Evaluation of the direct agglutination test based on freeze-dried Leishmania donovani promastigotes for the serodiagnosis of visceral leishmaniasis in Sudanese patients.
The direct agglutination test (DAT) based on freeze-dried (FD) Leishmania donovani antigen was evaluated for the serodiagnosis of kala-azar in a rural setting in eastern Sudan. The performance of the FD-DAT was compared with standard liquid antigen (LQ) by testing serum samples and blood samples collected on filter paper of microscopically and PCR-confirmed VL patients, apparently healthy endemic controls and patients with other relevant infectious diseases for the region. In the present study, the FD-DAT had a sensitivity of 96.8% and a specificity of 96.2%. The LQ-DAT had a sensitivity of 91.0% and a specificity of 96.6%. A high degree of agreement (97.3%; r-value 0.94) was observed between the FD-DAT and the LQ-DAT, as well as between the FD-DAT performed on serum samples and corresponding blood samples collected on filter paper (agreement 97.8%; r-value 0.79). The FD-DAT is very suitable as diagnostic test for kala-azar in remote rural conditions as it is sensitive, specific and stable. The antigen is affordable, reproducible and available, which contributes to the sustainability of the DAT as a diagnostic test for VL.
Blue Nile Research and Training Institute, University of Gezira, Gezira, Sudan.
Khalid A A
KA
Abdallah
Bakri Y M
BY
Nour
Henk D F H
HD
Schallig
Adil
A
Mergani
Zohal
Z
Hamid
Abdallah Abd
AA
Elkarim
Osman K
OK
Saeed
Ahmed A
AA
Mohamadani
D000372:Agglutination Tests / Q000379:methods; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000276:immunology; D005612:Freeze Drying; D006801:Humans; D007893:Leishmania donovani / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000175:diagnosis*; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan