Modelling Marburg Virus Disease in Syrian Golden Hamsters: Contrasted Virulence Between Angola and Ci67 Strains

Background. Marburg virus (MARV) has caused numerous sporadic outbreaks of severe hemorrhagic fever in humans. Human case fatality rates of Marburg virus disease (MVD) outbreaks range from 20% to 90%. Viral genotypes of MARV can differ by over 20%, suggesting variable virulence between lineages may accompany this genetic divergence. Comparison of existing animal models of MVD employing different strains of MARV support differences in virulence across MARV genetic lineages; however, there are few systematic comparisons in models that recapitulate human disease available. Methods. We compared features of disease pathogenesis in uniformly lethal hamster models of MVD made possible through serial adaptation in rodents. Results. No further adaptation from a previously reported guinea pig-adapted (GPA) isolate of MARV-Angola was necessary to achieve uniform lethality in hamsters. Three passages of GPA MARV-Ci67 resulted in uniform lethality, where 4 passages of a GPA Ravn virus was 75% lethal. Hamster-adapted MARV-Ci67 demonstrated delayed time to death, protracted weight loss, lower viral burden, and slower histologic alteration compared to GPA MARV-Angola. Conclusions. These data suggest isolate-dependent virulence differences are maintained even after serial adaptation in rodents and may serve to guide choice of variant and model used for development of vaccines or therapeutics for MVD.