Limits...
The Right Tool for the Job: Detection of Soil-Transmitted Helminths in Areas Co-endemic for Other Helminths.

Periago MV, Diniz RC, Pinto SA, Yakovleva A, Correa-Oliveira R, Diemert DJ, Bethony JM - PLoS Negl Trop Dis (2015)

Bottom Line: The CR of a single dose of mebendazole varied significantly between the KK and MM for both A. lumbricoides (p = 0.016) and hookworm (p = 0.000), with lower rates obtained with the KK.The MM did not add any diagnostic value over the KK in areas where both STHs and trematodes were co-endemic.The lower sensitivity of the MM would have an important impact on the administration of selective school-based treatment in this area since if only the MM were used, 36 (13.9%) children diagnosed with A. lumbricoides would have gone untreated.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Imunologia Celular e Molecular, Centro de Pesquisa René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil.

ABSTRACT

Background: Due to the recent increased use of the McMaster (MM) fecal egg counting method for assessing benzimidazole drug efficacy for treating soil-transmitted helminth (STH) infections, the aim of the current study was to determine the operational value of including the MM method alongside the Kato-Katz (KK) fecal thick smear to increase the diagnostic sensitivity when STHs are co-endemic with trematode helminths (e.g., Schistosoma mansoni).

Methods: A cross-sectional study was conducted in school-aged children aged 4-18 years in the northeastern region of the State of Minas Gerais (Brazil), where Necator americanus, Ascaris lumbricoides, Trichuris trichiura, and S. mansoni are co-endemic. One fecal sample from each participant was collected and transported to the field laboratory for analysis. Coprological diagnosis was performed on each fecal sample by three different methods: Formalin-Ether Sedimentation (FES), KK and the MM technique. The diagnostic sensitivity and negative predictive value (NPV) of each technique was calculated using the combination of all three techniques as the composite standard. In order to determine the agreement between the three techniques Fleiss´ kappa was used. Both the Cure Rate (CR) and the Fecal Egg Count Reduction (FECR) were calculated using the two quantification techniques (i.e., the MM and KK).

Results: Fecal samples from 1260 children were analyzed. The KK had higher diagnostic sensitivity than the MM for the detection of both A. lumbricoides (KK 97.3%, MM 69.5%) and hookworm (KK 95.1%, MM 80.8%). The CR of a single dose of mebendazole varied significantly between the KK and MM for both A. lumbricoides (p = 0.016) and hookworm (p = 0.000), with lower rates obtained with the KK. On the other hand, the FECR was very similar between both techniques for both A. lumbricoides and hookworm.

Conclusion: The MM did not add any diagnostic value over the KK in areas where both STHs and trematodes were co-endemic. The lower sensitivity of the MM would have an important impact on the administration of selective school-based treatment in this area since if only the MM were used, 36 (13.9%) children diagnosed with A. lumbricoides would have gone untreated.

No MeSH data available.


Related in: MedlinePlus

Scatter plots of arithmetic egg counts (eggs per gram of feces—EPG) comparing the Kato-Katz direct fecal smear (KK) and the McMaster counting method (MM).The graphs are presented separately for each soil-transmitted helminths: A. Ascaris lumbricoides, B. Hookworm, C. Trichuris trichiura. Correlation was measures using Spearman’s correlation coefficient: 0.86 for A. lumbricoides, 0.88 for hookworm and 0.63 for T. trichiura.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4524677&req=5

pntd.0003967.g002: Scatter plots of arithmetic egg counts (eggs per gram of feces—EPG) comparing the Kato-Katz direct fecal smear (KK) and the McMaster counting method (MM).The graphs are presented separately for each soil-transmitted helminths: A. Ascaris lumbricoides, B. Hookworm, C. Trichuris trichiura. Correlation was measures using Spearman’s correlation coefficient: 0.86 for A. lumbricoides, 0.88 for hookworm and 0.63 for T. trichiura.

Mentions: The maximum EPG count, geometric and arithmetic mean of the EPG counts, standard deviation from the mean, and lower and upper 95% confidence intervals for STHs and S. mansoni obtained with the KK and MM counting techniques are summarized in Table 3. This table also summarizes the infection intensities of the positive samples, stratified into light, moderate or heavy infections. The mean EPG was significantly higher with the KK than the MM, as evaluated using the related-samples Wilcoxon Ranked Signed Test (p<0.001), for hookworm (207.39 vs. 86.53 EPG) and A. lumbricoides (3940.01 vs. 1329.33 EPG) but not for T. trichiura (p = 0.396). The maximum EPG value was lower with the KK for T. trichiura (252 vs. 400 EPG), although it was higher for both A. lumbricoides (129,120 vs. 51,250 EPG) and for hookworm (20,616 vs. 3850 EPG). The relationship between the EPG values obtained for each sample by each technique followed a linear trend as shown by scatter plots presented in Fig 2. The correlation between the KK and MM based on Spearman’s correlation coefficient was significant for all three STHs (0.86 for A. lumbricoides, 0.88 for hookworm and 0.63 for T. trichiura).


