Relationship between Microscopic Agglutination Test and Real-Time PCR Assay for Detection of Seropositivity of Pathogenic <i>Leptospira</i> Infections in Cattle in Chile: A Pilot Study

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Bibliographic Details
Main Authors: Paz Loebel, Lucía Azócar-Aedo, Alfredo Rodríguez, María Gallardo
Format: Article
Language:English
Published: Compuscript Ltd 2025-03-01
Series:Zoonoses
Online Access:https://www.scienceopen.com/hosted-document?doi=10.15212/ZOONOSES-2025-0003
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Summary:<div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d1449481e140"> <!-- named anchor --> </a> <h5 class="section-title" id="d1449481e141">Objectives:</h5> <p dir="auto" id="d1449481e143">This study was aimed at evaluating the relationship between microscopic agglutination test (MAT) seropositivity and real-time polymerase chain reaction (PCR) reactivity in cattle. An additional objective was assessment of the diagnostic value of both tests in detecting seropositivity and infection caused by pathogenic <i>Leptospira</i>. </p> </div><div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d1449481e148"> <!-- named anchor --> </a> <h5 class="section-title" id="d1449481e149">Methods:</h5> <p dir="auto" id="d1449481e151">Blood and urine samples were collected from 61 bovines in the Los Lagos region of Chile. The MAT detected a panel of eight <i>Leptospira</i> serogroups, whereas real-time PCR was conducted with a TaqMan probe targeting the <i>Leptospira</i> lipL32 gene. </p> </div><div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d1449481e159"> <!-- named anchor --> </a> <h5 class="section-title" id="d1449481e160">Results:</h5> <p dir="auto" id="d1449481e162">The seropositivity rate for pathogenic <i>Leptospira</i> was 39.3% (95% confidence interval [95% CI], 27.04–51.57) according to the MAT, and <i>Tarassovi</i> and <i>Sejroe</i> were the most frequently detected serogroups. The antibody titers ranged from 1:200 to 1:800. The positivity rate determined with real-time PCR was 29.5% (95% CI, 18.05–40.94), and the leptospiral concentrations ranged from 1.07 to 12,500 leptospires per milliliter urine. Among the 24 animals with MAT-reactive serum samples, 18 also had urine samples with positive real-time PCR results; thus 75% of animals had positive results with both techniques. The kappa coefficient between tests of 0.784 (95% CI, 0.539–1.0) indicated substantial agreement. The sensitivity and specificity of real-time PCR versus MAT were 75.0% (95% CI, 57.7–92.3) and 100%, respectively. The positive and negative predictive values were 100% and 86.7% (95% CI, 75.7–96.4), respectively. </p> </div><div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d1449481e173"> <!-- named anchor --> </a> <h5 class="section-title" id="d1449481e174">Conclusion:</h5> <p dir="auto" id="d1449481e176">The results demonstrated the complementary nature of MAT and real-time PCR analyses in diagnosing bovine leptospirosis: combined use of both tests enhanced diagnostic accuracy. Real-time PCR detected <i>Leptospira</i> infection and bacterial renal excretion, thus providing insights into the presence and extent of environmental contamination, whereas the MAT identified seropositivity, antibody titers, and the serogroups associated with infection. </p> </div>
ISSN:2737-7466
2737-7474