Patient description: A 17 year old boy complains of vomiting, non-bloody diarrhea, abdominal pain, fever, chills and loss of appetite for the past 3 days. He ate a salad at a restaurant prior to his diarrhea onset. Physical exam was remarkable for pallor, jaundice, and diffuse abdominal tenderness. Lab results were as follows: Hemoglobin: 9.7 g/dL Platelet: 110,000 /cu.mm Creatinine: 3.6 mg/dL blood urea nitrogen (BUN): 73 mg/dL direct bilirubin: 2.4 mg/dL lactate dehydrogenase (LDH): 881 IU/L (normal: 110-265 IU/L) Peripheral blood smear showed a moderate number of schistocytes and helmet cells. Shiga-like toxin-producing E. coli (STEC) stx1/stx2 were found in stools. He has no other underlying disease and he is not on any medications.

Clinical trial eligibility criteria: eligible ages (years): 3.0-999.0,  Anthrax Bacillus Infections Subjects of any age, including pregnant women, are eligible for if they meet one of the five listed below, are hemodynamically and clinically stable, and agree to stored samples. Women of child-bearing age or potential will not be excluded from participation but pregnancy status will be determined at time of enrollment in order to optimize subsequent evaluation and care. 1. Inhalation Anthrax (acute or recovering infection) --nonspecific febrile illness followed by sepsis and/or respiratory failure AND --B anthracis isolation (via culture) from any site OR 2 supportive lab tests OR --nonspecific febrile illness followed by sepsis and/or respiratory failure with no alternative diagnosis AND --one supportive lab test OR direct epidemiological link to a confirmed environmental exposure 2. Cutaneous Anthrax (acute or recovering infection) --characteristic lesion (papule->vesicular->depressed black eschar plus or minus edema, erythema, necrosis or ulceration) AND --B anthracis isolation (culture) from any site OR 2 supportive lab tests --Characteristic lesion with no alternative diagnosis AND --one supportive lab test OR direct epidemiological link to a confirmed environmental exposure 3. Gastrointestinal Anthrax (acute or recovering infection) --Severe abdominal pain often associated with bloody vomiting/diarrhea followed by fever/septicemia AND --B anthracis isolation (culture) from any site OR 2 supportive lab tests --Severe abdominal pain often associated with bloody vomiting/diarrhea followed by fever/septicemia with no alternative diagnosis AND --1 supportive lab test OR direct epidemiological link to a confirmed environmental exposure These definitions were subsequently updated by the CDC in 2010 to accept clinically compatible symptoms plus one of the following: a positive culture, a positive immunohistochemical stain for antigen, a 4-fold increase in anti-PA IgG or a positive documented exposure with detection of DNA via PCR (26). 4. Exposed individuals who are clinically asymptomatic. 5. Past or imminent vaccination in healthy (non-anthrax exposed). 6. Hemodynamically and clinically stable at time of evaluation at NIH Hemodynamically: stable vital signs Clinically: no obvious signs of disease progression (e.g. worsening pleural effusions or increasing cutaneous edema) acute/newly recovered patients must be receiving standard antimicrobial therapy 7. Participant agrees to stored samples  Inability to sign informed consent or lack of designated Health Power of Attorney