Infectious Diseases Overview
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Questions and Answers

What is a consequence of HIV infection in the thymus?

  • Failure to regenerate more T cells (correct)
  • Heightened T cell function
  • Increased T cell regeneration
  • Decreased production of B cells

    • Which organism is NOT a common secondary infection associated with a weakened immune system due to HIV?

  • Escherichia coli (correct)
  • Mycobacterium tuberculosis
  • Cryptococcus neoformans
  • Cytomegalovirus

    • What is one mechanism of pathogenicity that can lead to disease?

  • Producing antibodies
  • Facilitating T cell proliferation
  • Inhibiting microbial clearance
  • Direct invasion of host cells (correct)

    • Which step is NOT part of the infection process discussed?

    <p>Initiating T cell activation</p> Signup and view all the answers

    How does chronic inflammatory response affect T cells?

    <p>Reduces T cell function</p> Signup and view all the answers

    What is the primary route of transmission for rhinoviruses causing the common cold?

    <p>Inhalation of airborne droplets</p> Signup and view all the answers

    What is a key characteristic of the Bacillus anthracis organism?

    <p>It forms endospores.</p> Signup and view all the answers

    Which anthrax type has the highest fatality rate if untreated?

    <p>Inhalation anthrax</p> Signup and view all the answers

    What is a common symptom of cutaneous anthrax?

    <p>Typical black eschar</p> Signup and view all the answers

    What is the mode of infection for gastrointestinal anthrax?

    <p>Ingestion of infected meat</p> Signup and view all the answers

    What factor contributes to the pathogenicity of Bacillus anthracis?

    <p>Presence of a polysaccharide capsule</p> Signup and view all the answers

    What is the typical onset period for inhalation anthrax?

    <p>1 week to 2 months</p> Signup and view all the answers

    What symptom is associated with injection contracted anthrax?

    <p>Swelling at the injection site</p> Signup and view all the answers

    What prevents vegetative bacteria cells from being destroyed by the immune system?

    <p>The capsule of the bacteria</p> Signup and view all the answers

    Which toxin is responsible for hyperinflammation via MAPKK?

    <p>Lethal toxin</p> Signup and view all the answers

    What are some common signs of influenza syndrome?

    <p>Fever and muscle aches</p> Signup and view all the answers

    Which microorganism is NOT associated with upper respiratory tract infections?

    <p>Mycobacterium tuberculosis</p> Signup and view all the answers

    What characterizes infectious diseases?

    <p>Signs, symptoms, and pathology</p> Signup and view all the answers

    What is the genetic material of the influenza virus?

    <p>Segmented negative sense single-stranded RNA</p> Signup and view all the answers

    Which of these is a route of transmission for respiratory tract infections?

    <p>Inhalation of air droplets</p> Signup and view all the answers

    What does the term 'influenza' derive from?

    <p>The Italian word for influence</p> Signup and view all the answers

    Which type of inflammatory reaction is typically associated with mycobacterial infections such as leprosy?

    <p>Granulomatous</p> Signup and view all the answers

    Which stain is specifically used for identifying Histoplasma in tissue samples?

    <p>Gomori Grocott</p> Signup and view all the answers

    What type of antibody would be used to identify Treponema pallidum in gastric syphilis?

    <p>Anti-Treponema antibody</p> Signup and view all the answers

    Which method is NOT typically used for identifying microorganisms in tissue samples?

    <p>Spectroscopy</p> Signup and view all the answers

    What type of samples are typically analyzed using PCR for identifying microbial infections?

    <p>Tissue samples</p> Signup and view all the answers

    Which infectious disease has been associated with the development of resistance to antimicrobial drugs as an emerging disease?

    <p>Tuberculosis</p> Signup and view all the answers

    Which type of tissue stain would you use for visually identifying Cryptococcus in a biopsy sample?

    <p>Acian blue</p> Signup and view all the answers

    What is one limitation of immunohistochemistry in identifying microorganisms in tissue samples?

