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Infectious Diseases
Chapter 12
Medical Considerations
Contraction, Transmission, and
Stages of Disease

Transmission of Infectious Disease
Interaction of Host, Infectious Agent, and
Environment
 Reservoirs
 Direct vs. Indirect Transmission

 Routes

Bloodborne, airborne, sexual, fecal-oral, and foodborne
 Risk

of Exposure
of Infection
Theoretical vs. measurable
Contraction, Transmission, and
Stages of Disease

Factors Affecting Disease Transmission
Mode of Entry
 Virulence
 Number of Organisms Transmitted
 Host Resistance
 Other Host Factors

Contraction, Transmission, and
Stages of Disease

Phases of the Infectious Process
Latent Period
 Communicable Period
 Incubation Period

 Seroconversion

Disease Period
and the window phase
The Body’s Defenses against
Disease
Barriers to Entry



Intact Skin
Respiratory System
The Immune System


The Reticuloendothelial System (RES)
Identifies Foreign Material


Includes antigens of most bacteria and viruses.
An inflammatory response triggers
mechanisms designed to remove foreign
material.
Cellsalive.com

Viral antigens
The Body’s Defenses against
Disease

The Immune System (cont.)

Leukocytes
 Neutrophils
and macrophages
Cell-Mediated Immunity
 Humoral Immunity

 Results
in the formation of antibodies.
 Memory and specificity.

Antibodies (Immunoglobulins)
 IgG,
IgM, IgA, IgD, and IgE
 Autoimmunity
•neutrophil, ingesting
Streptococcus
pyogenes
The Body’s Defenses against
Disease

The Complement System

The Body’s “Rapid Response” System
 Proteins
that work with antibody formation and
inflammatory reaction to fight infection.
 Recognizes endotoxins of certain bacteria.

The Lymphatic System

Structures
 Spleen,
thymus, lymph nodes, and ducts.
 Collects and filters lymph.

Facilitates Phagocytosis in Lymph Nodes.
Brady; Paramedic Care Principles & Practice
Infection Control in Prehospital
Care
Infection Control

Recovery
Wash your hands immediately after patient
contact.
 If you sustain a wound and are exposed to
the body fluids of others, wash the wound
with soap and water immediately.
 Dispose of biohazardous wastes in
accordance with local laws and regulations.

Infection Control
 Recovery
(cont.)
Place potentially infectious wastes in leak
proof biohazard bags. Bag and label soiled
linen.
 Decontaminate contaminated clothing and
reusable equipment.
 Handle uniforms in accordance with agency
policy.

Infectious Diseases of Immediate
Concern

Human Immunodeficiency Virus


Pathogenesis
Risk to the General Public



Found in blood, blood products, and body fluids.
Common methods of transmission include sexual contact
and shared needles.
Risk to Health Care Workers



Transmission to health care workers is actually rare.
Accidental needlesticks are the most common source.
High-risk exposures are those involving a large volume of
blood, deep percutaneous injury, actual intramuscular
injection, or a high antibody-retrovirus titer in the source
Diseases of Immediate Concern

HIV (cont.)

Clinical Presentation
 Fatigue,
fever, sore throat, lymphadenopathy,
splenomegaly, rash, and diarrhea.
 Kaposi’s sarcoma.
 Secondary (opportunistic) infections and weight
loss.
 Dementia, psychosis, and peripheral neurological
disorders develop as AIDS progresses.
Diseases of Immediate Concern to
EMS Providers

Hepatitis

General Signs & Symptoms




Symptoms are similar regardless of type of infection.
Headache, fever, weakness, joint pain, anorexia, nausea,
vomiting, and URQ abdominal pain.
Jaundice, clay-colored stool, and dark urine develop as the
disease progresses.
Hepatitis A (Infectious or Viral Hepatitis) (HVA)



Transmitted by fecal-oral route.
Typically is mild; many patients are asymptomatic.
Rarely serious and lasts 2–6 weeks.
Diseases of Immediate Concern to
EMS Providers

Hepatitis (cont.)

Hepatitis B (Serum Hepatitis) (HBV)
 Virus
is transmitted through direct contact with
infected blood, semen, vaginal fluids, or saliva.
 Risk is significantly higher for EMS providers.

5-35% of all needlesticks result in infection.
 Vaccination
is available and recommended for all
EMS workers.
 60–80% of infected individuals are asymptomatic.
Diseases of Immediate Concern to
EMS Providers

Hepatitis (cont.)

