Comparison of Four Parasitological Techniques for Laboratory Diagnosis of Eggs from Spirometra spp. in Wild Mammal Fecal Samples.

PURPOSE: This study aimed to compare the performance of four different microscopic coproparasitological techniques in relation to egg recovering and the frequency of alterations in the eggs observed through each technique.

METHODS

A total of 213 fecal samples from free-living carnivorous mammals were collected between 2017 and 2018 in Itatiaia National Park, RJ, Brazil. Faust and modified Sheather floatation techniques as well as Lutz and modified Ritchie sedimentation techniques were applied.

RESULTS

The total positivity rate for Spirometra spp. eggs was 24.4%, and these were detected mainly through Lutz and modified Ritchie sedimentation techniques, with substantial agreement (kappa = 0.73; p = 0.00 < 0.05; McNemar p value = 1.0; Fisher's exact test p = 0.616). Faust and modified Sheather flotation techniques did not present good egg recovery, with frequencies of 6.6% and 7.5%, respectively. Eggs with morphological alterations were mostly observed through Faust (17.3%) and modified Sheather (13.5%). Both flotation techniques presented statistically significant frequencies of deformed eggs, in comparison with the sedimentation techniques (p = 0.00). Low frequencies of deformed eggs were observed when the samples were analyzed through modified Ritchie and Lutz sedimentation techniques.

CONCLUSIONS

From these results, sedimentation techniques such as modified Ritchie and Lutz methods were more efficient for diagnosing the eggs of this helminth in fecal material from free-living carnivores and should always be used when analyzing fecal samples from hosts of different species.