Rapid and efficient detection methods of pathogenic swine enteric coronaviruses

Abstract

Porcine enteric coronaviruses (CoVs) cause highly contagious enteric diarrhea in suckling piglets. These COV infections are characterized by clinical signs of vomiting, watery diarrhea, dehydration, and high morbidity and mortality, resulting in significant economic losses and tremendous threats to the pig farming industry worldwide. Because the clinical manifestations of pigs infected by different CoVs are similar, it is difficult to differentiate between the specific pathogens. Effective high-throughput detection methods are powerful tools used in the prevention and control of diseases. The immune system of piglets is not well developed, so serological methods to detect antibodies against these viruses are not suitable for rapid and early detection. This paper reviews various PCR-based methods used for the rapid and efficient detection of these pathogenic CoVs in swine intestines. KEY POINTS: 1. Swine enteric coronaviruses (CoVs) emerged and reemerged in past years. 2. Enteric CoVs infect pigs at all ages with high mortality rate in suckling pigs. 3. Rapid and efficient detection methods are needed and critical for diagnosis.

Keywords: Pathogenic enteric coronaviruses; RT-PCR, detection methods; Swine Diarrhea.

Fig. 1

The schematic diagram of the workflow for swine enteric coronavirus detection by RT-PCR. Porcine fecal or tissue samples are homogenized in sterile PBS and centrifuged to remove debris. The supernatant is filtered through a 0.45-μm filter and used to total RNA extraction. The total RNAs are subjected to reverse transcription using random primer to generate cDNA. With this cDNA as template, the PCR amplification is carried out either by specific individual coronavirus or by pan-CoV primers first then followed by specific primers targeting individual swine enteric coronavirus when necessary. The PCR products are subjected to DNA electrophoresis and observed under UV light to identify the desired bands