Classification of induced malaria case in an elimination setting: investigation of transfusion-transmitted malaria cases.

BACKGROUND: Since the National Malaria Elimination Action Plan was launched in China in 2010, local malaria transmission has decreased rapidly. Zero indigenous cases were reported since 2017. However, after 2010, the proportion of imported cases in China increased from 45.7% in 2010 to 99.9% in 2016, and almost all provinces of China have reported imported cases in recent years. Prevention of the reintroduction of malaria into China is crucial for the maintenance of its malaria-free status. Hence, it is of utmost importance to correctly identify the source of malaria infections within the country. CASE INTRODUCTION AND RESPONSE: In 2016 and 2017, three laboratory-confirmed cases of malaria caused by Plasmodium falciparum were identified in patients with no previous travel history to endemic areas were reported in Jiangsu Province, China, where malaria due to P. falciparum was eliminated about 30 years ago. These were diagnosed after 41, 31 and 39 days of seeking treatment, respectively, and all of them had received blood transfusions. Further investigations indicated that two of the cases had received blood from foreign students (from Indonesia and Ghana), and the other had received blood from an individual who had worked in Equatorial Guinea. All three blood donors were traced, and found to be carrying asymptomatic P. falciparum infections by microscopic examination and PCR. Furthermore, five polymorphic microsatellite markers (C1M4, C4M62, C13M13, C14M17, and C13M63) were typed and used to link parasites from the donors with those of the transfusion-receiving patients. CONCLUSIONS: Three transfusion-transmitted malaria cases were identified in China, all of which were due to the transfusion of blood donated by individuals who had contracted malaria outside the country. These cases can provide a reference for those faced with similar challenges in malaria case identification and classification in other regions. In addition, a stricter screening policy including the use of appropriate detection methods for malaria parasites should be developed and adopted for blood donation in regions undergoing malaria elimination.

[Integration and demonstration of key techniques in surveillance and forecast of schistosomiasis in Jiangsu Province I Layout and effect of the demonstration sites for schistosomiasis surveillance and forecast].

OBJECTIVE: To explore and integrate the key techniques used in the surveillance and forecast of schistosomiasis in the water regions along the Yangtze River, so as to provide technical support for identifying rapidly the risk of schistosomiasis transmission and implementing control measures targeting the risk. METHODS: According to the distribution of water systems and water regions along the Yangtze River in Jiangsu Province, the demonstration sites for surveillance and forecast of schistosomiasis were set across the province, where the integration and demonstration of the techniques regarding monitoring of Schistosoma japonicum infection in sentinel mice, human and animal activities, release of forecast information, and emergency treatment of water regions at risk of infection were performed. The pattern of human and animal activities was compared with the S. japonicum infection in sentinel mice in the demonstration sites, and the operability of the release of information and emergency treatment of the risk of S. japonicum infection was evaluated. RESULTS: A total of 50 demonstration sites for surveillance and forecast of schistosomiasis were set in fixed anchor points, opening of the navigation lock to the Yangtze River, freight terminal, agritainment places, ferry, large construction places, and places for guaranteeing the Youth Olympic Games in 23 counties (districts) of 5 cities, Jiangsu Province. During the period between May. and September, 2014, the infectivity of water body was monitored by using 5 batches of sentinel mice, with a 99.06% (4,954/5,001) gross recovery rate of mice. S. japonicum infection was detected in a demonstration site, and an infected mouse was found, with a 0.02% (1/4,933) gross positive rate of sentinel mice. The field survey showed 2 088 person-times contacting water, including 91.95% (1,920/2,088) contacting water due to the production such as capturing fish, harvesting and cultivating crops, and repairing and building boats, and 8.05% (168/2 088) contacting water due to the life activity, such as fishing, washing vegetables and playing with water. The people contacted water predominantly in August and September (49.57%). A total of 859 boats containing 1,877 boatmen were observed, 68.22% (586/859) of which were fishing boats containing 1,306 fishermen (69.58%). There were 32 sheep found in 4 demonstration sites, and 3 sheep were seen in the demonstration site with infected sentinel mouse. Four blue forecasts (emergence of water contact) and one orange forecast (S. japonicum-infected sentinel mouse detected) were released across the province, with one forecast map released which showed 5 sites with fishing and one site with sheep grazing, one emergency response system initiated, mollusciciding implemented in 10 hm2 high-risk regions, 120 sheep grazed in fence, and 35 fishermen given health-education materials, schistosomiasis examination and preventive therapy. In addition, no acute schistosomiasis occurred in the demonstration site with S. japonicum-infected sentinel mice. CONCLUSIONS: The integration and demonstration of the techniques regarding monitoring of S. japonicum infection in sentinel mice, human and animal activities, release of forecast information, and emergency treatment of water regions at risk of infection provides an effective approach for the large-scale surveillance and forecast of schistosomiasis.

[Impact of implementation of Three Gorges Project on schistosomiasis endemic situation and control in Nanjing City].

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.

[Surveillance and risk assessment system of schistosomiasis in Jiangsu Province. I. Distribution of surveillance site and effectiveness of the system].

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.

[Establishment and application of quality control system for detection of schistosomiasis in Jiangsu Province I ability of serological detection among county-level personnel].

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.

[Effect of health education on schistosomiasis control in heavy endemic areas].

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.

[Prevalence of intestinal nematodes during 2004-2008 in Nanjing].

Surveys on intestinal nematode infection were conducted in 65 monitoring sites in Nanjing City during 2004-2008. Eggs in stool samples from 46226 residents were examined by modified Kato-Katz thick smear method in the 5 years. The prevalence was reduced from 3.0% in 2004 to 0.7% in 2008, decreased by 75.3%. The prevalence in rural area (2.9%) was higher than that of city (0.9%) (chi2=1024.63, P<0.01). The highest prevalence was in the group of under 10 years (5.2%) (chi2=331.18, P<0.01).

[Endemic situation of schistosomiasis at the national surveillance sites of Nanjing, 2006].

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.