Communicable Diseases

Chain of Infection

It refers to the sequence of events that allows an infectious disease to spread from one host to another. Infection occurs when all links in the chain are present. Breaking any link can prevent disease transmission.

Infectious agent

The microorganism capable of causing disease.

Bacteria

Viruses

Fungi

Parasites

Prions

Enumerate the infectious agents

Sterilization

Disinfection

Antimicrobial therapy

Prevention of infection from infectious agents

Reservoir

The place where the microorganism lives, grows, and multiplies.

Humans

Animals

Soil

Water

Medical equipment

Examples of reservoir

Environmental sanitation

Proper waste disposal

Cleaning and disinfection of equipment

Prevention of infection from reservoir

Portal of exit

The route through which the pathogen leaves the reservoir.

Respiratory secretions

Blood

Urine

Feces

Wound drainage

Examples of portal of exit

Covering coughs and sneezes

Proper wound dressing

Safe handling of body fluids

Prevention of infection from portal of exit

Mode of Transmission

The method by which the pathogen spreads.

Direct

Indirect

Droplet

Airborne

Vector-Borne

Examples of Mode of Transmission

Handwashing

Use of PPE

Isolation precautions

Environmental cleaning

Prevention of infection from mode of transmission

Handwashing

Game Changer:

___ is the single most effective method to prevent transmission.

Portal of Entry

The route by which microorganisms enter the host.

Respiratory tract

Gastrointestinal tract

Urinary tract

Broken skin

Mucous membranes

Examples of portal of entry

Aseptic technique

Wound care

Proper catheter care

PPE use

Prevention of infection from portal of entry

Susceptible host

A person at risk of infection due to inadequate defenses.

Extremes of age

Malnutrition

Chronic illness

Immunosuppression

Stress

Risk factors for a susceptible host

Immunization

Adequate nutrition

Health promotion

Disease management

Prevention of infection to a susceptible host

Primary prevention

Secondary prevention

Tertiary prevention

3 Levels of Prevention

Primary Prevention

Actions taken before disease occurs to prevent its development. Prevent disease and promote health.

Examples

• Immunization

• Health education

• Proper nutrition

• Regular exercise

• Smoking cessation

• Use of seat belts

• Hand hygiene

Nursing Activities

• Community education

• Vaccination campaigns

• Lifestyle counseling

Secondary prevention

Actions taken to detect disease early and initiate prompt treatment. Early diagnosis and treatment.

Examples

• Blood pressure screening

• Blood glucose testing

• Mammography

• Pap smear

• Colonoscopy

• Tuberculosis screening

Nursing Activities

• Screening programs

• Early case finding

• Diagnostic testing

Tertiary prevention

Actions taken after disease has occurred to prevent complications and restore function. Reduce disability and improve quality of life.

Examples

• Cardiac rehabilitation

• Physical therapy

• Occupational therapy

• Dialysis

• Support groups

Nursing Activities

• Rehabilitation

• Patient education

• Long-term care management

Prevent disease

Early detection

Rehabilitation

Game Changer:

Primary Prevention = ___

• Vaccination

• Health promotion

Secondary Prevention = ___

• Screening

• Diagnostic tests

Tertiary Prevention = ___

• Prevent complications

• Restore function

Transmission-Based Precautions

These are additional infection-control measures used along with Standard Precautions for patients known or suspected to be infected with highly transmissible pathogens.

Contact Precautions

Droplet Precautions

Airborne Precautions

3 Categorizations of Transmission-Based Precautions

Standard Precautions (Applied to All Patients)

Assume that all blood, body fluids, secretions, excretions, non-intact skin, and mucous membranes may contain infectious organisms.

Components

• Hand hygiene

• Personal protective equipment (PPE)

• Safe injection practices

• Respiratory hygiene/cough etiquette

• Proper disposal of sharps

• Environmental cleaning

Contact Precautions

Used for infections transmitted through direct or indirect contact with the patient or contaminated objects.

PPE Required

• Gloves

• Gown

Room Placement

• Private room preferred

• Cohort with patients having the same infection if necessary

Examples of diseases where we apply contact precautions

C. difficile

Game Changer:

For ______, wash hands with soap and water because alcohol-based hand rubs are less effective against spores.

• Wear gloves before entering room

• Wear gown if contact with patient/environment is anticipated

• Use dedicated equipment when possible

• Perform hand hygiene before and after patient contact

Nursing Interventions for contact precaution

Droplet precautions

Used for infections spread through large respiratory droplets (>5 microns) produced by coughing, sneezing, or talking.

