Modifications in a Reference Freeze-Dried Direct Agglutination Test to Improve Visceral Leishmaniasis Detection.

Currently, a significantly lower temperature (35°C) than initially established (56°C) is indicated as the maximum temperature storage for the commercial reference visceral leishmaniasis (VL) freeze-dried direct agglutination test (FD-DAT). Despite an approximately 50% loss in the number of promastigotes in an FD-DAT batch that expired 7 years earlier, the promastigotes maintained a similar morphology to the equivalent valid batch implying most likely that auto-agglutination, rather than aging, is the main reason for expiry. The substitution of normal saline which was initially recommended for reconstitution, by citrate-saline/formaldehyde (CSF) as an anti-clumping/preservative agent resulted in restoration of validity comparable with that of the freeze-dried original or the liquid direct agglutination test (LQ-DAT) version (Friedman ANOVA test = 1.

Are We Now Well Prepared for Another Major Visceral Leishmaniasis Epidemic in Sudan?

To minimize the chance for future visceral leishmaniasis (VL) epidemics such as the 1988-1991 epidemic in Sudan, several VL detection tools have been introduced. There are many VL diagnostics with excellent sensitivities, specificities, and ease of use reported. However, additional test characteristics should be considered for use in the detection of future VL epidemics.

User and environment friendly direct agglutination test for the sero-diagnosis of visceral leishmaniasis: exclusion of formaldehyde and β-mercaptoethanol in test execution.

Purpose: Based on world-wide evaluation, the direct agglutination test (DAT) is now generally acknowledged as one of the leading diagnostics for visceral leishmaniasis (VL). To enhance more routine and mass application, but simultaneously ensure safety to both user and environment, further improvements need to be introduced.

Methodology: In the current format, a two-sixfold titre decrease was observed due to using formaldehyde as an antigen preservative in DAT.

Identification of an area predominantly endemic for childhood and adolescent visceral leishmaniasis in central Sudan.

Although widely spread throughout Sudan, visceral leishmaniasis (VL) is predominantly endemic in the Gedaref, southern Blue-Nile, and Umrimta areas located in the eastern, southern, and central regions, respectively. Regardless of form (endemic or epidemic), VL occurrence follows similar patterns as all ages and both sexes are affected. From January 2005 to May 2016, we received a total of 563 patients with high suspicion for VL from various endemic areas; 159 were children and adolescents (0.

Local Production of a Liquid Direct Agglutination Test as a Sustainable Measure for Control of Visceral Leishmaniasis in Sudan.

A prerequisite for the control of visceral leishmaniasis (VL) is the accessibility to reference diagnostics. The high price of the freeze-dried direct agglutination test (FD-DAT) and the short shelf-life time of the rK39 strip test (rK39) have limited the application of these tests in Sudan. An original liquid DAT (LQ-DAT) with high reproducibility compared with the FD-DAT and rK39 has been routinely produced in our laboratory since 1999.

Successful substitution of fetal calf serum by human plasma for bulk cultivation of Leishmania donovani promastigotes.

The potential of human plasma (HP) or serum (HS) as a replacement for fetal calf serum (FCS) was evaluated in a liver infusion tryptose (LIT) medium for bulk cultivation of Leishmania donovani promastigotes. The promastigote yield with the LIT-FCS standard medium was 0.4-1.

Validation of a β-ME ELISA for detection of anti Leishmania donovani antibodies in Eastern Sudan.

Background: A β-mercaptoethnol (β-ME)-treated promastigote antigen of L. donovani was successfully employed in direct agglutination test (DAT) for the diagnosis of visceral leishmaniasis (VL).

Objective: The β-ME-treated antigen was further incorporated into an enzyme-linked immunosorbent assay set-up (β-ME ELISA) and evaluated for VL diagnosis against outcome of reference freeze-dried DAT (FD-DAT) and rK39 strip test (RKT) commercial kits.

Qualitative and semi-quantitative comparison of an rK39 strip test and direct agglutination test for detection of anti-Leishmania donovani antibodies in the Sudan.

Background: Until now, the comparison of the rK39 strip test (RKT) and direct agglutination test (DAT) for detection of visceral leishmaniasis (VL) is exclusively based on either positive or negative qualification of the reaction outcome.

Objective: In this study, we compared the diagnostic performance of RKT and DAT for VL both qualitatively and semi-quantitatively.

Methods: For comparison based on semi-quantitative grounds, the execution of RKT and DAT was according to the standard procedures.

Use of a newly developed beta-mercaptoethanol enzyme-linked immunosorbent assay to diagnose visceral leishmaniasis in patients in eastern Sudan.

Corroboration of serology results is essential for restricting the risk of inappropriate antileishmanial prescription. A direct agglutination test (DAT) and a recently developed beta-mercaptoethanol-modified enzyme-linked immunosorbent assay (beta-ME ELISA) based on the use of antigen prepared as described for the DAT were applied to 416 sera from two Sudanese populations with and without clinical evidence of visceral leishmaniasis (VL). Of 285 sera with the lowest antileishmanial DAT titers ( View Article and Find Full Text PDF