COMMUNICABLE DISEASE

Normal Flora (Resident Microbes )

Microorganisms (usually bacteria) that normally exist in the body and are Harmless

Transient Microbes

Microorganisms that we acquire when we interact with other humans or our environment

Under some conditions, the interaction with endogenous microbes can be harmful for the host, and opportunistic infections may occur.

Body Defenses

First Line of Defense (External Defense System)

Second Line of Defense (Immune Response)

First Line of Defense (External Defense System)

SKIN

Chemical Barriers (secretions such as tears, saliva, sweat and mucus)

Second Line of Defense (Immune Response)

White Blood Cells (Leukocytes) seek out and destroy disease-causing organisms or substances through the lymphatic system

types of (Immune Response)

• Neutrophils • T helper cells • Cytotoxic T cells • Macrophages • Dendrite cells • B cells • Suppressor T cells

How Reproduction of Microorganisms Injure the Patient?

• Competes with the host metabolism

• Cellular damage produced by microbes

• Intracellular multiplication

The Infectious Process

Pathogenesis of Infectious Diseases

• Entry of the pathogen into the body

• Attachment of pathogen to some tissues within the body

• Multiplication of the pathogen

• Invasion/spread of the pathogen

• Evasion of host defenses

Infection

Entry and multiplication of an infectious agent in or on the tissue of a host causing CLINICAL SIGNS and SYMPTOMS.

Colonization

Infectious agent fails to cause injury to the host. (WITHOUT SIGNS AND SYMPTOMS)

Infectious Disease

State in which the infected host displays a decline in wellness due to the infection

Virulence

How harmful the pathogen is.

Colonization x Infection x Infectious Disease

Microbiology Laboratory Reports (Primary source of information about most bacterial infections)

3 components:

• Smear and stain

• Culture- organism identification

• Sensitivity- antimicrobial susceptibility

Why Does Infection Occur?

• Antibiotic and Antiviral Drug Resistance

• Multiple strains (viruses/influenza) that a single vaccine cannot protect against them.

• New infectious agents occasionally arise (HIV and Coronavirus).

• Opportunistic organism can cause infection in immunocompromised patients.

• Microbes localize in the body making the treatment difficult (bones and CNS)

• No immunization.

• Increase in air travel can spread virulent organisms to a heavily populated area within hours and over great distances.

• Biologic warfare and bioterrorism (anthrax and plague).

• Use of immunosuppressive drugs and invasive procedures increases the risk of infection.

4 Stages of Infection

INCUBATION PERIOD

PRODROMAL STAGE

ILLNESS STAGE

CONVALESCENT STAGE

INCUBATION PERIOD

agent’s entry in the host and the onset of symptoms

• Silent stage (no symptoms)

• Transmission and replication

PRODROMAL STAGE

onset of nonspecific symptoms until specific symptoms begin to manifest

• Vague complaint (mild and generalized symptoms)

• E.g. low-grade fever, body weakness, fatigue

ILLNESS STAGE

manifesting specific symptoms of an infectious process.

• Clinical stage

CONVALESCENT STAGE

acute symptoms begin to disappear until the client returns to previous state of health

• Healing stage

Kinds of Infection

1. Subclinical or Asymptomatic

2. Latent infection

3. Exogenous Infection (Cross infection)

4. Endogenous Infection

5. Health care-associated Infections (HAIs) (nosocomial infection)

1. Subclinical or Asymptomatic

• Laboratory-verified infection that presents no signs and symptoms.

• A person may be a carrier and can transmit infection to others

2. Latent infection

Occurs when microorganism remains inactive and dormant in the host and may last for years

3. Exogenous Infection (Cross infection)

Due to microorganism entering the host’s body from the environment.

4. Endogenous Infection

Normal flora is transmitted to sites outside their natural habitat

5. Health care-associated Infections (HAIs) (nosocomial infection)

• Develops while the patient is in a health care facility.

• Mostly transmitted through direct contact

Disease

• Any condition that impairs or damages the normal structure or function of an organ or the body

Geographical Distribution of Diseases

Endemic

Epidemic

Pandemic

Sporadic

Endemic

• Disease found in a certain geographical area/region or in a specific group of people within a country.

• Ex. Schistosomiasis is rampant in Samar and Leyte provinces

Epidemic

• Disease that occur in greater than expected numbers in a specific area over a particular time. • A sudden rise in the number of cases more than what is expected.

• Ex. Increase of diarrheal disease in an evacuation area.

Pandemic

An epidemic that affects several countries or continents. Ex. HIV/AIDs

Sporadic

• Diseases that occur occasionally and irregularly with no specific pattern. Usually involve few people during a particular time. • Ex. Tetanus, gas gangrene

Primary prevention

• Promote health • Prevent exposure • Prevent disease

Secondary prevention

Stop or slow the progression of disease to prevent or limit permanent damage, through the early detection and treatment of disease

Tertiary prevention

• Limit the impact of that damage

Disease is the result of all agent forces within the dynamic system consisting of the following:

• Agent

• Host

• Environment

Infectious Agent

Microorganisms or pathogens that cause infection

Factors influencing the cause of disease:

Pathogenicity

Infectivity

Virulence

Infective dose

Pathogenicity

ability of organism to cause disease.

Infectivity

ability of the organism to infect the host.

Virulence

ability of the organism to produce disease.

Infective dose

number of organisms and the amount of toxin released by the organism needed to induce the disease.

Host

1. Patient (case)

2. Carrier

3. Suspect

4. Contact

1. Patient (case)

infected and manifests the sign and symptoms of the disease.

• Someone who needs medical care and treatment.

2. Carrier

appears healthy but harbors the organism.

• Capable of transmitting the disease but does not manifest its signs and symptoms.

3. Suspect

Person whose medical history, signs and symptoms suggest that such a person is suffering from that particular disease

4. Contact

Person who has been in close association with an infected person, animal, object.

Environment Components

Physical- inanimate surroundings (geophysical condition and climate)

Biological- living things around the affected individual (plants and animal life)

Socio-economic- level of economic development (crowding, sanitation availability of health services)

Chains of Infection

Infectious Agent

Reservoir

Portal of Exit

Mode of Transmission

Portal of Entry

Susceptible Host

Infectious Agent

An Organism that causes disease.

Reservoir

The place where an infectious agent lives and multiply

Portal of Exit

Route in which the organism leaves the reservoir

Mode of Transmission

How the infectious agent travels from the infected person to another person

Portal of Entry

Any body opening that allows the infectious agent to enter

Susceptible Host

A non-infected person who could get infected.

General IPC measures:

UNIVERSAL PRECAUTION - Set of guidelines focused on preventing blood-borne pathogens.

Isolation Precautions

• Standard precaution

• Transmission-based precaution

Standard Precaution

• Principle: “All blood, body fluids, secretions, excretions (except sweat), non-intact skin, and mucous membranes may contain transmissible infectious agents.”

Patient Placement

Empiric Precautions

Cohort Isolation

Designated ward-specific Precautions

Empiric Precautions

single room

Cohort Isolation

Patients with same infectious condition= same room, if single room is not feasible.

Designated ward-specific Precautions

In hospitals with a consistent large number of patients with the same infectious condition= allocated specific ward

Social Hand Hygiene

at least 20 seconds

When hands are visibly dirty or contaminated with biological materials:

Hand wash with soap and water.

When hands are not visibly soiled:

Use alcohol-based, waterless antiseptic agents for routine decontamination

In areas with known virulent or resistant organisms are likely to be present:

Use antimicrobial agents (e.g., Chlorhexidine gluconate)

Exposure to sporeforming pathogens (C. difficile outbreaks)

Use Gloves and perform hand washing with antimicrobial soap and water

Surgical masks Placed on healthcare personnel

to protect them from contact with infectious material from patient

-Respirators reduce airborne pathogens

Surgical masks Placed on coughing patient

to limit potential dissemination of infectious respiratory secretions.

Decontamination of the Environment

environment should be cleaned with a neutral detergent and water except in circumstances that require additional disinfection (e.g., blood and body fluid spillages) or contamination of specific organism that require patient to be isolated.

Blood spillage management

Cover spillage with disinfectant

Body fluid management

Do not use chlorinebased disinfectants directly on acidic solution

Disinfection of Equipment

Non-critical equipment (Low-Risk)

Semi-critical /critical (Intermediate/High risk)

Non-critical equipment (Low-Risk)

Use neutral detergent and water

Semi-critical /critical (Intermediate/High risk)

decontamination and sterilization.

