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1.
Article in Chinese | WPRIM | ID: wpr-837610

ABSTRACT

ObjectiveTo investigate the factors affecting the degradation of niclosamide in the soil, so as to provide the evidence for the assessment of the environmental safety in the field snail control with niclosamide. MethodsA high performance liquid chromatography was established for the determination of niclosamide in the field. Then, the degradation of niclosamide was investigated in soils with different moistures (10%, 30%, 50%, 70% and 90%), temperatures [(15 ± 1), (25 ± 1), (35 ± 1) °C], initial concentrations (1, 5, 10 mg/kg) and in sterilized and non-sterilized soils. In addition, the degradation of niclosamide was fitted with the first-order kinetics equation, and the degradation half-life was calculated. Results The niclosamide residues gradually decreased over time in soils with different moistures, and a higher rate of degradation was seen in soils with a higher moisture. The degradation half-life of niclosamide reduced from 4.258 d in the soil with a 10% moisture to 2.412 d in the soil with a 90% moisture. The niclosamide residues gradually decreased over time in soils with different temperatures, and a higher rate of degradation was seen in soils with a higher temperature. The degradation half-life of niclosamide reduced from 4.398 d in the soil with a temperature of (15 ± 1) °C to 2.828 d in the soil with a temperature of (35 ± 1) °C. The degradation half-lives of niclosamide were 3.212, 3.333 d and 3.448 d in soils containing niclosamide at initial concentrations of 1, 5 mg/kg and 10 mg/kg, and > 30 d and 3.273 d in sterilized and non-sterilized soils. Multiple linear regression analysis revealed that soil microorganisms (P = 0.010), moisture (P = 0.000) and temperature (P = 0.002) affected the half-life of niclosamide degradation. Conclusions The degradation of niclosamide in soils fits the first-order kinetics equation, and presence of microorganisms, a high temperature and high moisture may accelerate the degradation of niclosamide in the soil.

2.
Article in Chinese | WPRIM | ID: wpr-819002

ABSTRACT

Schistosomiasis was once heavily endemic in Jiangsu Province. Following the control efforts for several decades, schistosomiasis was almost eradicated in all endemic counties in Jiangsu Province in 1980, and transmission control was achieved in the province in 2011. According to the principle of “implementing the control measures with adaptation to local circumstances and guiding the control programs with classified interventions”, an integrated strategy with emphasis on the management of both infectious sources and snails has been recently employed for schitsosomiasis control in Jiangsu Province. In addition, a sensitive and highly effective surveillance system has been built and the application of novel techniques and information construction has been intensified to effectively interrupt the transmission of schistosomiasis in the Province. Transmission interruption of schistosomiasis was achieved in all endemic counties in Jiangsu Province. The paper summarizes the endemic situation of schistosomiasis, progress of schistosomiasis control, and major schistosomiasis control measures implemented during the stage of transmission interruption in Jiangsu Province.

