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

Saul José Semião-Santos, Laura Barral Veloso, Paulo Paes de Andrade, Marcia Almeida de Melo, Luis Miguel Lourenço Martins, Artur Armando de Moura Marinho, José Antunes Afonso de Almeida, Lénea Maria da Graça Campino, Abdallah el Harith

¹Instituto de Ciências Agrárias e Ambientais Mediterrânicas. Universidade de Évora, Évora, Portugal

²Departamento de Genética, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil

³Laboratório de Biologia Molecular do Semiárido, Unidade Acadêmica de Medicina Veterinária, Universidade Federal de Campina Grande, Patos, Paraíba, Brazil

⁴Departamento de Medicina Veterinária, Universidade de Évora, Évora, Portugal

⁵Departamento de Zootecnia, Universidade de Évora, Évora, Portugal

⁶Unidade de Leishmanioses, Instituto de Higiene e Medicina Tropical, Lisboa, Portugal

⁷Ahfad University for Women, Omdurman, Sudan

Correspondence
Abdallah el Harith harith17{at}yahoo.com

Journal of Medical Microbiology 2014; 63(Pt 1):106–110 · https://doi.org/10.1099/jmm.0.063891-0

Abstract

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.