**Question:** Diseases under international surveillance includes all except:

A. Cholera
B. Dengue fever
C. Typhoid fever
D. Plague

**Correct Answer:** D. Plague

**Core Concept:** International Surveillance of Diseases

International surveillance of diseases refers to the monitoring, reporting, and analysis of infectious diseases across borders to ensure early detection, prevention, and control of outbreaks. This helps in maintaining public health security globally.

**Why the Correct Answer is Right:** Plague is a bacterial infection primarily caused by Yersinia pestis, which primarily affects rodents and their fleas. It is usually transmitted to humans through contact with infected animals or through the bite of an infected flea or tick. While plague is a severe disease, it is not typically considered an international concern and is not usually under international surveillance due to its relatively low prevalence and specific mode of transmission.

**Why Each Wrong Option is Incorrect:**

A. Cholera: Cholera is an acute diarrheal disease caused by the bacterium Vibrio cholerae. It is a major public health concern globally, primarily transmitted through contaminated water or food, and frequently undergoes international surveillance.

B. Dengue fever: Dengue fever is a viral infection transmitted by Aedes mosquitoes. It is a common global health issue under international surveillance due to its rapid spread and potential for severe complications.

C. Typhoid fever: Typhoid fever is an infectious disease caused by the bacterium Salmonella typhi, primarily transmitted through contaminated food or water. It is commonly under international surveillance to monitor and prevent its spread.

**Clinical Pearl:** International surveillance of diseases is crucial for early detection, prevention, and control of emerging infectious diseases and pandemics. It helps in implementing targeted control measures, ensuring public health security at a global level.