    <p>Limited availability of specific antibodies</p> Signup and view all the answers

    What is the primary purpose of determining the cause of an infectious disease?

    <p>Diagnosis, treatment, prognosis, and prevention</p> Signup and view all the answers

    Which of the following is NOT classified as a causative agent of infectious disease?

    <p>Fungi and Archaea</p> Signup and view all the answers

    What type of transmission involves inhalation of air droplets containing microorganisms?

    <p>Aerosol transmission</p> Signup and view all the answers

    Which of these routes of transmission is associated with eating contaminated food?

    <p>Oral transmission</p> Signup and view all the answers

    Which infectious agent is specifically non-cellular?

    <p>Viruses</p> Signup and view all the answers

    What characteristic distinguishes fungi as a type of infectious agent?

    <p>Eukaryotic nature</p> Signup and view all the answers

    Which of the following microbe types has not yet been identified as an infectious agent?

    <p>Archaea</p> Signup and view all the answers

    Which organism type is typically a vector for transmitting infectious agents?

    <p>Arthropods</p> Signup and view all the answers

    What is the incubation period in the phases of infectious disease?

    <p>The time between infection and the appearance of signs and symptoms</p> Signup and view all the answers

    Which characteristic describes chronic diseases?

    <p>They are usually asymptomatic for long periods</p> Signup and view all the answers

    How does a systemic disease differ from a local disease?

    <p>Systemic diseases affect multiple body sites</p> Signup and view all the answers

    What typically characterizes the decline phase of an infectious disease?

    <p>Subside of symptoms as recovery begins</p> Signup and view all the answers

    What type of disease is characterized by no symptoms between outbreaks and illness?

    <p>Latent disease</p> Signup and view all the answers

    Which is true of a primary infection?

    <p>It is the initial infection in a previously healthy person</p> Signup and view all the answers

    When does the recovery phase of an infectious disease occur?

    <p>When symptoms have disappeared and the body regains strength</p> Signup and view all the answers

    What is an example of an acute disease?

    <p>Ebola</p> Signup and view all the answers

    Signup and view all the answers

    Study Notes

    Infectious Diseases

    • Infectious diseases are caused by contagious agents that can transmit infection and cause pathological effects in tissues and cells.
    • Determining the cause is crucial for diagnosis, treatment, prognosis, and prevention.
    • Infectious diseases are often easily transmitted, especially through air and water.
    • Causative agents are microscopic organisms (microbes).
    • Transmission routes include aerosol, oral, direct contact, fomite, vector-borne, and zoonotic.

    Etiological Agents

    • Bacteria (prokaryotes)
    • Viruses (non-cellular)
    • Fungi (eukaryotes)
    • Protozoa (eukaryotes)
    • Prions (proteins, non-cellular)
    • Helminths (non-microbial, eukaryotes)
    • Arthropods (non-microbial, eukaryotes)
    • Archaea (no known infectious agents, but possible role in periodontal disease)

    Bacillus anthracis

    • Gram-positive bacilli forming endospores. Found in the environment.
    • Causes cutaneous, gastrointestinal, inhalation, and injection anthrax.
    • Cutaneous anthrax (most common, 95%): wound contamination from spores.
    • Gastrointestinal anthrax: ingestion of spores.
    • Inhalation anthrax: inhalation of spores.
    • Injection anthrax: needles contaminated with soil or material (swelling, nausea, vomiting).
    • Welders' anthrax: B. cereus group creating anthrax toxin (pneumonia-like symptoms).
    • Pathogenesis involves spore germination, phagocytosis, lymph spread, and prevention of phagocytosis by a capsule.
    • Toxins include edema toxin, lethal factors, and protective antigen.
    • May cause septicemia, brain, and meningeal infection or pulmonary blockage.

    Transmission Routes and Airborne Pathogens

    • Many microorganisms can spread by inhaling airborne droplets.
    • Upper respiratory tract pathogens: Staphylococcus aureus, Neisseria meningitidis, Streptococcus pyogenes, Corynebacterium diphtheriae, Haemophilus influenzae, common cold virus.
    • Lower respiratory tract pathogens: Influenza virus, Mycobacterium tuberculosis, Coccidioides immitis, Bordetella pertussis, Streptococcus pneumoniae, pneumonia viruses, Coxiella burnetii, Chlamydophila pneumoniae.

