Mini-FLOTAC, Kato-Katz and McMaster: three methods, one goal; highlights from north Argentina

Abstract

BackgroundCopro-parasitological diagnosis is still a challenge in management of helminth infections at individual and community levels in resource-limited settings.The aim of our study was to compare the performance of three quantitative techniques: Kato-Katz, McMaster and Mini-FLOTAC methids. The study was carried out in Oran, Northern Argentina.Methods200 schoolchildren were enrolled to provide a single stool sample, which was tested for helminth infections with Kato-Katz, McMaster and Mini-FLOTAC methods. The Mini-FLOTAC was performed with two flotation solutions (FS2 saturated saline and FS7 zinc sulphate). Preparation and reading time for each of the three methods was calculated both when processing single and multiple samples.ResultsOut of 193 schoolchildren examined, 40% were positive for any helminth infection by any method; the most prevalent was Hymenolepis nana (23%) followed by Ascaris lumbricoides (17%) and a third group of less prevalent helminths: Enterobius vermicularis, Trichuris trichiura and hookworms (11% all together). Mini-FLOTAC FS2 was more sensitive than FS7 for H. nana (93% vs 78%) and for other helminths (85% vs 80%), whereas FS7 was more sensitive for A. lumbricoides (87% vs 61%). Kato-Katz method was more sensitive than McMaster method for A. lumbricoides (84% vs 48%) and for other helminths (48% vs 43%) except for H. nana (49% vs 61%). As for egg counts, Mini-FLOTAC FS2 reported 904 eggs per gram of faeces (EPG) for H. nana (vs 457 with McMaster and 111 with Kato-Katz) and 1177 EPG for A. lumbricoides (vs 1315 with Kato-Katz and 995 with McMaster); FS2 detected the highest EPG for both H.nana and A.lumbricoides (904 vs 568 and 1177 vs 643 respectively), the differences were not statistically significant. The technique feasibility was calculated: Kato-Katz mean time was 48 minutes/sample, Mini-FLOTAC 13 minutes/sample and McMaster 7 minutes/sample. However, especially for Kato-Katz and Mini-FLOTAC, the mean time (min/sample) decreased significantly when processing multiple samples.ConclusionsMini-FLOTAC is a promising technique for helminth diagnosis, it is more sensitive than Kato-Katz and McMaster for H. nana and as sensitive as Kato-Katz and more sensitive than McMaster for A. lumbricoides identification. Egg counts differences although relevant, did not reach statistical significance.

Novel approaches to the diagnosis of Strongyloides stercoralis infection

“…Until now, faecal surveys on the prevalence of STHs have often relied on stool concentration methods such as the Kato-Katz [ [15][16][17][18], Mini-FLOTAC and McMaster [19] techniques. With standard methods, prevalence studies are affected by a lack of sensitivity.…”

A low‐cost, automated parasite diagnostic system via a portable, robotic microscope and deep learning

“…Due to the limited field of view, imaging an entire slide currently takes approximately 12 minutes. This can be compared with 7 to 40 minutes for manual counting . However, when submitting to the CNN, the images are first downsampled by a factor of 4 in each direction.…”

“…Traditional diagnosis of intestinal parasite infection is performed via manual microscopic observation of fecal samples. These samples are prepared with a wide variety of preparation methods, with the Kato‐Katz and modified McMaster method being among the simplest, most accurate, and therefore most common methods , with the more complex FLOATAC protocol becoming increasingly popular due to its high performance, albeit with increased complexity and sample processing time , However, current gold‐standard FEC techniques require relatively costly microscopes and a highly trained observer, and may require transportation of fresh samples under refrigeration to the laboratory for later analysis. Thus, there is a need to develop low‐cost, portable instrumentation that can effectively count the eggs of multiple species of intestinal parasites outside of a laboratory setting and without the need for a trained user.…”

Rationale for Quality Assurance in Fecal Egg Monitoring of Soil-Transmitted Helminthiasis

“…The Kato-Katz method has been the World Health Organization (WHO) standard for diagnosing STHs in humans for nearly two decades due to its low cost and minimal equipment requirement, but many of the FEC methods developed for the veterinary field also hold promise for human application 5–9. Veterinary techniques being adapted for human use include the McMaster method, common in agricultural parasitology, and the FLOtation TrAnslation Cringoli (FLOTAC) and Mini-FLOTAC, which have higher sensitivities than Kato-Katz and McMaster 7,8…”