Behnam Mohammadi-Ghalehbin; Gholam Reza Hatam; Bahador Sarkari; Mehdi Mohebali; Zabih Zarei; Mansoureh Jaberipour; Shahab Bohlouli
Volume 8, Issue 4 , December 2011, , Pages 244-250
Abstract
Background: Visceral leishmaniasis (VL) is caused by Leishmania infantum in Mediterranean basin and is an endemic disease in some parts of Iran. Canines are the main reservoirs of VL in most of the endemic areas. Different serological methods have been introduced for diagnosis of canine visceral leishmaniasis ...
Read More
Background: Visceral leishmaniasis (VL) is caused by Leishmania infantum in Mediterranean basin and is an endemic disease in some parts of Iran. Canines are the main reservoirs of VL in most of the endemic areas. Different serological methods have been introduced for diagnosis of canine visceral leishmaniasis (CVL). Objective: In this survey a Fucose-Mannose Ligand (FML) ELISA, using native L. infantum antigen, was developed and its validity for detection of infected dogs in comparison with direct agglutination test (DAT) and PCR was evaluated. Methods: Blood samples of sixty ownership dogs (≤ 3 years old) were collected from Meshkin-shahr district in Ardabil province, North-west of Iran. Sera were separated for serological assays (DAT and FMLELISA) and the buffy coats were collected for molecular evaluation. Results: Two out of the 60 (3.33%) samples were found to be positive (antibody titer of ≥ 1/320) in DAT while seven of the 60 (11.66%) samples were positive by FML-ELISA. Nine out of 60 (15%) buffy coat samples showed a band about 680 bp indicative of L. infantum in PCR. Three out of 60 dogs had Kala-azar symptoms and were positive by PCR and FML-ELISA, while two of these three dogs had antibody titers >1/320 in their serum samples. The sensitivity and specificity of FML-ELISA for the detection of CVL in both symptomatic and asymptomatic dogs were found to be 77.8% and 100%, respectively. Conclusion: Considering the acceptable sensitivity and high specificity of FMLELISA, use of this serological method can be recommended for epidemiological surveys of CVL.
Elfadil Abass; Abdelhafeiz Mahamoud; Durria Mansur; Mehdi Mohebali; Abdollah el Harith
Volume 8, Issue 3 , September 2011, , Pages 150-158
Abstract
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 ...
Read More
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. Methods: Two-hundred and ninety-two sera from patients with high VL suspicion of whom 105 had confirmed L. donovani infection were tested. Results: Relatively higher sensitivities of 93.3% (95% CI: 88.4- 98.2) and 92.4% (95% CI: 87.3-97.5) were determined for β-ME ELISA and FD-DAT as compared to 83.8% (95% CI: 76.7-90.8) for RKT. Of 73 VL sera that scored maximum absorbance values (>0.81) in β-ME ELISA, 66 (90.4%) tested at the highest agglutination titres (>1:51200) in FD-DAT as did 56 (76.7%) also at comparable reaction intensities (3 + colour intensity) in RKT. Compared with FD-DAT (94.7%, 95% CI: 91.5-97.9) or RKT (93.0%, 95% CI: 89.3-96.6), lower specificity was estimated for β-ME ELISA (90.4%, 95% CI: 86.1-94.6). Based both on positive and negative microscopy for L. donovani in organ aspirates of all VL suspects enrolled (292), significantly higher correlation (p<0.01, 0.919) was established between β-ME ELISA and FD-DAT than between β-ME ELISA and RKT (p<0.01, 0.824). Taking into calculation the combined estimates of sensitivity, specificity, positive and negative predictive values, higher agreement (94.8%) was determined between total performance of β-ME ELISA and FD-DAT than between that of β-ME ELISA and RKT (90.7%). Conclusion: Based on results and merits discussed, we recommend application of this β-ME ELISA both for diagnosis of VL at laboratory level and confirmation of results obtained with DAT or RKT in the field.