Lymphoid pathology of MAYV-infected rhesus macaques.

Macaque lymphoid tissues were collected during necropsy, fixed, paraffin embedded, sectioned, and stained with hematoxylin and eosin (HE). Histology was examined, and select representative images are shown for the three animals. (A; Bar = 1 cm) The axillary skin of NHP 2 is discolored red-tan. (B; Bar = 1 cm) The axillary lymph nodes in all three animals were enlarged and erythematous. (C; Bars = 500 μm, inset 50 μm) The axillary lymph nodes have mild lymphofollicular hyperplasia and medullary sinus histiocytosis with hemophagocytosis. (D; Bars = 500 μm, inset 300 μm) Perifollicular sinusoids are congested. (E; Bar = 50 μm) Perifollicular sinusoids (black and white arrows) have reticuloendothelial hypertrophy and are engorged with macrophages, lymphocytes, and erythrocytes. There is rare erythrophagocytosis. (F; Bar = 50 μm) An increased number of neutrophils are within the red pulp (arrowheads). (EPS)