Image Challenge of the Week!

A 22-year old man presented with progressive headache, painless unilateral vision loss, fever, and axillary lymphadenopathy. CT head and lumbar puncture were negative. RPR and Lyme titers were negative. Fundoscopic examination revealed the following:

stellate neuroretinitis
Curr Opin Ophthalmol. 1999 Jun;10(3):209-16.

What is this finding and the likely etiology in the context of the patient’s symptoms?

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