A 22 year old man presents with fever for 10 days, in association with chills and sweating.

One month ago, he returned from a trip to Ecuador, where he consumed the local food and water, traveled in the jungle, swam in a local lake, and received many insect bites. He had been vaccinated against hepatitis B and yellow fever before the trip.

His medical history is unremarkable. He has a single stable sexual partner and denies using recreational drugs.