Schistosomiasis mansoni in Bananal (State of Säo Paulo, Brazil). II. Intermediate hosts
Mem. Inst. Oswaldo Cruz
;
97(suppl.1): 37-41, Oct. 2002. mapas, graf
Article
in English
| LILACS, SES-SP
| ID: lil-325027
RESUMO
We conducted monthly snail captures in Bananal, State of Säo Paulo, Brazil, between March 1998 and February 2001, to identify Schistosoma mansoni vectors, estimate seasonal population changes, and delimit foci. We also evaluated the impact of improvements in city water supply and basic sanitation facilities. We identified 28,651 vector specimens, 28,438 as Biomphalaria tenagophila, 49 of them (0.2 percent) infected with S. mansoni, and 213 as B. straminea, none of the latter infected. Vectors predominated in water bodies having some vegetation along their banks. Neither population density nor local vegetation could be linked to vector infection. We found the first infected snails in 1998 (from March to May). Further captures of infected snails ocurred, without exception, from July to December, when rainfall was least. Irrespective of season, overall temperature ranged from 16.5ºC to 21ºC; pH values, from 6.0 to 6.8. Neither factor was associated with snail population density. Frequent contact of people with the river result from wading across it, extracting sand from its bottom, fishing, washing animals, etc. Despite a marked reduction in contamination, cercaria shedding persists. Whatever the location along its urban course, contact with river Bananal, particularly of the unprotected skin, entails risks of infection
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Schistosoma mansoni
/
Snails
/
Schistosomiasis mansoni
/
Disease Vectors
Type of study:
Prognostic study
Limits:
Animals
/
Humans
Country/Region as subject:
South America
/
Brazil
Language:
English
Journal:
Mem. Inst. Oswaldo Cruz
Year:
2002
Type:
Article
/
Congress and conference
Institution/Affiliation country:
Superintendência de Controle de Endemias/BR
/
Universidade de São Paulo/BR
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