Development and evaluation of an immunochromatographic strip for rapid detection of porcine hemagglutinating encephalomyelitis virus

The incidence of PHE among pigs in many countries is on the rise, and it has caused great economic losses to the pig industry. Therefore, the development of a sensitive, specific, and easily-performed assay is crucial for the rapid detection and surveillance of PHE-CoV infection and transmission.

An immunochromatographic strip was developed for the detection of PHE-CoV. The colloidal gold-labeled MAb 4D4 was used as the detection reagent, and the MAb 1E2 and goat anti-mouse IgG coated the strip's test and control lines, respectively. The immunochromatographic strip was capable of specifically detecting PHE-CoV with a HA unit of 2 within 10 min. Storage of the strips at room temperature for 6 months or at 4°C for 12 months did not change their sensitivity or specificity. Using RT-PCR as a reference test, the relative specificity and sensitivity of the immunochromatographic strip were determined to be 100% and 97.78%, respectively. There was an excellent agreement between the results obtained by RT-PCR and the immunochromatographic strips (kappa = 0.976). Additionally, there was a strong agreement between the sandwich enzyme-linked immunosorbent assay (ELISA) and immunochromatographic strips (Kappa = 0.976). When the immunochromatographic strips were used for diagnosing PHE-CoV infection in the Jilin Province, the PHE-CoV-positive rate ranged from 61.54% in the Jilin district to 17.95% in the Songyuan district.

Based on its high specificity, sensitivity, and stability, the immunochromatographic strip would be suitable for on-site detection of PHE-CoV for surveillance and epidemiological purposes.