The risk surveillance of schistosomiasis in Yunnan, 2021 / 中国热带医学

@#Abstract: Objective　To evaluate the potential transmission risk of schistosomiasis in Yunnan Province, and to provide strategic basis for the prevention and control. Methods　Based on the prevalence of schistosomiasis, the social and environmental factors that may lead to the epidemic, 1-3 villages from 3 provincial-level and 15 county-level counties (cities and districts) were selected as the evaluated villages in 2021. The risk of schistosomiasis spread was analyzed comprehensively by consulting, reviewing and collecting routine surveillance data of schistosomiasis in the villages, combined with snail and wild feces survey. The risk level was evaluated for the positive snails, positive wild feces, resident infection, average density of live snails and snail frame occurrence rate. Results　Totally 7 snail counties schistosomiasis transmission was blocked of 18 epidemic counties and the rest were eliminated counties. A total of 152 447 snail frames were investigated and 3 043 frames with snails, 15 895 snails were captured and included 15 727 live snails in the 32 evaluated villages. The total area of snail was 58.87 hm2 and the area of reoccurrence was 34.19 hm2 with snail frame occurrence rate of 2.00% and average density of live snails 0.103 2/0.11 m2, and no positive snails were found by loop-mediated isothermal amplification (LAMP) assay. A total of 1 374 wild feces were collected in 27 evaluated villages of 14 epidemic counties, mainly from cattle, dogs, sheep, equine animals, pigs and so on, all of which were negative. According to the risk assessment of epidemic spread, Yongle Village and Yongsheng Village in Eryuan County, Zhiming Village in Chuxiong City were Ⅱ risk, and the rest were Ⅲ risk. Conclusions　Although the risk of transmission is low in Yunnan Province, the risk of transmission and spread still exists. It is necessary to strengthen the risk monitoring, control of snail and effective management of livestock to prevent the rebound of the epidemic.

Axonal mRNA localization and local translation in neurodegenerative disease.

The regulation of mRNA localization and local translation play vital roles in the maintenance of cellular structure and function. Many human neurodegenerative diseases, such as fragile X syndrome, amyotrophic lateral sclerosis, Alzheimer's disease, and spinal muscular atrophy, have been characterized by pathological changes in neuronal axons, including abnormal mRNA translation, the loss of protein expression, or abnormal axon transport. Moreover, the same protein and mRNA molecules have been associated with variable functions in different diseases due to differences in their interaction networks. In this review, we briefly examine fragile X syndrome, amyotrophic lateral sclerosis, Alzheimer's disease, and spinal muscular atrophy, with a focus on disease pathogenesis with regard to local mRNA translation and axon transport, suggesting possible treatment directions.

The role of hydrogen sulfide in gastric mucosal damage.

Gastrointestinal disease is a major global threat to public health. In the past few decades, numerous studies have focuses on the application of small molecule gases in the disease treatment. Increasing evidence has shown that hydrogen sulfide (H2S) has anti-inflammatory and anti-oxidative effects, and can regulate gastric mucosal blood flow in the gastric mucosa. After gastric mucosa damage, the level of H2S in the stomach decreases. Administration of H2S can protect and repair the damaged gastric mucosa. Therefore, H2S is a new target for the repair and treatment of gastric mucosa damage. In this review, we introduce the roles of H2S in the treatment of gastric mucosa damage and provide the potential strategies for further clinical treatment.

[Analysis of Oncomelania hupensis status in schistosomiasis surveillance sites of Yunnan Province in 2015].