3.
Article in Chinese | WPRIM | ID: wpr-818949

ABSTRACT

Objective To compare the difference of fertility of Biomphalaria glabrata snails between self-fertilization and cross-fertilization and to observe the circadian rhythm of laying eggs, the effect of light on laying eggs and the tolerance of the snail to water and food deficiency, so as to provide the evidence for control and elimination of B. glabrata snails in the field. Methods Under laboratory conditions, a single B. glabrata egg for self-fertilization was separated and hatched individually, and young snails were raised in different plastic boxes individually. The eggs for cross-fertilization were hatched and the young snails were fed in the same plastic box. The ability of spawn, the development of the eggs, and the number of snails growing from young to adult snails were compared between the self-fertilization and cross-fertilization. The snails were in the water under four environments, all day illumination, all day without illumination, daytime lighting and night without illumination, and daytime without illumination but night lighting. The eggs were collected and counted daily. The circadian rhythm of spawn and the effect of illumination on spawn were observed. The adult snails were divided into 6 groups and exposed to the environments with relative humidity of 0, 65%, 87% and 100%, respectively. The survival rates of the adult snails exposed to the different environments after different time were observed. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were observed. Results In the 25 °C water, the average laying egg number for 15 days per snail was (8.77 ± 16.92) eggs/snail in the self-fertilization snail. The average laying egg number for 15 days per snail was (149.71 ± 142.28) eggs/snail in the cross-fertilization snails. There was a significant difference between the self-fertilization snail and cross-fertilization snail (t = 0.999 999, P < 0.01). The hatching rate and reproductive maturation rate of the self-fertilization snails and cross-fertilization snails were 50.1% and 78.9%, and 19.3% and 3.8%, respectively, There was a significant difference (the hatching rate: χ2 = 18.18, P < 0.01, the reproductive maturation rate: χ2 = 11.83, P < 0.01) . In the natural environment of daytime with illumination and nighttime with darkness, the amount of laying 20 eggs of B. glabrata snail was (944.07 ± 392.53) eggs/day during a whole day, among them the amount of laying eggs during daytime account for 10.1% and the amount of laying eggs during nighttime account for 89.9%, and the laying egg was given priority to with the night. The above results suggested that the dark environment was conducive to B. glabrata snails to lay eggs. The above results suggested that light can promote the increase of spawning of B. glabrata. When B. glabrata was exposed to the environments with the relative humidity of 0, 65%, 87% and 100% at 25 °C, respectively, and the longest survival times of snails were 7, 70, 150 d and 100 d, respectively. In the 25 °C water, the snails could survive for 50 days without food. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were 100%, 100%, 100%, 100%, 70%, 30%, 0, 0, 0 and 0, respectively. Conclusions B. glabrata can achieve the reproductive process by cross-fertilization or self-fertilization. There is a significant difference in reproductive ability between the cross-fertilization snail and self-fertilization snail, cross-fertilization is stronger than self-fertilization, but the rate of reproduction in the self-fertilization is higher than that in the cross-fertilization. It is indicated that B. glabrata that survive after the dry season plays an important role in the maintenance of local snail populations and transmission of schistosomiasis mansoni.

4.
Article in Chinese | WPRIM | ID: wpr-818582

ABSTRACT

Schistosomiasis was once heavily endemic in Jiangsu Province. Following the control efforts for several decades, schistosomiasis was almost eradicated in all endemic counties in Jiangsu Province in 1980, and transmission control was achieved in the province in 2011. According to the principle of “implementing the control measures with adaptation to local circumstances and guiding the control programs with classified interventions”, an integrated strategy with emphasis on the management of both infectious sources and snails has been recently employed for schitsosomiasis control in Jiangsu Province. In addition, a sensitive and highly effective surveillance system has been built and the application of novel techniques and information construction has been intensified to effectively interrupt the transmission of schistosomiasis in the Province. Transmission interruption of schistosomiasis was achieved in all endemic counties in Jiangsu Province. The paper summarizes the endemic situation of schistosomiasis, progress of schistosomiasis control, and major schistosomiasis control measures implemented during the stage of transmission interruption in Jiangsu Province.

