Evaluation of rK39 Rapid Diagnostic Tests for Canine Visceral Leishmaniasis: Longitudinal Study and Meta-Analysis

Abstract

BackgroundThere is a need for sensitive and specific rapid diagnostic tests (RDT) for canine visceral leishmaniasis. The aims of this study were to evaluate the diagnostic performance of immunochromatographic dipstick RDTs using rK39 antigen for canine visceral leishmaniasis by (i) investigating the sensitivity of RDTs to detect infection, disease and infectiousness in a longitudinal cohort study of natural infection in Brazil, and (ii) using meta-analysis to estimate the sensitivity and specificity of RDTs from published studies.MethodologyWe used a rK39 RDT (Kalazar Detect Canine Rapid Test; Inbios) to test sera collected from 54 sentinel dogs exposed to natural infection in an endemic area of Brazil. Dogs were sampled bimonthly for up to 27 months, and rK39 results compared to those of crude antigen ELISA, PCR, clinical status and infectiousness to sandflies. We then searched MEDLINE and Web of Knowledge (1993–2011) for original studies evaluating the performance of rK39 RDTs in dogs. Meta-analysis of sensitivity and specificity was performed using bivariate mixed effects models.Principal FindingsThe sensitivity of the rK39 RDT in Brazil to detect infection, disease and infectiousness was 46%, 77% and 78% respectively. Sensitivity increased with time since infection, antibody titre, parasite load, clinical score and infectiousness. Sixteen studies met the inclusion criteria for meta-analysis. The combined sensitivity of rK39 RDTs was 86.7% (95% CI: 76.9–92.8%) to detect clinical disease and 59.3% (37.9–77.6%) to detect infection. Combined specificity was 98.7% (89.5–99.9%). Both sensitivity and specificity varied considerably between studies.ConclusionThe diagnostic performance of rK39 RDTs is reasonable for confirmation of infection in suspected clinical cases, but the sensitivity to detect infected dogs is too low for large-scale epidemiological studies and operational control programmes.

An rK28-Based Immunoenzymatic Assay for the Diagnosis of Canine Visceral Leishmaniasis in Latin America

“…Among various options for canine VL serology, the immunoenzymatic assays using Leishmania crude, 7,27 chimeric, 28 rK39, 29 or rK28 30 antigens have offered a number of serological tools. In this study, we presented two kits, a VL Qt-ELISA, a conventional OPD version ELISA, and an innovative naked-eye VL Ql-ELISA to diagnose canines, discriminating VL infected from noninfected dogs, the most important reservoirs in domestic cycle of Leishmania.…”

“…The usefulness of these tests in areas that are distant from big cities could contribute to the diagnosis and knowledge on VL prevalence in dogs in endemic areas. 7,8,29 The naked-eye VL Ql-ELISA version presented here does not required skilled personnel or complex laboratory equipment. Good performance and effectiveness in the diagnosis of VL canine reservoir are based on an easy, user-friendly, sensitive, and specific assay for medium-complexity laboratories.…”

Serological, parasitological and molecular tests for canine visceral leishmaniosis diagnosis in a longitudinal study

“…The sensitivity of a diagnostic technique is very important with regard to detecting the canine VL reservoir (QUINNELL et al, 2013). In our study, PCR on blood samples was seen to have greater sensitivity than the DPP or ELISA tests within the first six months of the follow-up period (Table 1).…”

“…These studies involved different designs with different diagnostic techniques (QUINNELL et al, 2001(QUINNELL et al, , 2003(QUINNELL et al, , 2013FRANÇA-SILVA et al, 2005;OLIVA et al, 2006;CARSON et al, 2009;GRIMALDI et al, 2012a;COURA-VITAL et al, 2013), and this makes comparisons with the data presented here more difficult.…”

“…The characteristics of the diagnostic methods are important parameters for the detection of an infected and infectious dog when selecting a test for use in the large-scale control of infected dogs (QUINNELL et al, 2013). In general, the parasitological examination presents low sensitivity (ALVAR et al, 2004;OLIVA et al, 2006;REIS et al, 2006;LAURENTI, 2009), while PCR has high sensitivity (SOLANO-GALLEGO et al, 2009).…”