Can vaccines against canine visceral leishmaniasis interfere with the serological diagnostics recommended by the Brazilian Ministry of Health?

Campos, Monique Paiva; Luca, Paula Mello De; Renzetti, Alinne Rangel dos Santos; Souza, Sara Maria Marques de; Júnior, Artur Augusto Velho Mendes; Barros, Renata Simões; Figueiredo, Fabiano Borges

doi:10.1590/0103-8478cr20160846

Cited by 5 publications

(5 citation statements)

References 13 publications

(14 reference statements)

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“…In our study we did not evaluate groups of vaccinated dogs, but we believe that the antigens validated in the present study do not detect antibodies from animals vaccinated in the ELISA because they have different epitopes. In the study conducted by Campos et al, 40 dogs vaccinated with Leish-Tec ® were not reagent to DPP and L. major -like-ELISA in the 30, 180 and 360 days after the vaccination protocol.…”

Section: Discussionmentioning

confidence: 97%

Validation of ELISA with recombinant antigens in serological diagnosis of canine Leishmania infantum infection

Fujimori

Almeida

Barrouin‐Melo

et al. 2021

Mem. Inst. Oswaldo Cruz

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BACKGROUND Dogs are the main peridomiciliary reservoir of Leishmania infantum thus the correct diagnosis of infection is essential for the control of the transmission and treatment as well. However, the diagnosis is based on serological assays that are not fully effective. OBJECTIVE We aimed to establish an effective serological assay for the diagnosis of L. infantum infected dogs using Leishmaniaderived recombinant antigens. METHODS Leishmania derived rK39-, rK28-, rKR95-based enzyme-linked immunosorbent assay (ELISA) was standardized using symptomatic and asymptomatic L. infantum-infected dogs. Then 2,530 samples from inquiry in endemic areas for VL were evaluated and the results compared with recommended assays by the Brazilian Ministry of Health (MH algorithm). Further samples from a cohort of 30 dogs were searched. FINDINGS For rK39-, rK28-and rKR95-ELISA the sensitivity was around 97% and specificity 100%. The positivity of these three ELISA in the inquiry samples was 27-28%, around 10% higher than the assays currently in use. When cohort samples were searched, we observed likely false-negative results (> 65%) with supposedly negative samples that turned positive six months later with the assays in use (MH algorithm). MAIN CONCLUSIONS For the diagnosis of L. infantum-infected dogs, rK39-based ELISA showed better diagnostic performance than other assays in use in Brazil and worldwide.

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Section: Discussionmentioning

confidence: 97%

Validation of ELISA with recombinant antigens in serological diagnosis of canine Leishmania infantum infection

Fujimori

Almeida

Barrouin‐Melo

et al. 2021

Mem. Inst. Oswaldo Cruz

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“…Another aspect worth mentioning is the necessity to verify, prior to the diagnostic test, any possible anti-Leishmania vaccination of the dogs, considering that serological tests may not distinguish between infected and vaccinated animals. (41) Studies have diverged with regard to the results obtained on cross-reactivity: Campos et al (42) recently demonstrated no cross-reactivity of DPP ® CVL for up to 12 months after vaccination of animals in a nonendemic area, whereas Marcondes et al (43) reported that the test can cross-react with vaccine antibodies for up to six months after vaccination. Therefore, such information must be considered before the interpretation of test results.…”

Section: Discussionmentioning

confidence: 99%

Validation of the Dual-path Platform chromatographic immunoassay (DPP® CVL rapid test) for the serodiagnosis of canine visceral leishmaniasis

Figueiredo

Vasconcelos

Madeira

et al. 2018

Mem. Inst. Oswaldo Cruz

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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.

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“…Considering that the main screening and confirmatory tests of canine infection in Brazil are serological, it is possible that the antibody responses elicited by the vaccine interfere with the diagnosis, leading to the inability to distinguish between vaccinated and naturally infected animals. We have recently demonstrated that in a non-endemic area, and up to 1 year after Leish-Tec ® immunization, vaccinated dogs remained negative in the DPP/EIE serological protocol used by the BMH ( 22 , 23 ). On the other hand, the high degree of serological response in rA2 ELISAs observed in previous studies with sera of CVL animals ( 19 – 21 ) led us to evaluate the potential role of this protein for diagnosis, focusing on possible differences in the responses elicited against immunodominant linear B cell epitopes in a group of Leish-Tec ® vaccinated dogs and in two groups of CVL animals (symptomatic and asymptomatic), naturally infected by L. infantum .…”

Section: Introductionmentioning

confidence: 99%

Leishmania infantum Virulence Factor A2 Protein: Linear B-Cell Epitope Mapping and Identification of Three Main Linear B-Cell Epitopes in Vaccinated and Naturally Infected Dogs

et al. 2018

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In Brazil, canine visceral leishmaniasis (CVL) is caused by Leishmania infantum, presenting a broad spectrum of clinical manifestations. Dogs are the main parasite reservoir in urban areas and canine cases precede human infection. Currently, A2 protein based Leish-Tec® vaccine is the only vaccine commercially available against CVL in Brazil. Considering that the main screening and confirmatory tests of canine infection are serological, it is possible that the antibody response elicited after vaccination interfere with diagnosis, leading to the inability to distinguish between vaccinated and infected animals. In order to identify the specific B-cell response induced after vaccination, A2 protein sequence was screened for main linear B-cell epitopes using in silico prediction (Bepipred) and immunological confirmation by ELISA. Three amino acid sequences were described as potential B-cell epitopes (SV11-SAEPHKAAVDV, PP16-PQSVGPLSVGPQSVGP, and VQ34-VGPLSVGPQSVGPLSVGPLSVGPQAVGPLSVGPQ). Specific IgG ELISAs were performed in sera of 12 immunized dogs living in non-endemic areas, followed for up to 1 year after immunization. The results were compared with those obtained in a group of 10 symptomatic and 10 asymptomatic CVL dogs. All predicted epitopes were confirmed as linear B-cell epitopes broadly recognized by sera from studied dogs. Total IgG ELISAs demonstrated distinct patterns of response between peptides in the immunized and CVL groups. VQ34 peptide was recognized by the majority of sera from vaccinated and symptomatic dogs, and increases after vaccination. PP16 induced low levels of specific IgG that increased 1 year after immunization. Interestingly, a low frequency of reactivity was found against SV11 in naturally infected dogs (symptomatic and asymptomatic), while 83.3% of vaccinated dogs presented positive responses 1 year after immunization. The two animals in the vaccinated group that did not respond to SV11 1 year after immunization presented positive serology both 30 days and 6 months after immunization. In summary, we identified three main linear B-cell epitopes in A2 based vaccine. Moreover, the humoral response against SV11 presented marked differences between infected and Leish-Tec vaccinated dogs, and should be further investigated, in large trials, to confirm its potential as a serological marker able to distinguish between infected and vaccinated dogs.

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Can vaccines against canine visceral leishmaniasis interfere with the serological diagnostics recommended by the Brazilian Ministry of Health?

Cited by 5 publications

References 13 publications

Validation of ELISA with recombinant antigens in serological diagnosis of canine Leishmania infantum infection

Validation of ELISA with recombinant antigens in serological diagnosis of canine Leishmania infantum infection

Validation of the Dual-path Platform chromatographic immunoassay (DPP® CVL rapid test) for the serodiagnosis of canine visceral leishmaniasis

Leishmania infantum Virulence Factor A2 Protein: Linear B-Cell Epitope Mapping and Identification of Three Main Linear B-Cell Epitopes in Vaccinated and Naturally Infected Dogs

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