A review on the diagnosis of animal trypanosomoses

Marc Desquesnes,Géraldine Bossard,Denis Sereno,Sophie Ravel,Alireza Sazmand,Sophie Thévenon,Philippe Solano,Philippe Jacquiet,Alain Boulangé,Marisa Gonzatti,Philippe Truc,Stéphane Herder,Vincent Jamonneau,Geoffrey Gimonneau,David Berthier,Sathaporn Jittapalapong

doi:10.1186/s13071-022-05190-1

Abstract

This review focuses on the most reliable and up-to-date methods for diagnosing trypanosomoses, a group of diseases of wild and domestic mammals, caused by trypanosomes, parasitic zooflagellate protozoans mainly transmitted by insects. In Africa, the Americas and Asia, these diseases, which in some cases affect humans, result in significant illness in animals and cause major economic losses in livestock. A number of pathogens are described in this review, including several Salivarian trypanosomes, such as Trypanosoma brucei sspp. (among which are the agents of sleeping sickness, the human African trypanosomiasis [HAT]), Trypanosoma congolense and Trypanosoma vivax (causing “Nagana” or animal African trypanosomosis [AAT]), Trypanosoma evansi (“Surra”) and Trypanosoma equiperdum (“Dourine”), and Trypanosoma cruzi, a Stercorarian trypanosome, etiological agent of the American trypanosomiasis (Chagas disease). Diagnostic methods for detecting zoonotic trypanosomes causing Chagas disease and HAT in animals, as well as a diagnostic method for detecting animal trypanosomes in humans (the so-called “atypical human infections by animal trypanosomes” [a-HT]), including T. evansi and Trypanosoma lewisi (a rat parasite), are also reviewed. Our goal is to present an integrated view of the various diagnostic methods and techniques, including those for: (i) parasite detection; (ii) DNA detection; and (iii) antibody detection. The discussion covers various other factors that need to be considered, such as the sensitivity and specificity of the various diagnostic methods, critical cross-reactions that may be expected among Trypanosomatidae, additional complementary information, such as clinical observations and epizootiological context, scale of study and logistic and cost constraints. The suitability of examining multiple specimens and samples using several techniques is discussed, as well as risks to technicians, in the context of specific geographical regions and settings. This overview also addresses the challenge of diagnosing mixed infections with different Trypanosoma species and/or kinetoplastid parasites. Improving and strengthening procedures for diagnosing animal trypanosomoses throughout the world will result in a better control of infections and will significantly impact on “One Health,” by advancing and preserving animal, human and environmental health.Graphical

Highlights

The family Trypanosomatidae comprises 14 monoxenous genera infecting insects (e.g. Leptomonas, Herpetomonas) and five dixenous genera having invertebrates as vectors (one genus infecting plants [Phytomonas] and the other fourDesquesnes et al Parasites & Vectors (2022) 15:64 infecting animals and humans)
Among the four genera infecting animals and humans, two are anecdotic, i.e. Endotrypanum found in sloths and Porcisia found in porcupine; the other two genera, namely Trypanosoma and Leishmania, contain pathogenic parasites of medical and veterinary importance
We focus on the diagnosis of trypanosomes in animals; in a “One Health concept” [14], this focus includes human pathogens, providing that animals carry and/or are affected by these pathogens, and/or play a role in the epidemiology of the human diseases

Summary

Introduction

Desquesnes et al Parasites & Vectors (2022) 15:64 infecting animals and humans). Among the four genera infecting animals and humans, two are anecdotic, i.e. Endotrypanum found in sloths and Porcisia found in porcupine; the other two genera, namely Trypanosoma and Leishmania, contain pathogenic parasites of medical and veterinary importance. Both Trypanosoma and Leishmania are widely distributed over the world, and they affect humans, animals or both, as anthroponotic or zoonotic agents [1]. Leishmaniasis has a high medical impact, with approximately 70,000 deaths recorded annually and an estimated 350 million individuals at risk [2]. Trypanosomoses are significant diseases of domestic and wild mammals, affecting millions of livestock in Africa, the Americas and Asia [5], as well as of humans in Africa and Latin America [6,7,8,9,10]

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