A novel and low-cost cross-priming amplification assay for rapid detection of Babesia duncani infection.

Babesia duncani, responsible for human babesiosis, is one of the most important tick-borne intraerythrocytic pathogens. Traditionally, babesiosis is definitively diagnosed by detecting parasite DNA in blood samples and examining Babesia parasites in Giemsa-stained peripheral blood smears. Although these techniques are valuable for determining Babesia duncani, they are often time-consuming and laborious. Therefore, developing rapid and reliable B. duncani identification assays is essential for subsequent epidemiological investigations and prevention and control. In this study, a cross-priming amplification (CPA) assay was developed, combined with a vertical flow visualization strip, to rapidly and accurately detect B. duncani infection. The detection limit of this method was as low as 0.98 pg/μl of genomic DNA from B. duncani merozoites per reaction at 59 °C for 60 min. There were no cross-reactions between B. duncani and other piroplasms infective to humans and mammals. A total of 592 blood samples from patients bitten by ticks and experimental infected hamsters were accurately assessed using CPA assay. The average cost of the CPA assay is as low as approximately $ 0.2 per person. These findings indicate that the CPA assay may therefore be a rapid screening tool for detection B. duncani infection, based on its accuracy, speed, and cost-effectiveness, particularly in resource-limited regions with a high prevalence of human babesiosis.