Pathogenesis+-+Lassa+Fever

The pathogenesis of the Lassa Virus is not fully understood. The virus can enter the body multiple ways including the bloodstream, respiratory or digestive tract, and lymph vessels triggering a cell-mediated immune response. The virus targets endothelial cells and macrophages. The body responds to the attack by presenting the viral peptides of MHC Class I to cytotoxic T cells, specifically CD8 T cells. Capillary lesions begin to grow as the virus replicates in the reticuloendothelial cells causing platelet loss, vascular permeability, and hemorrhaging in organs. The hemorrhages are caused by the inability of the platelets to aggregate and clot.

Although the body reacts with a cell-mediated immune response (phagocytes, NK cells, cytotoxic T cells) IgM antibodies appear on the scene 10-14 days after infection.

Clotting Platelets

Lassa Virus

Sources http://www.bio.davidson.edu/courses/immunology/students/spring2003/sole/lassa.htm http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1000836