**Question:** Disease highly transmitted during incubation period is - a) Pertussis, b) Cholera, c) Measles, d) Brucellosis, e) Chickenpox

**Core Concept:** The incubation period is the time between contracting a disease and its onset. Some diseases are highly transmissible during this period, as the infected person may appear asymptomatic but can still infect others.

**Why the Correct Answer is Right:** Cholera (b) is a waterborne infectious disease caused by the bacterium Vibrio cholerae. Although the incubation period for cholera is relatively short (2-14 days), the disease is highly transmissible due to the high level of fecal-oral transmission, where infected individuals shed the bacterium in their diarrhea and vomit.

**Why Each Wrong Option is Incorrect:**

a) Pertussis (pertussis) has a relatively longer incubation period (10-21 days), making it less likely to be considered highly transmissible during this time compared to cholera.
c) Measles (measles) has a moderate incubation period (10-12 days), but the highly contagious nature of the respiratory droplets during the infectious period makes it less transmissible during the incubation period.
d) Brucellosis (Brucella spp. infections) has a longer incubation period (1-30 days), making it less likely to be considered highly transmissible during this time compared to cholera.
e) Chickenpox (varicella) has a moderate incubation period (14-21 days), but the highly contagious nature of the respiratory droplets during the infectious period makes it less transmissible during the incubation period.

**Clinical Pearl:** Infectious diseases with short incubation periods, high transmission rates during the infectious phase, and poor environmental control measures can be highly transmissible during the incubation period. This understanding is crucial in public health measures and preventive strategies, particularly in areas with low socioeconomic status and inadequate sanitation.