**Question:** Diseases under surveillance by WHO under International Health Regulations are all, EXCEPT:

A. SARS
B. MERS
C. COVID-19
D. Cholera

**Core Concept:** The International Health Regulations (IHR) are a set of rules established by the World Health Organization (WHO) to prevent the international spread of diseases. These regulations aim to ensure that countries take appropriate and timely measures to prevent, prepare for, and respond to public health emergencies. By monitoring and reporting certain diseases, WHO keeps track of public health risks and helps countries to implement necessary actions to protect global public health.

**Why the Correct Answer is Right:** Option D, Cholera, is NOT excluded from the list of diseases under surveillance by WHO under IHR. Cholera is a waterborne bacterial infection caused by Vibrio cholerae. The IHR monitors diseases that pose a public health risk to more than one country, which is the case for cholera due to its potential for causing severe dehydration and diarrhea, leading to severe health outcomes and requiring coordinated global response.

**Why Each Wrong Option is Incorrect:**

A. SARS (Severe Acute Respiratory Syndrome): Although SARS caused a global outbreak in 2003, it was eventually contained, and the spread of the disease was not sustained beyond the initial outbreak. As a result, SARS is not typically monitored under IHR regulations.

B. MERS (Middle East Respiratory Syndrome): Similar to SARS, the MERS outbreak in 2012 was contained, and the disease did not become a sustained global health threat. Therefore, MERS is also not typically monitored under IHR regulations.

C. COVID-19 (Coronavirus Disease 2019): COVID-19, caused by the SARS-CoV-2 virus, emerged in late 2019 and led to a global pandemic. As a result of its global impact, COVID-19 is actively monitored under IHR regulations, making it an exception to the exclusion mentioned in the question.

**Clinical Pearl:** The International Health Regulations focus on diseases that pose a significant threat to global public health. While the question mentions diseases under surveillance by WHO, it highlights that certain diseases are excluded from this surveillance. However, COVID-19 is an exception due to its global impact and severity. This demonstrates the importance of monitoring emerging infectious diseases and the role of WHO in coordinating public health responses globally.