Infectious Diseases
CHAPTER 33: INFECTIOUS DISEASES
Page 1
Title: Chapter 33 Infectious Diseases
Author: Becky Mannel, OTD, MOT/OTR/L, 092 OST
Page 2: CHAIN OF TRANSMISSION (INFECTION)
Definition: Process by which an infectious agent is conveyed from a reservoir to a susceptible host.
Importance: Understanding each infectious disease helps in prevention by disrupting transmission links.
Page 3: COMPONENTS OF CHAIN OF TRANSMISSION
Infectious Agent
Types: Bacteria, Fungus, Protozoon, Rickettsia, Virus
Susceptible Host
Types: Animals, Elderly, Newborns, Humans, Acute/Chronically ill individuals, Immune-suppressed, Unvaccinated
Reservoir
Sources can include: Equipment, Food, Soil, Water
Pathways
Entry: Body orifices, Blood, Mucous membranes, Secretions
Exit: Blood, Excretions, Broken skin
Means of Transmission
Types: Airborne, Contact, Droplet, Vector (e.g., insects), Vehicle
Page 4: INFECTIOUS DISEASE MECHANISMS
Infectious Agents: Virus, Bacteria, Fungus, Parasite, Prion
Reservoir Hosts:
Environmental, Food, Water, Soil, Contaminated surfaces, Human, Animal, Zoonosis
Page 5: PATHWAYS OF EXIT AND ENTRY
Pathways of Exit: Blood, Exudates, Excretions, Secretions
Pathways of Entry: Body orifices, Mucous membranes, Broken skin
Page 6: MEANS OF TRANSMISSION
Direct Transmission:
Via contact, secretions, mucous membranes, and droplets in close proximity
Indirect Transmission:
Airborne, Vector-borne, Vehicle-borne; droplet nuclei can remain airborne
Page 7: SUSCEPTIBLE HOST RISK FACTORS
Factors include:
Tobacco/Alcohol use, Genetics, Age, Immunity, Poverty, Lack of clean water, Preexisting health conditions
Page 8: INFECTIOUS DISEASE CLASSIFICATION TABLE (33.1)
Classification by Microbiology and Transmission:
Bacterial: TB, Clostridium difficile (C diff)
Viral: HIV, COVID-19
Fungal: Candida, Ringworm, Meningitis
Parasitic: Malaria, Hepatitis B
Prion: Creutzfeldt-Jakob disease (CJD)
Page 9: PREVENTION OF DISEASE SPREAD IN HEALTH/SOCIAL CARE
Strategies include:
Blocking transmission pathways
Standard precautions such as hand hygiene
Cough etiquette and transmission-based precautions (contact, droplet, airborne)
Page 10: IMPACT OF SOCIAL AND STRUCTURAL DETERMINANTS OF HEALTH
Social determinants contribute to disparities in infectious disease distribution:
Economic stability, Education access, Health care quality, Neighborhood environments, Community context
Factors include stigma leading to poor health outcomes
Page 11: HIV (HUMAN IMMUNODEFICIENCY VIRUS)
Page 12: HIV DESCRIPTION AND DEFINITIONS
Zoonotic transmission with two types:
HIV-1: Derived from SIV strains in apes
HIV-2: Derived from SIV strains in sooty mangabey monkeys
Effect: Attaches to CD4+ T cells, damaging immune responses
Page 13: HIV ETIOLOGY
Transmissions occur through:
Blood, Serum, Semen, Breast milk
Needle/syringe sharing, unprotected sexual intercourse
Cannot be transmitted via hugging, kissing, or sharing personal objects
Page 14: HIV INCIDENCE AND PREVALENCE
2019 statistics:
Globally, ~38 million people affected, ~1.7 million newly infected
23% decline in cases since 2010
690,000 died in 2019; majority of cases in Sub-Saharan Africa
U.S. incidence mostly men who have sex with men
Page 15: HIV SIGNS AND SYMPTOMS
Three stages:
Stage 1: Highly infectious, flu-like symptoms
Stage 2: Few symptoms, but CD4 count decreases
Stage 3: AIDS with symptoms like weakness, weight loss, swollen lymph glands
Symptoms in infants and children include lymphadenopathy and pneumonia
Page 16: DIAGNOSTIC TESTING
Tests include:
Enzyme immunoassays, Nucleic acid tests
Page 17: HIV COURSE AND PROGNOSIS
Highly Active Antiretroviral Therapy (HAART) improves prognosis
Risks of premature aging and cognitive impairments associated with HIV
Page 18: TREATMENT OPTIONS
Recommended therapies:
Combination Antiretroviral Therapy (cART)
Pre-exposure prophylaxis (PrEP)
Page 19: HIV IMPACT ON OCCUPATIONAL PERFORMANCE
Affected areas:
Poor sleep, Mobility, Financial management, Engagement in education, Grooming
Page 20: TUBERCULOSIS (TB)
Page 21: TB DESCRIPTION AND DEFINITIONS
Infectious bacterial disease caused by Mycobacterium tuberculosis
Commonly affects:
Lungs, bronchial areas leading to pulmonary scar tissue
Can also affect meninges, bones, joints, gastrointestinal system
Page 22: TB TRANSMISSION
Transmission occurs via cough droplets inhaled into alveoli, leading to inflammatory response
Page 23: TB INHALATION MECHANISM
Droplets containing TB bacilli are inhaled into the respiratory system and can reach lymph nodes where they multiply
Page 24: TB INCIDENCE AND PREVALENCE
TB is a leading cause of death, particularly linked to socio-economic factors
In 2018, 8 countries accounted for 2/3 of new cases
Most cases are found in individuals aged 15-64, with a higher prevalence in males compared to females
Page 25: TB SIGNS AND SYMPTOMS
Latent TB: Not transmissible, dormant but can test positive
Active TB: Shows symptoms such as cough, chest pain, fever
Other potential effects include alterations in cardiorespiratory function and requirement for self-isolation
Page 26: TB DIAGNOSIS
Methods include:
Blood test, Mantoux Test, Sputum smear, Sputum culture, Chest radiography
Page 27: TB COURSE AND PROGNOSIS
Active TB recoverable with first-line antibiotics over 6 months
Risk of fatality is higher with active TB; potential for drug-resistant strains
Page 28: TB MANAGEMENT
Treatment encompasses:
Duration of oral medication from a minimum of 6 months to 2 years
Directly Observed Therapy (DOT) programs
Community-based treatments and possible surgical intervention
Page 29: TB IMPACT ON OCCUPATIONAL PERFORMANCE
Impacted areas include:
Daily activities such as shopping, caring for others, grooming, and sexual activity.