The toxicity of cadmium and zinc at concentrations ranging from 0.1 to 100 microg/l was investigated against the activity of Diplostomum spathaceum (Rudolphi, 1819) cercariae. Over a 24 h exposure period a significant reduction in cercarial activity occurred in solutions of cadmium, zinc, and a mixture of cadmium and zinc at all concentrations. Reduced cercarial activity also occurred in all to...

The furcocercus cercariae of Neodiplostomum seoulense (Digenea: Neodiplostomidae) penetrate the skins of tadpoles and shed their tails. The speculated mechanism of this tail loss was physical efforts required to produce a vigorous zigzag motion during skin penetration; no other mechanism has been proposed. We examined the relationship between the host serum and cercarial tail loss. Cercariae of...

A cyclohexanecarboxamide derivative, N-phenyl-N-[1-(piperidine-1-carbonyl)cyclohexyl] benzamide (MNRC-5), was evaluated for its inhibitory effects on Schistosoma mansoni cercarial serine protease activity and cercarial penetration. MNRC-5 exerted an inhibitory effect on S. mansoni cercarial serine protease at serial concentrations of the specific chromogenic substrate Boc-Val-Leu-Gly-Arg-PNA fo...

BACKGROUND Cercarial elastase is the major invasive larval protease in Schistosoma mansoni, a parasitic blood fluke, and is essential for host skin invasion. Genome sequence analysis reveals a greatly expanded family of cercarial elastase gene isoforms in Schistosoma mansoni. This expansion appears to be unique to S. mansoni, and it is unknown whether gene duplication has led to divergent prote...

While making longitudinal observations on schistosome cercarial shedding, Pitchford and Visser found that there is an annual fluctuation in the minimum time for cercarial development, which is apparently related to temperature (1). Schistosome control strategy could be designed to take advantage of this fluctuation if it were predictable. Inspired by the successes of physiological time models (...

Centrocestus armatus is an intestinal parasite belonging to the family Heterophyidae. We developed an apparatus for recovering cercariae and clarified the infection dynamics of this parasite. To clarify the circadian rhythm of cercarial shedding in the summer season, we filtrated 30 l of river water every 2 h for 24 h. Cercariae were first detected between 06:00 and 08:00 h, increased over time...

During the complex lifecycle of Schistosoma mansoni, a large variety of glycans is expressed. To many of these glycans, antibodies are induced by the infected host and some might be targets for vaccines or diagnostic tests. Spatial changes in glycan expression during schistosome development are largely unexplored. To study the surface-exposed glycans during the important initial stages of infec...

Compatibility between Schistosoma mansoni and Biomphalaria straminea when exposed to the parasite on the first four months of age was assessed for five parasitological aspects: indices of infection and mortality, duration of precercarial and cercarial periods, and rate of cercarial emission. Infections were made on molluscs from laboratory colonies, at the following ages: 8, 13, 18, 21, 53, 83 ...