AUTHOR=Kamau Maureen W. , Witte Carmel , Goosen Wynand , Mutinda Mathew , Villinger Jandouwe , Getange Dennis , Khogali Rua , von Fricken Michael E. , Fèvre Eric Maurice , Zimmerman Dawn , Linton Yvonne-Marie , Miller Michele 

TITLE=Comparison of test performance of a conventional PCR and two field-friendly tests to detect Coxiella burnetii DNA in ticks using Bayesian latent class analysis

JOURNAL=Frontiers in Veterinary Science

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2024.1396714

DOI=10.3389/fvets.2024.1396714

ISSN=2297-1769

ABSTRACT=<sec><title>Introduction</title><p><italic>Coxiella burnetii</italic> (<italic>C. burnetii</italic>)-infected livestock and wildlife have been epidemiologically linked to human Q fever outbreaks. Despite this growing zoonotic threat, knowledge of coxiellosis in wild animals remains limited, and studies to understand their epidemiologic role are needed. In <italic>C. burnetii</italic>-endemic areas, ticks have been reported to harbor and spread <italic>C. burnetii</italic> and may serve as indicators of risk of infection in wild animal habitats. Therefore, the aim of this study was to compare molecular techniques for detecting <italic>C. burnetii</italic> DNA in ticks.</p></sec><sec><title>Methods</title><p>In total, 169 ticks from wild animals and cattle in wildlife conservancies in northern Kenya were screened for <italic>C. burnetii</italic> DNA using a conventional PCR (cPCR) and two field-friendly techniques: Biomeme’s <italic>C. burnetii</italic> qPCR Go-strips (Biomeme) and a new <italic>C. burnetii</italic> PCR high-resolution melt (PCR-HRM) analysis assay. Results were evaluated, in the absence of a gold standard test, using Bayesian latent class analysis (BLCA) to characterize the proportion of <italic>C. burnetii</italic> positive ticks and estimate sensitivity (Se) and specificity (Sp) of the three tests.</p></sec><sec><title>Results</title><p>The final BLCA model included main effects and estimated that PCR-HRM had the highest Se (86%; 95% credible interval: 56–99%), followed by the Biomeme (Se = 57%; 95% credible interval: 34–90%), with the estimated Se of the cPCR being the lowest (24%, 95% credible interval: 10–47%). Specificity estimates for all three assays ranged from 94 to 98%. Based on the model, an estimated 16% of ticks had <italic>C. burnetii</italic> DNA present.</p></sec><sec><title>Discussion</title><p>These results reflect the endemicity of <italic>C. burnetii</italic> in northern Kenya and show the promise of the PCR-HRM assay for <italic>C. burnetii</italic> surveillance in ticks. Further studies using ticks and wild animal samples will enhance understanding of the epidemiological role of ticks in Q fever.</p></sec>