Kato technique
Encyclopedia
The Kato technique is a laboratory method for preparing human stool samples prior to searching for parasite eggs.
eggs. 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: 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. The other main argument against the Kato technique is that it is messy and therefore exposes technicians to an unnecessarily high risk of infection.
Indications
The Kato technique is now most commonly used for detecting schistosomeSchistosoma
A genus of trematodes, Schistosoma, commonly known as blood-flukes and bilharzia, includes flatworms which are responsible for a highly significant parasitic infection of humans by causing the disease schistosomiasis, and are considered by the World Health Organization as the second most...
eggs. It has in the past been used for other helminth eggs as well. It cannot be used to identify hookworm
Hookworm
The hookworm is a parasitic nematode that lives in the small intestine of its host, which may be a mammal such as a dog, cat, or human. Two species of hookworms commonly infect humans, Ancylostoma duodenale and Necator americanus. A. duodenale predominates in the Middle East, North Africa, India...
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: the problem may be that eggs of Schistosoma mansoni
Schistosoma mansoni
Schistosoma mansoni is a significant parasite of humans, a trematode that is one of the major agents of the disease schistosomiasis. The schistosomiasis caused by Schistosoma mansoni is intestinal schistosomiasis....
tend to clump together which means that even slides prepared from the same specimen may contain widely different egg counts. 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
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.Further reading
- Glinz D., Silué K.D., Knopp S., Lohourignon L.K., Yao K.P. et al. (2010). "Comparing Diagnostic Accuracy of Kato-Katz, Koga Agar Plate, Ether-Concentration, and FLOTAC for Schistosoma mansoni and Soil-Transmitted Helminths". PLoS Neglected Tropical DiseasesPLoS Neglected Tropical DiseasesPLoS Neglected Tropical Diseases is an open access, online scientific journal devoted to the study of neglected tropical diseases. Submissions go through pre-publication peer review for scientific rigor and relevance to a specific set of overlooked diseases, including helminth, bacterial, viral,...
4(7): e754. doi:10.1371/journal.pntd.0000754.