Comparison of Kato-Katz thick smear, Mini-FLOTAC, and Flukefinder for the detection and quantification of Fasciola hepatica eggs in artificially spiked human stool

We compared the diagnostic performance of the standard method (Kato-Katz) with two recently developed methods (Mini-FLOTAC and Flukefinder) for the detection and quantification of Fasciola hepatica eggs in human stool. Uninfected human stool samples were artificially spiked with F. hepatica eggs to reach final concentrations of 14, 28, 41, or 96 eggs per gram of stool (epg). Only Flukefinder showed 100% sensitivity in all but the samples with the lowest concentration of eggs (14 epg), in which it had a sensitivity of 60%. Each of the methods underestimated the true fecal egg counts (FECs), Flukefinder resulting in the most biased egg counts (egg counts 0.18 times lower than the expected FECs). Only the Flukefinder resulted in more precise results (coefficient of variance < 30%) from FECs of 96 epg onward. The outcome of this study indicates that the Flukefinder is a useful alternative diagnostic method for human fascioliasis in stool

Evaluatie van de mini-FLOTAC-methode voor de detectie van gastro-intestinale parasieten bij grote huisdieren

A new technique, mini-FLOTAC, has recently been developed for the microscopic diagnosis of infections with gastro-intestinal nematodes in domestic animals. In this comparative study of diagnostic techniques, the mini-FLOTAC technique was compared to the commonly used McMaster technique for the detection and quantification of gastro-intestinal parasites in livestock as well as for the evaluation of the time needed to perform the assays. One hundred fecal samples (78 horses, 11 bovines, 6 sheep and 5 goats) were examined with both the mini-FLOTAC and McMaster technique. This revealed that more infections with gastro-intestinal parasites could be diagnosed with the mini-FLOTAC technique than with the McMaster technique, but the comparative study also showed a very high correlation (correlation coefficient = 0.90, p < 0.001) between both techniques regarding the number of eggs per gram feces (EPG) detected. The time needed to examine the samples with the mini-FLOTAC technique (13 minutes) was significantly higher (P < 0.05) than the time needed with the McMaster technique (6 minutes). This difference in time also depended on the observed EPG value, as with high EPG values, the difference in time between both techniques increased even more. In conclusion, the mini-FLOTAC technique can be preferred when an accurate diagnosis of a low infection level is necessary, e.g. to detect anthelmintic resistance. In other circumstances, the faster McMaster technique can be considered as the preferable technique

Molecular identification of hookworm isolates in humans, dogs and soil in a tribal area in Tamil Nadu, India

Background : Hookworms (Necator americanus and Ancylostoma duodenale) remain a major public health problem worldwide. Infections with hookworms (e.g., A. caninum, A. ceylanicum and A. braziliense) are also prevalent in dogs, but the role of dogs as a reservoir for zoonotic hookworm infections in humans needs to be further explored. Methodology/Principal Findings : As part of an open-label community based cluster-randomized trial in a tribal area in Tamil Nadu (India; 2013-2015), a total of 143 isolates of hookworm eggs from human stool were speciated based on a previously described PCR-RFLP methodology. The presence of hookworm DNA was confirmed in 119 of 143 human samples. N. americanus (100%) was the most prevalent species, followed by A. caninum (16.8%) and A. duodenale (8.4%). Because of the high prevalence of A. caninum in humans, dog samples were also collected to assess the prevalence of A. caninum in dogs. In 68 out of 77 canine stool samples the presence of hookworms was confirmed using PCR-RFLP. In dogs, both A. caninum (76.4%) and A. ceylanicum (27.9%) were identified. Additionally, to determine the contamination of soil with zoonotic hookworm larvae, topsoil was collected from defecating areas. Hookworm DNA was detected in 72 out of 78 soil samples that revealed presence of hook-worm-like nematode larvae. In soil, different hookworm species were identified, with animal hookworms being more prevalent (A. ceylanicum: 60.2%, A. caninum: 29.4%, A. duodenale: 16.6%, N. americanus: 1.4%, A. braziliense: 1.4%). Conclusions/Significance : In our study we regularly detected the presence of A. caninum DNA in the stool of humans. Whether this is the result of infection is currently unknown but it does warrant a closer look at dogs as a potential reservoir

Prevalence & risk factors for soil transmitted helminth infection among school children in south India

Background & objectives: Soil-transmitted helminths (STH) are a major public health problem in tropical and sub-tropical countries, affecting the physical growth and cognitive development in schoolage children. This study was aimed to assess the prevalence and risk factors of STH infection among school children aged 6-14 yr in Vellore and Thiruvanamalai districts in south India. Methods: Children aged 6-14 yr, going to government and government aided schools (n=33, randomly selected) in Vellore and Thiruvanamalai districts were screened to estimate the prevalence of STH, and a case control study was done on a subset to assess the risk factors for the infection. Results: The prevalence of STH was 7.8 per cent, varying widely in schools from 0 to 20.4 per cent, in 3706 screened children. Hookworm (8.4%) rates were high in rural areas, while Ascaris (3.3%) and Trichuris (2.2%) were more prevalent among urban children. Consumption of deworming tablets (OR=0.25, P<0.01) offered protection, while residing in a field hut (OR=6.73, P=0.02) and unhygienic practices like open air defaecation (OR=5.37, P<0.01), keeping untrimmed nails (OR=2.53, P=0.01) or eating food fallen on the ground (OR=2.52, P=0.01) were important risk factors for STH infection. Interpretation & conclusions: Our study indicated that school children with specific risk factors in the studied area were vulnerable subpopulation with elevated risk of STH infection. Identifying risk factors and dynamics of transmission in vulnerable groups can help to plan for effective prevention strategies