Evaluation of Two rK39 Dipstick Tests, Direct Agglutination Test, and Indirect Fluorescent Antibody Test for Diagnosis of Visceral Leishmaniasis in a New Epidemic Site in Highland Ethiopia

Abstract

Abstract. We assessed the performance characteristics of two rK39 immunochromatographic tests, a direct agglutination test (DAT), and an indirect immunofluorescent antibody test (IFAT) in the site of a new epidemic of visceral leishmaniasis (VL) in northwestern Ethiopia. The study population was composed of 179 patients with suspected VL and 67 controls. The sensitivities of Kalazar Detect ® , DiaMed-IT Leish ® , DAT, and IFAT in 35 polymerase chain reaction-confirmed VL cases were 94.3%, 91.4%, 91.4%, and 100%, respectively, and the specificities were 98.5%, 94%, 98.5%, and 98.5%, respectively. In a Bayesian latent class analysis of all 246 specimens, the estimated sensitivities were 90.5%, 89%, 88.8%, and 96% for Kalazar Detect ® , DiaMed-IT Leish ® , DAT, and IFAT, respectively; DAT showed the highest estimated specificity (97.4%). Both rK39 immunochromatographic tests perform as well as DAT, and are suitable for VL diagnosis in first-level health centers in this area of Ethiopia.

Usefulness of the rK39-Immunochromatographic Test, Direct Agglutination Test, and Leishmanin Skin Test for Detecting Asymptomatic Leishmania Infection in Children in a New Visceral Leishmaniasis Focus in Amhara State, Ethiopia

“…In addition, a recent study in Libo Kemkem that evaluated the performance of DAT and two rK39-ICT tests indicated that either approach is suitable for VL diagnosis in this area of Ethiopia. 35 However, our study population was asymptomatic and higher positivity rates have been reported for DAT versus rK39-ICT when these methods are used to assess asymptomatic infection in other VL-endemic areas. 7 Given that performance of a serologic test can depend on the stage of the disease/infection, the lower performance of rK39-ICT can be explained by its ability to detect antibody response against only a single antigen (rK39), whereas the DAT relies on detection of antibodies against a wide range of Leishmania antigens (whole freeze-dried promastigote).…”

Low Prevalence of Leishmania Infection in Post-Epidemic Areas of Libo Kemkem, Ethiopia

“…The combined use of these methods, which has performed well in VL diagnosis in this area, 15 yielded just a 1% prevalence for the 4-to 15-year-old age range. The prevalence of Leishmania infection is expected to increase with age 11 ; however, the presence of only one active case in the study population and the low prevalence even among the older children suggest a low prevalence for the general population.…”

Use of the Kala-Azar Detect® and IT-LEISH® rapid tests for the diagnosis of visceral leishmaniasis in Brazil

“…The adequate performance of these tests combined with their ease of use provided greater access to diagnostic services in remote endemic areas. Since then, rapid tests have been evaluated and validated in different endemic areas (Ritmeijer et al 2006, Cañavate et al 2011. In Brazil, the rapid test Kala-Azar Detect ® (InBios International, Seattle, WA) was first evaluated in 2003 in 128 VL cases and 50 controls, showing a sensitivity of 90% and a specificity of 100% (Carvalho et al 2003).…”