Cross-priming amplification combined with immunochromatographic strip for rapid on-site detection of African swine fever virus

African swine fever (ASF) is a highly contagious disease caused by African swine fever virus (ASFV) in domestic pigs and wild boars. Up to now, no commercial vaccines against ASF are available. With the rapid development of international trade and modern logistics and the frequent trade activities with Africa, Europe and neighboring countries, the risk of cross-border transmission of ASF to ASF-free regions is increasing. Therefore, there is an urgent need to establish a convenient and low-cost diagnostic method for rapid and on-site detection of the virus to timely implement the control measures. In this study, a cross-priming amplification in combination with immunochromatographic strip (CPA-strip) was established for rapid detection of ASFV. The CPA-strip assay displayed no cross-reactivity to other swine viruses. The minimum detection limit of this method was 200 copies. Forty-five clinical swine blood samples collected from Uganda were examined by the novel assay, 6 out of 45 samples were tested positive for ASFV. The agreement rate between the CPA-strip assay and the universal probe library-based real-time PCR was 97.8% (44/45). In addition, a total of 100 tissue samples and 57 blood samples from Chinese swine herds were tested to be negative. We concluded that the established CPA-strip method is suitable for on-site detection of ASFV.