Detection of norovirus genogroup IV, klassevirus, and pepper mild mottle virus in sewage samples in South Korea

Norovirus (NoV) genogroup (G) IV has been infrequently isolated from patients suffering from acute gastroenteritis (AGE), although this virus has not been detected in Korea. Klassevirus, a novel virus belonging to the family Picornaviridae and a possible etiologic agent of AGE, and pepper mild mottle virus (PMMoV), which originates from processed pepper products and is shed in human feces, are suggested to be new indicators of fecal pollution. We aimed to investigate the presence of NoV-GIV, klassevirus, and PMMoV in sewage samples collected in Korea. Between December 2010 and February 2012, influent sewage samples were collected every month from a wastewater treatment plant located in the eastern part of Seoul in Korea. The sewage samples were concentrated by the adsorption elution method using an HA (pore size of 0.45 mu m with mixed cellulose ester) electronegative filter with an acid-rinse procedure. RT-PCR was performed using specific primers for the capsid gene of NoV-GII and NoV-GIV, the coat gene of PMMoV, and the VP0/VP1 gene of klassevirus. Among the 14 sewage samples tested, klassevirus was detected in eight (57.1 %), PMMoV in eight (57.1 %), NoV-GII in five (35.7 %), and NoV-GIV in three (21.4 %). NoV-GIV was detected in December 2010 and January and March 2011. PMMoV and klassevirus were frequently detected in winter. Phylogenetic analysis revealed that the NoV-GIV detected in this study belonged to G-IV1 lineage. This is the first study to confirm the presence of NoV-GIV, klassevirus, and PMMoV in sewage samples in Korea.