scholarly journals Performance of an indigenous β-mercaptoethanol-modified antigen in comparison with a commercial reference in direct agglutination test for detection of canine visceral leishmaniasis

2014 ◽  
Vol 63 (1) ◽  
pp. 106-110
Author(s):  
Saul José Semião-Santos ◽  
Laura Barral Veloso ◽  
Paulo Paes de Andrade ◽  
Marcia Almeida de Melo ◽  
Luis Miguel Lourenço Martins ◽  
...  

We compared the performance of a locally produced β-mercaptoethanol-modified promastigote antigen (β-ME-Ag) of an indigenous Leishmania infantum strain against that of a trypsinized Leishmania donovani reference (REF-Ag) in the direct agglutination test (DAT) for detection of canine visceral leishmaniasis (CVL). One hundred and fifty-one serum samples collected from dogs belonging to four groups with different conditions were included. At a DAT titre of 1 : 320, statistically determined as optimal cut-off value for β-ME-Ag, and 1 : 160 for REF-Ag, a sensitivity and a specificity of 100 % were estimated for β-ME-Ag in comparison with 96.6 % and 100 %, respectively, for REF-Ag. Overall, levels of agglutination titres recorded for the two antigens were highly concordant (Cohen’s κ = 0.879) in both the CVL and non-CVL groups. Based on current results, and ease experienced in processing the antigen and reading the test outcome, we recommend incorporation of β-ME-Ag in DAT for confirmation or exclusion of suspected CVL in dogs.

2016 ◽  
Vol 221 ◽  
pp. 9-13 ◽  
Author(s):  
Edward Oliveira ◽  
Juliana Wilke Saliba ◽  
Diana Oliveira ◽  
Edelberto Santos Dias ◽  
Gustavo Fontes Paz

1996 ◽  
Vol 16 (3-4) ◽  
pp. 235-239 ◽  
Author(s):  
Linda Oskam ◽  
Rob J. Slappendel ◽  
Eef G.M. Beijer ◽  
Nel C.M. Kroon ◽  
Cor W. van Ingen ◽  
...  

2007 ◽  
Vol 14 (12) ◽  
pp. 1592-1595 ◽  
Author(s):  
Durria Mansour ◽  
Elfadil M. Abass ◽  
Mohamed el Mutasim ◽  
Abdelhafeiz Mahamoud ◽  
Abdallah el Harith

ABSTRACT Corroboration of serology results is essential for restricting the risk of inappropriate antileishmanial prescription. A direct agglutination test (DAT) and a recently developed β-mercaptoethanol-modified enzyme-linked immunosorbent assay (β-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 (≤1:100 to 1:1,600), 270 (94.7%) scored comparable minimum β-ME ELISA absorbance values (≤0.1 to 0.26). In 117 sera that demonstrated the highest DAT titers (1:12,800 to ≥1:25,600), 86 (73.5%) scored maximum (0.81 to ≥1.35) and 30 (25.6%) medium (0.27 to 0.80) β-ME ELISA absorbance values. VL diagnosis was established for 142 (44.1%) patients in the VL-symptomatic group (n = 322), based on positive microscopy for Leishmania donovani in lymph node aspirates or positive DAT (titer, ≥1:3,200). Of the 125 sera from the symptomatic patients for whom microscopy was positive for VL, 111 (88.8%) had comparable positive DAT and β-ME ELISA readings. In all 17 sera from the symptomatic DAT-positive patients for whom leishmaniasis was not established by microscopy but who responded favorably to antileishmanial therapy, absorbance values (≥0.27) indicative of VL were obtained by β-ME ELISA. Of 197 symptomatic patients for whom microscopy was negative for VL, 172 (87.3%) tested negative in β-ME ELISA and 180 (91.4%) in DAT. Based on the high reliability demonstrated here for VL detection, β-ME ELISA fulfills the requirement of confirming DAT results in patients manifesting suspected VL.


2019 ◽  
Vol 28 (1) ◽  
pp. 172-176 ◽  
Author(s):  
Filipa Teixeira Rodrigues ◽  
Catarina Pereira ◽  
Jitender Prakash Dubey ◽  
Miguel Nóvoa ◽  
Miguel Quaresma ◽  
...  

Abstract Toxoplasma gondii and Leishmania infantum are zoonotic protozoal parasites. Serum samples were obtained from 186 donkeys (Equus africanus asinus) from Portugal and assessed for antibodies to T. gondii by the modified agglutination test (MAT). For titration of antibodies to Leishmania spp. the direct agglutination test was used (DAT). Eleven donkeys were seropositive for T. gondii with titres of 20 (n = 7), 80 (n = 2), 640 (n = 1) and ≥ 2560 (n = 1). One donkey was seropositive for Leishmania spp. (titre of 800). Donkeys in Portugal are exposed to and can be infected with T. gondii and Leishmania spp.


