An assessment of a composite sampling method for counting strongyle eggs in sheep faeces

Abstract

The conventional method for estimating the average strongyle egg count for a group of sheep was compared with a single count from a group composite faecal sample. Sixty-one groups of field samples were used. Composite samples were prepared in the laboratory by pooling equal amounts of faeces from individual samples. Data were logtransformed for analysis to meet the assumption of normality. There were no significant differences in the variances and overall mean counts obtained by the 2 methods. The regression line of log (composite count) on log (group arithmetic mean) did not differ significantly from the line of identity. When untransformed egg count data were categorised as low, moderate and high, the 2 methods were in agreement for 53 of the 61 groups. The mixing and counting process used for both methods (modified McMaster technique) gave highly repeatable results (repeatability = 0.94). The composite method was a quicker and valid alternative to the conventional method for monitoring helminthosis in sheep flocks.

Comparison of individual and pooled stool samples for the assessment of intensity of Schistosoma mansoni and soil-transmitted helminth infections using the Kato-Katz technique

“…First, our results confirm that pooling stool samples provided intensity estimates for both STH and S. mansoni infections comparable to those obtained after examination of individual stool samples when using the Kato-Katz technique. These findings of comparable infection intensity estimates are in line with previous studies assessing pooling strategies to evaluate helminth infections in both animals [ 12 – 15 ] and humans [ 8 ]. Second, it shows that time for processing and examination of samples using Kato-Katz can significantly be reduced, suggesting that the same funds would support examination of 3 to 5 times more subjects when individual stool samples are pooled into pools of 5 or 20, respectively.…”

Comparison of individual and pooled urine samples for estimating the presence and intensity of Schistosoma haematobium infections at the population level

“…For example, in this setting it is expected that examining 30 ml of a pool of 20 individual samples instead of 10 ml would already increase the sensitivity from 63.3 to 95.1 % (= 1-(1–0.633) 3 ). The quantitative performance highlights that pooling provides comparable estimates of infection intensity, and this finding is in line with previous studies assessing pooling of stool samples as an alternative strategy to evaluate helminth infections in both animals [ 6 – 8 ] and humans [ 9 , 10 ], highlighting that pooling of urine samples could translate into important cost-savings in large-scaled epidemiological surveys required to monitor the progress of MDA programmes.…”

“…However, this strategy of individually screening a large number of subjects faces some important financial and technical obstacles, particularly when MDA programmes are mainly operating in resource-limited settings. In veterinary medicine, pooling samples has been applied to reduce number of diagnosis, and hence reducing the costs for monitoring the impact of measures to control helminth infections [ 6 – 8 ]. Recently, pooling stool samples has also been evaluated for the assessment of two NTDs, including soil-transmitted helminthiasis and schistosomiasis ( Schistosoma mansoni ) [ 9 , 10 ].…”

Anthelmintic resistance in ovine gastrointestinal nematodes in inland southern Queensland

“…In the laboratory, 15 samples from each treatment group were subdivided into three groups of five each, with each subgroup analysed by the modified McMaster technique. Eggs were enumerated at ×40 magnification with 1 egg equivalent to 40 epg of faeces.…”