Chapter 10_1 flashcards
(48 cards)
Host (Infection Context)
Human or animal colonized by a pathogen. [cite: 2]
Pathogen: Definition
Microorganisms capable of causing infectious disease. [cite: 2]
Colonization: Definition
Pathogen living in/on a host; does not necessarily mean infection exists. [cite: 2]
Infection: Definition
The invasion, colonization, and multiplication of pathogens within the host, often leading to host symptoms. [cite: 2]
Virulence: Definition & Factors
Ability of a pathogen to produce disease. [cite: 3] Virulence factors enhance infectivity (e.g., toxins, adhesion factors, evasive factors). [Text]
Reservoir (Infection Context)
Source of a pathogenic organism; may or may not be suffering from the disease (e.g., person, animal, fomite like an inanimate object). [cite: 3]
Vector (Infection Context)
A living being that can carry a pathogen from a reservoir to a host (e.g., mosquito, tick, flea); not considered infected itself. [cite: 3]
Epidemiology: Definition
The study of disease distributions in human populations. [cite: 4]
Incidence vs. Prevalence (Epidemiology)
Incidence: Number of NEW cases of infection within a population. [cite: 4] Prevalence: Number of active ONGOING cases of infection at any given time. [cite: 4]
Endemic vs. Epidemic vs. Pandemic
Endemic: Incidence and prevalence of a disease are relatively stable in a region. [cite: 4] Epidemic: Abrupt increase in the incidence of disease within a geographic region. [cite: 4] Pandemic: Global spread of a specific disease. [cite: 4]
Normal Microbial Flora: Definition & Functions
Organisms that live in or on the human body (e.g., skin, GI tract, vagina) and perform advantageous functions like secreting nutrients and competitively inhibiting harmful pathogens. [cite: 5] Do not cause disease within their normal niche. [cite: 5]
Carriers (Infectious Disease)
Individuals who harbor specific microbes that do not cause disease for them but can be transmitted to and cause infection in susceptible individuals. [Text]
Immunocompetence vs. Immunosuppression
Immunocompetence: Individual’s ability to protect oneself from infectious agents due to a strong immune system. [cite: 6] Immunosuppression: A defective immune system placing a person at risk for infections. [cite: 6]
Opportunistic Infection: Definition
An infection caused by a microorganism that flourishes because of a host’s deficient immune system or compromise of physical barriers. [cite: 6]
Hospital-Acquired / Health Care-Acquired Infection (Nosocomial Infection)
An infection caused by microorganisms that originated within the clinical environment. Often difficult to treat due to antibiotic-resistant bacteria. [cite: 6]
Bacteria: General Characteristics
Unicellular prokaryotes. [cite: 7] Categorized based on shape (cocci, bacilli, spirochetes), aerobic/anaerobic capabilities, and laboratory staining (Gram stain). [cite: 7] Named by Genus species (e.g., Neisseria gonorrhoeae). [cite: 7]
Gram Stain: Purpose & Differentiation
Most common clinical microbiology stain used to identify bacteria based on cell wall composition. [cite: 8] Gram-positive: Thick peptidoglycan cell wall, stains purple. [cite: 8] Gram-negative: Thin cell wall, stains pink. [cite: 8]
Viruses: General Characteristics
Acellular microorganisms that depend on a host cell’s metabolic processes for their life cycle. [cite: 9] Consist of DNA or RNA genome surrounded by a protein coat. [cite: 9] Can cause acute, chronic, or latent infections, and sometimes cancer cell growth. [cite: 9]
Fungi: General Characteristics & Types of Infections
Mold-like organisms. [cite: 11] Fungal infections are called mycoses. [cite: 11] Dermatophytes (e.g., tinea/ringworm) cause superficial infections (skin, hair, nails). [cite: 11] Invasive/systemic mycoses (e.g., Candida albicans) common in immunocompromised. [cite: 11]
Parasites: Main Categories & Examples
Protists: Unicellular eukaryotes like protozoa (cause giardiasis, malaria). [cite: 12] Helminths: Worms that cause infection (pinworms, tapeworms). [cite: 12] Insects: Can directly cause disease or serve as vectors (e.g., ticks transmitting Lyme disease bacteria). [cite: 12]
Prions: Definition & Mechanism
Proteinaceous infectious agents capable of causing brain diseases. [cite: 13] They convert existing host proteins into abnormal, resistant prion-type proteins, which accumulate and cause spongiform encephalopathy. [cite: 13]
Two Primary Levels of Immunity
- Innate Immunity: Nonspecific, first level of defense. [cite: 14] 2. Adaptive Immunity: Specific, second line of defense, involves memory. [cite: 14]
Innate Immunity: Components
Anatomical barriers (skin, mucous membranes, cilia), antipathogenic chemicals (stomach acid, low skin pH, tears, interferon), acute inflammatory reaction, WBCs (macrophages, neutrophils etc.), the complement system, coagulation system, and cytokines. [cite: 14, 24]
Adaptive Immunity: Characteristics & Cells
Slower to respond than innate immunity. [cite: 25] Characterized by specificity and memory for specific pathogens. [cite: 14] Main cells: T lymphocytes (CD4+ helper cells, CD8+ cytotoxic cells) and B lymphocytes (produce antibodies/immunoglobulins). [cite: 25]