Parasitology ◽  
2017 ◽  
Vol 144 (14) ◽  
pp. 1964-1970 ◽  
Author(s):  
E. OLIVEIRA ◽  
D. OLIVEIRA ◽  
F. A. CARDOSO ◽  
J. R. BARBOSA ◽  
A. P. MARCELINO ◽  
...  

SUMMARYIn this study, we assessed the sensitivity, specificity, and diagnostic accuracy of a previously developed direct agglutination test (DAT) using a freeze-dried antigen derived fromLeishmania infantumpromastigotes and composed in a prototype kit for visceral leishmaniasis (VL) diagnosis, named DAT-LPC. To evaluate DAT-LPC reproducibility, the kit was used to analyse 207 serum samples from VL patients and 80 serum samples from patients with other parasitic infections or healthy subjects in four laboratories from different public health institutions in Brazil. DAT-LPC showed sensitivity between 96·2 and 99·5% (P= 0·14), specificity ranging from 96·2 to 97·5% (P= 0·95), and diagnostic accuracy ranging from 96·5 to 99% (P= 0·34). The inter-laboratory reproducibility of qualitative results was classified as excellent (κindex: 0·94–0·97). The reproducibility of the end-titre results in relation to the reference laboratory, ranged from 31 to 85%. These results demonstrate an excellent performance of the DAT-LPC, and validate it for the diagnosis of VL that could replace the immunofluorescent antibody test as the routine diagnostic test in the Brazilian public health system.


2013 ◽  
Vol 62 (8) ◽  
pp. 1165-1169 ◽  
Author(s):  
Abdelhafeiz Mahamoud ◽  
Hussam Ali Osman ◽  
Durria Mansour ◽  
Abdallah el Harith

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 0.4–1.8×107 ml−1, and yields of 0.5–3.4×107 (P = 0.527) and 0.4–2.4×107 (P = 0.062) were recorded for two LIT medium variants containing HP or HS as supplement instead of FCS. Significantly, higher promastigote yields of 1.3–4.9×107 ml−1 were demonstrated when LIT medium was supplemented with HP of blood group O but not A, B, AB or equally pooled ABO (P = 0.007–0.020). Matching (P = 0.56) strong positive (1 : 10 2400 to ≥1 : 262 144 00) and weak negative (1 : 5–1 : 160) direct agglutination test (DAT) titres, respectively, were demonstrated in 24 visceral leishmaniasis (VL) and 45 non-VL sera for both standard LIT-FCS and alternative LIT-HP derived antigens. Our findings indicate strong potential for sustainable production of promastigotes for important diagnostic procedures such as DAT in the VL affected areas.


2010 ◽  
Vol 18 (2) ◽  
pp. 346-348 ◽  
Author(s):  
Kamlesh Gidwani ◽  
Albert Picado ◽  
Bart Ostyn ◽  
Shri Prakash Singh ◽  
Rajiv Kumar ◽  
...  

ABSTRACTThe persistence of anti-Leishmania donovaniantibodies in past visceral leishmaniasis (VL) cases was retrospectively assessed by means of the direct agglutination test (DAT) and the rK39 enzyme-linked immunosorbent assay (ELISA). Antibody titers remained high for an extended period of time in past cases of VL. These results highlight the need to carefully elicit the history of patients with VL symptoms.


Parasitology ◽  
2008 ◽  
Vol 135 (9) ◽  
pp. 1035-1041 ◽  
Author(s):  
S. FARAJNIA ◽  
B. DARBANI ◽  
H. BABAEI ◽  
M. H. ALIMOHAMMADIAN ◽  
F. MAHBOUDI ◽  
...  

SUMMARYThe purpose of this study was to prepare recombinant K26 antigen fromLeishmania infantumand evaluate its performance by enzyme-linked immunosorbent assay (ELISA) test for serodiagnosis of visceral leishmaniasis (VL) in endemic regions of Iran. The results were compared with those obtained by direct agglutination test (DAT) and whole cell ELISA using crude parasite antigen. Of 93 sera from patients with confirmed VL, 90 sera were positive with rK26 ELISA (sensitivity=96·8%), whereas 85 sera were positive with DAT (sensitivity=91·4%) and 89 sera were positive with whole cell ELISA (sensitivity=95·7%). Of 130 subjects who either had other infectious diseases (n=30) or were healthy (n=100), rK26 ELISA were negative in all cases (specificity=100%), whereas DAT were negative in 116 cases (specificity=89·2%) and whole cell ELISA was negative in 114 cases (specificity=87·7%). The results of this study indicate that the rK26 ELISA is more sensitive and specific than conventional methods and could be used for reliable diagnosis of VL caused byLeishmania infantum.


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