Diarrhea disease is one of major threats that afflict the global pork industry in 55 recent years, which has caused an estimated loss of multi-million dollar annually. 56 Various pathogens that can cause diarrhea in swine have been identified, and swine 57 enteric coronaviruses are the most destructive pathogens that are able to result 58 vomiting, dehydration and lethal watery diarrhea in piglets [1] . To date, four swine 59 enteric coronaviruses have been defined, including three Alphacoronaviruses widely applied for detecting and identifying pathogens [27] [28] [29] [30] . 89 Up to now, the predominant control measures of swine diarrhea disease are the 90 rapid and accurate diagnoses of pathogens at the early stage to prevent further 91 circulations in swine. Currently, the most commonly detection methods for swine 92 enteric coronaviruses such as ELISA (enzyme-linked immunosorbent assay), PCR and 93 IHC (immunohistochemistry), all depend on laboratory diagnosis and possessed the 94 advantages of high sensitivity and accuracy, and have been widely used [31] [32] [33] [34] . 95 However， most of these diagnostic assays are complex, time-consuming, and require a 96 large of reagents and well-equipped laboratories, which limit their application in 97 remote areas. Therefore, it is urgent to develop portable POC devices with characters 98 of simple, timely, multi-target and strong pertinence, so as to detect pathogens early, showed that the developed microfluidic-RT-LAMP chip system was accurate, 111 sensitive, specific and reproducible for point-of-care diagnosis, which was advantaged 112 for the early diagnosis of diarrhea in swine farms, especially in remote areas, and 113 adopting effective measures to control the spread of the diseases. The microfluidic chip made of PMMA that was used in this study was a CD-shape 132 with a diameter of 80 mm and a thickness of 2.5 mm, which was fabricated by the 133 micro-injection molding technology. To form an integrated microfluidic chip, a kind 134 of pressure-sensitive film was applied to seal the micro-channel of chip via suitable 135 pressure. The microfluidic chip comprised four independent units, each of which was 136 consisted of a sample well, a vent and eight micro reaction wells ( Figure 1A ). The 137 ball valve played a significant role throughout the process ensuring that the reaction 138 mixture diffused into the adjacent pipe and the reaction wells were filled with liquid.
The volume of each micro reaction well was 5 μL. The supporting microfluidic To ensure the accuracy of the three LAMP systems, the amplification products were 172 further determined by standard agarose gel electrophoresis. Table 1 .
To determine the accuracy of the LAMP reaction, the target templates were 227 successfully amplified from the target-contained sample and presented ladder-like 228 bands with agarose gel electrophoresis ( Figure 2D ). 287 The specificity, sensitivity and reproducibility test results have illustrated that the 288 microfluidic-RT-LAMP chip detection system is stable, rapid, convenient and portable.
To further verify the actual performance of the microfluidic-RT-LAMP chip detection 