Table 1 Overview of promising methods that can be developed to meet the needs of field applicable animal trypanosomosis diagnostic tests

Pan-Trypanosoma IgG ELISA based on WCLSA (mixt Trypanosoma spp or T. evansi antigens)

­ Large scale epidemiological studies and followups of Trypanosomoses control campaigns

­ Highly sensitive pan-pathogenic Trypanosoma antibody detection test

­ Not a species-specific method

­ Produce and lyophilize large scale of WCLSA and reference sera

­ Potential zoonotic application

­ Requires adaptation of the anti-IgG conjugate to the host species

­ Set up in vitro production of parasites for a well standardized antigen production

­ Possible application in all geographical areas

­ Potential application to T. cruzi in humans and animals

­ May hardly be converted into a POCD

Species–specific POCD method based on IgG detection for ATAO

­ Support decision-treatment and choice of appropriate treatments

­ Species-specific or even subspecies specific test

­ Speciesor sub-species-specific tests have low sensitivity

­ Identify several antigens being: species-specifics, early and late as well as immuno-dominant

­ Detect, specifically, carriers of tsetse-transmitted trypanosomes

­ Applicable at field level

­ The use of recombinant antigens could impair the sensitivity of the test

­ Standardize the production of multiple recombinant antigens within a POCD tests

­ Identify animals carrying human threatening trypanosomes

­ Under a PCP, can support treatment-decision in the field

POCD based on IgM detection

­ Any situation requiring an ATAO diagnosis

­ The presence of IgMs in the host blood, is continuously renewed during parasitaemic phases

­ Fluctuating levels of IgM along infection (can be resolved by serial sampling of suspected animals)

­ Identify a predominant VAT of clonally reproduced trypanosomes (T. vivax mechanically transmitted and T. equiperdum…)

POCD based on antigen detection

­ Sensitive detection of active infection

­ Amount of circulating antigens more stable than the parasitaemia itself

­ Low levels of circulating species-specific antigens in the host's blood

­ Identify and produce suitable antigens despite the high costs of preliminary tests

­ Treatment-decision

­ Presence of antigens in a sufficient amount, can support a treatment-decision

­ Identification of species-specific and exclusive antigens for certain species remains hypothetic

­ For high sensitivity, mixed of constitutive, excretory-secretory, variable and non-variable species-specific antigens is required

­ Species-specific identification

POCD based on molecular detection of 7-SL sRNA

­ Large scale epidemiological studies and follow-ups of ATAO control campaigns

­ 7SL sRNA signal detected at high levels in the serum of actively infected animals

­ The sensitivity of this technique remains to be confirmed in field samples for actively, chronically or sub-clinically infected animals

­ Apply this technique in POCD while maintaining sufficient sensitivity and acceptable cost

­ Detection of active infection

­ Allows distinguishing T. brucei, T. congolense and T. vivax

­ Treatment-decision

­ Early clearance of 7SL sRNA levels allow detecting active infection and demonstrating treatment efficacy

­ Cost of the technique may not be low enough for a large adoption

­ Species-specific identification

Visual PSR assay

­ Large scale epidemiological studies and follow-ups of ATAO control campaigns

­ Rapid visual test

­ The sensitivity of this technique remains to be confirmed in field samples for actively, chronically or sub-clinically infected animals

­ Obtain a sufficient sensitivity and an acceptable cost;

­ Being able to develop specific PSRs for al pathogenic Trypanosoma species

­ Detection of active infection

­ Applicable at field level

­ Treatment-decision

­ Species-specific test

­ Cost of the technique may not be low enough for a large adoption

­ Species-specific identification