OBJECTIVE: To understand the Oncomelania hupensis distribution and infection status in the schistosomiasis surveillance sites of Yunnan Province, so as to provide the evidence for making the control and prevention measures. METHODS: Eighteen administrative villages were selected as the surveillance sites where the schistosomiasis endemic was serious in 18 epidemic counties, one village for one county. The snail status was investigated with the systematic sampling and environmental sampling methods, and the infection status of the snails was detected by a microscope and loop-mediated isothermal amplification (LAMP). The surveillance database was established and descriptively analyzed. RESULTS: In 2015, the total surveillance area was 1826.55 hm², and the area with snails was 55.03 hm², that was reduced by 57.70% as compared to that in 2013, and by 40.63% as compared to that in 2014. No new snail area was discovered, and also no schistosome infected snails were discovered. Totally 718,532 frames were surveyed, and the occurrence rate of frames with snails was 0.45% and the density of living snails was 0.013 9 snail/0.1 m². In the endemic controlled areas, the snail area and density of living snails were both the highest. The snails concentrated on the environments of paddy field, ditch, bottomland, small reservoir, and dry land, and the vegetations of rice, dry crop, weed and wood. The snail area, occurrence rate of frames with snails, total number of snails and number of living snails all showed a downward trend. No infected snails were found for three years. CONCLUSIONS: The Oncomelania hupensis snails have been effectively controlled in the national schistosomiasis surveillance sites of Yunnan Province. However, the comprehensive snail control measures still should be continually strengthened in order to consolidate the achivements.

[Evaluation of effectiveness of comprehensive schistosomiasis control project in Yunnan Province from 2004 to 2013].

OBJECTIVES: To evaluate the effect of comprehensive schistosomiasis control project in Yunnan Province after its implementation for ten years, so as to provide the evidence for formulating the future prevention and control strategy. METHODS: The data of the schistosomiasis comprehensive control project and the endemic situation were collected and analyzed to evaluate the control effect of the project in Yunnan Province from 2004 to 2013. RESULTS: After the comprehensive control project implementation for ten years, the Oncomelania hupensis snail area in Yunnan Province decreased from 4,364.79 hm2 in 2004 to 1,528.50 hm2 in 2013, with a reduction rate of 64.98%, and the occurrence rate of frames with snails and the density of living snails decreased from 4.71% and 0.26 snails/0.1 m2 in 2004 to 1.35% and 0.04 snails/0.1 m2 in 2013, with the reduction rates of 71.34% and 84.62%, respectively. The schistosome infected snails were found only in 2011 and 2013 since 2008. In 2013, the infection rates of human (0.0021%) and cattle (0.0209%) decreased by 99.84% and 99.44%, respectively, compared to those in 2004, and no acute schistosome infection cases were found since 2008. The 212 villages with relatively serious endemic situation (Type One, Type Two and Type Three) all declined to the slight endemic villages (Type Four and Type Five), therefore, they reached the criteria of schistosomiasis transmission controlled or interrupted. The awareness rates of schistosomiasis control among villagers and students in endemic areas were above 90% and 98%, respectively. CONCLUSION: The effect of the comprehensive schistosomiasis control project is significant in Yunnan Province, but the task to consolidate and enlarge the control results still remains a challenge.

[Molluscicidal effect of 5% powder of niclosamide ethanolamine salt granules (NEG) in field of mountainous areas in Yunnan Province].

OBJECTIVE: To evaluate the molluscicidal effect of 5% powder of niclosamide ethanolamine salt granules (NEG) in the field of mountainous areas in Yunnan Province. METHODS: The grasslands with Oncomelania hupensis snail habitats were chosen in Beideng Village, Heqing County, Yunnan Province, and were divided into 7 groups (groups of NEG 30 g/m2, NEG 40 g/m2, NEG 50 g/m2, NEG 40 g/m2 plus obstacle clearing, 50% niclosamide ethanolamine salt wettable powder (WPN) 6 g/m2, WPN 6 g/m2 plus obstacle clearing, and fresh water). The snail death rates and the densities of living snails were investigated and the results were compared in the different groups 7 d, 15 d, and 30 d after the implementation. RESULTS: Seven d, 15 d, and 30 d after the implementation, the snail death rates of the groups of NEG 30 g/m2, 40 g/m2, and 50 g/m2 were from 72.75 % to 95.83%, and the average descent rates of living snail densities were from 72.26% to 95.54%. Seven d, 15 d, and 30 d after the implementation, in the NEG 40 g/m2 group, the snail death rates were from 81.69% to 87.19%, and the average descent rates of living snail densities were from 81.42% to 87.91% ; in the NEG 40 g/m2 plus obstacle clearing group, the snail death rates were from 84.89% to 88.24% and the average descent rates of living snail densities were from 85.63% ~ 88.22%; in the WPN 6 g/m2 group, the snail death rates were from 85.23% to 86.17% and the average descent rates of living snail densities were from 85.76% to 86.05%; in the WPN 6 g/m2 plus obstacle clearing group, the snail death rates were from 88.89% to 92.10% and the average descent rates of living snail densities were from 86.71% to 92.20%. The obstacle clearing improved the molluscicidal effect. CONCLUSION: NEG has a good molluscicidal effect in the field of mountainous areas in Yunnan Province.

