Community Medicine Cheat Sheet
Disease Control Needs the Right Level
Communicable disease control: chain of infection, incubation and communicability, GeneXpert, IDSP surveillance and route-specific measures for NEET-PG prep.
MedNext Academy | 3 min read
Disease Control Needs the Right Level
Communicable disease control: chain of infection, incubation and communicability, GeneXpert, IDSP surveillance and route-specific measures for NEET-PG prep.
Communicable and non-communicable disease control works by breaking a specific link in the chain of infection or targeting risk factors, supported by essential primary-care tests and India's surveillance programmes.
High-yield lines
- The epidemiological triad of agent, host and environment underlies every communicable disease.
- The chain of infection has six links: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry and susceptible host.
- Breaking any single link in the chain of infection interrupts transmission.
- The incubation period is the time from infection to first symptom and helps distinguish point-source from propagated epidemics.
- In measles the period of communicability runs from about 4 days before to 4 days after the rash appears.
- Tuberculosis is spread by airborne droplet nuclei and communicability usually ends about two weeks into effective treatment.
- Cholera is caused by Vibrio cholerae O1 or O139 and spreads by the faeco-oral route through contaminated water and food.
- Dengue is transmitted by the day-biting Aedes aegypti mosquito and control relies on source reduction and larvicidal measures.
- Rabies management includes wound washing with soap and water for 15 minutes plus category-based vaccine and immunoglobulin.
- Cartridge-based nucleic acid amplification testing such as GeneXpert is the essential primary-care test for presumptive pulmonary tuberculosis.
- The Integrated Disease Surveillance Programme and its digital Integrated Health Information Platform provide the framework for outbreak reporting.
- Control measures group into source reduction, transmission interruption and host protection.
- An essential primary-care test is one whose result changes first-contact care, notification or outbreak control.
- India faces a triple burden of communicable disease, rising non-communicable disease and persisting undernutrition.
Mapped competency codes
- CM8.1
- CM8.2
- CM8.3
- CM8.4
- CM8.5
- CM8.6
- CM8.7
Continue into the full chapter
This summary maps to CM8-epidemiology-of-communicable-and-non-communicable-diseases.
Frequently Asked Questions
What are the six links in the chain of infection?
Infectious agent, reservoir, portal of exit, mode of transmission, portal of entry and susceptible host; breaking any one link stops transmission.
When is a measles case infectious?
From about 4 days before to 4 days after the appearance of the rash, which is why isolation and vaccination of susceptibles are time-critical.
Which test confirms presumptive pulmonary tuberculosis at primary care?
Cartridge-based nucleic acid amplification testing such as GeneXpert, or smear microscopy, via the national tuberculosis programme pathway.
How are communicable disease control measures categorised?
As source reduction, transmission interruption and host protection through immunisation, chemoprophylaxis or behaviour change.
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