Microfluidic-RT-LAMP chip for the point-of-care detection of emerging and re-emerging enteric coronaviruses in swine

Porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome-coronavirus (SADS-CoV) are three emerging and re-emerging coronaviruses (CoVs). Symptoms caused by these three viruses are extremely similar, including acute diarrhea, vomiting and even death in piglets. To date, strict biosecurity is still the most effective disease prevention and control measures, and the early detection of pathogens is the most important link. Here, we developed a microfluidic-RT-LAMP chip detection system for the first time, which could detected PEDV, PDCoV and SADS-CoV simultaneously, and had advantages of rapid, simple, sensitive, high-throughput, and accurate at point-of-care settings. The lowest detection limits of the microfluidic-RT-LAMP chip method are 101 copies/μL, 102 copies/μL and 102 copies/μL for PEDV, PDCoV and SADS-CoV, respectively. The whole detection procedure can be finished rapidly in 40 min without any cross-reaction with other common swine viruses. A total of 173 clinical swine fecal samples characterized with diarrheal symptoms were used to evaluate the performance of the newly developed system, which presented good stabilities (C.V.s<5%) and specificities (100%), and possessed sensitivities of 92.24%, 92.19% and 91.23% for PEDV, PDCoV and SADS-CoV respectively. In summary, the established microfluidic-RT-LAMP chip detection system could satisfy the demanding in field diagnoses, which was suitable for promotion in remote areas due to its fast, portable and cost-effective characters.