M9 (Sir Jerry)

Communicable Disease

• An illness due to an infectious agent or its toxic products.

• Criteria:

  • Transmitted directly or indirectly

  • Susceptible host

  • Presence of agent, vector, or inanimate object

• Examples: Rabies, UTI

TRUE

“Communicable” and “Infectious” are being used interchangeably. True or False?

TRUE

All contagious are communicable and infectious. True or False?

FALSE

All communicable and infectious are contagious. True or False?

Infectious Disease

• An illness wherein there is a presence of a living microorganism in the body

• May not be transmitted through ordinary contact (vector, droplets, and indirect contact)

• Example: Chickenpox (respiratory droplets)

Contagious Disease

An illness that is easily transmitted from one person to another through direct or indirect means.

Chain of Infection

Causative Agent → Reservoir → Portal of Exit → Mode of Transmission → Portal of Entry → Susceptible Host

Causative Agent

Any microbe capable of producing a disease.

• Bacteria

• Virus

• Rickettsia(e)

• Chlamydia(e)

• Fungi

• Protozoa

• Parasite

Bacteria

• One-celled membrane microbes with double cell membranes that protect them from harm.

• Reproduce rapidly and are considered as the most common cause of fatal infectious diseases.

• Classified according to:

  • Shape (cocci, bacilli, spirillae)

  • Need for oxygen (aerobic, anaerobic)

  • Response to staining (gram (+) or (-), or acid-fast)

  • Motility (motile, non-motile)

  • Tendency to capsulate (encapsulated, capsulated)

  • Capacity to form spores (spore-forming, non-spore-forming)

• Example: Tuberculosis, Syphilis

Virus

• Smallest known microbes

• Cannot replicate independently of the host’s cells; invade and stimulate the host’s cells to participate in the formation of additional microbes

• Example: COVID-19 virus, HIV, influenza/flu

Rickettsia(e)

• Small, gram (-) bacteria-like microbes that can induce life-threatening infections.

• Require a host cell for replication

• Usually transmitted through a bite of an arthropod carrier, such as lice, ticks, fleas

• Example: rocky mountain fever, typhus fever, Q fever

Chlamydia(e)

• Common cause of infection of the urethra, bladder, fallopian tubes, and prostate gland

• Most common infection is transmitted through sexual contact (STI)

• Bacteria: chlamydiasis

Fungi

• Thrive inside or outside the body; may be harmful or beneficial

• Example: athlete’s foot, candidiasis, pneumocystis carinii (most common opportunistic microbe in HIV)

Protozoa

• Simple single-celled organisms of the animal kingdom

• Example: malaria, amoeba

Parasite

• Live on or inside other organisms (hosts), usually at the host’s expense

• Do not usually kill their host but take only the nutrients they need

• Example: tapeworm, ringworm, ascariasis

Variability of Pathogenicity

Pathogenicity is the ability of the causative agent to cause a disease:

• Mode of Action

• Infectivity

• Virulence

• Antigenicity

• Toxigenicity

Mode of Action

How the organisms produce a pathologic process.

Infectivity

Invasiveness; ability to invade and multiply.

Virulence

• Degree of the microbe’s pathogenicity

• Capacity of pathogen to overcome/destroy immunity

• Causes tissue damage

Antigenicity

• Ability to induce an immune response to the host

• Capacity of pathogen to withdraw being detected by the antibody (stealth)

Toxigenicity

• Amount and destructive potential of released toxin, ability to cause a toxic effect

Toxin

Any poisonous protein that is produced by bacterial action.

Exotoxin

Exists outside of the bacteria and circulates independently of the cell body.

Endotoxin

Confined within the body of the bacteria and released only when bacteria are broken down.

Reservoir

The environment and object on which an organism survives and multiplies.

Types:

• Human reservoir

• Animal reservoir

• Non-living reservoir

Human Reservoir

• Frank cases (very ill)

• Sub-clinical or ambulatory

• Carriers

Incubatory Carrier

A person who is incubating the illness.

Convalescent Carrier

A person who is at the recovery stage of illness but continues to shed the pathogenic microorganism.

Intermittent Carrier

A person who occasionally sheds the pathogenic microorganism.

Chronic/Sustained Carrier

A person who always has the infectious organism in his or her system.

Animal Reservoir

Zoonotic such as rabies.

Non-Living Reservoir

Examples are tetanus (soil, wood, rust), hepatitis, cholera (infected water), AGE (water; long-standing food), Clostridia (soil)

Portal of Exit

The path or way in which the microorganism leaves the reservoir.

• Respiratory system

• GU tract system

• GI system

• Skin and mucous membranes (Integumentary)

• Placenta

Mode of Transmission

• The means by which the infectious agent passes through from the portal of exit of the reservoir to the susceptible host

• Modes:

  • Contact

  • Air-Borne

  • Vehicle

  • Vector-Borne

Contact Transmission

• Direct

• Indirect

• Droplet spread

Direct Contact Transmission

Person-to-person transfer

Indirect Contact Transmission

Occurs when the susceptible host comes in contact with a contaminated object.

Droplet Spread

• Bigger; more than 5 mm

• 3-feet caution; equivalent to 1 yard

• Heavier, lesser travel tendency

• Contact with respiratory secretions when the infected person coughs, sneezes, or talks

Air-Borne Transmission

Occurs when fine microbial particles or dust particles containing microbes remain suspended in the air for a prolonged period.

• Less than 5 mm; smaller, and have high travel tendency

Vehicle Transmission

• Transmission through articles or substances that harbor the organism until it is ingested or inoculated into the host.

Vector-Borne Transmission

Occurs when a reservoir such as fleas, flies, mosquitoes, ticks, snails, transfers the microbes to another living organism

• Example: dengue, filariasis, elephantiasis

Portal of Entry

Venue through which the organism gains entrance into the susceptible host.

Susceptible Host

A person presumably not possessing resistance against a particular causative agent.

Depends on factors that increase or decrease host vulnerability:

• age (young/old), sex, and genes

• Geographic and environmental factors

• General condition (physical, emotional, and mental states)

• Underlying diseases (DM, lymphoma, leukemia, neoplasm, uremia)

• Treatment (antimicrobial, corticosteroids, radiation, immunosuppressive drugs)

Stages of Infection

• Incubation period

• Prodromal stage

• Illness stage

• Convalescent stage

Incubation Period

• Time from the invasion of the disease to the period before the appearance of first symptoms.

• Asymptomatic

• Example: chickenpox - 10-14 days, HIV and hepatitis - 2-6 months

Prodromal Stage

• Interval from the onset of nonspecific signs and symptoms to more specific manifestations

• Malaise, low-grade fever, fatigue

• Growth and multiplication of microorganisms; capable of spreading to others

Illness Stage

Time when the client manifests signs and symptoms specific to type of infection.

Convalescent Stage

• Containment of infection, progressive elimination of pathogen

• Recovery, but still (+) presence of pathogen

Sporadic

• Diseases that occur occasionally and irregularly with no specific pattern

• Absence or presence of disease

Endemic

• Constant presence of a disease or infectious agent within a geographical area

• Example: malaria in palawan

Epidemic

• Occurs in greater numbers (population, particular region, or community) than what is expected in a specific area over a specific time

• Example: bird flu, FND, swine flu, polio, SARS

Pandemic

• Epidemic that affects several countries or continents.

• Example: SARS ,HIV, COVID-19, Spanish flue, plague

Immunity

The body’s ability to resist infection afforded by the presence of circulating antibodies and WBC.

Types of Immunity

• Natural

• Artificial

• Sub-Clinical

Natural Immunity

Inherent to the body; not brought by immunization

• Passive: acquired through placental transfer (IgG); breastmilk (IgA)

• Active: acquired through recovery from a certain disease, with exposure (IgM)

Artificial Immunity

• Passive: acquired through the administration of antitoxin, antiserum, and/or gamma globulin; has shorter and immediate effect

• Active: acquired through the administration of vaccine and toxoid; give time to build antibodies; has longer effect and cannot be given for immediate use (IgM)

Sub-Clinical Immunity

Acquired through constant exposure to a particular disease or organism

Types of Antigens

• Inactivated

• Attenuated

Inactivated Antigen

• Killed microorganisms; does not mutate

• Characteristics

  • Not long lasting

  • Multiple doses needed

  • Booster doses needed

• Example: flu vaccine, DPT, hepatitis vaccine

Attenuated Antigen

• Live organism but weakened; can mutate

• Characteristics

  • Single dose needed

  • Long-lasting immunity

• Example: BCG, MMR, chickenpox, OPV

Isolation Precautions

• Standard precautions

• Transmission-based precautions

Standard Precautions

• First level which apply to all patients at all times.

• Signs and symptoms of infection are not always obvious and therefore may unknowingly pose risk for a susceptible person.

• Inclusions:

  • Hand hygiene

  • Personal protective equipment

  • Injection safety

  • Environmental cleaning

  • Medical equipment

  • Respiratory hygiene/cough etiquette

Transmission-Based Precautions

• Second level which are intended for individuals who have a known or suspected infection with certain organisms

• Inclusions:

  • Contact precautions

  • Droplet precautions

  • Airborne precautions

Seven Categories Recommended in Isolation

• Strict isolation

• Contact isolation

• Respiratory isolation

• Tuberculosis isolation

• Enteric isolation

• Drainage/secretion isolation

• Universal isolation

Strict Isolation

• Done to prevent highly contagious or virulent infections

• Patient’s things are considered as infected

  • 5 Moments of Hand hygiene

  • Articles used → discarded, bagged, labeled before decontamination

  • Negative pressure

Contact Isolation

Done to prevent the spread of infection primarily by close or direct contact.

Respiratory Isolation

Done to prevent transmission of infectious diseases over short distances through air.

Tuberculosis Isolation

For TB patient with positive smear or with chest x-ray which strongly suggest active TB

Confirmatory test: sputum (PTB)

• 3 specimen tabs, done first thing in the morning

Treatment

• 6-12 months

• 2 weeks as non-contagious, but needs continuity of medical compliance

Enteric Isolation

For infections that are spread through direct contact with feces.

• usually affects pediatric patients

Drainage/Secretion Isolation

Done to prevent infections that are transmitted by direct or indirect contact with purulent materials or drainage from an infected body site.

Universal Isolation

• Applied when handling blood and body fluids.

• Applied for patients with HIV/HCV

• Intended to prevent parenteral, mucous membrane, and non-intact skin exposure to healthcare workers to `blood-borne pathogens

• Necessary to prevent infections that are transmitted by direct contact (body fluids)

Alcohol-Based Hand Rub

Used when the hand is visibly not soiled; ideal

Soap and Water

Used when hands are visibly soiled, or after caring for patients with known or suspected infection.

Aseptic Technique

What technique is utilized in preparing medications?

Cleaning

Removal of visible soil and organic contamination from a device or environmental surface using the physical action of scrubbing with a surfactant or detergent and water, or an energy-based process (e.g., ultrasonic cleaners) with appropriate chemical agents.

Disinfection

• A less lethal process of microbial inactivation (compared to sterilization)

• Eliminates virtually all recognized pathogenic microorganisms but not necessary all microbial forms (e.g., bacterial spores)

• Do not use disinfectant products as cleaners unless labeled suitable for such use

Reusable Medical Equipment

• Accompanied by instructions for cleaning and disinfection or sterilization as appropriate.

• Example: endoscopes

Single-Use Devices (SUDS)

Labeled by the manufacturer for only a single use and do not have reprocessing instructions

Reusable Medical Equipment Classification

• Critical items

• Semi-critical items

• Noncritical items

• Environmental surfaces

Critical Items

• Objects that enter sterile tissue or the vascular system and must be sterile prior to use

• Example: surgical instruments

Semi-Critical Items

• Contact mucous membranes or non-intact skin and require high-level disinfection (at a minimum) before reuse

• Example: endoscopes (upper endoscopy and colonoscopy)

Noncritical Items

• May come in contact with intact skin but not mucous membranes

• Should undergo low or intermediate-level disinfection depending on the nature and degree of contamination

• Example: BP cuffs

Environmental Surfaces

• Generally do not have contact with the patient during the delivery of care

• Cleaning may be all that is needed for the management of these surfaces

• If disinfection is indicated, low-level disinfection is appropriate

• Example: floors, walls

Hand Hygiene

Reduce the risk of spreading infections in ambulatory care settings.

Personal Protective Equipment (PPE)

Intended to protect the HCP from exposure to or contact with infectious agents.

Injection Safety

Prevent transmission of infectious diseases during preparation and administration of parenteral medications.

Respiratory Hygiene/Cough Etiquette

• Element of standard precautions

• Highlights the need for prompt implementation of infection prevention measures at the first point of encounter with the facility/ambulatory settings

• For patients with accompanying family members/friends with undiagnosed transmissible respiratory infections

• Applies to any person with signs of illness

Contact Precautions

Applied to patients with:

• Stool incontinence (norovirus, rotavirus, clostridiuum difficile), draining wounds, uncontrolled secretions, pressure ulcers

• Ostomy tubes and/or bags draining body fluids

• Generalized rash or exanthems

• Placed in an exam room (prioritize stool incontinence, draining wounds, skin lesions that cannot be covered/uncontrolled secretions)

• utilize gloves, gown, and hand hygiene; disinfect exam room

• Use separate bathroom

Droplet Precautions

Applied to patients known or suspected to be infected with a pathogen that ca be transmitted by droplet route:

• Respiratory viruses (influenza, parainfluenza, adenovirus, respiratory syncytial virus, human metapneumovirus)

• Bordetella pertussis

• For first 24 hours of therapy: neisseria meningitidis, group A streptococcus

• Placed in a closed exam room (prioritize excessive cough and sputum production); if not available, provide face mask and separate area far from other patients; avoid coming into close contact; respiratory hygiene; disinfect exam room

• Utilize face mask, gloves, gown, goggles, hand hygiene

Airborne Precautions

Applied to patients known or suspected to be infected with a pathogen that can be transmitted by airborne route

• Tuberculosis

• Measles

• Chickenpox (until crusting over of lesions)

• Localized (immunocompromised patient) or disseminated herpes zoster (until crusting over of lesions)

• Separate entrance; place in airborne infection isolation room (AIIR); If not available, provide face mask

• Placed in closed exam room; instruct patient to keep facemask on—change when it becomes wet; same procedure as other precautions

• Utilize fit-tested N-95 or higher-level disposable respirator, gloves, gown, goggles, face shield, hand hygiene

• Vacant the exam room for generally one hour.