrated schistosomiasis control measures with emphases on environmental improvements may effectively control snail breeding and spread in rivers connecting the Yangtze River in endemic areas of schistosomiasis; however, the maintenance of the project and snail surveillance and control should be intensified following the completion of the integrated schistosomiasis control measures.

Objective: To understand the changes of hydrological regime in the Yangtze River and schistosomiasis endemic situation in Nanjing City after the implementation of Three Gorges Project., Methods: The data of hydrological regime of the Yangtze River, schistosomiasis epidemic situation, and Oncomelania hupensis snail status were collected and analyzed in Nanjing City from 2002 to 2012., Results: After the implementation of the Three Gorges Project in 2003, the water level of the Yangtze River slightly rose from January to April, the average water levels in May and August both reduced compared with those in 2002, and the time of water withdrawal was moved up. The water level of the Yangtze River slightly reduced from November to December. The endemic situation of schistosomiasis showed a decline tendency in the areas along the Yangtze River in Nanjing City. In 2012, the rates of human and bovine infected with Schistosoma japonicum both reduced by 100% as compared with those in 2002, and the snail area, infected snail area and snail density were reduced by 48.45%, 100% and 95.76% respectively as compared with those in 2002., Conclusion: After the implementation of the Three Gorges Project, the schistosomiasis endemic situation shows a decline tendency in the areas along the Yangtze River in Nanjing City, but the long-term monitoring still need to be carried out.

Objective: To establish the surveillance and risk assessment system of schistosomiasis in Jiangsu Province, so as to provide technical support for timely understanding of the risk of schistosomiasis transmission and implementation of targeted control measures., Methods: The surveillance sites of schistosomiasis were assigned according to the epidemic status and endemic type of schistosomiasis as well as the characteristics of the water system, and the prevalence of Schistosoma japonicum in humans and domestic animals, and snail status were investigated. In addition, the quality control of serum detection of S. japonicum infections was performed. The prevalence of human and animal S. japonicum infections, snail status and missing diagnosis of serum detection were analyzed and compared among regions., Results: A total of 27 surveillance sites of schistosomiasis were set up in 26 counties of 10 cities, Jiangsu Province, including 14 sites in transmission-interrupted villages and 13 sites in transmission-controlled villages, and 15 sites in marshland and lake regions, 9 sites in plain regions with water network and 3 sites in mountainous region. In the 27 surveillance sites, a total of 16 617 residents were screened for S. japonicum infection by using dipstick dye immunoassay (DDIA), and 326 were sero-positive, with a sero-prevalence of 1.96% (2.17% for men and 1.8% for women). Of the 326 individuals undergoing parasitological examination, 2 positive cases were detected in the marshland and lake region, with a S. japonicum human prevalence of 0.01%. Of the 762 floating population detected, 10 were positive for blood test, with a sero-prevalence of 1.31%, and no egg-positive individuals were detected. No infection was found in the 476 domestic animals. Of the 746 settings surveyed, a total of 240.7 hm2 snail area was detected, with a mean snail density of 0.06 snails/0.1 m2, and no infected snails were found. There were 780 quality-control sera detected in 26 surveillance sites of schistosomiasis, and the gross coincidence rate was 95.13%, with misdiagnosis rate of 1.28% and missing diagnosis rate of 19.23%., Conclusion: The surveillance sites of schistosomiasis show reasonable distribution in Jiangsu Province, and the endemic situation of schistosomiasis appears a low level in the whole province.

Objective: To evaluate the ability for serological screening of schistosomiasis among county-level personnel, so as to provide the evidence for establishing the quality control system of field detection of schistosomiasis., Methods: The standard serum panel was prepared for the quality assessment of schistosomiasis diagnostic capability, and detected by county-level personnel in the endemic field simultaneously using single-blind method. The rates of coincidence, misdiagnosis and missed diagnosis were calculated compared with the standard results., Results: Totally 780 samples of standard serum were detected in 26 counties, and showed 134 positive and 646 negative samples. The rates of coincidence, misdiagnosis and missed diagnosis were 95.13%, 1.28% and 19.23%, respectively, and there was a significant difference between the detection results and the standard results (chi2 = 11.6053, P = 0.0007). Among the 26 counties investigated, the misdiagnosis occurred in 5 counties (19.23%) and missed diagnosis occurred in 21 counties (80.77%). The misdiagnosis rate and missed diagnosis rate of serological screening of schistosomiasis were 0-2.08% and 16.67%-33.33% in beach, hilly, water net and marshland endemic areas, respectively, and no significant differences were found in the misdiagnosis rate and the missed diagnosis rate among various types of endemic areas (chi2 = 1.590 and 1.757, P = 0.6671 and 0.6244). The rates of misdiagnosis and the missed diagnosis were 1.14% and 1.39%, and 18.18% and 20.00% in the schistosomiasis transmission-controlled and the schistosomiasis transmission-interrupted areas, respectively, and no significant differences were found in the misdiagnosis rate and missed diagnosis rate between the schistosomiasis transmission-controlled and transmission-interrupted areas (chi2 = 0.008 and 0.001, P = 0.931 and 0.974)., Conclusions: The missed diagnosis is a major cause for the reduction of quality of schistosomiasis detection at the county level in Jiangsu Province, and the coincidental detection of schistosomiasis with standard serum in the field is one of effective approaches for the control of the quality of schistosomiasis detection.

This paper described the evaluation on the effect of health education on schistosomiasis control in a pilot where a series of interventions were conducted, so as to provide the effective strategy of health education for improving schistosomiasis control.

Three endemic villages were selected as the national surveillance sites and Schistosoma japonicum infection in residents and livestock was investigated in 2006. The positive rate of serological (IHA) and stool examinations was 10.06% (307/3,053) and 0.13% (4/3,053) for local residents, 10.8% (7/65) and 0 (0/7) for moving people respectively. No infected livestock was found.