The direct agglutination test (DAT) based on a freeze-dried antigen and the rK39
dipstick test were evaluated for the sero-diagnosis of visceral leishmaniasis
(VL). The sensitivity and specificity of both tests were determined using sera
from confirmed VL patients (n = 21), healthy controls (n = 19) and from patients
with other confirmed infectious diseases (n = 42). The DAT had a sensitivity and
a specificity of 100%. The rK39 had a sensitivity of 85.7% and a specificity of
82%. Both tests were also used to screen blood samples of confirmed VL patients
(n = 15) and serum samples of VL suspects (n = 61). The DAT found all blood samples
of confirmed VL patients positive and tested 98.4% of the serum samples of the
VL suspects positive. In contrast, rK39 detected in 9/15 blood samples (60%) antibodies
against
Leishmania chagasi
and found 85.3% of the serum samples
of the suspected patients positive. Although the rK39 dipstick is more rapid and
user friendlier than the DAT, the latter has a superior sensitivity and specificity.
Furthermore, the reagents used for DAT do not require cold storage, whereas the
buffer of the rK39 must be stored at 4°C. Therefore, the DAT is the most
suitable test for the sero-diagnosis of VL under field conditions.
