Resistance to niclosamide in Oncomelania hupensis, the intermediate host of Schistosoma japonicum: should we be worried?

As the currently only available molluscicide, niclosamide has been widely used for snail control for over 2 decades in China. There is therefore a concern about the emergence of niclosamide-resistant snail populations following repeated, extensive use of the chemical. The purpose of this study was to investigate the likelihood of niclosamide resistance in Oncomelania hupensis in China.

In vivo activity of dihydroartemisinin against Schistosoma mansoni schistosomula in mice.

Dihydroartemisinin, an anti-malarial agent, has been shown to exhibit activity against Schistosoma japonicum and S. mansoni. The purpose of the present study was to investigate the in vivo activity of dihydroartemisinin against juvenile S.

[Studies on resistance of Schistosoma to praziquantel XIIV sensitivity of Schistosoma japonicum to praziquantel in marshland and lake endemic regions of Chinese Mainland].

Objective: To compare the sensitivities of different isolates of Schistosoma japonicum in marshland and lake regions of Chinese Mainland to praziquantel, so as to provide experimental evidence for establishing the techniques of detecting and monitoring praziquantel sensitivity.

Methods: Mice were infected with cercariae released from the S. japonicum-infected snails collected from the marshland and lake endemic regions of Hunan, Hubei, Jiangxi, Anhui and Jiangsu provinces, grouped, and treated with praziquantel at single oral doses of 37.

[Distribution of niclosamide spreading oil on water surface and its efficacy against cercariae of Schistosoma japonicum].

Objective: To investigate the distribution and spreading speed of niclosamide spreading oil, as well as its effect against cercariae of Schistosoma japonicum.

Methods: The foamed plastic with a diameter of 4 mm served as a buoyage, which was placed at the center of the still water surface. The niclosamide spreading oil was dropped at 0.

[Studies on standardization of methods for screening molluscicides in laboratory IV sensitivity of Oncomelania snails from different months to niclosamide].

Objective: To understand the sensitivity of Oncomelania snails collected from different months to niclosamide, so as to provide the scientific evidence for the standardization of methods for molluscicide screening and efficacy evaluation in laboratory.

Methods: The snails collected from the marshland of Zhenjiang City, Jiangsu Province month by month from June 2010 to May 2011. After being raised in laboratory for 24 h, the snails were randomly grouped, and then immersed in different concentrations of 50% wettable powder formulation of niclosamide ethanolamine salt at (25 +/- 1) degrees C with a humidity of 60%.

[Studies on resistance of Schistosoma to praziquantel XIV experimental comparison of susceptibility to praziquantel between PZQ-resistant isolates and PZQ-susceptible isolates of Schistosoma japonicum in stages of adult worms, miracidia and cercariae].

Objective: To investigate the changes of sensitivity to praziquantel (PZQ) about PZQ-resistant isolates of Schistosoma japonicum established in laboratory by means of the resistance-inducement method during the stages of adult worms, cercariae and miracidia, so as to provide the basis for establishing the sensitivity-detecting technique to praziquantel.

Methods: A Jiangsu laboratory-maintaining isolate and a Hunan field-collecting isolate of S. japonicum that were never treated with PZQ were as PZQ-susceptible isolates, and two PZQ-induced isolates that were established via drug-treated passage in laboratory were as PZQ-resistant isolates.

[Studies on resistance of Schistosoma to praziquantel XIII resistance of Schistosoma japonicum to praziquantel is experimentally induced in laboratory].

Objective: To investigate the possibility of the emergence of praziquantel resistance in Schistosoma japonicum in Mainland China under drug pressure.

Methods: S. japonicum cercaria were released from the infected Oncomelania hupensis snails collected from the marshland in Hunan Province that was endemic for schistosomiasis japonica and raised in the laboratory of Jiangsu Institute of Parasitic Diseases, and mice were infected.

[Studies on spray of niclosamide ethanolamine salt. I. development and effect assessment of spray of niclosamide ethanolamine salt].

Objective: To develop a spray of niclosamide ethanolamine salt for prevention of bovine from Schistosoma japonicum infection, and explore its characteristics and effect.

Methods: The solubilizers, penetrating agents, emulsifiers were screened, and the spray of niclosamide ethanolamine salt was formulated according to the screening results. The niclosamide ethanolamine salt was determined by using a HPLC technique, and the stability was observed.

[Study on preservation of niclosamide in water samples].

Objective: To investigate the preservation condition of niclosamide in water samples and establish a high performance liquid chromatography (HPLC) method by solid-phase extraction (SPE) which is used for determination and preservation of niclosamide in water samples.

Methods: Under the simulated setting in laboratory, niclosamide was formulated into the solutions of 0.50, 1.

[Surveillance and forecast system of schistosomiasis in Jiangsu Province V monitoring of infectivity of Schistosoma japonicum miracidia of Yangtze River].

Objective: To establish an approach to monitor the Schistosoma japonicum miracidia in waterbody of the Yangtze River, and monitor the infectivity of water body, so as to provide the evidence for tracing and controlling infection source and interrupting the transmission of schistosomiasis, and Oncomelania snail control.

Methods: The floating bottle-nylon bag sentinel snails method was employed. A total of 45 surveillance sites were selected along the Jiangsu section of the Yangtze River, 500 snails were placed into each site from May to September, once every month.

A strategy for emergency treatment of Schistosoma japonicum-infested water.

Background: Schistosomiasis japonica, caused by contact with Schistosoma japonicum cercaria-infested water when washing, bathing or production, remains a major public-health concern in China. The purpose of the present study was to investigate the effect of a suspension concentrate of niclosamide (SCN) on killing cercaria of S. japonicum that float on the water surface, and its toxicity to fish, so as to establish an emergency-treatment intervention for rapidly killing cercaria and eliminating water infectivity.

Effect of the in vivo activity of dihydroartemisinin against Schistosoma mansoni infection in mice.

Dihydroartemisinin, formerly known as an antimalarial drug, is the main metabolite of the mother compound artemisinins, as well as of artemether and artesunate. It has been shown that the drug exhibits antischistosomal efficacy against Schistosoma japonicum. The purpose of the current study was to assess the in vivo effect of dihydroartemisinin against Schistosoma mansoni infection in mice.

Effects of artemether, artesunate and dihydroartemisinin administered orally at multiple doses or combination in treatment of mice infected with Schistosoma japonicum.

Artemether and artesunate, derivatives of the antimalarial artemisinin, as well as their main metabolite, dihydroartemisinin, all exhibit antischistosomal activities. The purpose of the current study was to compare the effects of artemether, artesunate and dihydroartemisinin administered orally at multiple doses or combination in treatment of mice infected with Schistosoma japonicum. We carried out experiments with mice, infected with 40 cercariae of S.