• Transmission Distance - Typically within 3–6 feet (1–2 meters).

PPE Required

• Surgical mask

Room Placement

• Private room preferred

• Maintain spatial separation

Examples of diseases where we apply droplet precautions

• Wear surgical mask when within 3–6 feet of patient

• Encourage respiratory hygiene

• Limit patient transport

• Place mask on patient during transport

Nursing Interventions for droplet precaution

Airborne precaution

Used for infections spread by airborne droplet nuclei (<5 microns) that remain suspended in the air for long periods.

PPE Required

• N95 respirator (or higher-level respirator)

Room Placement

• Negative-pressure isolation room (Airborne Infection Isolation Room)

Examples of diseases where we apply airborne precautions

• Wear N95 respirator before entering room

• Keep room door closed

• Limit patient transport

• Place surgical mask on patient during transport

Nursing Interventions for airborne precaution

Tuberculosis (TB)

It is a chronic communicable disease caused by Mycobacterium tuberculosis that primarily affects the lungs but may also involve other organs such as the kidneys, bones, meninges, and lymph nodes.

Pulmonary Tuberculosis

Game Changer:

Most common and most infectious form of TB.

Location

Disease Activity

Drug resistance

Infectiousness

4 Classifications of Tuberculosis

Pulmonary Tuberculosis (PTB)

• Most common form of TB

• Involves the lungs

• Usually contagious when active

Signs and Symptoms

• Cough >2 weeks

• Hemoptysis

• Chest pain

• Night sweats

• Weight loss

• Low-grade fever

Extrapulmonary Tuberculosis (EPTB)

TB that occurs outside the lungs

Lymph nodes

Bones (Pott’s disease)

Kidneys

Meninges

Pleura

Pericardium

Common sites of extrapulmonary TB

Enlarged lymph nodes

Manifestation of TB in the lymph nodes

Back pain and deformity

Manifestation of TB in the bones

Hematuria

Manifestation of TB in the kidneys

Meningitis symptoms

Manifestation of TB in the Meninges

Pleural effusion

Manifestation of TB in the Pleura

Pericarditis

Manifestation of TB in the pericardium

infectious

Extrapulmonary tuberculosis is usually less _____ than pulmonary tuberculosis.

Active

Game Changer:

• Latent TB is asymptomatic and noninfectious.

• ___ pulmonary TB is contagious.

Latent Tuberculosis Infection (LTBI)

Characteristics

• TB bacteria present in the body

• No symptoms

• Not contagious

• Positive TST or IGRA

• Normal chest X-ray

Active Tuberculosis Disease

Characteristics

• Organisms actively multiplying

• Symptoms present

• Infectious (especially pulmonary TB)

• Abnormal chest X-ray

• Positive sputum studies

Drug-Susceptible TB

Responds to standard RIPE therapy.

Rifampicin/rifampin

Isoniazid

Pyrazinamide

Ethambutol

Streptomycin

Meaning of RIPES

Multidrug-Resistant Tuberculosis (MDR-TB)

Resistance to:

• Isoniazid (INH)

• Rifampin (RIF)

Characteristics

• More difficult to treat

• Longer treatment duration

• Higher mortality risk

Extensively Drug-Resistant Tuberculosis (XDR-TB)

MDR-TB plus resistance to additional second-line anti-TB drugs.

Characteristics

• Very limited treatment options

• Severe public health concern

Open TB

Characteristics

• Positive sputum smear

• Organisms present in secretions

• Highly infectious

Nursing Priority

• Airborne precautions

Closed TB

Characteristics

• Negative sputum smear

• Organisms not readily transmitted

• Less infectious

Pulmonary Tuberculosis (PTB)

Extrapulmonary Tuberculosis (EPTB)

Classification of TB according to Location

Latent Tuberculosis Infection (LTBI)

Active Tuberculosis Disease

Classification of TB according to Location

Drug-Susceptible TB

Multidrug-Resistant Tuberculosis (MDR-TB)

Extensively Drug-Resistant Tuberculosis (XDR-TB)

Classification of TB according to Drug Resistance

Open TB

Closed TB

Classification of TB based on Infectiousness

Pulmonary Tuberculosis

Respiratory Symptoms

• Persistent cough (>2 weeks)

• Hemoptysis

• Chest pain

• Dyspnea

• Night sweats

• Weight loss

• Fever

• Fatigue

• Anorexia

Chronic cough + Night sweats + Weight loss.

Game Changer:

What are the Classic Triad?

