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Kato–Katz thick smears as a DNA source of soil-transmitted helminths

  • K.J.L. Monteiro (a1), D.A. Calegar (a1), Amazonas Research Group (a2), F.A. Carvalho-Costa (a1) (a3) and L.H. Jaeger (a1)...


Despite the reduction in the prevalence of soil-transmitted helminthiases in many regions of the world, morbidity rates remain high in some rural regions. The Kato–Katz technique is a simple, inexpensive and field-applicable tool commonly used for the diagnosis and worm-burden characterization of these infections. Molecular studies have revolutionized our understanding of the epidemiology and evolutionary genetics of parasites. In this study we recovered helminthic DNA from Kato–Katz slides (n = 93) prepared in 2011 in the Brazilian Amazon. We achieved DNA recovery by polymerase chain reaction (PCR) in 84% of cases for Ascaris sp. and 75% of cases for hookworms. The sequencing confirmed the specific species of the amplicons. The slides stored for a few years could be analysed using this methodology, allowing access to DNA from a large collection of samples. We must consider the Kato–Katz thick smears as a source of helminth DNA. This can significantly reduce logistical difficulties in the field in terms of obtaining, preserving, transporting and initial processing of samples.


Corresponding author

Author for correspondence: L.H. Jaeger, E-mail:


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Current address: Laboratório de Células Tronco e Parasitologia Molecular, Departamento de Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal de Juiz de Fora, José Lourenço Kelmer, s/n, São Pedro, Juiz de Fora, Brazil. Zip Code: 36036-900

Amazonas Research Group: D.C. Portela Camara, A.C. de Souza, A.T. de L. Barbosa, A.M. de A. Cabral, C.V.C. Guacho, D. de J. Hardoim, F.B. dos Santos, L.S. de Assunção, M.H. da Silva, M.M. Portilho, V.A. Marques, M.N. Bóia



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