Figure 1. Study design to evaluate reproductive tissue pathology and tissue tropism in strain 13/N guinea pig model of Lassa virus infection. Tissues collected from a total of 57 adult strain 13/N guinea pigs inoculated subcutaneously with a target dose of 10⁴ FFU of LASV (equivalent to ≈2 × 10⁴ 50% tissue culture infectious dose;, representing 3 independent studies, were examined by PCR, hematoxylin and eosin, immunohistochemistry, or in situ hybridization. Animals were separated into 3 study groups on the basis of time of sampling and clinical outcome: those serially euthanized at predetermined study endpoints (2, 4, 8, 12, or 16 dpi [n = 5 at each timepoint]) to investigate early infection with highly pathogenic LASV-Josiah strain; terminal animals that reached endpoint criteria because of disease after LASV-Josiah infection (unvaccinated [n = 9] or vaccinated with 𝛾-irradiated viral replicon particle [VRP] [n = 2]); and survivors euthanized at 41–42 dpi. Survivors were 15 animals infected with LASV-Josiah (vaccinated preexposure with VRP [n = 5] or gamma-irradiated VRP [n = 3], vaccinated postexposure with VRP [n = 5], or unvaccinated [n = 2] and 6 animals infected with strain NJ2015 [all unvaccinated (n = 6)]). Shaded symbols indicate animals that exhibited overt signs (defined as weight loss >10%, temperature >39.5°C for >2 consecutive days, or presence of clinical signs [i.e., clinical score >1 on >1 days). dpi, days postinfection; FFU, focus-forming units; LASV, Lassa virus; V, vaccinated.