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1.
Mem. Inst. Oswaldo Cruz ; 84(2): 205-12, abr.-jun. 1989. tab
Artigo em Francês | LILACS | ID: lil-79138

RESUMO

1200 adult Biomphalaria glabrata were submitted during 6 weeks to anhydrobiosis condition. Some snails were health, some were previously infected 3 days or 12 days ago with 8 ñ 2 miracidia of Schistosoma mansoni, others were shedding cercariae . The snails were put on soil or buried into hermetically closed, or ventilated, plastic boxes. There was no survival of snails kept in sealed boxes, or among positive snails, but 44% of control health snails and 40,6% of infected (for 3 or 12 days) snails in ventilated boxes were living at the term of the desiccation stage. Survival was better for "on soil" snails than for "buried" snails, but difference was shown between 3-days and 12-days infection. The surving desiccated B. glabrata had a lesser death rate and a lesser cercarial production than infected snails kept in water. An inferior production of male cercariae comparatively to female and to "mixed" cercariae was demonstrated by statistical analysis of the cercarial sheddings. In all positive snails, periodic variations of cercarial production was shown, whatever the sex of those cercariae. In addition many pauses of the sheddings were established by the authors


Assuntos
Animais , Biomphalaria/parasitologia , Dessecação , Schistosoma mansoni/fisiologia
2.
Mem Inst Oswaldo Cruz ; 84(2): 205-12, 1989.
Artigo em Francês | MEDLINE | ID: mdl-2517564

RESUMO

1200 adult Biomphalaria glabrata were submitted during 6 weeks to anhydrobiosis condition. Some snails were healthy, some were previously infected 3 days or 12 days ago with 8 +/- 2 miracidia of Schistosoma mansoni, others were shedding cercariae. The snails were put on soil or buried into hermetically closed, or ventilated, plastic boxes. There was no survival of snails kept in sealed boxes, or among positive snails, but 44% of control healthy snails and 40.6% of infected (for 3 or 12 days) snails in ventilated boxes were living at the term of the desiccation stage. Survival was better for "on soil" snails than for "buried" snails, but no difference was shown between 3-days and 12-days infection. The surviving desiccated B. glabrata had a lesser death rate and a lesser cercarial production than infected snails kept in water. An inferior production of male cercariae comparatively to female and to "mixed" cercariae was demonstrated by statistical analysis of the cercarial sheddings. In all positive snails, periodic variations of cercarial production was shown, whatever the sex of those cercariae. In addition many pauses of the sheddings were established by the authors.


Assuntos
Biomphalaria/fisiologia , Dessecação , Animais , Biomphalaria/parasitologia , Schistosoma mansoni , Esquistossomose mansoni/parasitologia
3.
Mem Inst Oswaldo Cruz ; 82(4): 551-6, 1987.
Artigo em Francês | MEDLINE | ID: mdl-3507918

RESUMO

410 Biomphalaria glabrata (Caribbean strain of Guadeloupe) have been infected with one miracidium of Schistosoma mansoni, 110 snails, used as controls have been kept into water; the survival rate was 96.4% after 4 weeks and 25.4% produced cercariae. 300 snails were kept on wet soil, and submitted for 6 weeks to progressive desiccation. The survival rate was 23.4% but only 9 of them produced cercariae. Periodic variations of the production of male and female larvae have been shown by the weekly test of the cercariae productions. In previously desiccated snails, the production of male and female cercariae is similar while in controls the production of female larvae is more important. In experimental snails, the larval development seems to be stopped during anhydrobiosis. The production of cercariae is just delayed for the length of the dry keeping.


Assuntos
Biomphalaria/parasitologia , Dessecação , Schistosoma mansoni/crescimento & desenvolvimento , Animais , Feminino , Masculino , Fatores Sexuais
4.
Ann Parasitol Hum Comp ; 59(1): 79-94, 1984.
Artigo em Francês | MEDLINE | ID: mdl-6721371

RESUMO

380 B. glabrata infected with 1 miracidium of S. mansoni produced 87 positive snails (22,9%), 38 of which sending out male cercariae and 49 female cercariae. The snails belonged to 3 experimental series kept at 27 degrees and 24 degrees C for 15 weeks under continuous lighting. There was no difference between the proportions of both sexes. The survival of the positive snails was favoured by the male sex. The shedding of female cercariae was greater than shedding of male. During those 15 weeks, the cercarial shedding of both sexes showed large and recurring changes. A certain correlation seems to exist between the sex of cercariae, the abundance and the frequency of cercarial shedding, and the longevity of the parasitized snails. All those factors could take a part in the epidemiology of the schistosomiasis.


Assuntos
Biomphalaria/parasitologia , Schistosoma mansoni/patogenicidade , Animais , Larva , Fatores Sexuais
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