<prompt> An emerging viral pathogen causing pyelonephritis in kidney allografts is -RotavirusHerpes simplexPolyomavirusInfluenza virus  <response>: Diseases caused by human polyomavirus infections are most common among immunocompromised people; disease associations include BK virus with nephropathy in renal transplant and non-renal solid organ transplant patients, JC virus with progressive multifocal leukoencephalopathy, and Merkel cell virus MCV Ref Davidson 23rd edition pg 877 