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https://www.arca.fiocruz.br/handle/icict/34543
AVALIAÇÃO DE MÉTODOS DIAGNÓSTICOS PARA ESQUISTOSSOMOSE MANSONI EM UMA ÁREA DE BAIXA ENDEMICIDADE NO MUNICÍPIO DE MONTES CLAROS, MINAS GERAIS, BRASIL
Siqueira, Liliane Maria Vidal | Date Issued:
2011
Alternative title
Evaluation of diagnostic methods for Schistosomiasis mansoni in a low endemic area in the city of Montes Claros, Minas Gerais, BrazilAdvisor
Co-advisor
Affilliation
Fundação Oswaldo Cruz. Centro de Pesquisa Rene Rachou. Belo Horizonte, MG, Brasil.
Abstract in Portuguese
Este estudo populacional, baseado na avaliação de dois métodos parasitológicos e um método molecular para o diagnóstico da esquistossomose mansoni foi realizado numa área de baixa transmissão na localidade de Pedra Preta, Montes Claros- MG. Um total de 201 pessoas participou desta pesquisa, todas moradoras da área rural desta localidade. Quatro amostras de fezes foram obtidas de todos participantes e analisadas utilizando o método Kato-Katz (12 lâminas da primeira, duas da segunda, terceira e quarta amostra, totalizando 18 lâminas) e o método parasitológico comercial, TF-Test®, o qual foi realizado de forma quantitativa. Além disso, a técnica de PCR-ELISA foi aplicada em 500 mg de fezes na primeira amostra. Os resultados foram analisados comparativamente ao método de Kato-Katz. Todos os positivos para S. mansoni foram tratados com praziquantel e os positivos para os outros helmintos tratados com albendazol. Para avaliação de cura após o tratamento, os positivos foram acompanhados 30, 90 e 180 dias após o tratamento, pelas duas técnicas parasitológicas. A análise dos dados envolveu determinação da prevalência, sensibilidade dos métodos diagnósticos, carga parasitária e definição de um Padrão Ouro , consistindo da soma de todas as amostras e lâminas examinadas pelo método de Kato-Katz e pelo método de TF-Test®.
Abstract
This population study, based on the evaluation of two parasitological
methods and one molecular biological technique for the diagnos
is of schistosomiasis
mansoni was carried out in a low transmission area in Pedra Preta, Montes Claros,
Minas Gerais, Brazil.
A
total
of
201 inhabitants of the rural area participated in this
research. Four stool samples were obtained from all participants
and analyzed
according to the Kato
-
Katz method (12 slides of the first, 2 of the second, the third
and fourth sample, summing up 18 slides) and a commercial test, the TF
-
Test, which
was performed quantitatively. Furthermore the technique of PCR
-
ELISA was
applied
in 500mg stool of the first sample. The results were analyzed in comparison to the
Kato
-
Katz technique. All positives for schistosomiasis were treated with Praziquantel
and those for other helminthes with Albendazole. Positive patients were followe
d up
30, 90, and 180 days after treatment with both parasitological techniques in order to
establish the cure rate. The data analysis involved the determination of prevalence,
sensitivity of the diagnostic methods, worm burden and the definition of the “go
ld
standard” obtained
by summing the results of all samples examined by the Kato
-
Katz
technique and the TF
-
Test
®
.
The results show that the prevalence obtained by
examination of one Kato
-
Katz slide (the methodology adopted by the Brazilian control
program)
in comparison to
the
“gold
st
andard” rises from 8.0% to 35.8%, which is a
4.5 fold increase. This indicates that the prevalence of schistosomiasis in so called
low transmission areas is significantly underestimated. The PCR
-
ELISA technique
detected
36 (18
.0%) positives, which is more
than
those 29 (14.4%) identified by
12
Kato
-
Katz slides examin
ing
the same stool sample. Therefore the combination of
different techniques that reveals results closer to the real prevalence of
schistosomiasis gains paramount i
mportance
,
whenever transmission control is the
focus. This study also shows a low rate of re
-
infection (1.5%), which indicates that an
in depth diagnostic survey is more effective and
probably may p
revent successive
treatments.
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