Comparison of serological and molecular tests for detection of Trypanosoma evansi in domestic animals from Ghardaïa district, South Algeria.
Abstract: Trypanosoma evansi (T. evansi) is a hemoflagellate parasite that affects a broad range of mammalian hosts and that causes a disease called surra. Diagnosis of surra based on clinical symptoms alone is inaccurate. Therefore, a variety of serological and molecular diagnostic tests are used to assist in the detection of T. evansi infections. The aim of this study was to compare the diagnostic performance of four serological tests (CATT/T.evansi, immune trypanolysis, ELISA with purified variant surface glycoprotein RoTat 1.2 and with whole cell lysate) and two molecular PCR tests targeting sequences within the ribosomal genes locus (ITS1 TD PCR and 18S qPCR). Tests were carried out on blood samples from 161 dromedary camels, 93 horses, 129 goats, 168 sheep, 127 bovines and 76 dogs. Latent class analysis was carried out to calculate the sensitivity and specificity of each diagnostic test. Cohen's Kappa test was used to assess the concordance between the different diagnostic tests. Overall positivity rates observed with the serological tests were as follows: 3.1 % with CATT/T.evansi, 4.9 % with ELISA/RoTat 1.2, 3.4 % with ELISA/whole lysate and 2.0 % with immune trypanolysis (TL). Among the 754 samples tested with the molecular tests, 1.7 % were positive with 18S qPCR and 1.3 % with ITS1 TD PCR. Cohen's Kappa test showed agreement ranging from fair to substantial (k = 0.2-0.8) between serological diagnostic tests. However, it showed a perfect agreement (k = 0.868) between molecular diagnostic tests. Latent class analysis showed that all serological tests were 100 % sensitive, in contrast to the molecular tests with 47 % sensitivity. All tests, though, were highly specific (≥ 97 %). Given the persistence of circulating antibodies after cure, detectable by serological tests, it is recommend combining a serological and a molecular diagnostic test for accurate diagnosis of infection with T. evansi in domestic animals.
Copyright © 2020 Elsevier B.V. All rights reserved.
Publication Date: 2020-03-19 PubMed ID: 32222595DOI: 10.1016/j.vetpar.2020.109089Google Scholar: Lookup
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- Comparative Study
- Journal Article
Summary
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This research paper revolves around the comparison of diagnostic tests for detecting Trypanosoma evansi, a disease-causing parasite, in various domestic animals from Algeria. It looked at four different serological tests and two molecular tests, assessing their effectiveness and consistency in identifying the pathogen.
About Trypanosoma evansi
- Trypanosoma evansi is a parasite that can infect various mammalian hosts.
- The infection it causes is known as “surra,” and it can’t be accurately diagnosed based on symptoms alone.
- Therefore, scientists rely on molecular and serological tests to identify the infection.
Aim and Methodology of the Study
- The research aimed to compare the effectiveness of four serological tests and two molecular PCR tests in diagnosing T. evansi.
- The tests were performed on blood samples from various domestic animals including camels, horses, goats, sheep, bovines, and dogs.
- The sensitivity and specificity of each diagnostic test were calculated using latent class analysis.
- Cohen’s Kappa test was used to gauge the concordance between different diagnostic tests.
Results
- The highest positivity rate observed with serological tests was 4.9% with the ELISA/RoTat 1.2 test. The overall positivity rate with the molecular tests was low (1.3-1.7%).
- Cohen’s Kappa test showed fair to substantial agreement between serological diagnostic tests (k=0.2-0.8) and perfect agreement (k=0.868) between molecular diagnostic tests.
- The latent class analysis showed that the serological tests were 100% sensitive, while the molecular tests were significantly less sensitive at 47%.
- However, all tests were found to be highly specific (≥ 97%).
Conclusion
- Despite the high sensitivity of serological tests, the persistence of circulating antibodies detectable by these tests even after the infection has been cured suggests using a combination of serological and molecular tests for an accurate diagnosis of T. evansi.
