COMMUNICABLE DISEASE CHAIN.doc

COMMUNICABLE DISEASE CHAIN Each case of communicable disease is the result of an orderly progression in a series of events. Transmission is a process in which several events happen one after the other in the form of a chain. Hence, this process is known as a chain of transmission or communicable disease chain. Six major factors can be identified: the infectious agent, the reservoir, the route of exit, the mode of transmission, the route of entry and the susceptible host. We will now consider each of these factors in turn. For the nurse in the community health sector, knowledge of the portals of exit and entry and modes of transmission provides a basis for determining appropriate control measures. In general, control measures are usually directed against the segment in the infection chain that is most susceptible to intervention, unless practical issues dictate otherwise. For some diseases, the most appropriate intervention may be directed at controlling or eliminating the agent at its source. In other cases interruption of direct transmission may be accomplished by isolation of someone with infection, or counseling persons to avoid the specific type of contact associated with transmission. Some strategies that protect portals of entry are simple and effective. For example, bed nets are used to protect sleeping persons from being bitten by mosquitoes that may transmit malaria. Other interventions aim to increase a host’s defenses. For example Vaccinations promote development of specific antibodies that protect against infection. On the other hand, prophylactic use of antimalarial drugs, recommended for visitors to malaria-endemic areas, does not prevent exposure through mosquito bites, but does prevent infection from taking root. Finally, some interventions attempt to prevent a pathogen from encountering a susceptible host.

In summary, when you find the 'Weakest Link' and break the chain, ensures that the risk of an infection developing is non-existent. REFERENCES American Academy of Pediatrics. Red Book: 2009 Report of the Committee on Infectious Diseases. 28th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2009. Brachman, Philip S. (2006, June). Ecology of Infection. Retrieved May, 2010 from http://www.cdcfoundation.org/fellowships/knight/Principles%20of%20Epidemiology %20Part%20II.swf. Public Health Agency of Canada. (2010, May). What Determines Health? Retrieved May, 2010 from http://www.phac-aspc.gc.ca/ph-sp/determinants/index-eng.php.