5.
Article in Chinese | WPRIM | ID: wpr-818497

ABSTRACT

Objective To compare the difference of fertility of Biomphalaria glabrata snails between self-fertilization and cross-fertilization and to observe the circadian rhythm of laying eggs, the effect of light on laying eggs and the tolerance of the snail to water and food deficiency, so as to provide the evidence for control and elimination of B. glabrata snails in the field. Methods Under laboratory conditions, a single B. glabrata egg for self-fertilization was separated and hatched individually, and young snails were raised in different plastic boxes individually. The eggs for cross-fertilization were hatched and the young snails were fed in the same plastic box. The ability of spawn, the development of the eggs, and the number of snails growing from young to adult snails were compared between the self-fertilization and cross-fertilization. The snails were in the water under four environments, all day illumination, all day without illumination, daytime lighting and night without illumination, and daytime without illumination but night lighting. The eggs were collected and counted daily. The circadian rhythm of spawn and the effect of illumination on spawn were observed. The adult snails were divided into 6 groups and exposed to the environments with relative humidity of 0, 65%, 87% and 100%, respectively. The survival rates of the adult snails exposed to the different environments after different time were observed. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were observed. Results In the 25 °C water, the average laying egg number for 15 days per snail was (8.77 ± 16.92) eggs/snail in the self-fertilization snail. The average laying egg number for 15 days per snail was (149.71 ± 142.28) eggs/snail in the cross-fertilization snails. There was a significant difference between the self-fertilization snail and cross-fertilization snail (t = 0.999 999, P < 0.01). The hatching rate and reproductive maturation rate of the self-fertilization snails and cross-fertilization snails were 50.1% and 78.9%, and 19.3% and 3.8%, respectively, There was a significant difference (the hatching rate: χ2 = 18.18, P < 0.01, the reproductive maturation rate: χ2 = 11.83, P < 0.01) . In the natural environment of daytime with illumination and nighttime with darkness, the amount of laying 20 eggs of B. glabrata snail was (944.07 ± 392.53) eggs/day during a whole day, among them the amount of laying eggs during daytime account for 10.1% and the amount of laying eggs during nighttime account for 89.9%, and the laying egg was given priority to with the night. The above results suggested that the dark environment was conducive to B. glabrata snails to lay eggs. The above results suggested that light can promote the increase of spawning of B. glabrata. When B. glabrata was exposed to the environments with the relative humidity of 0, 65%, 87% and 100% at 25 °C, respectively, and the longest survival times of snails were 7, 70, 150 d and 100 d, respectively. In the 25 °C water, the snails could survive for 50 days without food. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were 100%, 100%, 100%, 100%, 70%, 30%, 0, 0, 0 and 0, respectively. Conclusions B. glabrata can achieve the reproductive process by cross-fertilization or self-fertilization. There is a significant difference in reproductive ability between the cross-fertilization snail and self-fertilization snail, cross-fertilization is stronger than self-fertilization, but the rate of reproduction in the self-fertilization is higher than that in the cross-fertilization. It is indicated that B. glabrata that survive after the dry season plays an important role in the maintenance of local snail populations and transmission of schistosomiasis mansoni.

6.
Article in Chinese | WPRIM | ID: wpr-815892

ABSTRACT

Schistosomiasis is one of zoonoses (diseases that are naturally transmitted between vertebrate animals and human),and it is widespread in tropical and sub-tropical regions. It is one of the important infectious diseases that the World Health Organization plans to eliminate. Hybridization within Genus Schistosoma is an emerging public health concern in our changing world.Schistosoma spp. are dioecious trematode, in which there are lots of species infecting human and animals. Several schistosome species also overlap in their geographical and host range, which allows male and female schistosomes of different species to pair within their definitive hosts. The hybridization among different species and the production of dominant hybrid species and changes of their biological characteristics, such as host selectivity, fertility and infectivity, can lead to the evolution of schistosoma species, regional distribution of the population, the changes of epidemic patterns, and pathogenicity to human and animals, and all of them have an impact on the global schistosomiasis elimination plan.

7.
Article in Chinese | WPRIM | ID: wpr-815891

ABSTRACT

With the acceleration of the process of global integration, China’s international exchanges and cooperation with other countries have been further increased. The personnel exchange has led to the frequent occurrence of imported schistosomiasis from abroad, which seriously endangers people’s health. This paper reviews the prevalence and transmission risks of oversea imported schistosomiasis, providing the reference for the entry and exit health quarantine and prevention and control of schistosomiasis in China.

