Panels show multifocal mild to severe perivascular and neuropil infiltration of lymphocytes and monocytes (blue arrows in A-C); meningitis in a sulcus (black arrow in A); glial cell activation with notable astrocytosis, neuron degeneration, and neuronophagia
(arrowhead in B); occasional hemorrhage (blue arrow in D); mild periventricular spongiosis (blue arrows in C); and meningitis (black arrow in C).
6,7) Occasional necrotic neurons and neuronophagia
were also present.
Microscopy of the meninges, cerebellum, midbrain, pons, medulla, and cervical cord demonstrated extensive lymphocytic meningomyelitis and encephalitis, characterized by prominent neuronophagia
in motor nuclei (Figure, B).
Pathologic findings in the birds included hepatomegaly and splenomegaly; some also had encephalitis manifesting as multifocal areas of neuronophagia
Inflammatory cells were clustered around dying anterior horn cells, which is an indication of neuronophagia
Inflammatory cells were clustered around dying anterior horn cells, an indication of neuronophagia
C) Dorsal root ganglion showing spinal ganglion with satellitosis (arrow) and neuronophagia
of ganglion cells (arrowhead).
The affected hemisphere shows microglial nodules with or without neuronophagia
, perivascular cuffs of small lymphocytes and monocytes, and gliosis.
of these neurons by microgliosis was not a common feature and appeared delayed but was occasionally seen in individual neurons with an eosinophilic irregular granular content, especially in the gray matter of the spinal cord.
Histologically, both birds had severe encephalitis characterized by congestion, neuronal and Purkinje cell necrosis, gliosis, satellitosis, neuronophagia
, and endothelial cell swelling and vasculitis.
Additionally, histopathologic findings in patients with respiratory weakness and WNV infection have demonstrated neuronophagia
and leukocytic inflammation of the dorsal motor nuclei of the vagus and glossopharyngeal nerves, which is similar to that seen in the spinal anterior horns (26).
4, showed multifocal perivascular cuffing, lymphocytic meningitis, and focal encephalitis, characterized by focal neuronal necrosis and neuronophagia
with associated microglial nodules (Figure 6B).