Detection of Chagas infections using Trypanosoma evansi crude antigen demonstrates high cross-reactions with Trypanosoma cruzi Marc Desquesnes a, * , Marie-France Bosseno b , Simone Fre ´de ´rique Brenie `re b a Centre de Coope ´ration Internationale en Recherche Agronomique pour le De ´veloppement (Cirad), UMR 17 Trypanosomes, Campus de Baillarguet TA30/G, Montpellier F-34000, France b Institut de Recherche pour le De ´veloppement (IRD), De ´partement Socie ´te ´ et Sante ´, UR 008 Pathoge ´nie et Epide ´miologie des Trypanosomatide ´s, 911 Av. Agropolis, BP 64501, 34394 Montpellier Cedex 5, France Received 30 August 2006; received in revised form 17 January 2007; accepted 18 January 2007 Available online 30 January 2007 Abstract Antigenic similarities between salivarian trypanosomes are known for a long time, but similarities between salivarian and stercorarian trypanosomes have been very little investigated. Phylogenetically, these genus and species appear to be far. However, in a preliminary work we had shown strong reactions of chagasic human sera using T. evansi antigens in Western-blotting and ELISA. In the current work an ELISA test using T. evansi crude antigens was probed with one hundred and two sera of chagasic Bolivian patients previously diagnosed which presented different pathologies. The sensitivity of the ELISA T. evansi was 92.6% similar to that of ELISA T. cruzi. The specificity evaluated using 20 sera of patients infected by Leishmania sp. reaches a comparable value of that obtained with the T. cruzi immunofluorescent assay. Finally, the sensitivity and the specificity of the ELISA T. evansi were not really different from conventional serology of Chagas. In spite of their taxonomic position in various sections and their old divergence, these observations prove a strong antigenic community between T. cruzi and T. evansi. Consequently, the common antigens which remain to be characterized, could be an alternative source of antigen for the detection of antibodies against T. cruzi. Given that T. evansi seems to have strong antigenic communities with the majority of the pathogenic current trypanosomoses of mammals, it is very attractive to identify and characterize these highly conserved antigens which could be suitable targets to develop tools for diagnosis, prophylaxy and chemotherapy against several human and animal trypanosomoses. # 2007 Elsevier B.V. All rights reserved. Keywords: Trypanosoma genus; Trypanosoma evansi; Trypanosoma cruzi; Antigenic cross-reaction; Serodiagnosis; ELISA; Phylogeny 1. Introduction Trypanosomes present in mammals are classified into two sections, based on the site of multiplication of the parasite in its intermediary host. Trypanosomes having their cycle in the anterior part of the digestive tract of insects belong to the Salivaria section, while those multiplying in the posterior part of the digestive tract belong to the Stercoraria section. Whether this classification is a reflect of the phylogeny of trypanosome is not evident. Stercorarian trypanosomes include the sub-genera Herpeto- soma (Trypanosoma lewisi, etc.), Megatrypanum (Trypanosoma theileri, etc.) and Schizotrypanum with Trypanosoma cruzi the agent of Chagas disease, etc., while Salivarian trypanosomes include the sub-genera Tejeraia (Trypanosoma rangeli), Dutto- nella (Trypanosoma vivax), Nannomonas (Trypanosoma con- golense, etc.), Trypanozoon (Trypanosoma brucei, Trypansoma evansi, etc) and Pycnomonas (Trypanosoma suis). Antigenic similarities among salivarian trypanosomes are known for long; indeed cross reactions between T. congolense, T. vivax, T. evansi and T. brucei spp. have been recorded (Gray and Luckins, 1977; Ijagbone et al., 1989; Ferenc et al., 1990). Consequently, indirect-ELISA are not considered as species- specific tests (Gardiner and Mahmoud, 1990). Cross reactions between close parasites are generally explored either to prevent false positive interpretation of the tests (Monzon and Colman, 1988; Desquesnes et al., 2001), or to take advantage of them through an inter-specific detection test (Desquesnes and Tresse, 1999a). www.elsevier.com/locate/meegid Infection, Genetics and Evolution 7 (2007) 457–462 * Corresponding author. Fax: +33 4 67 59 37 98. E-mail addresses: marc.desquesnes@cirad.fr (M. Desquesnes), breniere@mpl.ird.fr (S.F. Brenie `re). 1567-1348/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.meegid.2007.01.007