Seropositive dog for L. (L.) infantum overlapping spatial distribution of cutaneous disease (original) (raw)
PLoS ONE, 2014
The techniques used for diagnosis of canine visceral leishmaniasis (CVL) in Brazil ELISA and IFAT have been extensively questioned because of the accuracy of these tests. A recent change in the diagnosis protocol excluded IFAT and included the Dual-Path Platform (DPP) . We evaluated the prevalence and incidence rates of Leishmania spp. before and after the change in the protocol. In addition, based on our results, we propose a new alternative that is less expensive for the screening and confirmation of CVL. Plasma samples were obtained from a serobank from dogs evaluated in a cross-sectional study (1,226 dogs) and in a cohort study of susceptible animals (n = 447), followed for 26 months. Serology testing was performed using ELISA, IFAT, and DPP. The incidence and prevalence of CVL were determined by using the protocol of the Visceral Leishmaniasis Control and Surveillance Program until 2012 (ELISA and IFAT using filter paper) and the protocol used after 2012 (DPP and ELISA using plasma). The prevalence was 6.2% and the incidence was 2.8 per 1,000 dog-months for the protocol used until 2012. For the new diagnosis protocol for CVL resulted in an incidence of 5.4 per 1,000 dog-months and a prevalence of 8.1%. Our results showed that the prevalence and incidence of infection were far greater than suggested by the previously used protocol and that the magnitude of infection in endemic areas has been underestimated. As tests are performed sequentially and euthanasia of dogs is carried out when the serological results are positive in both tests, the sequence does not affect the number of animals to be eliminated by the Control Program. Then we suggest to municipalities with a large demand of exams to use ELISA for screening and DPP for confirmation, since this allows easier performance and reduced cost.
We investigated the performance of the DPP®canine visceral leishmaniasis (CVL) rapidtest, a novel immunochromatographic assay launched by BioManguinhos (Brazil), whichwas recently included in the new Brazilian protocol for screening CVL in serological surveys.The present study compared the DPP®with the ELISA and IFA produced by BioManguinhos(Brazil) both with L. major-like antigens and with in-house tests using Leishmania infantumchagasi (in-house ELISA and in-house IFA). We analyzed the sera from clinically symp-tomatic (n = 47) and asymptomatic (n = 38) infected dogs from an endemic area of CVL, aswell as from healthy (n = 18) dogs, in addition to the sera of dogs (n = 81) infected withother pathogens. The DPP®and the in-house ELISA showed a sensitivity of 90.6% and 94.1%,respectively, and specificity of 95.1% and 97.5%, respectively, and both presented cross-reactivity only with the sera of dogs with babesiosis, 44% for the DPP®and 22% for thein-house ELISA. The clinical groups were detected equally by the two assays. The ELISABioManguinhos, IFA BioManguinhos, and in house-IFA showed a good sensitivity, 90.6%,96.5% and 89.4%, respectively, but very low specificity, 77.8%, 69.1% and 65.8%, respec-tively, due to the high cross-reactivity with the sera from the animals harboring otherpathogens. The in-house ELISA provided the highest accuracy (95.8%), followed by theDPP®(92.7%), ELISA BioManguinhos (84.3%), IFA BioManguinhos (83.1%), and in-house IFA(78.0%). The simultaneous use of the DPP®and ELISA BioManguinhos reached a sensitiv-ity of 99.1% and 82.1% when used sequentially. In conclusion, the DPP®performed well asserological test for CVL, and detected both asymptomatic and symptomatic dogs in equalproportions. Although its sensitivity is not ideal yet, discarding the IFA and including theDPP®improved the accuracy of the new Brazilian CVL diagnostic protocol, particularly ofdetecting truly infected dogs. Moreover, considering the higher specificity of DPP®(95.1%vs 77.8%), positive predictive value (95.1% vs 81.1%) and positive likelihood value (18.3% vs4.1%) in comparison with the ELISA BioManguinhos, the use of DPP®as a confirmatory testinstead of a screening test is suggested.
Memórias do Instituto Oswaldo Cruz, 2018
BACKGROUND Visceral leishmaniasis is a major public health challenge in South America, and dogs are its main urban reservoir. OBJECTIVE Validation of the canine Dual-path Platform immunoassay for canine visceral leishmaniasis (DPP ® CVL) for a sample set composed of 1446 dogs from different Brazilian endemic areas. METHODS A well-defined reference standard by means of parasitological culture, immunohistochemistry, and histopathology was used. Animals were classified as asymptomatic, oligosymptomatic, or symptomatic. Sensitivity and specificity were assessed as a single set and in clinical groups. A reproducibility assessment of the tests was conducted using the Kappa (κ) index at three different laboratories (A, B, and C). FINDINGS Overall, 89% sensitivity and 70% specificity were obtained for the entire sample set. Analysis of the clinical groups showed a gradual decrease in the sensitivity and an increase in the specificity with the reduction of clinical signs in the dogs that were assessed, reaching a sensitivity of 75% (42.8-94.5%) among asymptomatic dogs and lower specificity of 56% (46.2-66.3%) among symptomatic dogs. Inter-laboratory agreement was substantial (κ AB = 0.778; κ AC = 0.645; κ CB = 0.711). MAIN CONCLUSIONS The test performance is somewhat dependent on canine symptomatology, but such influence was less evident than in previous studies. Favourable results for sensitivity and specificity can be obtained even in asymptomatic animals; however, caution is needed in these evaluations, and the results suggest that the immunochromatographic test may be further improved for better investigation in asymptomatic dogs. The results obtained confirm the usefulness of DPP ® CVL for application in serological surveys.