The Right Tool for the Job: Detection of Soil-Transmitted Helminths in Areas Co-endemic for Other Helminths.

Periago MV, Diniz RC, Pinto SA, Yakovleva A, Correa-Oliveira R, Diemert DJ, Bethony JM - PLoS Negl Trop Dis (2015)

Scatter plots of arithmetic egg counts (eggs per gram of feces—EPG) comparing the Kato-Katz direct fecal smear (KK) and the McMaster counting method (MM).The graphs are presented separately for each soil-transmitted helminths: A. Ascaris lumbricoides, B. Hookworm, C. Trichuris trichiura. Correlation was measures using Spearman’s correlation coefficient: 0.86 for A. lumbricoides, 0.88 for hookworm and 0.63 for T. trichiura.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4524677&req=5

pntd.0003967.g002: Scatter plots of arithmetic egg counts (eggs per gram of feces—EPG) comparing the Kato-Katz direct fecal smear (KK) and the McMaster counting method (MM).The graphs are presented separately for each soil-transmitted helminths: A. Ascaris lumbricoides, B. Hookworm, C. Trichuris trichiura. Correlation was measures using Spearman’s correlation coefficient: 0.86 for A. lumbricoides, 0.88 for hookworm and 0.63 for T. trichiura.
Mentions: The maximum EPG count, geometric and arithmetic mean of the EPG counts, standard deviation from the mean, and lower and upper 95% confidence intervals for STHs and S. mansoni obtained with the KK and MM counting techniques are summarized in Table 3. This table also summarizes the infection intensities of the positive samples, stratified into light, moderate or heavy infections. The mean EPG was significantly higher with the KK than the MM, as evaluated using the related-samples Wilcoxon Ranked Signed Test (p<0.001), for hookworm (207.39 vs. 86.53 EPG) and A. lumbricoides (3940.01 vs. 1329.33 EPG) but not for T. trichiura (p = 0.396). The maximum EPG value was lower with the KK for T. trichiura (252 vs. 400 EPG), although it was higher for both A. lumbricoides (129,120 vs. 51,250 EPG) and for hookworm (20,616 vs. 3850 EPG). The relationship between the EPG values obtained for each sample by each technique followed a linear trend as shown by scatter plots presented in Fig 2. The correlation between the KK and MM based on Spearman’s correlation coefficient was significant for all three STHs (0.86 for A. lumbricoides, 0.88 for hookworm and 0.63 for T. trichiura).

Bottom Line: The CR of a single dose of mebendazole varied significantly between the KK and MM for both A. lumbricoides (p = 0.016) and hookworm (p = 0.000), with lower rates obtained with the KK.The MM did not add any diagnostic value over the KK in areas where both STHs and trematodes were co-endemic.The lower sensitivity of the MM would have an important impact on the administration of selective school-based treatment in this area since if only the MM were used, 36 (13.9%) children diagnosed with A. lumbricoides would have gone untreated.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Imunologia Celular e Molecular, Centro de Pesquisa René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil.

ABSTRACT

Background: Due to the recent increased use of the McMaster (MM) fecal egg counting method for assessing benzimidazole drug efficacy for treating soil-transmitted helminth (STH) infections, the aim of the current study was to determine the operational value of including the MM method alongside the Kato-Katz (KK) fecal thick smear to increase the diagnostic sensitivity when STHs are co-endemic with trematode helminths (e.g., Schistosoma mansoni).

Methods: A cross-sectional study was conducted in school-aged children aged 4-18 years in the northeastern region of the State of Minas Gerais (Brazil), where Necator americanus, Ascaris lumbricoides, Trichuris trichiura, and S. mansoni are co-endemic. One fecal sample from each participant was collected and transported to the field laboratory for analysis. Coprological diagnosis was performed on each fecal sample by three different methods: Formalin-Ether Sedimentation (FES), KK and the MM technique. The diagnostic sensitivity and negative predictive value (NPV) of each technique was calculated using the combination of all three techniques as the composite standard. In order to determine the agreement between the three techniques Fleiss´ kappa was used. Both the Cure Rate (CR) and the Fecal Egg Count Reduction (FECR) were calculated using the two quantification techniques (i.e., the MM and KK).

Results: Fecal samples from 1260 children were analyzed. The KK had higher diagnostic sensitivity than the MM for the detection of both A. lumbricoides (KK 97.3%, MM 69.5%) and hookworm (KK 95.1%, MM 80.8%). The CR of a single dose of mebendazole varied significantly between the KK and MM for both A. lumbricoides (p = 0.016) and hookworm (p = 0.000), with lower rates obtained with the KK. On the other hand, the FECR was very similar between both techniques for both A. lumbricoides and hookworm.

Conclusion: The MM did not add any diagnostic value over the KK in areas where both STHs and trematodes were co-endemic. The lower sensitivity of the MM would have an important impact on the administration of selective school-based treatment in this area since if only the MM were used, 36 (13.9%) children diagnosed with A. lumbricoides would have gone untreated.

No MeSH data available.


Related in: MedlinePlus