title: Evaluating the accuracy of molecular diagnostic testing for canine visceral leishmaniasis using latent class analysis.
abstract: Host tissues affected by Leishmania infantum have differing degrees of parasitism. Previously, the use of different biological tissues to detect L. infantum DNA in dogs has provided variable results. The present study was conducted to evaluate the accuracy of molecular diagnostic testing (qPCR) in dogs from an endemic area for canine visceral leishmaniasis (CVL) by determining which tissue type provided the highest rate of parasite DNA detection. Fifty-one symptomatic dogs were tested for CVL using serological, parasitological and molecular methods. Latent class analysis (LCA) was performed for accuracy evaluation of these methods. qPCR detected parasite DNA in 100% of these animals from at least one of the following tissues: splenic and bone marrow aspirates, lymph node and skin fragments, blood and conjunctival swabs. Using latent variable as gold standard, the qPCR achieved a sensitivity of 95.8% (CI 90.4-100) in splenic aspirate; 79.2% (CI 68-90.3) in lymph nodes; 77.3% (CI 64.5-90.1) in skin; 75% (CI 63.1-86.9) in blood; 50% (CI 30-70) in bone marrow; 37.5% (CI 24.2-50.8) in left-eye; and 29.2% (CI 16.7-41.6) in right-eye conjunctival swabs. The accuracy of qPCR using splenic aspirates was further evaluated in a random larger sample (n = 800), collected from dogs during a prevalence study. The specificity achieved by qPCR was 76.7% (CI 73.7-79.6) for splenic aspirates obtained from the greater sample. The sensitivity accomplished by this technique was 95% (CI 93.5-96.5) that was higher than those obtained for the other diagnostic tests and was similar to that observed in the smaller sampling study. This confirms that the splenic aspirate is the most effective type of tissue for detecting L. infantum infection. Additionally, we demonstrated that LCA could be used to generate a suitable gold standard for comparative CVL testing.
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors: Manuela da Silva
authors: Mda S
authors: Solcà
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors: Leila Andrade
authors: LA
authors: Bastos
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors: Carlos Eduardo Sampaio
authors: CE
authors: Guedes
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors: Marcelo
authors: M
authors: Bordoni
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors: Lairton Souza
authors: LS
authors: Borja
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Escola de Medicina Veterinária, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
authors: Daniela Farias
authors: DF
authors: Larangeira
authors: Instituto de Matemática -Departamento de Estatística, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
authors: Pétala Gardênia
authors: PG
authors: da Silva Estrela Tuy
authors: Instituto de Matemática -Departamento de Estatística, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
authors: Leila Denise Alves Ferreira
authors: LD
authors: Amorim
authors: Centro de Referência em Doenças Endêmicas Pirajá da Silva (PIEJ), Jequié, Bahia, Brazil.
authors: Eliane Gomes
authors: EG
authors: Nascimento
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT - DT), Salvador, Bahia, Brazil.
authors: Geraldo Gileno
authors: GG
authors: de Sá Oliveira
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors: Washington Luis Conrado
authors: WL
authors: dos-Santos
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Escola de Medicina Veterinária, Universidade Federal da Bahia, Salvador, Bahia, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT - DT), Salvador, Bahia, Brazil.
authors: Deborah Bittencourt Mothé
authors: DB
authors: Fraga
authors: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT - DT), Salvador, Bahia, Brazil.
authors: Patrícia Sampaio Tavares
authors: PS
authors: Veras
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D004283:Dog Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology; D004285:Dogs; D019353:Endemic Diseases; D005260:Female; D007893:Leishmania donovani / Q000235:genetics; D007898:Leishmaniasis, Visceral / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D008297:Male; D025202:Molecular Diagnostic Techniques; D059208:Parasite Load; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity