INFECTION

Definition

Infection Control- Identifying and reducing the risk of infections Developing or Spreading.

Infection-

  • "The lodgement and multiplication of organism in the tissue of host constitutes infection"
  •  An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce.

Nature of Infection

  • Micro-organism bacteria, fungi, viruses, protozoa and worms.
  • Most are harmless (Non-Pathogenic)
  • Pathogenic organisms can cause infection.
  • Infection exists when pathogenic organisms enter the body, reproduce and cause disease.

Chain of Infection 

  • Chain of infection is a process of infection that begins when an agent leave its reservoir through portal of exit & is conveyed by mode of transmission then enters through an appropriate portal of entry to infect a susceptible host.
  • Chain of infection is a process in which a favorable condition is required for microorganism to spread or transfer from reservoir to a susceptible host.

  1. Infectious Agent/Pathogen.
  2. Reservoir-
  3. Portal of Exit-
  4. Mode of Transmission 
  5. Portal of Entery-
  6. Host

1. Infectious Agent/Pathogen-

  • These are any microorganism that can cause a disease such as a bacteria, virus, parasite, or fungus. Reasons that the organism will cause an infection are virulence (ability to multiply and grow), invasiveness (ability to enter tissue), and pathogenicity (ability to cause disease).
  • Any organism is capable of causing infection if all the links/components are present.

2. Reservoir-

 It is the place where the microorganism resides, thrives, and reproduces, i.e., food, water, toilet seat, elevator buttons, human feces, respiratory secretions etc.

3. Portal of Exit-

 It is the place where the microorganism leaves the reservoir, such as the respiratory tract (nose, mouth), intestinal tract (rectum via stool), urinary tract, or blood and other body fluids.

4. Mode of Transmission- 
Mode of transmission is the means by which an organism transfers from one carrier to another by either direct transmission or indirect transmission.

5. Portal of Entery-

The opening where an infectious disease enters the host’s body such as mucus membranes, open wounds, or tubes inserted in body cavities like urinary catheters or feeding tubes.

6. Host-

person who cannot resist a micro-organism invading the body, multi-plying and resulting infection. The host is susceptible to the disease, lacking immunity or physical resistance to overcome the invasion by the pathogenic microorganism.


Stages of Infection-

  1. Incubation Stage
  2. Prodromal Stage
  3. Illness Stage.
  4. Decline Stage-
  5. Convalescence Stage.

1. Incubation Stage

  • During this stage, a sick person may actually spread the disease-causing microorganisms without knowing because this is symptom-less stage where microbes can multiply inside the body and also spread to other people.
  • The length of this period is dependent on the kind of microorganism that invades the person and his/her immune system For example, the incubation period of chickenpox is 14-16 days and COVID-19 for 5-14 days.

2. Prodromal Stage

  • During this stage, although the person does not feel weak, sick, or may not appear sick, the virus has become stronger than the body’s defenses.
  • The illness may be spread to other people.
  • This is a short stage of disease development where a person begins to feel that they are getting sick.

3. Illness Stage.

  • The illness has developed.
  • In case of flu, fever, aches, and pains, and other symptoms are present.
  • This is the stage where a person feels the typical signs and symptoms associated with the disease.

4. Decline Stage-

  • This is the stage of disease development where the immune system begins to bring microbial replication under control which leads to the lessening of the signs and symptoms associated with the disease.
  • Damaged tissues begin to repair, and pathogen numbers decrease.

5. Convalescence Stage.

  • This is the final stage of the disease process where the microbial replication is fully stopped and the person returns to the pre-illness stage.
  • Although depending on the disease, the person may not proceed to this stage and may die from their disease or be disabled.

Factors Increasing Susceptibility to Infection -

 There are many factors increasing susceptibility to infection-

  1. Age
  2. Nutritional status
  3. Life style
  4. Smoking
  5. Environmental factors
  6. Medications
  7. Chronic disease
  8. Nursing and medical procedure

1. Age-

Infant, children and older  people are more susceptible to infection. older peoples are more susceptible hosts because their immune response declines with aging.

2. Nutritional status -

Poor nutrition can also increase susceptibility to illness.

3. Life style-

Life style risk factors such as aging, poor nutrition, infection and exposure to toxicants can also increase susceptibility to illnesses.

4. Smoking-

Smoking is a major risk factor for pulmonary infections. Smoking mostly affected the smokers and are at increased risk for infection.

5. Environmental factors -

Increased exposure to pathogens in one's work situation, living situation (eg. healthcare worker, nursing home) and other environmental factors increase the risk of infection.

6. Medications -

Some medications are given for the purpose of reducing the immune response and increase your risk of infection.

7. Chronic disease -

Many chronic diseases such as diabetes, COPD, hypertension and cancer can also increase the risk for infections.

8. Nursing and medical procedure-

Several  procedures such as urinary catheterization and IV line inserted procedure are increased risk of infection.

 
 

 

 

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