A 24 year old male service member currently stationed on Guam presented with 3 days of subjective fever, headache, myalgias (specifically lower back), severe fatigue, and insomnia that worsened throughout the day. In addition, he noted drenching night sweats and anorexia associated with variable weight loss. He did not report diarrhea, abdominal pain or vomiting. He denied any rashes. He had no ill contacts at the time of initial presentation, and denied recent travel, insect bites, consumption of unusual foods or unpasteurized milk products. He had been immunized against hepatitis A and B, typhoid, influenza, and took no routine medications.
One day after this patient presented, three other patients presented with almost identical symptoms specifically complaining of the headache, extreme fatigue and lower back pain. By day three, four additional patients had presented; two to the clinic, and two to the local ER - Fig. 1, epidemic curve. 
All patients denied recent travel, sick contacts or consumption of unpasteurized or raw food. A point source outbreak was suspected because of the epidemic curve. The cluster of cases presented approximately 2 weeks after a particular water exposure during a hash running event on the south side of Guam where 20 or so hikers had gotten lost and spent the night in the jungle. They noted multiple exposures to wet river banks, mud, and swamps.
On exam, all the patients were ill appearing with most prostrate on the examination table. The majority of their exams were normal, with no hepatosplenomegaly, rashes or conjunctival injection noted. Most patients did have abrasions along either the upper arms, or lower legs. All patients demonstrated a temperatures ranging from 101.2-103 F and all were tachycardia.
The majority of laboratory testing was normal, with the exception of slightly elevated serum creatinine and one patient with elevated liver enzymes and creatinine kinase levels. See Table 1. 
Microbiologic testing included negative blood culture and multiple serologic studies, the results of which are shown in Table 2. Of note, all patients demonstrated a seroconversion to leptospirosis on convalescent blood samples. Clinical course: All patients responded well to treatment with intravenous normal saline and antiemetics. All were empirically treated with doxycycline 100 mg twice daily and their symptoms resolved over the course of 3 to 4 days. Anorexia continued well into the third day of treatment with antibiotics, with most reporting weight loss between 5 and 15 lb.