ABSTRACT
Objective To explore the relationship between the distribution characteristics and the habitat factors of the invasive B. straminea in South China. Methods From October 2016 to August 2017, the breeding condition and habitat factors of B. straminea were investigated in the rivers of Shenzhen and its adjacent areas in the dry season, normal season and wet reason. The generalized additive model (GAM) was used to study the main habitat factors affecting the distribution density of B. straminea. Results The distribution characteristics of B. straminea showed obvious aggregation and unevenness in space. In terms of time, the density of snails was the highest in the dry season, followed by the normal water season and the least in the wet season. The GAM model analysis showed that the main habitat factors affecting the distribution density of B. straminea were water depth, water temperature, flow velocity, dissolved oxygen, and total phosphorus. When the flow velocity and water temperature were 0.25 m / s and 26 °C, respectively, the largest distribution density of snails might appear. The distribution density of B. straminea was positively correlated with dissolved oxygen and total phosphorus. Conclusion B. straminea is suitable to live in the water environment with poor water quality. In the future, the monitoring should be strengthened to provide reference for the prevention and control of the spread of the snails.
ABSTRACT
Objective To study the dynamic diffusion characteristics of Biomphalaria straminea in Shenzhen, Dongguan and Huizhou of Southern China. Methods B. straminea was monitored at 25 investigation points along 10 river channels in Shenzhen, Dongguan and Huizhou by salvaging method. The diffusion characteristics of snails along with water in the Guihua New Village section of the Guanlan River and the Dawei Village section of the Longgang River were analyzed by GPS location drift test. In addition, the influence of flooding on the diffusion of B. straminea in the Kuichong River both before and after Typhoon "Shanzhu" was analyzed by monitoring the hydrology and distribution of snails. Results In March and October from 2016 to 2018, a total of 1 176 kg of floating objects were salvaged in rivers in Shenzhen, Dongguan and Huizhou. Scattered B. straminea were found on water hyacinths. Drift test of floats with GPS showed that the average drift speed of GPS floating objects was close to the river surface velocity. Affected by river current and wind direction, the GPS floats quickly drifted to the river bank and stopped in the stagnant area due to the blockade of water plants, stone and the bending of the shoreline. The drift distance of each time was between 136 - 715m. The test results of salvaged floating objects found that the loss rates of B. straminea were 46.70% - 60.00% and 22.10% - 30.80%, in the Guihua New Village section of the Guanlan River and the Dawei Village section of the Longgang River, respectively, which were significantly affected by the floating weight, river velocity and drifting distance. The analysis of the hydrology and distribution of B. straminea in the Kuichong River both before and after Typhoon "Shanzhu" showed that the density of B. straminea in the river was significantly reduced by the flood. Conclusion B. straminea is mainly transported as suspended matter in water body, and flooding was an important factor in its long-distance diffusion.
ABSTRACT
In 1980s, Biomphalaria straminea, an intermediate host of Schistosoma mansoni, was found in Shenzhen City, Guangdong Province, China, and currently, this snail has colonized in Shenzhen City and spread to peripheral cities involving of Dongguan and Huizhou. Since imported cases infected with S. mamoni have been reported from time to time in China, Mainland China is facing the potential risk of transmission of schistosomiasis mansoni. With the deepening of the opening-up policy, notably the implementation of the Belt and Road Initiative, there is an increase in the risk of transmission of schistosomiasis mansoni in Mainland China. Increasing the understanding on schistosomiasis mansoni, improving the awareness toward schistosomiasis mansoni prevention and control, and identifying, reporting and managing imported cases with S. mansoni infection or pathogen carriers, are of particular importance to prevent the development of entire life cycle of S. mansoni and the resultant schistosomiasis mansoni transmission in China. To protect public health, a consensus has been reached pertaining to the surveillance and control strategy of imported schistosomiasis mansoni by Chinese infectious disease experts and parasitologists, with aims to improve the awareness and capability for the diagnosis, treatment and control of imported schistosomiasis mansoni among Chinese disease control and prevention institutions and medical institutions, and decrease and even eliminate the risk of schistosomiasis mansoni transmission in China.