[Monitoring of sentinel mice and risk assessment of schistosomiasis transmission in key regions of Yunnan Province in 2014].

OBJECTIVE: To establish and perfect the surveillance and forecast system of schistosomiasis, and timely discover the suspicious high risk environments for preventing the human and livestock from schistosomiasis. METHODS: Eight villages of three counties were selected as survey points. Then, the surveillance and forecast of sentinel mice were carried out in the key water regions. The recovered sentinel mice were dissected in laboratory. The sentinel mouse serum antibodies against schistosome were detected by ELISA, the suspicious water contacts of residents and livestock were investigated and the results were analyzed, and the epidemic risk was assessed. RESULTS: Totally 300 sentinel mice were placed, the recovery rate was 94.67%, and the mortality rate was 8.80%. There were no mice with positive serum antibodies against schistosome, and the results of the dissection of all the sentinel mice were negative. The humans who contacted with the suspicious water were mainly villagers, students, children and fishermen by washing hands and feet, washing vegetables, harvesting, fishing and swimming. The Oncomelania hupensis snail areas, human infection rates, and cattle infection rates were obviously declined in recent 3 years. However, the epidemic risks still existed. CONCLUSION: Although schistosomiasis transmission was effectively controlled in the three counties, the comprehensive control measures still should be strengthened.

[Analysis of schistosomiasis endemic status of national surveillance sites in Yunnan Province, 2014].

OBJECTIVE: To master the dynamic endemic status and influencing factors of schistosomiasis in Yunnan Province, so as to provide the evidence for making the control and prevention measures. METHODS: Four villages of four schistosomiasis heavy endemic counties were selected as survey sites. Then, the serological screening and etiological tests were carried out in the residents, and the basic situations of the survey sites were investigated. The infection status of the livestock and relevant information of Oncomelania hupensis snails were surveyed. All the results were analyzed statistically. RESULTS: Totally 4310 residents were surveyed by the indirect hemagglutination assay with the examination rate of 79.68% and serum positive rate of 8.40%. The positive rate reached upwards 12.53% in Qiandian Village of Eryuan County. The serum positive rate of the female was higher than that of the male, and the positive rates of the 30 years and older age groups were higher than those of the other age groups. The serum positive rates of the peasants, migrant labourers and residents with the junior high school education level were higher. No positive feces were found. A total of 24 advanced cases were reported. No positive livestock and snails were found, and the average density of living snails was 0.023 3-0.056 6/0.1 m2. CONCLUSION: Right now, the schistosomiasis is at a low prevalence status in Yunnan Province, and the endemic situation has been effectively controlled.

[Current prevalence situation and control strategy of schistosomiasis in Yunnan Province].

OBJECTIVE: To evaluate the current prevalence situation of schistosomiasis in Yunnan Province, so as to provide the evidence for making further control strategy. METHODS: The data of schistosomiasis were collected and analyzed statistically in Yunnan Province in 2014. RESULTS: There were 7 transmission controlled counties and 11 interrupted counties in Yunnan Province in 2014, and Oncomelania hupensis snails were not found in 5 of the 11 interrupted counties for at least 5 years. In the transmission controlled areas, the schistosomiasis endemic villages, population, farm cattle, and snail areas accounted for 80.94%, 83.72%, 79.32% and 82.00% of whole schistosomiasis endemic areas in Yunnan Province, respectively. The infection source was not completely eliminated. CONCLUSION: In the transmission controlled areas, the elimination of infection source should still be strengthened; in the transmission interrupted areas, the import infection sources should be prevented.