Sputum Culture

Game Changer:

Gold Standard for Confirming Tuberculosis

Sputum Acid-Fast Bacilli (AFB)

Sputum Culture

Mantoux Test (Tuberculin Skin Test)

Interferon-Gamma Release Assay (IGRA)

Chest X-Ray

Diagnostic evaluation for Tuberculosis

Important side effects of RIPE Therapy

Treatment phases of RIPE Therapy

Directly Observed Therapy (DOT)

Purpose

• Ensure compliance

• Prevent resistance

• Improve cure rates

Nutrition

• High-calorie diet

• High-protein diet

• Adequate hydration

Take Vitamin B6 (Pyridoxine)

Health teaching for Isoniazid use

Expect orange-red urine, tears, and sweat

Health teaching for rifampin use

Report visual changes immediately

Health teaching for Ethambutol use

TB

Game Changer:

It is transmitted by airborne droplets, requires N95 and negative-pressure isolation, sputum culture is the gold standard, and RIPE therapy is the standard treatment regimen.

Dengue Fever

It is an acute viral infection caused by the Dengue virus, transmitted primarily by the bite of infected Aedes aegypti and Aedes albopictus mosquitoes.

It is a major public health concern in tropical countries, including the Philippines.

Dengue Virus (DENV)

Causative Agent of Dengue

Four serotypes:

• DENV-1

• DENV-2

• DENV-3

• DENV-4

Aedes aegypti mosquito

▪ Vector that bites during daytime

▪ Breeds in stagnant clean water

▪ Most active during early morning and late afternoon

Cytokines

Proteins that help control inflammation in your body. They allow your immune system to fight germs and other substances

Dengue Without Warning Signs

Dengue With Warning Signs

Severe Dengue

WHO Classification of Dengue

Dengue Without Warning Signs

Classification of Dengue

Symptoms

• Fever

• Headache

• Retro-orbital pain

• Muscle and joint pain

• Rash

• Nausea and vomiting

• Persistent vomiting

• Severe abdominal pain

• Clinical fluid accumulation

• Mucosal bleeding

• Restlessness

• Lethargy

• Hepatomegaly

• Increasing hematocrit with decreasing platelets

Warning Signs of Dengue

Severe Bleeding

Severe Plasma Leakage

• Dengue shock syndrome (DSS)

Severe Organ Involvement

• Liver failure

• Myocarditis

• Encephalopathy

Sever Dengue Manifestations (BPO)

Febrile Phase

Critical Phase

Recovery Phase

3 Phases of Dengue

Febrile Phase

Duration: 2–7 days

Manifestations

• High fever (40°C)

• Severe headache

• Retro-orbital pain

• Myalgia

• Arthralgia

• Rash

Critical Phase

Duration: 24–48 hours

• Occurs when fever starts to decrease.

Manifestations

• Plasma leakage

• Bleeding

• Shock

• Hemoconcentration

Recovery Phase

Manifestations

• Reabsorption of fluids

• Improved appetite

• Increased urine output

• Stable vital signs

Breakbone Fever

Game Changer:

Dengue

• Febrile Phase is "____" because of severe muscle and joint pain.

• Critical Phase is Most dangerous phase

CBC

NS1 antigen test

Dengue Serology

Torniquet test

Diagnostic evaluation for dengue

Plasma leakage

Game Changer:

Rising hematocrit + falling platelet count =

Fluid management

Game Changer:

___ is the cornerstone of dengue treatment.

bleeding risk

Game Changer:

For a person with dengue, Avoid

• Aspirin

• Ibuprofen

• NSAIDs

Rationale: Increased ___

Assess

Fluid Monitoring

Bleeding Precautions

Promote rest

Patient Education

Nursing management for Dengue

Avoid:

• IM injections

• Rectal temperatures

• Aspirin-containing drugs

Use:

• Soft toothbrush

• Electric razor

Bleeding Precautions for Dengue

Dengue Hemorrhagic Fever (DHF)

Dengue Shock Syndrome (DSS)

Dengue complications

Dengue Hemorrhagic Fever (DHF)

• Increased vascular permeability

• Thrombocytopenia

• Hemorrhage

Dengue Shock Syndrome (DSS)

• Massive plasma leakage

• Hypovolemic shock

Signs

• Narrow Pulse Pressure: Early sign of shock

• Hypotension

• Cold Clammy Skin

• Tachycardia

Retro-orbital pain

Game Changer:

___ is a classic symptom of Dengue

Critical

Game Changer:

The ___ phase of Dengue begins when the fever subsides and is the most dangerous stage.

Paracetamol

Game Changer:

___ is the antipyretic of choice for Dengue