Guinea pig challenge dose titration study.

Guinea pigs were weighed on the day of infection and grouped to minimize weight differences across experimental groups (n = 4 per virus challenge dose, n = 2 for sham-infected controls). The animals were inoculated by i.p. injection of 0.1 ml containing 4, 40, 400, or 4,000 PFU of JUNV-R or sham infected with MEM. The guinea pigs were observed for 20 days for morbidity and mortality following JUNV-R challenge. Animal weights and body temperatures were recorded daily. Animals that lost 20% or more of body weight relative to their starting weight or which had a body temperature decline of 4°C or more relative to their baseline temperature were humanely euthanized.