Breaking the Chain of Infection

Infections are just one of the health dilemmas experienced by many. There are 6 identified links in the chain of infections: agent, reservoir, portal of exit, modes of transmission, portal of entry and the host. The ultimate answer to control the occurrence of infection is to break the chain.

I. Infectious Agents

Infectious agents can be in the form of bacteria, viruses and fungi that are invisible to the naked eye and can be found everywhere in our environment.

II. Reservoir

The agents' reservoir are their own habitat. It is where they live, optimally grow and reproduce. Reservoirs can be classified into 3, human, animal and environmental. Some infectious diseases are transmitted via human reservoir which includes respiratory infections,measles, mumps, streptococcal infection and sexually transmitted diseases. Humans can also acquire infectious diseases from animal reservoirs whereby this diseases are commonly transmitted from animal to animal. Environmental reservoir includes the plants, soil and water that are also responsible in the transmission of infectious diseases.

III. Portal of Exit

This is the path where agent leave their reservoir. This includes human body excretions and secretions, open skin due to wounds, respiratory and gastro-intestinal tract and mucous membrane.

V. Portal of Entry

Portal of entry refers on how the infectious agent enters into a susceptible host. In like manner, pathogen causing diseases enter a host body in the same portal they used to exit the source host.

IV. Modes of Transmission

Modes of transmission can be classified into 2 main categories: Direct and Indirect. In Direct mode of transmission it has two main divisions which are direct contact and droplet spread.

Direct contact happens through situation like skin-to-skin contact, kissing and sexual intercourse. Infectious disease can be also gained through direct contact with contaminated soil or any type of vegetation that harbors infectious diseases.

Droplet spread occurs when splashes of aerosols produced by sneezing, blowing or coughing are dispense through the air. These particles are large and can be transmitted to a person few feet away from the infected host.

On the other hand, indirect mode of transmission is subdivided into (1) airborne transmission whereby droplet nuclei from infected agent are suspended into the air. These droplet nuclei are less than 5 microns in size may remain on air for many hours making it more transferrable to any susceptible host. (2) Vehicleborne transmission transmits infectious agents through food, water, biologic products and fomites. (3). Vectoreborne transmission on the other hand, spread infectious disease through mosquitoes, fleas and ticks.

VI. Host

The host is the final link in the chain of infection. Susceptibility of the host to acquire infectious diseases depends on his genetic makeup, immune response and his system’s ability to resist infection.