Healthcare waste management:

• Black - Dry noninfectious waste.

• Green -Wet noninfectious waste.

• Yellow - Infectious waste.

• Puncture proof containers - Sharps

Needlestick Prevention

• Do not recap used needles.

• Instead, place it directly into punctureresistant containers at the point of use.

• Use one-handed scoop technique or deploy safety device attached to the needle.

• Sharps containers must be locked when two-thirds full prevent overfilling. Do not push the needles into a container that is full.

Airborne Precaution

• Isolation room with negative pressure (minimum 6 air exchanges), rapid turnover of air and air either highly filtered or exhausted directly outside.

• Healthcare workers must always wear N95 respirators.

• Room doors should remain close at all times.

• Nurse should validate negative air pressure of the room

Droplet Precaution

close respiratory or mucous membrane contact with respiratory droplet

• Wear surgical face mask

• Stand 3-6 feet away form the patient.

• Room doors may be opened.
• May cohort patient.

Contact Precaution

• Used for organisms that are spread by skin-to-skin contact (direct contact) or contact with environment (indirect contact).

• Hand hygiene

• Gloves and gown are a must.

• Preferably private room.

• Masks are not needed.

• Doors do not need to be closed.

Protective Environment (Reverse Isolation)

Expanded isolation technique used for immunocompromised condition.

• Stem cell transplantation

• Conditions that severely suppress immune system (HIV/AIDs; Cancer)

Interventions

• Special airflow and filtration rooms (+ air pressure, smooth surfaces).

• Staff must be free from signs and symptoms of illness.

• Sterile PPE when caring for patient.

• Limit visitors (<12 y.o. are not allowed).

Health CareAssociated Infections

Specific criteria: Length of time in the facility before the onset or appearance of the infection.

• If new symptoms appear within 48 hours of admission, 3 days after discharge, or 30 days after an operation

Nursing interventions to prevent HAI

• Primary way to break the chain of infection: HAND WASHING.

• Preventive measures: IMMUNIZATION

• Disposal of infectious materials to moistureresistant biohazard containers.

• Reducing catheter related infections:

Specific Organism with HAI Potential

Clostridium Difficile

Methicillin-Resistant Staphylococcus Aureus (MRSA)

Vancomycin-Resistant Enterococcus

Clostridium Difficile

Handwashing with soap and water is recommended

Methicillin-Resistant Staphylococcus Aureus (MRSA)

Vancomycin and Linezolid are the treatment of choice

Vancomycin-Resistant Enterococcus

penicillin formulations (ampicillin), aminoglycosides (gentamycin), and linezolid

Aspects of Care of Patients with Communicable Diseases

Preventive Aspect: Health Education, Immunization, Immunity

Curative Aspect: Medical Management (physicians), Nursing Management

Rehabilitative Aspect: Activity, Nutrition

• Measles and Polio are highly heat sensitive=

store in freezer

Only BCG is discarded 4 hours after reconstitution

(immunization is scheduled in the morning)

Types of Antigen:

Inactivated (killed organism)

Live attenuated (weakened)

Inactivated (killed organism)

• Multiple doses are needed. • A booster dose is needed.

Live attenuated (weakened)

• Only single dose is needed • Confers to long lasting immunity

What Damages Vaccine?

• Heat and light (especially live vaccines)

• Freezing damages the killed vaccine and toxoid

• Antiseptics, disinfectants, detergents and alcohol lessens potency of vaccine. (Use WATER when cleaning the ref/freezer

Contraindications to Vaccines

All vaccines may be given at the same visit,

If vaccines must be given of separate visits interval should at least 4 weeks.

If patient develops encephalitis, anaphylaxis or a moderate to severe sequelae of a previous vaccine, DO NOT GIVE THE NEXT DOSE!

Some live vaccines (varicella &MMR) must not be given to immunocompromised people and pregnant.

Reducing Risk To The Patient

• Catheter-related sepsis should be suspected in a patient who has unexplained fever, redness, swelling, and drainage around a vascular catheter insertion site.

• Patient teaching must emphasize that home needs must be “clean” not sterile.

• For immunocompromised patient, restrict visitors who are sick, and family members should be reminded to follow recommendations for hygiene, storage, and safe cooking times and temperatures