title: A recently isolated Lassa virus from Mali demonstrates atypical clinical disease manifestations and decreased virulence in cynomolgus macaques.
abstract: The virulence of Soromba-R, a Lassa virus strain recently isolated from southern Mali, was assessed in 2 animal models of Lassa fever: inbred strain 13 guinea pigs and cynomolgus macaques. In both models, the Malian isolate demonstrated tissue tropism and viral titers similar to those of historical Lassa virus isolates from Sierra Leone (Josiah) and Liberia (Z-132); however, the Soromba-R isolate was found to be less pathogenic, as determined by decreased mortality and prolonged time to euthanasia in macaques. Interestingly, in addition to the classic indicators of Lassa fever, Soromba-R infection presented with moderate to severe pulmonary manifestations in the macaque model. Analysis of host responses demonstrated increased immune activation in Soromba-R-infected macaques, particularly in neutrophil-activating or -potentiating proinflammatory cytokines or growth factors, including tumor necrosis factor α, macrophage inflammatory protein 1α, interleukin 1β, and granulocyte colony-stimulating factor, as well as interleukin 5, which may be responsible for the decreased lethality and uncharacteristic clinical presentation. These results suggest that the strain of Lassa virus circulating in Mali might be less pathogenic than strains circulating in the historical region of endemicity and may result in an atypical presentation for Lassa fever, which could complicate clinical diagnosis.
authors.affiliation: Laboratory of Virology, Division of Intramural Research, NationalInstitute of Allergy and Infectious Diseases/National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, USA.
authors.forename: David
authors.initials: D
authors.lastname: Safronetz
authors.forename: James E
authors.initials: JE
authors.lastname: Strong
authors.forename: Friederike
authors.initials: F
authors.lastname: Feldmann
authors.forename: Elaine
authors.initials: E
authors.lastname: Haddock
authors.forename: Nafomon
authors.initials: N
authors.lastname: Sogoba
authors.forename: Douglas
authors.initials: D
authors.lastname: Brining
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Geisbert
authors.forename: Dana P
authors.initials: DP
authors.lastname: Scott
authors.forename: Heinz
authors.initials: H
authors.lastname: Feldmann
mesh_terms: D000818:Animals; D054405:Chemokine CCL3 / Q000097:blood / Q000276:immunology; D002522:Chlorocebus aethiops; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000097:blood / Q000276:immunology; D006168:Guinea Pigs; D006403:Hematologic Tests; D007150:Immunohistochemistry; D053583:Interleukin-1beta / Q000097:blood / Q000276:immunology; D015850:Interleukin-6 / Q000097:blood / Q000276:immunology; D007835:Lassa Fever / Q000276:immunology / Q000473:pathology* / Q000821:virology; D007836:Lassa virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity*; D008168:Lung / Q000473:pathology / Q000821:virology; D008252:Macaca fascicularis; D008297:Male; D008302:Mali; D012367:RNA, Viral / Q000097:blood; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000276:immunology; D014709:Vero Cells; D019562:Viral Load; D014766:Viremia / Q000821:virology; D014774:Virulence
chemical_list: D054405:Chemokine CCL3; D053583:Interleukin-1beta; D015850:Interleukin-6; D012367:RNA, Viral; D014409:Tumor Necrosis Factor-alpha; D016179:Granulocyte Colony-Stimulating Factor