Evaluation of established and new methods for the detection of Toxocara spp. in cats and dogs without a gold standard – A Bayesian latent class analysis
Deliah Tamsyn Winterfeld , Birgit Schauer , Majda Globokar , Nikola Pantchev , Susan Mouchantat , Franz Josef Conraths , Helge Kampen , Gereon Schares , Pavlo Maksimov , Jana Schulz
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引用次数: 0
Abstract
The commonly used detection method for Toxocara canis and Toxocara cati eggs in faecal samples is the sedimentation-flotation technique (SF). Based on this method, a sequential sieving protocol (SF-SSV) was developed to achieve a higher sensitivity in detecting Toxocara spp. eggs. In addition, two automated DNA extraction methods for faecal samples were applied. Faecal samples of cats (n = 125) and dogs (n = 175) were tested to detect Toxocara spp. with all four methods. Two populations were investigated; one was considered positive based on previous examinations (n = 120), and the other one represented a field population-based sample (n = 180). In general, the parasitological methods (SF, SF-SSV) had in all cases higher estimated sensitivities than the DNA detection methods. For both, cats and dogs, the SF-SSV had significantly higher sensitivities than the DNA detection methods. The estimates for specificity were above 90 % in each analysis, but lowest for the SF-SSV. By DNA detection, T. cati-specific methods tended to have higher diagnostic sensitivities than T. canis-specific methods, but not statistically significant. Traditional methods of evaluating diagnostic tests require a gold standard and a pool of appropriate reference samples. Since there is no gold standard for detecting Toxocara spp. in cats and dogs, Bayesian Latent Class Analysis (BLCA), a probabilistic approach estimating test performance, is a useful tool to estimate sensitivity and specificity based on the available data. This study highlights the challenge of obtaining suitable samples for model estimation, especially in field settings where Toxocara spp. prevalence is typically very low.
期刊介绍:
The journal Veterinary Parasitology has an open access mirror journal,Veterinary Parasitology: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review.
This journal is concerned with those aspects of helminthology, protozoology and entomology which are of interest to animal health investigators, veterinary practitioners and others with a special interest in parasitology. Papers of the highest quality dealing with all aspects of disease prevention, pathology, treatment, epidemiology, and control of parasites in all domesticated animals, fall within the scope of the journal. Papers of geographically limited (local) interest which are not of interest to an international audience will not be accepted. Authors who submit papers based on local data will need to indicate why their paper is relevant to a broader readership.
Parasitological studies on laboratory animals fall within the scope of the journal only if they provide a reasonably close model of a disease of domestic animals. Additionally the journal will consider papers relating to wildlife species where they may act as disease reservoirs to domestic animals, or as a zoonotic reservoir. Case studies considered to be unique or of specific interest to the journal, will also be considered on occasions at the Editors'' discretion. Papers dealing exclusively with the taxonomy of parasites do not fall within the scope of the journal.