[Investigation on infection sources of schistosomiasis in mountainous regions, Nanjian County, Yunnan Province].

OBJECTIVE: To understand the types of schisotsome infection sources and their roles in schistosomiasis transmission in mountainous endemic regions in Yunnan Province, so as to provide the evidence for implementing the comprehensive control measures based on infection source control. METHODS: Two villages of typical mountainous regions in Nanjian County were chosen for field investigation. The Oncomelania hupensis snail status was surveyed by the methods of systematic and environmental sampling. The infections of schistosomiasis were surveyed in residents with the indirect haemagglutination and the hatching method, in livestock with the hatching method and in wild animals with the anatomical method and the hatching method. The distribution and pollution status of wild faeces were investigated in the snail environments nearby villages or with livestock frequent activities. The positives of schistosomiasis in wild faeces were tested with the hatching method. The pollution index of wild feces was calculated. RESULTS: A total of 533.56 hm2 were investigated in two villages, and the area with snails was 16.52 hm2. The rate of frame with snails was 1.03%, the average density of snails was 0.07 snails/0.1 m2, and no positive snails were found. The positive rate of blood examinations of population was 1.61%, but no persons were positive with the hatching method. The infection rates were 0.90%, and 0.62% in cattle and equus, respectively, and there were no positives in other livestock. Totally 472 piles of wild feces of 6 species (human, cattle, equus, goat, pig and dog) distributed in the investigation areas, and among them, the densities of wild feces of cattle, equus, and dog were 7.2, 4.3 piles/hm2, and 2.1 piles/hm2 respectively, being relatively higher than others. The hatching positive rates of wild faeces of cattle, equus, and dog were 2.27% (3/132), 2.63% (2/76), and 3.70% (1/27), respectively. The relative pollution indexes of wild faeces of cattle, equus, and dog were 80.68%, 15.89%, and 3.43%, respectively. CONCLUSIONS: After schistosomiasis transmission is controlled, the potential epidemic factors still remain in the mountainous endemic regions of schistosomiasis in Yunnan Province. The cattle are still the most infection source of schistosomiasis, but equus and dog as infection sources should be not neglected. We should extend the investigation and monitor scope of the infection sources, and carry out scientific and feasible control technique and management measures.

[Conditions of schistosomiasis laboratories at county level].

OBJECTIVE: To understand the conditions of schistosomiasis laboratories at county level, so as to supply the information for diagnostic capacity building. METHODS: A questionnaire survey was conducted at 40 random selected counties which were in charge of national surveillance for schistosomiasis. The information of staffs, areas of laboratories, equipment configuration and diagnostic methods from each laboratory were collected. The serum specimens and Kato-Katz thick smears from the national surveillance sites were randomly selected and retested by provincial staffs to evaluate the testing ability of the personnel. RESULTS: The average age of laboratory staffs was 40.93 +/- 9.56 years old, 69.39% of staffs were older than 35 years, 86.22% of them had education background below bachelor degree. Except missed professional titles of 4 persons, the staffs with primary, middle and high professional titles accounted for 56.63%, 39.29% and 2.04%, respectively. The laboratory areas varied greatly while independent schistosomiasis stations had the lowest areas with 52.81 +/- 40.08 m2, and the equipment configurations of laboratories were in a low level. The consistency rates of primary test and reexamination for serum specimens and thick smear slides were 95.89% and 99.53%, respectively, with the Kappa value over 0.90. Nine immunodiagnostic kits were used in these laboratories, and Kato-Katz technique and miracidium hatching technique were the main parasitological methods. CONCLUSIONS: The personnel structure of laboratories at primary prevention and treatment facilities for schistosomiasis is unreasonable, while the basic infrastructure of laboratories is backward and the use of diagnostic assays/methods is disordered. The diagnostic capacity building should be strengthened, and the construction and management of schistosomiasis laboratories should be standardized.