Volume 97, Issue 3
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Soil-transmitted helminths, or parasitic intestinal worms, are among the most prevalent and geographically widespread parasitic infections in the world. Accurate diagnosis and quantification of helminth infection are critical for informing and assessing deworming interventions. The Kato–Katz thick smear technique, the most widely used laboratory method to quantitatively assess infection prevalence and infection intensity of helminths, has often been compared with other methods. Only a few small-scale studies, however, have considered ways to improve its diagnostic sensitivity. This study, conducted among 4,985 school-age children in an area of rural China with moderate prevalence of helminth infection, examines the effect on diagnostic sensitivity of the Kato–Katz technique when two fecal samples collected over consecutive days are examined and compared with a single sample. A secondary aim was to consider cost-effectiveness by calculating an estimate of the marginal costs of obtaining an additional fecal sample. Our findings show that analysis of an additional fecal sample led to increases of 23%, 26%, and 100% for , and hookworm prevalence, respectively. The cost of collecting a second fecal sample for our study population was approximately USD4.60 per fecal sample. Overall, the findings suggest that investing 31% more capital in fecal sample collection prevents an underestimation of prevalence by about 21%, and hence improves the diagnostic sensitivity of the Kato–Katz method. Especially in areas with light-intensity infections of soil-transmitted helminths and limited public health resources, more accurate epidemiological surveillance using multiple fecal samples will critically inform decisions regarding infection control and prevention.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...