Ciência Rural
ABSTRACT: Leishmaniosis is a great public health problem affecting both humans and animals. The disease is caused by the protozoan Leishmania spp., which has a complex cycle involving a phlebotomine vector. The ELISA test (Enzyme-Linked Immunosorbent Assay) along with a chromatographic immunoassay was defined by the Brazil Health Ministry as the confirmatory screening protocol in 2011. Uruguaiana city is 630 km away from Porto Alegre, which makes it difficult to send samples and diagnose leishmaniasis, as well as receive quick results. In view of this, the present study evaluated an in-house indirect ELISA method compared to indirect immunofluorescence assay (IFA) and dual-path platform chromatographic immunoassay (DPP-BioManguinhos®) for the detection of an immune response to Leishmania spp. in canine species. The serological evaluation included 48 canines from the western border of Brazil (Uruguaiana and Barra do Quaraí city). Among the 48 canine samples tested, 18 were positive w...
Memórias do Instituto Oswaldo Cruz, 2019
BACKGROUND Studies aimed at validating canine visceral leishmaniasis diagnostic tests present heterogeneous results regarding test accuracy, partly due to divergences in reference standards used and different infection evolution periods in animals. OBJECTIVE This study aimed to evaluate the accuracy of the rapid test-dual path platform (TR-DPP) (Biomanguinhos®), EIE-Leishmaniose-Visceral-Canina-Biomanguinhos (EIE-LVC) (Biomanguinhos®), enzyme-linked immunosorbent assay (ELISA) rK39 (in-house), and the direct agglutination test (DAT-Canis) against a reference standard comprising parasitological and molecular techniques. METHODS A phase II/III validation study was carried out in sample sera from 123 predominantly asymptomatic dogs living in an area endemic for visceral leishmaniasis. FINDINGS Sixty-nine (56.1%) animals were considered infected according to the reference standard. For each test, the sensitivity and specificity, respectively, were as follows: TR-DPP, 21.74% [confidence interval (CI)95% 13.64% to 32.82%] and 92.59% (CI95% 82.45% to 97.08%); EIE-LVC, 11.59% (CI95% 5.9% to 21.25%) and 90.74% (CI95% 80.09% to 95.98%); ELISA rK39, 37.68% (CI95% 27.18% to 49.48%) and 83.33% (CI95% 71.26% to 90.98%); and DAT-Canis, 18.84% (CI95% 11.35% to 29.61%) and 96.30% (CI95% 87.46% to 98.98%). CONCLUSION We concluded that improving the sensitivity of serum testing for diagnosing asymptomatic dogs must constitute a priority in the process of developing new diagnostic tests to be used in the visceral leishmaniasis control program in Brazil.
Cadernos de Saúde Pública, 2021
Dogs are the main reservoirs in the domestic transmission cycle of visceral leishmaniasis, and the diagnosis is essential for the effectiveness of the control measures recommended by the Brazilian Ministry of Health. We assessed the diagnostic performance of the ELISA-Vetlisa/BIOCLIN prototype with serum samples from 200 dogs, in triplicate, including symptomatic, oligosymptomatic, asymptomatic, and healthy dogs, originated by two distinct panels (A and B) characterized by parasitological tests as the reference standard. In this study, the prototype kit showed a 99% sensitivity (95%CI: 94.5-100.0) and a 100% specificity (95%CI: 96.4-100.0). The sensitivity of the prototype kit did not vary significantly with the clinical status of the dogs. Considering the final result classification (positive or negative), agreement between the results of repeated tests was almost perfect (kappa = 0.99; 95%CI: 0.98-1.00). ELISA-Vetlisa/BIOCLIN is a promising option for the serological diagnosis of canine visceral leishmaniasis in Brazil.
