Acute respiratory infections (such as influenza-like illness and upper respiratory tract infection) and acute infectious diarrhea are, for the most part, conditions that do not require medical management or specific treatment. Depending on the level of their transmission in the community, however, these diseases place significant clinical and financial burden on the healthcare system, particularly on emergency departments (ED). The investigators propose a prospective multicenter cohort study with which they aim to validate clinical decision rules combining 1) rapid molecular tests and 2) risk stratification tools to identify patients at low risk for complications related to acute respiratory infection and acute infectious diarrhea. The use of these clinical decision rules by nurses in ED triage could allow low-risk patients to be sent directly home for self-treatment without having to see the emergency physician. By eliminating the need for physician assessment, paraclinical testing and prolonged waiting in the ED, these triage-based clinical decision rules could provide a new, safe care pathway for acute respiratory infections and acute infectious diarrhea, reducing the burden on the patient, the healthcare system, and society.

Acute Respiratory Infections :

Inclusion Criteria:

1. 18 years of age or older;
2. Able to consent to the study;
3. Reachable by phone;
4. Consent to be reached directly by phone;
5. At least one of the following respiratory symptoms consistent with an acute respiratory infection for 10 days or less, i. Cough and/or ii. Purulent sputum and/or iii. Pharyngeal pain and/or iv. Nasal congestion and/or v. Rhinorrhea and/or vi. Agueusia and/or vii. Anosmia;
6. A triage score of 3 (30 minutes), 4 (60 minutes) or 5 (120 minutes) on the Canadian Triage and Acuity Scale (CTAS);
7. Triaged by the ED nurse and managed according to standard ED care protocols;
8. Resident of Québec;
9. Holder of a Québec health insurance number.

Exclusion Criteria:

1. Cognitive impairment that prevents the patient from reliably answering the risk stratification tool or research questions;
2. Resident of a long-term care facility;
3. Refusal of nasopharyngeal swab.

Acute infectious diarrhea :

Inclusion Criteria:

1. 18 years of age or older;
2. Able to consent to the study;
3. Reachable by phone;
4. Consent to be reached directly by phone;
5. At least three loose or liquid stools over a 24-hour period and for 10 days or less;
6. A triage score of 3 (30 minutes), 4 (60 minutes) or 5 (120 minutes) on the Canadian Triage and Acuity Scale (CTAS);
7. Triaged by the ED nurse and managed according to standard ED care protocols;
8. Resident of Québec.
9. Holder of a Québec health insurance number.

Exclusion Criteria:

1. Known neutropenia (<500 neutrophils);
2. Active inflammatory bowel disease;
3. Anorectal pathology;
4. Recent colonic surgery (< 6 months);
5. Cognitive impairment preventing the patient from reliably answering the risk stratification tool or research questions;
6. Resident of a long-term care facility;
7. Refusal of the rectal swab.

Participants will be recruited according to their symptoms when presenting to the ED. They can be included in the acute respiratory infection group, the acute infectious diarrhea group or both.