8.
Article in Chinese | WPRIM | ID: wpr-815888

ABSTRACT

Recently, China’s participation in global health governance has been paid increasing global attention. This paper analyzed the current status and needs of African schistosomiasis control, the participation of China and international organizations in African schistosomiasis control and the progress of China Aid of Schistosomiasis Control in Zanzibar, with China Aid of Schistosomiasis Control in Zanzibar as an example. It is suggested that China may improve the capability of participation in global public health governance and international reputation through strengthening intergovernmental and international collaborations, providing successful disease control experiences and products and improving capability and team building.

9.
Article in Chinese | WPRIM | ID: wpr-704270

ABSTRACT

Objective To predict the colonization risk and potential geographical distribution of Biomphalaria glabrata in the Mainland China based on the past period temperature data.Methods The survival extreme high temperatures and low tem-peratures of B.glabrata eggs,young and adult B.glabrata snails and the average effective accumulated temperature of genera-tion development were determined in laboratory conditions.The temperature data in January and July from 1955 to 2010 were collected from the national meteorological monitoring sites in the southern part of China,including Chongqing,Zhejiang,Yun-nan,Sichuan,Jiangxi,Hunan,Hainan,Guizhou,Guangdong,Guangxi and Fujian provinces(11 provinces).A database of ambient temperature related to B.glabrata was established based on the Geographic Information System(GIS).The colonization risk and potential geographical distribution of B.glabrata in the southern part of China were analyzed and predicted by ArcGIS 10.1 software.Results The half lethal low temperatures of B.glabrata eggs,young and adult B.glabrata snails were 6.80,6.34℃ and 6.60℃ respectively;the half lethal high temperatures of B.glabrata eggs,young and adult B.glabrata snails were 35.99,33.59℃ and 32.20℃,respectively.The developmental threshold temperature was 7.16℃;the average effective accumu-lated temperature of generation development was(1 970.07 ± 455.10)days-degree.The GIS overlay analysis of the half lethal low and high temperatures of B.glabrata showed that the local temperature conditions in all Hainan and part regions in Yunnan,Guangxi,Guangdong and Fujian were conformed to the survival temperature of B.glabrata snails.The regions,where the aver-age effective accumulated temperature was more than the average effective accumulated temperature of generation development of B.glabrata,were Guangdong and Hainan,and part regions of other 9 provinces.The overlay analysis of GIS maps of the sur-vival extreme high temperatures and low temperatures of B.glabrata with the GIS map of the average effective accumulated tem-perature of generation development in 2010 showed that the whole region of Hainan and part regions of Guangdong,Guangxi,Yunnan and Fujian were potential geographical distribution regions of colonization risk of B.glabrata.The overlay analysis of GIS maps of the survival extreme high temperatures and low temperatures of B.glabrata with the GIS map of the average effective accumulated temperature of generation development from 1955 to 2010 showed that the potential geographical distribution re-gions of B.glabrata was expanding from the whole region of Hainan and part regions of Guangdong in 1955 to the whole region of Hainan and part regions of Guangdong,Guangxi,Yunnan and Fujian in 2010.Conclusions If B.glabrata snails were intro-duced into the Mainland China,the potential geographical distribution regions would be the whole region of Hainan and part re-gions of Guangdong,Guangxi and Yunnan.The changes of risk range and risk intensity present the trends of expanding and in-creasing from the south to the north gradually.

10.
Article in Chinese | WPRIM | ID: wpr-704265

ABSTRACT

Parasitic diseases are common infectious diseases closely related to poverty,which are mainly endemic in the trop-ical and subtropical regions.Africa is the major epidemic area of parasitic diseases,and the global burden of malaria and schisto-somiasis is over 85% in Africa.This paper reviews the disease burden,regional distribution and control strategies of the main parasitic diseases in Africa,in order to promote the prevention and control of parasitic diseases in this area.