ABSTRACT
Invasion of alien species has increasingly become a major environmental problem that damages human health, economic development and ecological security in China, which has been paid much attention. Until now, there have been 753 invasive species reported in China, and invasive medical molluscs include Pomacea canaliculata, Achatina fulica, and Biomphalaria straminea. This review summarizes the status of biologically invasive species in China, describes the species and distribution of invasive medical molluscs, analyzes the damages of the invasive medical molluscs-transmitted diseases, and proposes the preventive and control measures.
ABSTRACT
In 1980s, Biomphalaria straminea, an intermediate host of Schistosoma mansoni, was found in Shenzhen City, Guangdong Province, China, and currently, this snail has colonized in Shenzhen City and spread to peripheral cities involving of Dongguan and Huizhou. Since imported cases infected with S. mamoni have been reported from time to time in China, Mainland China is facing the potential risk of transmission of schistosomiasis mansoni. With the deepening of the opening-up policy, notably the implementation of the Belt and Road Initiative, there is an increase in the risk of transmission of schistosomiasis mansoni in Mainland China. Increasing the understanding on schistosomiasis mansoni, improving the awareness toward schistosomiasis mansoni prevention and control, and identifying, reporting and managing imported cases with S. mansoni infection or pathogen carriers, are of particular importance to prevent the development of entire life cycle of S. mansoni and the resultant schistosomiasis mansoni transmission in China. To protect public health, a consensus has been reached pertaining to the surveillance and control strategy of imported schistosomiasis mansoni by Chinese infectious disease experts and parasitologists, with aims to improve the awareness and capability for the diagnosis, treatment and control of imported schistosomiasis mansoni among Chinese disease control and prevention institutions and medical institutions, and decrease and even eliminate the risk of schistosomiasis mansoni transmission in China.
ABSTRACT
Invasion of alien species has increasingly become a major environmental problem that damages human health, economic development and ecological security in China, which has been paid much attention. Until now, there have been 753 invasive species reported in China, and invasive medical molluscs include Pomacea canaliculata, Achatina fulica, and Biomphalaria straminea. This review summarizes the status of biologically invasive species in China, describes the species and distribution of invasive medical molluscs, analyzes the damages of the invasive medical molluscs-transmitted diseases, and proposes the preventive and control measures.
ABSTRACT
Objective To understand the eco-hydraulics characteristics of Biomphalaria straminea,the intermediate host of Schistosoma mansoni. Methods The drainage method and settlement tube method were applied to measure B. straminea's den-sity and hydrostatic settling velocity respectively. Results The density of B. straminea was 1.04-1.16 g/cm3,and the average value was 1.08 g/cm3. The hydrostatic settling velocity was 2.32-12.92 cm/s. Conclusions The eco-hydraulics characteristics of B. straminea is different from Oncomelania hupensis,and more attention should be paid to the hydraulic measures for the con-trol of B. straminea.
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Neste estudo, objetivou-se mapear os criadouros de Biomphalaria spp., transmissoras da esquistossomose mansoni, presentes no município de São Bento, localizado na região da Baixada Maranhense, área na qual esta doença é endêmica. Foram visitados 16 dos 22 bairros existentes na cidade durante o período de agosto de 2012 a julho de 2013. Os caramujos foram coletados com auxílio de conchas de captura e pinças, armazenados e transportados para o Laboratório de Parasitologia Humana da Universidade Estadual do Maranhão, em São Luís, onde foram acondicionados em aquários de vidro e alimentados com folhas de alface. Os moluscos foram submetidos à análise parasitológica à procura de estágios larvais de Schistosoma mansoni e identificados pela conquiliologia e por meio de dissecções. Em 18 criadouros mapeados foram obtidos 1.195 exemplares de Biomphalaria glabrata e de B. straminea. Nenhum molusco eliminou cercárias de S. mansoni. Considerando os resultados obtidos e os aspectos epidemiológicos relacionados à transmissão da esquistossomose, o mapeamento das espécies vetoras no município permitirá a localização e identificação dos criadouros, o que poderá auxiliar substancialmente os serviços de saúde locais nas atividades de vigilância e controle da esquistossomose, além de nortear futuros estudos epidemiológicos sobre a esquistossomose mansoni na região da Baixada Maranhense
Subject(s)
Biomphalaria , Schistosomiasis mansoni , MolluscaABSTRACT
Biomphalaria straminea,the intermediary host of Schistosoma mansoni,was found by survey in local areas of Shen-zhen City in 1981,which was the first finding of the snail in inland China. By 2013,the snail had spread in large range of Shen-zhen City and overspread to the surrounding regions,Dongguan City and Huizhou City. Due to the facts that Shenzhen City has many international communications and is a key area of labor export,with high population mobility,while the reports of S. manso-ni infection in the returnees of our country from Africa have been increasing recently,it must be paid a high attention to whether the epidemic or transmission of schistosomiasis mansoni may happen under the present circumstance. This paper initially discusses the finding,distribution,spreading and overspreading and transmission risk of B. straminea in inland China and puts forward some related control suggestions.