Cite This Article
APA
Benfodil K, Büscher P, Abdelli A, Van Reet N, Mohamed-Herif A, Ansel S, Fettata S, Dehou S, Bebronne N, Geerts M, Balharbi F, Ait-Oudhia K.
(2020).
Comparison of serological and molecular tests for detection of Trypanosoma evansi in domestic animals from Ghardaïa district, South Algeria.
Vet Parasitol, 280, 109089.
https://doi.org/10.1016/j.vetpar.2020.109089 Publication
Researcher Affiliations
- High National Veterinary School of Algiers, Issad Street, Oued Smar, Bab Ezzouar, Algeria; Akli Mohand Oulhadj University, Department of Agriculture Science, Drissi Yahia Street, Bouira, Algeria. Electronic address: karimaensv@gmail.com.
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000 Antwerp, Belgium.
- Akli Mohand Oulhadj University, Department of Agriculture Science, Drissi Yahia Street, Bouira, Algeria.
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000 Antwerp, Belgium.
- High National Veterinary School of Algiers, Issad Street, Oued Smar, Bab Ezzouar, Algeria.
- High National Veterinary School of Algiers, Issad Street, Oued Smar, Bab Ezzouar, Algeria.
- Veterinary Practice, Thnia Street, Ghardaïa, Algeria.
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000 Antwerp, Belgium.
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000 Antwerp, Belgium.
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000 Antwerp, Belgium.
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000 Antwerp, Belgium.
- High National Veterinary School of Algiers, Issad Street, Oued Smar, Bab Ezzouar, Algeria.
MeSH Terms
- Algeria
- Animals
- Camelus
- Cattle
- Dogs
- Enzyme-Linked Immunosorbent Assay / veterinary
- Goat Diseases / diagnosis
- Goats
- Horse Diseases / diagnosis
- Horses
- Polymerase Chain Reaction / veterinary
- Serologic Tests / veterinary
- Sheep
- Sheep Diseases / diagnosis
- Trypanosoma / isolation & purification
- Trypanosomiasis / diagnosis
- Trypanosomiasis / veterinary
Conflict of Interest Statement
Declaration of Competing Interest None.
Citations
This article has been cited 6 times.- Boushaki D, Wallis J, Van den Broeck F, Schnaufer A. Molecular Analysis of Trypanosome Infections in Algerian Camels.. Acta Parasitol 2022 Sep;67(3):1246-1253.
- Habeeba S, Khan RA, Zackaria H, Yammahi S, Mohamed Z, Sobhi W, AbdelKader A, Alhosani MA, Muhairi SA. Comparison of Microscopy, Card Agglutination Test for Trypanosoma Evansi, and Real-time PCR in The Diagnosis of Trypanosomosis in Dromedary Camels of The Abu Dhabi Emirate, UAE.. J Vet Res 2022 Mar;66(1):125-129.
- Tirado TC, Moura LL, Shigunov P, Figueiredo FB. Methodological Appraisal of Literature Concerning the Analysis of Genetic Variants or Protein Levels of Complement Components on Susceptibility to Infection by Trypanosomatids: A Systematic Review.. Front Immunol 2021;12:780810.
- Van Reet N, Patient Pyana P, Dehou S, Bebronne N, Deborggraeve S, Büscher P. Single nucleotide polymorphisms and copy-number variations in the Trypanosoma brucei repeat (TBR) sequence can be used to enhance amplification and genotyping of Trypanozoon strains.. PLoS One 2021;16(10):e0258711.
- Boutellis A, Bellabidi M, Benaissa MH, Harrat Z, Brahmi K, Drali R, Kernif T. New Haplotypes of Trypanosoma evansi Identified in Dromedary Camels from Algeria.. Acta Parasitol 2021 Mar;66(1):294-302.
- Benaissa MH, Mimoune N, Bentria Y, Kernif T, Boukhelkhal A, Youngs CR, Kaidi R, Faye B, Halis Y. Seroprevalence and risk factors for Trypanosoma evansi, the causative agent of surra, in the dromedary camel (Camelus dromedarius) population in Southeastern Algeria.. Onderstepoort J Vet Res 2020 Dec 21;87(1):e1-e9.
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