Evaluation of DPP® and SNAP® Rapid Tests for diagnosis of Leishmania infantum canine infections
Revista da Sociedade Brasileira de Medicina Tropical, 2019
Introduction: Visceral leishmaniasis is a disease that affects humans, wildlife, and domestic species. Since dogs play a key role in urban Leishmania spp. transmission, the Brazilian government maintains the Monitoring and Control Program of Visceral Leishmaniasis (VLMCP) in endemic regions, which promotes awareness campaigns aiming to enhance the control of the infection. The VLMCP recommends the Dual Path Platform (DPP ®) canine visceral leishmaniasis test (Bio-Manguinhos, Brazil) for screening and enzyme-linked immunosorbent assay to confirm the infection. The DPP ® test is produced and distributed by the Health Ministry to the Municipal Health Centers responsible for the local VLMCP. The test is not available to all the clinics, forcing some veterinarians to use other rapid tests for screening and diagnosis of this disease in their daily routine. Methods: The present study was conducted to compare the performance of the DPP ® and SNAP ® tests using sera from the dogs with confirmed infections of L. infantum and from the dogs with no previous testing, residing in areas with a low Leishmania infection. Results: There was 97.0% agreement between the two tests. Sensitivity and specificity of the SNAP ® test were 96.3% and 100%, respectively. Agreement between both the antibody tests and the parasitological detection methods was 96.8%. The DPP ® test had 95.8% sensitivity and 100% specificity. Conclusions: The SNAP ® and the DPP ® tests were virtually equivalent in terms of detection of canine antibodies against L. infantum, and both the tests demonstrated high and similar levels of sensitivity and specificity.
Veterinary Parasitology, 2011
Canine visceral leishmaniasis (CVL) is caused by Leishmania donovani complex parasites including L. donovani, Leishmania infantum and Leishmania chagasi. As some studies suggest that L. chagasi and L. infantum may be very similar or even the same species, the aim of the present study was to evaluate a commercial rapid ELISA test, originally designed for L. infantum, in the diagnosis of CVL in dogs naturally infected by L. chagasi. A total of 400 serum canine samples, including 283 positive dogs for CVL from an endemic area, 86 clinically healthy dogs from a non-endemic area and 31 dogs seropositive for confounding infectious agents (Trypanosoma cruzi, Toxoplasma gondii, Neospora caninum, Babesia canis and Ehrlichia canis) were used for test validation. An overall sensitivity of 94.7% (95% CI = 91.41-97.01%) and specificity of 90.6% (95% CI = 83.80-95.21%) was found, with a high degree of agreement (k = 0.8445) to the indirect ELISA. When confounding infectious diseases were excluded, specificity increased to 100% (95% CI = 95.8-100%), with a higher degree of agreement (k = 0.8928). In conclusion, the commercial kit designed for L. infantum was a highly sensitive and specific device for detection of L. chagasi infection in dogs, which indicates high immunoreactivity similarities between L. infantum and L. chagasi.
Veterinary Parasitology, 2016
This study was based on the need to employ a sensitive and specific method with samples that could be easily collected for diagnosing dogs infected with Leishmania infantum. To this end, we used real time-PCR (qPCR) to assess the value of the oral swab (OS) in detecting infected sick dogs (SD; n = 62), including, for the first time, the analysis of apparently healthy infected dogs (AD; n = 30), both from endemic areas for visceral leishmaniasis (VL). For comparison, we also evaluated the performance of the conjunctival swab (CS), blood (BL), lymph node (LN) and serology. We detected the presence of Leishmania DNA in the oral cavity in 62 out of the 92 dogs studied. The OS positivity (67.4%) was equivalent to the CS (68.5%) (p > 0.05), higher than BL (52.2%) (p ≤ 0.05), and lower than LN (84.8%) (p ≤ 0.05). OS and CS performed well in SD dogs (82.3% and 83.9%, respectively) but not in AD dogs (36.7% for both samples). BL showed the lowest positivity (52.2%) and provided equivalent results between AD (60.0%) and SD (48.4%) dogs (p > 0.05). LN yielded the highest positivity (84.8%), and it was also higher in the SD population (93.5%) compared to the AD population (66.7%) (p ≤ 0.05). Parasite load was high in LN, moderate in OS and CS, and low in BL, showing the relationship between the levels of parasitism and the positivity rates found in these samples. Serology was positive in 82.2% of the SD group and in 70% of the AD dogs (p > 0.05). Among the 20 seronegative dogs, seven (35%) were positive in either OS or CS, and 12 (60%) were positive when both noninvasive samples were jointly considered. The OS/CS combination resulted in a significant increase of positivity (p ≤ 0.05) for the AD dogs (from 36.7% to 63.4%), as well as OS/serology (80%) and OS/CS/serology (83.4%). For the SD population, positivity reached up to 95.2% with the same combinations, showing that combination of samples and/or tests is required for the identification of dogs infected with L. infantum and that the OS and CS combination based on qPCR notably improves the detection of both AD and SD dogs. In conclusion, OS proved to be a suitable sample for the molecular diagnosis of infected dogs with clinical signs of VL, but not for dogs with inapparent infection. For these, we recommend the combination of OS results with CS and/or serology in order to reach relevant positivity for L. infantum. Finally, another advantage of using OS or both noninvasive samples is the increased likelihood of diagnosing seronegative dogs.