This study has the purpose to demonstrate prospect of benefit of EDI048 on clinical signs and symptoms of cryptosporidiosis to facilitate trial in target population, pediatric patients.

This study aims to investigate the efficacy of a new chemical entity, EDI048, in a controlled human infection model of cryptosporidiosis induced by administration of ABO809 in healthy adults, who become symptomatic with disease thereby demonstrating a prospect of benefit for use of EDI048 in children afflicted with cryptosporidiosis.

This study is a Placebo-controlled, participant- and investigator-blinded multicenter trial in healthy adult volunteers who are administered Cryptosporidium parvum oocysts (ABO809) to develop diarrhea and symptoms consistent with cryptosporidiosis. After developing diarrhea, participants will be randomized 1:1 to treatment with EDI048 or placebo in parallel.

Inclusion Criteria:

• Signed informed consent must be obtained prior to participation in the study.
• Ability to communicate well with the Investigator, and to understand and comply with the requirements of the study.
• Male and female participants must be between 18 to 50 years of age and in good health as determined by medical history, physical examination, vital signs, electrocardiogram, and laboratory tests at Screening and Baseline.
• Demonstrate thorough understanding of cryptosporidiosis and measures to prevent secondary spread via education provided at screening.
• Must have a body mass index (BMI) within the range of 18-32 kg/m2. BMI = Body weight (kg) / [Height (m)]2
• Have not received ABO809 or EDI048 in prior clinical trials.

Exclusion Criteria:

• History of Cryptosporidium infection.
• Current (based on screening laboratory tests) or history of infectious diarrhea associated with international travel in the last 12 months or C. difficile infection within 6 months prior to Screening.
• Employment as a healthcare worker with direct patient care, in a daycare center (e.g., for children or the elderly), or direct food handler (individuals who work directly with food in commercial establishments).
• Participants who share a home with any of the following:
• a pregnant woman,
• a person <4 years old or >65 years old,
• a person who is infirmed,
• a person who is immunocompromised (for reasons including corticosteroid therapy, HIV infection, cancer chemotherapy, or other chronic debilitating disease).
• Residents of dormitories with shared bathrooms would also be excluded.
• Any significant medical history including, but not limited to, conditions of the cardiac, pulmonary, gastrointestinal, renal, endocrine, reproductive, immune or other systems.
• Use of investigational drugs within 5 half-lives of the drug or its major metabolites or 30 days of enrollment (Day 1), whichever is longer.
• Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, unless they are using highly effective methods of contraception throughout the trial; pregnant or nursing (lactating) women.