ABSTRACT
Environmental changes from water resource developmental projects affect the epidemiology of water-associated diseases, as well as malaria and schistosomiasis. Aiming to investigate the occurrence and distribution of freshwater snails of medical and veterinary importance in the area of influence of the Peixe Angical hydroelectric dam, a survey has been conducted over four years (2004-2008). The study has revealed the occurrence of populations of Biomphalaria straminea (Dunker) in all municipalities surrounding the lake. Studies on parasite-mollusc compatibility were undertaken using 35 populations of B. straminea, descendants of specimens obtained from that area and three strains of Schistosoma mansoni (Sambon) (BH, CM and CMO). The main results are as follows: (i) among the 1,314 specimens used, eight had been infected (infection index of 0.6 percent) with only the BH strain, (ii) for B. straminea populations, the mortality index was 6.8 percent and, depending on the strain used, the indexes were 4.6 percent, 8.49 percent and 19 percent with BH, CM and CMO strains, respectively, (iii) the infection indexes varied according to the B. straminea populations, ranging from 0-12.5 percent and (iv) the duration of the precercarial period varied from 25-49 days. These results, in addition to environmental and social changes that took place in the Peixe Angical dam region, indicate the possibility of B. straminea emerging as a schistosomiasis vector in this area.
Subject(s)
Animals , Biomphalaria , Disease Vectors , Host-Parasite Interactions/physiology , Schistosoma mansoni/physiology , Brazil , Biomphalaria , Fresh Water , Power Plants , Schistosoma mansoniABSTRACT
Este trabalho avalia a ocorrência de moluscos planorbídeos na estação de psicultura do IBAMA em Uberlândia, Minas Gerais. Constatou-se a presença de Biomphalaria straminea em 39,5% dos tanques de criação. Nenhum dos caramujos estava infectado por Schistosoma mansoni, mas investigações complementares devem ser realizadas na área.
This work evaluates the occurrence of freshwater snails in the IBAMA's fish breeding station in Uberlândia, Minas Gerais State. We verified the presence of Biomphalaria straminea in 39.5% of all breeding tanks. None of the snails were infected by Schistosoma mansoni, but further investigation should be done in the area.
Subject(s)
Animals , Aquaculture , Biomphalaria , Disease Vectors , Brazil , Biomphalaria/parasitology , Schistosoma mansoni/isolation & purificationABSTRACT
Estudou-se a susceptibilidade de Biomphalaria straminea, originária do município de Taubaté, SP, comparativamente com Biomphalaria tenagophila, à infecção pela cepa S.J. de Schistosoma mansoni de São José dos Campos. Pretendeu-se determinar o potencial epidemiológico destas espécies como hospedeiros intermediários de S. mansoni frente a cepa valeparaibana. Foram inoculados individualmente 250 B. straminea e 250 B. tenagophila e mais o grupo controle. Tais moluscos ficaram sob observaçäo durante 60 dias. Foram depois esmagados para detectar presença de esporocistos nos órgãos internos. Ao término do experimento B. straminea não se mostrou suscetível à infecção pela cepa S.J. e B. tenagophila apresentou 82,2% e 83,2% de infecção nos três lotes (AU).