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Evaluating the accuracy of molecular diagnostic testing for canine visceral leishmaniasis using latent class analysis.

Solcà Mda S, Bastos LA, Guedes CE, Bordoni M, Borja LS, Larangeira DF, da Silva Estrela Tuy PG, Amorim LD, Nascimento EG, de Sá Oliveira GG, dos-Santos WL, Fraga DB, Veras PS - PLoS ONE (2014)

Bottom Line: The specificity achieved by qPCR was 76.7% (CI 73.7-79.6) for splenic aspirates obtained from the greater sample.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.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.

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.

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Related in: MedlinePlus

Sensitivity and specificity of the different diagnostic techniques employed in the biological samples obtained from Camaçari animals (n = 800).Vertical bars represent the 95% confidence intervals. A) Sensitivity and B) Specificity values obtained using the latent variable as the gold standard.
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pone-0103635-g002: Sensitivity and specificity of the different diagnostic techniques employed in the biological samples obtained from Camaçari animals (n = 800).Vertical bars represent the 95% confidence intervals. A) Sensitivity and B) Specificity values obtained using the latent variable as the gold standard.

Mentions: Using LCA, the sensitivity of the splenic aspirate qPCR (95%; 95%CI 93.5–96.5) was higher than for the other diagnostic tests: DPP CVL (86.4%; 95%CI 84.1–88.8), splenic parasite cultures (83.5%; 95%CI 80.8–86.2), the in-house ELISA (78.3%; 95%CI 75.5–81.2), and EIE CVL (72.5%; 95% CI 69.4–75.6) (Figure 2A). However, the specificity was highest for splenic parasite cultures (100%), followed by DPP CVL (95.6%; 95%CI 94.2–97), the in-house ELISA (90.6%; 95%CI 88.6–92.6), EIE CVL (84.1%; 95%CI 81.6–86.6), and splenic aspirate qPCR (76.7%; 95%CI 73.7–79.6) (Figure 2B).


Evaluating the accuracy of molecular diagnostic testing for canine visceral leishmaniasis using latent class analysis.

Solcà Mda S, Bastos LA, Guedes CE, Bordoni M, Borja LS, Larangeira DF, da Silva Estrela Tuy PG, Amorim LD, Nascimento EG, de Sá Oliveira GG, dos-Santos WL, Fraga DB, Veras PS - PLoS ONE (2014)

Sensitivity and specificity of the different diagnostic techniques employed in the biological samples obtained from Camaçari animals (n = 800).Vertical bars represent the 95% confidence intervals. A) Sensitivity and B) Specificity values obtained using the latent variable as the gold standard.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4116254&req=5

pone-0103635-g002: Sensitivity and specificity of the different diagnostic techniques employed in the biological samples obtained from Camaçari animals (n = 800).Vertical bars represent the 95% confidence intervals. A) Sensitivity and B) Specificity values obtained using the latent variable as the gold standard.
Mentions: Using LCA, the sensitivity of the splenic aspirate qPCR (95%; 95%CI 93.5–96.5) was higher than for the other diagnostic tests: DPP CVL (86.4%; 95%CI 84.1–88.8), splenic parasite cultures (83.5%; 95%CI 80.8–86.2), the in-house ELISA (78.3%; 95%CI 75.5–81.2), and EIE CVL (72.5%; 95% CI 69.4–75.6) (Figure 2A). However, the specificity was highest for splenic parasite cultures (100%), followed by DPP CVL (95.6%; 95%CI 94.2–97), the in-house ELISA (90.6%; 95%CI 88.6–92.6), EIE CVL (84.1%; 95%CI 81.6–86.6), and splenic aspirate qPCR (76.7%; 95%CI 73.7–79.6) (Figure 2B).

Bottom Line: The specificity achieved by qPCR was 76.7% (CI 73.7-79.6) for splenic aspirates obtained from the greater sample.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.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.

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.

Show MeSH
Related in: MedlinePlus