This is a prospective observational study to include participants with a spectrum of emerging or unknown pathogens with the objective to determine etiology and clinical characteristics of those diseases.

Infectious diseases remain one of the leading causes of death worldwide despite innovations in medical research and the availability of new treatments. Emerging diseases include outbreaks of previously unknown diseases or known diseases where the incidence in humans has significantly increased in the past two decades. Detailed studies on emerging and re-emerging infectious agents to better understand pathogens' biology and host pathogenesis are mostly lacking. This study protocol is to prepare for a rapid coordinated clinical investigation of acute infections of emerging and re-emerging infectious agents in Mali. In collaboration with the Mali Ministry of Health and Public Hygiene, we will conduct an observational study to include participants with a spectrum of emerging or unknown pathogens with the objective to determine etiology and clinical characteristics of those diseases. Patients with suspected emerging or re-emerging infectious diseases within 15 km of Point G Hospital in Bamako will be invited to participate in this study.

Participants referred or managed by the National Disease Surveillance Committee, primary healthcare facilities, level-3 hospitals, or other facilities Adults and children of any age

Unexplained fever (temperature greater than or equal to 38°C), recorded or reported, within 24 to 48 hours, regardless duration with at least one of the following signs or symptoms:

• Unexplained bleeding
• One or more generic symptoms (headache, tiredness, myalgia, arthralgia, diarrhea, anorexia, weight loss, rash)
• Jaundice
• One or more respiratory symptoms (cough, dyspnea, pharyngitis, rhinorrhea)
• Guillain-Barré syndrome
• Newborns with microcephaly or other brain defects
• Agree to have samples collected and stored for further studies

Exclusion criteria

- Participants may be excluded from enrolling in the study if they have any known medical disorders or other circumstances which, in the opinion of the investigator, might make participation unsafe or difficult (e.g. inability to obtain necessary samples, mental illness).

Subjects enrolled in this study will be identified by the National Epidemiological Monitoring Committee, the Department of Infectious and Tropical Diseases, or other services of the level-3 hospitals in the context of public health emergency or epidemic. Participants will be suspected of having a febrile illness due to an infectious pathogen that has not been formally identified by existing diagnostic strategies or standard of care testing.