Diagnostic value of the recombinant tandem repeat antigen TeGM6-4r for surra in water buffaloes

Abstract

Trypanosoma evansi infection, or surra, is currently affecting various species of animals, especially water buffaloes. Since diagnosis is an important aspect of surra control, development of novel diagnostic antigens is of interest to implement and improve the currently utilized methods. Our study evaluated the tandem repeat antigen TeGM6-4r in T. evansi antibody detection in water buffaloes. TeGM6-4r-based ELISA was performed with 20 positive and 8 negative controls and 484 field samples from water buffaloes in Northern Vietnam. To examine cross-reactivity, sera from Japanese cattle that had been experimentally infected with Theileria orientalis (n=10), Babesia bovis (n=3), Babesia bigemina (n=7) and Trypanosoma theileri (n=59) were included in the study. The sensitivity of the test was 80%. TeGM6-4r did not react with Theileria or Babesia infected sera, however it showed cross reactivity with 11/59 T. theileri infected samples. The reference test, CATT/T. evansi also reacted with 3/59 T. theileri infected sera. The lysate antigen-based ELISA reacted with 4/59 T. theileri, 9/10 Theileria and 3/10 Babesia infected sera. In contrast, TeGM6-4r-based ELISA was 86.3% sensitive and 58.3% specific in the screening of field samples. The average seroprevalence of T. evansi infection among water buffaloes in Northern Vietnam was 27.1% by CATT/T. evansi and 53.7% by TeGM6-4r. Seroprevalence in the five surveyed provinces ranged from 17.4% to 39.8% in the reference test, and 47.3% to 67.3% in the recombinant antigen based test. The finding indicated that the disease is still widely endemic in the area and that surveillance programs need to be carried out regularly to better control surra. We proposed TeGM6-4r as a useful serodiagnostic antigen for the detection and epidemiological surveillance of T. evansi infection among water buffaloes.

Isolation, cultivation and molecular characterization of a new Trypanosoma equiperdum strain in Mongolia

“…The blood parameters (white blood cell [WBC], red blood cell [RBC], hemoglobin [HGB], hematocrit [HCT], mean corpuscular volume [MCV], mean corpuscular hematocrit [MCH], mean corpuscular hemoglobin concentration [MCHC], and platelet [PLT] count) were measured using a Celltac α (Nihon Khoden, Tokyo, Japan); while the measurement of the blood chemistry parameters (alkaline phosphatase [ALP], alanine transaminase [ALT], aspartate aminotransferase [AST], albumin, total protein, total cholesterol, bilirubin, blood urea nitrogen [BUN], creatinine, and amylase) was outsourced (Table 1). Molecular diagnoses were then performed using DNA extracted from the blood and serum of the stallion by a KIN-PCR, a complement fixation test (CFT), a recombinant T. evansi GM6-4r antigen-based immunochromatographic test (ICT) and an enzyme-linked immunosorbent assay (ELISA) [10–13]. The collected cerebrospinal fluid (CSF) was centrifuged to concentrate the trypanosomes.…”

Serological and molecular detection of selected hemoprotozoan parasites in donkeys in West Omdurman, Khartoum State, Sudan

“…evansi crude antigen-based ELISA (TeCA-ELISA). The rTeGM6-4r antigen was produced, and ELISA was conducted as described previously [27]. Tr.…”

“…Tr. evansi cell lysate crude antigen (TeCA) was prepared according to the OIE manual [29], and ELISA was conducted as described previously [27]. For EP, merozoite antigen 2 (EMA-2)-and 48-kDa merozoite rhoptry protein (BC48)based ELISAs were performed as described previously [16,25] for detection of Th.…”

A TeGM6-4r antigen-based immunochromatographic test (ICT) for animal trypanosomosis

“…In contrast to previous studies which used an antigen consisting of two repeat units (TeGM6-2r) (Thuy et al 2012), we expressed a new recombinant antigen GM6 named TeGM6-4r, which consisted of four repeat units and was derived from T. evansi. This study is also a follow-up of our previous assessment and preliminary evaluation of TeGM6-4r-and TeGM6-4r-based ICT (Nguyen et al 2015;Nguyen et al 2014). The ICT was produced with some modifications, utilizing non-tagged recombinant TeGM6-4r instead of 6× His-tagged TeGM6-4r and comprehensively evaluated using nine positive and six negative controls from three water buffaloes experimentally infected with T. evansi and 437 field samples from Tanzanian and Ugandan cattle.…”