    Characteristics of Infectious Diseases

    • Signs: observable effects (fever, cough, vomiting).
    • Symptoms: subjective experiences (pain, nausea).
    • Influenza syndrome: caused by influenza virus.
    • Influenza virus genome: segmented negative-sense single-stranded RNA (ssRNA) with pleomorphic nucleocapsid.

    Phases of Infectious Diseases

    • Incubation period: time between infection and symptoms.
    • Prodromal phase: mild, non-specific symptoms.
    • Clinical phase: typical signs and symptoms appear.
    • Decline phase: symptoms subside.
    • Recovery phase: symptoms disappear, tissues heal.

    Types of Infectious Diseases by Duration, Location, and Timing

    • Acute diseases: develop and progress quickly (e.g., Ebola).
    • Chronic diseases: develop slowly and last longer (e.g., HPV).
    • Latent diseases: no symptoms between outbreaks and illness (e.g., HSV).
    • Local diseases: confined to a specific area (e.g., ringworm).
    • Systemic diseases: infect multiple body sites and tissues.
    • Primary infections: initial infection in a healthy person.
    • Secondary infections: infections resulting from a weakened immune system. (e.g., HIV)

    Pathogenesis of Infectious Diseases

    • Mechanisms: production of toxins and enzymes, direct invasion, triggering immune responses.
    • Steps in infection: entry, attachment, colonization, spread, replication, evasion of immune response, exit.

    Immune Response and Pathology

    • Immune responses can contribute to disease pathology by blocking, deactivating, and clearing the pathogen.
    • Some pathological effects result from more than one agent.
    • Common shared pathologies: respiratory infections, bloodstream infections, encephalitis, meningitis, endocarditis, gastrointestinal diseases, and skin & soft tissue infections.

    Skin and Soft Tissue Infections

    • Localizations: epidermis (impetigo), dermis (erysipelas), hair follicles (folliculitis, boils, carbuncles), subcutaneous fat (cellulitis), fascia (necrotizing fasciitis), muscle (gangrene).
    • Causative agents: Streptococcus pyogenes, Staphylococcus aureus, anaerobes, Clostridium perfringens.
    • Viral examples: Papilloma, HSV, VZV.

    Skin Manifestations by Systemic Infections and Diagnosis Methods

    • Skin signs can indicate systemic infections.
    • Diagnosis methods: microscopy (e.g., Ziehl-Neelson, Gomori Grocott), immunohistochemistry (antibodies for pathogens) and molecular biology techniques like PCR and ISH.

    Emerging Infectious Diseases

    • Emerging diseases are those newly appearing or rapidly increasing in incidence.
    • Factors include antimicrobial resistance, spread to new hosts, ineffective preventative measures, and unknown agents.

    Enteric Fever (caused by S. Typhi)

    • Gram-negative bacteria.
    • Human-specific.
    • Symptoms include high fever, headache, nausea, abdominal pain, constipation, and diarrhea.
    • S. Typhi uses Vi capsule for attachment employing N-acetylneuraminic acid (Neu5Ac) sialoglycans.

    Infectious Disease Management

    • Treatment: antibiotics (bacteria), antiviral drugs (viruses), antifungal drugs (fungi).
    • Prevention: vaccines, good hygiene, vector control, isolation/quarantine.
    • Diagnosis: clinical presentation, laboratory tests.

    Epidemiology

    • Epidemiology is the study of disease occurrence in populations.
    • Four branches: disease etiology, outbreak investigation, disease screening/surveillance, and clinical trials (treatments or effects).

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    Infectious Disease PDF

    Description

    This quiz covers the essential aspects of infectious diseases, including their causes, transmission routes, and various etiological agents. Explore the different types of microorganisms responsible for infections and gain insights into their transmission and impact on health.

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