Kato technique

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The Kato technique (also called the Kato-Katz technique) is a laboratory method for preparing human stool samples prior to searching for parasite eggs.

Indications[edit]

The Kato technique is now most commonly used for detecting schistosome eggs.[1] It has in the past been used for other helminth eggs as well. It cannot be used to identify hookworm eggs because they collapse within 30 to 60 minutes of preparation using this method. One study of 299 subjects infected with Schistosoma mansoni found that the method had poor reproducibility and is therefore no longer recommended for primary health care settings:[2] the problem may be that eggs of Schistosoma mansoni tend to clump together which means that even slides prepared from the same specimen may contain widely different egg counts.[3] The other main argument against the Kato technique is that it is messy and therefore exposes technicians to an unnecessarily high risk of infection.

Method[edit]

The published methods vary in detail, however one involves staining a sieved fecal sample and examining it under a microscope. The total number of stained eggs are counted and used to calculate the number of eggs per gram.[1]

History[edit]

It was developed in 1954 by the Japanese physician, Dr. Kan Kato (1913–2011), together with his adviser, Dr. Momoshige Miura (1891–1989), a renowned Japanese medical researcher and psychiatrist.[4][5][6] The technique was modified for use in field studies in 1972 by a Brazilian team of researchers led by the Brazilian Parasitologist, Naftale Katz (b.1940)[7][8], and this modification was adopted by the WHO as a gold standard for multiple helminth infections [9].

See also[edit]

References[edit]

  1. ^ a b Cheesbrough M (1998). "Parasitological Tests". District Laboratory Practice in Tropical Countries, Part 1. Cambridge: Cambridge University Press. pp. 220–221. ISBN 0-521-66547-7. 
  2. ^ Kongs A, Marks G, Verlé P, Van der Stuyft P (2001). "The unreliability of the Kato=Katz method for evaluating S. mansoni infection". Trop Med Intl Health. 6 (3): 163–69. doi:10.1046/j.1365-3156.2001.00687.x. PMID 11299032. 
  3. ^ Engels D, Sinzinkayo E, De Vlas SJ, Gryseels B (1997). "Intraspecimen fecal egg count variation in Schistosoma mansoni infection". Am J Trop Med Hyg. 57 (5): 571–7. PMID 9392598. 
  4. ^ Japanese Biographical Index. Walter de Gruyter. January 1, 2004. pp. 345,523. ISBN 978-3-11-094798-4. Retrieved August 31, 2017. 
  5. ^ Neves Santos, Fred Luciano; Lima Cerqueira, Elúzio José; Matos Soares, Neci (2005). "Comparison of the thick smear and Kato-Katz techniques for diagnosis of intestinal helminth infections". Revista da Sociedade Brasileira de Medicina Tropical. 38 (2). doi:10.1590/S0037-86822005000200016. ISSN 1678-9849. Retrieved August 31, 2017. 
  6. ^ J. Richardson, Dennis; Gross, Jeanette; Smith, Michael C. (July 2008). "Comparison of Kato–Katz Direct Smear and Sodium Nitrate Flotation for Detection of Geohelminth Infections". Comparative Parasitology. The Helminthological Society of Washington. 75 (2): 339–341. doi:10.1654/4340.1. Retrieved August 31, 2017. 
  7. ^ Katz, N.; Chaves, A.; Pellegrino, J. (November 1972). "A simple device for quantitative stool thick-smear technique in Schistosomiasis mansoni". Revista Do Instituto De Medicina Tropical De Sao Paulo. 14 (6): 397–400. ISSN 0036-4665. PMID 4675644. 
  8. ^ Santos, Fred Luciano Neves; Cerqueira, Elúzio José Lima; Soares, Neci Matos (March 2005). "Comparison of the thick smear and Kato-Katz techniques for diagnosis of intestinal helminth infections". Revista Da Sociedade Brasileira De Medicina Tropical. 38 (2): 196–198. doi:10.1590/S0037-86822005000200016. ISSN 0037-8682. PMID 15821801. 
  9. ^ Santos, Fred Luciano Neves; Cerqueira, Elúzio José Lima; Soares, Neci Matos (March 2005). "Comparison of the thick smear and Kato-Katz techniques for diagnosis of intestinal helminth infections". Revista Da Sociedade Brasileira De Medicina Tropical. 38 (2): 196–198. doi:10.1590/S0037-86822005000200016. ISSN 0037-8682. PMID 15821801. 

Further reading[edit]