Infection

Flashcard 1 (Defining Infection)

  • Front: What is an infection?

  • Back: An infection is the multiplication of a parasitic organism in or on a body.

Flashcard 2 (Infectious Agents)

  • Front: List the major categories of infectious agents.

  • Back:

    • Prions: ‘infectious protein’.

    • Viruses: Obligate intracellular agents.

    • Eubacteria (Bacteria) including Chlamydiae, Rickettsia, Mycoplasma, and Ureaplasma.

    • Fungi: Can be intra- and extracellular.

    • Protista (protozoa): Can be intra- and extracellular.

    • Animalia: Including Helminths and Arthropods. Arthropods can also act as vectors for disease transmission.

Flashcard 3 (Classification by Kingdom)

  • Front: Name the kingdoms used to classify infectious agents.

  • Back: Prion, Viruses, Eubacteria, Fungi, Protista, Animalia.

Flashcard 4 (Viral Pathogenicity - General)

  • Front: How do viruses generally cause disease?

  • Back: Viruses cause damage by entering a host cell and replicating at its expense.

Flashcard 5 (Viral Pathogenicity - Specific Mechanisms)

  • Front: List some specific mechanisms by which viruses cause harm.

  • Back:

    • Inhibit host cell DNA, RNA, or protein synthesis.

    • Damage the plasma membrane (e.g., Herpesvirus).

    • Direct cytolysis (e.g., Ebola).

    • Viral proteins in the cell membrane incite immune attack (e.g., Hepatitis B, autoimmunity).

    • Damage cells involved in antimicrobial defense (e.g., HIV).

    • Damage cells that have other dependent cells (e.g., poliovirus).

    • Cell activation or neoplastic transformation (e.g., Hepatitis B, papillomavirus).

Flashcard 6 (Latent Viral Infection)

  • Front: What is a latent viral infection?

  • Back: Infected but hidden, inactive, dormant. Recrudescence can occur.

Flashcard 7 (Host Innate Response to Viruses)

  • Front: What are the components of the host's innate immune response to viral infection?

  • Back: Interferon (alpha and beta) and inflammation.

Flashcard 8 (Host Adaptive Response to Viruses)

  • Front: What are the components of the host's adaptive immune response to viral infection?

  • Back: Antibody formation (humoral immunity) and cellular immunity (mediated by T cells).

Flashcard 9 (Bacterial Mechanisms - Multiplication)

  • Front: How does rapid bacterial multiplication cause disease?

  • Back: It competes with the host for nutrients (e.g., bacteremia in Anthrax).

Flashcard 10 (Bacterial Mechanisms - Exotoxins)

  • Front: What are exotoxins? Give examples.

  • Back: Substances produced by bacteria and released into the environment. Examples include diphtheria toxin, cholera toxin, tetanus, botulism.

Flashcard 11 (Bacterial Mechanisms - Endotoxins)

  • Front: What are endotoxins? What is their effect?

  • Back: Structural components of Gram-negative bacterial cell walls (lipopolysaccharide - LPS) that are potent activators of macrophages and stimulate the production of IL-1, TNF, and IL-6.

Flashcard 12 (Host Response to Bacteria - Neutrophils)

  • Front: What is the primary cellular defense against many bacteria? What does it often result in?

  • Back: The neutrophil. It often results in the formation of pus (pyogenic, purulent, suppurative inflammation).

Flashcard 13 (Other Host Defenses Against Bacteria)

  • Front: Besides neutrophils, what other components of the immune system defend against bacteria?

  • Back: Complement, macrophages, humoral (antibody), and cell-mediated immunity.

Flashcard 14 (Spread - Direct Contact)

  • Front: What is direct contact transmission?

  • Back: Person-to-person transmission.

Flashcard 15 (Spread - Indirect Contact)

  • Front: What is indirect contact transmission? What is a fomite?

  • Back: Transmission via inanimate objects (fomites).

Flashcard 16 (Spread - Vector-borne)

  • Front: What are vector-borne diseases? Give an example.

  • Back: Infections transmitted by the bite of infected arthropod species (e.g., Zikavirus is an arbovirus transmitted by mosquitoes).

Flashcard 17 (Spread - Droplet vs. Aerosol)

  • Front: What distinguishes droplet and aerosol (airborne) transmission?

  • Back: Respiratory transmission based on particle size. Aerosol/airborne involves particles <5um.

Flashcard 18 (Spread - Feco-oral)

  • Front: What is feco-oral transmission?

  • Back: Transmission involving fecal contamination and oral intake.

Flashcard 19 (Spread - Nosocomial)

  • Front: What are nosocomial infections?

  • Back: Hospital or ‘care’-acquired infections.

Flashcard 20 (Spread - Vertical)

  • Front: What is vertical transmission? Give an example.

  • Back: Parent to offspring through genetics or pregnancy (e.g., transplacental transmission of Zikavirus).

Flashcard 21 (Spread - Horizontal)

  • Front: What is horizontal transmission?

  • Back: Person to person after birth.

Flashcard 22 (Spread - Zoonotic)

  • Front: What are zoonotic diseases?

  • Back: Animal (usually vertebrate) disease spread to humans.

