A person under investigation (PUI) is defined as a patient who presents with both clinical and epidemiological risk factors for a specific infectious disease. In the case of infectious diseases that present risks of transmission to healthcare workers (HCWs) and patients, the use of the identify-isolate-inform framework is essential to protect staff and patients and the delivery of safe and effective care. This includes early identification of PUIs, institution of appropriate transmission-based precautions including use of specific personal protective equipment (PPE) and isolation, and prompt notification of relevant personnel, including relevant experts and authorities.
Depending on the specific infection suspected, once appropriate infection control measures have been implemented, clinical evaluation of PUIs can vary in complexity. In the case of Ebola virus disease (EVD), the need for specialized PPE and training, well-developed procedures, and dedicated space can be extremely resource-intensive and costly for facilities. In addition, depending upon the need to reduce risks to other patients and HCWs, regular laboratory and imaging equipment may not be available (or available at the standard frequency or turnaround time) to support medical care. Lastly, diagnostic tests needed to confirm the diagnosis may not be available at the healthcare facility and may instead be accessible through public health authorities. This testing may take several days to confirm the diagnosis or rule out the presence of the suspected infection. Thus, the potential period of evaluation for a PUI can extend well beyond a typical clinic or emergency department (ED) visit. Thoughtful and coordinated planning efforts are required across the community and across the hospital to be able to adequately care for the PUI.
Person under investigation Case definition Diagnosis Laboratory investigation Clinical care HHCD Emerging pathogens Infection control
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