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At least 37 records · Page 2Linked to original sources
PubMed1976

Immunisation of baboons against Schistosoma mansoni using irradiated S. mansoni cercariae and schistosomula and non-irradiated S. rodhaini cercariae.

In an attempt to develop a non-pathogenic procedure for immunising baboons against S. mansoni, groups of five baboons were exposed to three doses of 5000 6 Kr-irradiated S. mansoni cercariae or to similar numbers of normal S. rodhaini cercariae and challenged at week 15 with 500 normal S. mansoni cercariae. Faecal egg counts, worm and tissue egg counts, and histopathological examination, showed that neither of the immunising schedules had produced significant protection. In the second experiment baboons were injected by the intramuscular route with 31000 schistosomula of S. mansoni in three doses and the irradiation dose was reduced to near the minimum required for worm sterilisation (2-1--2-4 Kr). Challenge with 3500 normal cercariae of S. mansoni 21 weeks after the first immunising dose again showed no significant protection, although reductions of 20--30% were found in egg and worm counts resulting from the challenge. These results indicate that it may be difficult to develop an effective live vaccine for S. mansoni unless the antigenicity of the immunising larvae can be greatly increased.

Animals↗
PubMed2006

Morphological observations of Echinochasmus japonicus cercariae and the in vitro maintenance of its life cycle from cercariae to adults.

The cercaria morphology of Echinochasmus japonicus was investigated using light and scanning electron microscopy. Cercariae, liberated from naturally infected snails (Parafossarulus manchouricus), had ovoid bodies and diminutive tails. The cercaria tegument was covered with minute spines. Four type II sensory papillae were observed on the dorsal side of the oral sucker, and type I papillae were distributed on the dorsal tegument surfaces. When cercariae were kept in the same bath as the freshwater fish, Pseudorasbora parva, which were free from trematode infections, parasites encysted only in the gills of fishes at day 4 postinfection (PI). The outermost metacercaria wall was fully formed in host tissues at day 7 PI. Adult worms were recovered from the intestines of rats, chicks, and ducks 28 days after experimental exposure to metacercariae. The head crown of the adult was armed with 24 collar spines, which were interrupted dorsal to the oral sucker, and the species was identified as E. japonicus.

Animals↗
PubMed1977

Studies on the fresh water Cercariae in Leyte Island, Philippines. 2. Cercariae from Oncomelania quadrasi.

From 1975 to 1976, more than six thousand snails of Oncomelania quadrasi were observed for cercarial fauna in the north-eastern part of Leyte Island, Philippines. Altogether, six species of cercariae including that of Schistosoma japonicum were found, namely two furcocercariae, one monostome cercaria, two xiphidiocercariae and one tail-less cercaria. In this paper a description of their morphology, infection rate, locality, and some remarks on the presumptive life cycle is included with illustrations and photographs.

Animals↗
PubMed1998

Single-species infections of Echinostoma caproni cercariae in pulmonate snails and concurrent infections of E. caproni and Echinostoma trivolvis cercariae in Biomphalaria glabrata.

Single-species infections of Echinostoma caproni cercariae in various pulmonate snails showed that a higher percentage of cercariae encysted successfully in Biomphalaria glabrata than in other snail species and that the percentage encystment was significantly greater in B. glabrata than in either Helisoma trivolvis or Lymnaea elodes. There were significant differences in cyst diameter, thickness of outer and inner cysts, and diameter of excretory concretions between E. caproni and Echinostoma trivolvis metacercariae. These morphological differences helped to distinguish each species of cyst in concurrent cercarial infections of E. caproni and E. trivolvis in B. glabrata. Moreover, in concurrent infections E. trivolvis localised only in the saccular kidney, whereas E. caproni occurred in both the saccular kidney and the pericardium.

Animals↗
PubMed1995

[Cercaria dermatitis (swimmer's itch). Case report of cercaria dermatitis caused by Trichobilharzia (Digena, Schistosomatidae)].

A 63-year-old woman developed a pruritic exanthema on the extremities after one hour of work in her garden pond in Planegg, Southern Bavaria. As the appropriate vectors (ducks and snails) were present, we made the tentative diagnosis of cercarial dermatitis (swimmer's itch). By different serological methods (cercarial fluorescent antibody test, cercarial Hüllen reaction, circumoval precipitin test) antibodies against cercariae could be demonstrated in the serum of the patient 14 days later. Cercarial dermatitis appears worldwide, but in Central Europe the disease is often not recognized.

Animals↗