Diagnosis of Acute Mumps Infection during an Outbreak in a Highly Vaccinated Population: Mumps RNA or Mumps IgM Detection? - (Pages 1-4)
Jaythoon Hassan, Anna Rose Connell, Timothy Ronan Leahy, Jeff Connell and Cillian De Gascun
1National Virus Reference Laboratory, University College Dublin, Belfield, Dublin 4, 2National Children’s Research Centre, and 3Our Lady’s Children’s Hospital, Crumlin, Dublin 12, Ireland
Abstract: A large mumps outbreak commenced in Ireland in October 2014. The users of the National Virus Reference Laboratory were informed that oral fluid collection devices would be provided to allow the collection of oral fluid for the diagnosis of suspected acute mumps infection by RNA detection. Both mumps RNA and mumps IgM detection could be undertaken on a single oral fluid sample and hence would be more accurate in acute infection than serology alone. The aim of this study was to retrospectively assess whether changing the algorithm from serological testing for mumps IgM to molecular testing for mumps RNA in oral fluid samples was beneficial for the diagnosis of acute mumps infection during a mumps outbreak in a highly vaccinated population. A total of 1455 serum and 490 oral fluid samples were submitted for laboratory confirmation of mumps virus infection. Of the sera, 448 (30.8%) tested positive for the presence of mumps IgM. A total of 251 (51.2%) oral fluids had detectable mumps RNA. Despite the limitations of this laboratory based audit it is evident that during an outbreak, mumps RNA detection in oral fluid was beneficial for the specific, definitive diagnosis of acute mumps infection in a highly vaccinated population.
Keywords: Mumps outbreaks, Mumps RNA, Mumps IgM, Oral fluid.