sentence: However , more studies are needed to further investigate FRNAP-II / III concentrations in wastewater.Among PyVs , JCV had the highest concentrations ( 10 -10 gc / l ) in wastewater collected in Brazil and Chile ( Fumian et al ., 2010 ; Levican et al ., 2019 ) , however , it was less prevalent ( 10 -10 gc / l ) in the US ( Arizona ) , Spain and in the UK ( Wales ) ( Bofill-Mas et al ., 2006 ; Farkas et al ., 2018a ; Kitajima et al ., 2014 ; Rusi ñ ol et al ., 2015 ; Schmitz et al ., 2016 ) .