Hepatitis C (HCV)




Hepatitis D (HDV)


Primarily transmitted by IV drug abuse and sexual contact.
Chronic infection that can cause active disease years later.
May cause cirrhosis and end-stage liver disease.
Exists only concurrently with HBV.
Hepatitis E (HEV)

Is similar to HAV but primarily associated with contaminated
drinking water.
Diseases of Immediate Concern to
EMS Providers

Tuberculosis

General Info
 Most
common preventable infectious disease
 Drug-resistant TB
Skin Testing
 Pathogenesis
 Clinical Presentation

 Chills,
fever, fatigue, chronic cough, weight loss
 Night sweats
 Hemoptysis
Diseases of Immediate Concern to
EMS Providers

Tuberculosis (cont.)

EMS Response
 Index
of suspicion
 N95 and HEPA respirators

Postexposure Identification and Management
Diseases of Immediate Concern to
EMS Providers

Pneumonia

General




Differentiating pneumonia from CHF
Source pathogens
At-risk patient populations
History and Assessment



Community-acquired pneumonia.
Signs include acute onset of chills, fever, dyspnea, pleuritic
chest pain, cough, adventitious breath sounds.
In geriatric patients, the primary sign may be an altered
mental state.
Diseases of Immediate Concern to
EMS Providers

Pneumonia

Patient Management and PPE
 Management
should support oxygenation and
ventilation.
 Consider the possibility of TB.
 Consider placing a mask on yourself or the patient.

Immunization and Postexposure Management
 Routine
vaccination is not necessary.
 Antimicrobial agents and multidrug-resistant
strains.
Diseases of Immediate Concern to
EMS Providers

Chickenpox
Varicella Zoster Virus (VCV)
 Clinical Presentation

 Respiratory
symptoms, malaise, and low-grade
fever followed by a rash.
 Rash may be the first sign of illness and may be
limited or widespread; often prolific on the trunk.
 Transmission is through airborne droplets and
direct contact with lesions.
 Can be lethal in adult immunocompromised
patients.
Diseases of Immediate Concern to
EMS Providers

Chickenpox (cont.)

Assessing Immunity
 Past
history of chickenpox is sufficient.
Immunization
 EMS Response and Postexposure

 Observe
universal (standard) precautions.
 Get postexposure vaccination.
Diseases of Immediate Concern to
EMS Providers

Meningitis

Inflammation of the Meninges
 Caused

by a variety of pathogens.
Transmission Factors
 Host
resistance factors, weather
 Contact with oral secretions
 Crowding, close contact, smoking
Diseases of Immediate Concern to
EMS Providers

Meningitis (cont.)

Clinical Presentation





Incubation period of 4–10 days
Fever, chills, headache, nuchal rigidity, arthralgia, lethargy,
malaise, altered mental status, vomiting, and seizures
Brudzinski’s and Kernig’s signs
Immunization
EMS Response and Postexposure


Observe universal (standard) precautions.
Perform postexposure prophylaxis within 24 hours.
Other Airborne Diseases

Influenza and the Common Cold

Viral Infection
 Mutation
and virulence
 Epidemics

Symptoms
 Fever,
chills, malaise, muscle aches, nasal
discharge, mild cough
 Secondary infections
Management
 Immunization

Other Airborne Diseases

Measles

Viral Infection



Symptoms




Highly communicable, with lifelong immunity after disease.
Transmitted by airborne droplets and direct contact.
Presents similar to severe cold with fever, conjunctivitis,
photophobia, cough, and congestion.
Rash.
Management
Immunization
Other Airborne Diseases

Mumps

Viral Infection



Symptoms




Transmitted by airborne droplets and direct contact with
saliva of infected patient.
Occurs primarily in 5- to 15-year-old patients.
Painful enlargement of salivary glands
Symptoms of cold with earache, difficulty chewing, and
swallowing
Management
Immunization
Other Airborne Diseases

Rubella
Systemic Viral Infection
 Symptoms

 Sore


throat, low-grade fever, and fine pink rash
Management and Immunization
Respiratory Syncytial Virus (RSV)

Viral Infection
 Common
cause of pneumonias and bronchiolitis
 Commonly associated with lower respiratory
infections during the winter
Other Airborne Diseases

RSV (cont.)

Symptoms



Runny nose and congestion, followed by wheezing,
tachypnea, and signs of respiratory distress
Management
Pertussis (Whooping Cough)


Bacterial Infection
Symptoms


Catarrhal, paroxysmal, and convalescent phases
Management and Immunization