Flashcard 23 (Prevention - Avoid Contact)

  • Front: List strategies for preventing infection by avoiding contact.

  • Back:

    • Inherent barriers (e.g., skin).

    • Distancing.

    • Isolation (sick from healthy) vs. quarantine (potentially exposed).

    • Education on transmission routes.

    • Eradication of the infectious agent.

Flashcard 24 (Prevention - Induce Immunity - Passive)

  • Front: What is passive immunity? How can it be acquired?

  • Back: Transfer of antibodies (e.g., tetanus antitoxin) or sensitized lymphocytes. Provides immediate protection but no memory. Can occur naturally (mother to offspring via placenta/colostrum) or artificially (injection of antiserum).

Flashcard 25 (Prevention - Induce Immunity - Active)

  • Front: What is active immunity? What is the primary method to induce it?

  • Back: Stimulation of the host's immune system to produce its own response and memory. Primarily through vaccination. Vaccination is considered the most effective method in most circumstances if an effective vaccine exists.

Flashcard 26 (Prevention - Prophylaxis)

  • Front: What is prophylaxis in the context of infectious disease prevention?

  • Back: Administration of therapeutic compounds (treatments) or passive immunity before exposure to prevent disease.

Flashcard 27 (Vaccine Types)

  • Front: List different types of vaccines.

  • Back: Killed/inactivated, Toxoid, Live and Modified live (alter organism to be immunogenic and not pathogenic), RNA vaccine, Virus vector.

Flashcard 28 (Treatment - Specific)

  • Front: What is specific treatment for infectious disease? Give examples.

  • Back: Remove the cause (e.g., antimicrobial drugs). Examples: Antibiotics (antibacterial), antivirals, antiprotozoal.

Flashcard 29 (Treatment - Other Strategies)

  • Front: Besides specific treatments, what other strategies are used to treat infectious diseases?

  • Back: Relieve workload on affected organs, Symptomatic treatment (address clinical signs), Replace function if possible, Passive immunity (antitoxin/antiserum for exotoxin-mediated diseases).

Flashcard 30 (Disease Statistics - Incidence)

  • Front: Define incidence.

  • Back: Number of new cases of a disease each year.

Flashcard 31 (Disease Statistics - Prevalence)

  • Front: Define prevalence.

  • Back: Total number of occurrences of the disease in a year (total number affected).

Flashcard 32 (Disease Statistics - Case Fatality Rate (CFR))

  • Front: Define case fatality rate (CFR).

  • Back: Percentage of the population who show signs of a disease that die of the disease (deaths/disease).

Flashcard 33 (Disease Statistics - Infection Fatality Rate (IFR))

  • Front: Define infection fatality rate (IFR).

  • Back: Percentage of the population that will die from the disease (deaths/infection).

Flashcard 34 (WHO Disease Status)

  • Front: What terms does the WHO use to describe the status of an infection in a population?

  • Back: Endemic (native), Epidemic (many people), Pandemic (all of the people).

Flashcard 35 (Host-Parasite Interaction - Infected)

  • Front: What does it mean for a host to be 'infected'?

  • Back: Host has the infectious agent.

Flashcard 36 (Host-Parasite Interaction - Subclinical Infection)

  • Front: What is a subclinical infection?

  • Back: Infected but no clinical signs or symptoms.

Flashcard 37 (Host-Parasite Interaction - Clinical Disease)

  • Front: What is clinical disease (or a clinical case)?

  • Back: Infected and has disease.

Flashcard 38 (Host-Parasite Interaction - Latent)

  • Front: What does 'latent' mean in the context of infection?

  • Back: Infected but hidden, inactive, dormant.

Flashcard 39 (Host-Parasite Interaction - Carrier)

  • Front: What is a carrier?

  • Back: Subclinical and transmits to others.

Flashcard 40 (Host-Parasite Interaction - Shedder)

  • Front: What is a shedder?

  • Back: Shedding the virus or bacteria.

Flashcard 41 (Host-Parasite Interaction - Amplifier/Superspreader)

  • Front: What is a superspreader? What is an amplifier?

  • Back: A superspreader is an individual with a high viral load who ‘emits’ large numbers of infectious particles and often infects others who also become superspreaders. An amplifier is similar to a superspreader.

Flashcard 42 (Examples - Rotavirus)

  • Front: What are some key facts about Rotavirus infection in children?

  • Back: Nearly all children infected in the first 4 years. High incidence (25% per year) leading to 100% prevalence by age 4. Causes hospitalizations and deaths.

Flashcard 43 (Examples - Zikavirus)

  • Front: What are some key features of Zikavirus?

  • Back: Arbovirus transmitted by mosquitoes. Can cause viremia, systemic inflammation, and transplacental transmission leading to microencephaly.

Flashcard 44 (Examples - Herpesviruses)

  • Front: What is a key characteristic of Herpesviruses regarding disease mechanisms?

  • Back: As a group, the herpesviruses are capable of causing disease by inhibiting host cell DNA, RNA or protein syntheses, damaging the plasma membrane, direct cytolysis, inciting immune attack, damaging antimicrobial defense cells, damaging dependent cells, and cell activation or neoplastic transformation.