Trace-forward investigation of mice in response to lymphocytic choriomeningitis virus outbreak

Abstract

During follow-up of a 2012 US outbreak of lymphocytic choriomeningitis virus (LCMV), we conducted a trace-forward investigation. LCMV-infected feeder mice originating from a US rodent breeding facility had been distributed to >500 locations in 21 states. All mice from the facility were euthanized, and no additional persons tested positive for LCMV infection.

Keywords: animals; arenavirus; humans; lymphocytic choriomeningitis virus; mice; multistate outbreaks; viruses; zoonoses.

Figure 1

Algorithm used to determine whether mice were potentially infected with lymphocytic choriomeningitis virus (LCMV) during a multistate investigation, United States, 2012. This algorithm was used to determine whether 1) potentially infected mice remained at the facilities being assessed, 2) mice from the original shipment remained, 3) offspring from these mice remained, or 4) shipments of mice had been comingled or had shared equipment with mice from the original shipment. LCMV is easily maintained in a mouse colony, and a clear break among the population (i.e., a time when no remaining mice are maintained and equipment is disinfected) is necessary to ensure that no ongoing infection continues.

Figure 2

The distribution of mice potentially infected with lymphocytic choriomeningitis virus originating from facility A to ≈500 pet stores and other animal facilities in 21 states, United States, 2012.