  1. World Health Organization, 2017. Soil-Transmitted Helminth Infections. Geneva, Switzerland: World Health Organization. http://www.who.int/mediacentre/factsheets/fs366/en/. Accessed July 20, 2016.
  2. Hotez PJ, Brindley PJ, Bethony JM, King CH, Pearce EJ, Jacobson J, , 2008. Helminth infections: the great neglected tropical diseases. J Clin Invest 118: 13111321. [Google Scholar]
  3. World Health Organization, 1994. Bench Aids for the Diagnosis of Intestinal Parasites. Planches pour le diagnostic des parasites intestinaux. http://www.who.int/iris/handle/10665/37323. Accessed July 19, 2016.
  4. Na K, Chaves A, Pellegrino JP, , 1971. A simple device for quantitative stool thick-smear technique in Schistomiasis mansoni. ResearchGate 14: 397400. [Google Scholar]
  5. Yu JM, de Vlas SJ, Jiang QW, Gryseels B, , 2007. Comparison of the Kato-Katz technique, hatching test and indirect hemagglutination assay (IHA) for the diagnosis of Schistosoma japonicum infection in China. Parasitol Int 56: 4549. [Google Scholar]
  6. Speich B, Knopp S, Mohammed KA, Khamis IS, Rinaldi L, Cringoli G, Rollinson D, Utzinger J, , 2010. Comparative cost assessment of the Kato-Katz and FLOTAC techniques for soil-transmitted helminth diagnosis in epidemiological surveys. Parasit Vectors 3: 71. [Google Scholar]
  7. Levecke B, , ., 2011. A comparison of the sensitivity and fecal egg counts of the McMaster egg counting and Kato-Katz thick smear methods for soil-transmitted helminths. PLoS Negl Trop Dis 5: e1201. [Google Scholar]
  8. Glinz D, Silué KD, Knopp S, Lohourignon LK, Yao KP, Steinmann P, Rinaldi L, Cringoli G, N’Goran EK, Utzinger J, , 2010. Comparing diagnostic accuracy of Kato-Katz, Koga agar plate, ether-concentration, and FLOTAC for Schistosoma mansoni and soil-transmitted helminths. PLoS Negl Trop Dis 4: e754. [Google Scholar]
  9. Knopp S, , ., 2014. Diagnostic accuracy of Kato-Katz, FLOTAC, Baermann, and PCR methods for the detection of light-intensity hookworm and Strongyloides stercoralis infections in Tanzania. Am J Trop Med Hyg 90: 535545. [Google Scholar]
  10. Barda B, Cajal P, Villagran E, Cimino R, Juarez M, Krolewiecki A, Rinaldi L, Cringoli G, Burioni R, Albonico M, , 2014. Mini-FLOTAC, Kato-Katz and McMaster: three methods, one goal; highlights from north Argentina. Parasit Vectors 7: 271. [Google Scholar]
  11. Habtamu K, Degarege A, Ye-Ebiyo Y, Erko B, , 2011. Comparison of the Kato-Katz and FLOTAC techniques for the diagnosis of soil-transmitted helminth infections. Parasitol Int 60: 398402. [Google Scholar]
  12. Nikolay B, Brooker SJ, Pullan RL, , 2014. Sensitivity of diagnostic tests for human soil-transmitted helminth infections: a meta-analysis in the absence of a true gold standard. Int J Parasitol 44: 765774. [Google Scholar]
  13. Tarafder MR, Carabin H, Joseph L, Balolong E, Olveda R, McGarvey ST, , 2010. Estimating the sensitivity and specificity of Kato-Katz stool examination technique for detection of hookworms, Ascaris lumbricoides and Trichuris trichiura infections in humans in the absence of a “gold standard.” Int J Parasitol 40: 399404. [Google Scholar]
  14. Knopp S, Mgeni AF, Khamis IS, Steinmann P, Stothard JR, Rollinson D, Marti H, Utzinger J, , 2008. Diagnosis of soil-transmitted helminths in the era of preventive chemotherapy: effect of multiple stool sampling and use of different diagnostic techniques. PLoS Negl Trop Dis 2: e331. [Google Scholar]
  15. Booth M, Vounatsou P, N’goran EK, Tanner M, Utzinger J, , 2003. The influence of sampling effort and the performance of the Kato-Katz technique in diagnosing Schistosoma mansoni and hookworm co-infections in rural Côte d’Ivoire. Parasitology 127: 525531. [Google Scholar]
  16. Hall A, , 1981. Quantitative variability of nematode egg counts in faeces: a study among rural Kenyans. Trans R Soc Trop Med Hyg 75: 682687. [Google Scholar]
  17. Anderson RM, Schad GA, , 1985. Hookworm burdens and faecal egg counts: an analysis of the biological basis of variation. Trans R Soc Trop Med Hyg 79: 812825. [Google Scholar]
  18. Bossche HV, Thienpont D, Janssens PG, , 2012. Chemotherapy of Gastrointestinal Helminths. Springer Berlin Heidelberg: Heidelberg, Germany.
  19. Steinmann P, Du Z-W, Wang L-B, Wang X-Z, Jiang J-Y, Li L-H, Marti H, Zhou X-N, Utzinger J, , 2008. Extensive multiparasitism in a village of Yunnan province, People’s Republic of China, revealed by a suite of diagnostic methods. Am J Trop Med Hyg 78: 760769. [Google Scholar]
  20. Lin D-D, , ., 2008. Routine Kato–Katz technique underestimates the prevalence of Schistosoma japonicum: a case study in an endemic area of the People’s Republic of China. Parasitol Int 57: 281286. [Google Scholar]
  21. Liu C, , ., 2015. Soil-transmitted helminths in Southwestern China: a cross-sectional study of links to cognitive ability, nutrition, and school performance among children. PLoS Negl Trop Dis 9: e0003877. [Google Scholar]
  22. Wang X, Zhang L, Luo R, Wang G, Chen Y, Medina A, Eggleston K, Rozelle S, Smith DS, , 2012. Soil-transmitted helminth infections and correlated risk factors in preschool and school-aged children in rural southwest China. PLoS One 7: e45939. [Google Scholar]
  23. Dacombe RJ, Crampin AC, Floyd S, Randall A, Ndhlovu R, Bickle Q, Fine PEM, , 2007. Time delays between patient and laboratory selectively affect accuracy of helminth diagnosis. Trans R Soc Trop Med Hyg 101: 140145. [Google Scholar]
  24. Koga K, Kasuya S, Khamboonruang C, Sukhavat K, Ieda M, Takatsuka N, Kita K, Ohtomo H, , 1991. A modified agar plate method for detection of Strongyloides stercoralis. Am J Trop Med Hyg 45: 518521. [Google Scholar]
  25. World Health Organization, 2016. Intestinal Worms. Geneva, Switzerland: WHO. http://www.who.int/intestinal_worms/more/en/. Accessed July 20, 2016.

Data & Media loading...

Supplemental Table

  • Received : 08 Sep 2016
  • Accepted : 15 May 2017
  • Published online : 03 Jul 2017

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error