11.
Article in Chinese | WPRIM | ID: wpr-704234

ABSTRACT

Objective To set up and apply the evaluation standards for photography of schistosomiasis control theme,so as to offer the scientific advice for enriching the health information carrier of schistosomiasis control.Methods Through the litera-ture review and expert consultation,the evaluation standard for photography of schistosomiasis control theme was formulated. The themes were divided into 4 projects,such as new construction,natural scenery,working scene,and control achievements. Results The evaluation criteria of the theme photography were divided into the theme(60%),photographic composition (15%),focus exposure(15%),and color saturation(10%).A total of 495 pictures(sets)from 59 units with 77 authors were collected from schistosomiasis epidemic areas national wide.After the first-step screening and second-step evaluation,the prizes of 3 themes of control achievements and new construction,working scene,and natural scenery were selected,such as 6 pictures of first prize,12 pictures of second prize,18 pictures of third prize,and 20 pictures of honorable prize.Conclusions The eval-uation standards of theme photography should be taken into the consideration of the technical elements of photography and the work specification of schistosomiasis prevention and control.In order to improve the ability of records for propaganda purpose of schistosomiasis control and better play a role of guiding correct propaganda,the training and guidance of photography of profes-sionals should be carried out.

12.
Article in Chinese | WPRIM | ID: wpr-818839

ABSTRACT

Objective To establish an animal model of Sparganum mansoni (plerocercoid larva of S. mansoni) infection in mice and observe the changes of blood routine examinations and serum anti-sparganum antibody levels after the infection. Methods The spargana tapeworms were collected from frogs, and 25 Kunming mice were orally infected with the Sparganum tapeworms (3 tapeworms/mouse). Two days before the infection and 2, 7, 14, 21, 28, 35, 42 days and 49 days after the infection, the peripheral blood samples of mice were collected for the blood routine examinations and the detections of anti-S. mansoni IgG antibody with ELISA. Forty-nine days after the infection, all the mice were sacrificed to find out the Sparganum tapeworms in the bodies of mice. Results The count of the total white blood cells was significantly elevated on the second day of the mice infected with Sparganum. The serum anti-Sparganum antibody was detected on the 14th day of the infection in some mice, and on the 21st day of the infection, the serum anti-Sparganum antibody was detected in all the mice. After the mice were sacrificed, the Sparganum tapeworms were found out in many tissues and organs, and especially in the subcutaneous tissues and muscle. Conclusion The establishment of animal model of Sparganum infection is successful in mice with the oral method, and white blood cells and serum specific IgG antibody detection can be used as auxiliary diagnosis methods of S. mansoni infection.

13.
Article in Chinese | WPRIM | ID: wpr-818717

ABSTRACT

Objective To establish an animal model of Sparganum mansoni (plerocercoid larva of S. mansoni) infection in mice and observe the changes of blood routine examinations and serum anti-sparganum antibody levels after the infection. Methods The spargana tapeworms were collected from frogs, and 25 Kunming mice were orally infected with the Sparganum tapeworms (3 tapeworms/mouse). Two days before the infection and 2, 7, 14, 21, 28, 35, 42 days and 49 days after the infection, the peripheral blood samples of mice were collected for the blood routine examinations and the detections of anti-S. mansoni IgG antibody with ELISA. Forty-nine days after the infection, all the mice were sacrificed to find out the Sparganum tapeworms in the bodies of mice. Results The count of the total white blood cells was significantly elevated on the second day of the mice infected with Sparganum. The serum anti-Sparganum antibody was detected on the 14th day of the infection in some mice, and on the 21st day of the infection, the serum anti-Sparganum antibody was detected in all the mice. After the mice were sacrificed, the Sparganum tapeworms were found out in many tissues and organs, and especially in the subcutaneous tissues and muscle. Conclusion The establishment of animal model of Sparganum infection is successful in mice with the oral method, and white blood cells and serum specific IgG antibody detection can be used as auxiliary diagnosis methods of S. mansoni infection.

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