Infectious Disease Concepts Chapter 2
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Questions and Answers

What type of microbe was identified in Brandon's diagnosis of syphilis?

  • Virus
  • Fungus
  • Protozoan
  • Bacterium (correct)

    • What does pathogenicity refer to?

  • The effectiveness of a treatment
  • The resistance to antibiotics
  • The ability of an organism to cause disease (correct)
  • The ability of a microbe to replicate

    • Which of the following best describes the role of adhesins in the microbiota?

  • Assist in nutrient absorption
  • Facilitate the attachment to host cells (correct)
  • Enable the microbiota to replicate
  • Protect against pathogenic invasion

    • Brandon's sexual partners were contacted following his diagnosis. This action highlights the importance of:

    <p>Community health and disease prevention</p> Signup and view all the answers

    Which of the following best defines a pathogen?

    <p>A microbe that causes disease in humans</p> Signup and view all the answers

    What is the main treatment provided to Brandon for his syphilis infection?

    <p>Long-acting penicillin</p> Signup and view all the answers

    What is the relationship between normal microbiota and pathogens?

    <p>Normal microbiota can prevent pathogen colonization</p> Signup and view all the answers

    What characterizes ectoparasites and endoparasites?

    <p>Ectoparasites live on the surface of the host, endoparasites live inside the host</p> Signup and view all the answers

    What is the primary difference between infection and disease?

    <p>Infection occurs when a pathogen enters the body, while disease involves the development of symptoms.</p> Signup and view all the answers

    Which of the following describes a primary pathogen?

    <p>Causes disease in healthy hosts with moderate to high virulence.</p> Signup and view all the answers

    How is virulence commonly measured?

    <p>Through lethal dose 50% (LD50) and infectious dose 50% (ID50).</p> Signup and view all the answers

    What does 'invasiveness' refer to in the context of pathogens?

    <p>The capacity of bacteria to quickly spread through tissues.</p> Signup and view all the answers

    What is meant by the host range of a pathogen?

    <p>The different types of hosts a pathogen can infect and cause disease.</p> Signup and view all the answers

    Which of the following best defines disease?

    <p>A disruption in normal structure or function, recognizable by specific symptoms and signs.</p> Signup and view all the answers

    Acute infections typically result in symptoms that:

    <p>Develop rapidly and resolve quickly.</p> Signup and view all the answers

    What characteristic does an opportunistic pathogen possess?

    <p>Typically causes disease only in immunocompromised hosts.</p> Signup and view all the answers

    What is the cause of Rocky Mountain Spotted Fever (RMSF)?

    <p>Rickettsia rickettsii</p> Signup and view all the answers

    Which type of transmission occurs when an infectious agent is transferred from one person or animal to another?

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

    What describes indirect transmission of pathogens?

    <p>It involves an intermediary organism or object.</p> Signup and view all the answers

    What is a reservoir in the context of infections?

    <p>An environment or host that harbors a pathogen</p> Signup and view all the answers

    What role do asymptomatic carriers play in the spread of Neisseria meningitidis?

    <p>They can spread the pathogen without showing symptoms.</p> Signup and view all the answers

    Which mode of transmission is exemplified when a person catches a disease from contaminated water?

    <p>Indirect transmission through vehicles</p> Signup and view all the answers

    Which statement is true about the infection cycle?

    <p>It can be simple or complex depending on the pathogens involved.</p> Signup and view all the answers

    What was the condition of the streets during the rat epidemic in Canton in 1884?

    <p>Bodies were stacked due to high mortality.</p> Signup and view all the answers

    What defines an infectious disease?

    <p>A disease caused by a pathogen that can be transferred between hosts</p> Signup and view all the answers

    What is the primary difference between signs and symptoms of a disease?

    <p>Signs can be observed, while symptoms are experienced</p> Signup and view all the answers

    What are sequelae in the context of infectious diseases?

    <p>Long-term consequences that remain after an infection has resolved</p> Signup and view all the answers

    Which term describes the rate of illness due to a disease?

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

    What distinguishes an epidemic from an endemic disease?

    <p>Epidemics occur suddenly in a particular area, while endemics are consistently present</p> Signup and view all the answers

    What information does the Morbidity and Mortality Weekly Report provide?

    <p>Health topics and statistics regarding recent disease outbreaks</p> Signup and view all the answers

    What is a common sign of infection, specifically indicated by the increase in temperature?

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

    Which of the following describes the characteristic response known as immunopathology during an infection?

    <p>The immune system's response can damage host tissues while fighting the infection</p> Signup and view all the answers

    What bacterium was responsible for the Third Pandemic of bubonic plague?

    <p>Yersinia pestis</p> Signup and view all the answers

    Which of the following best defines a pandemic disease?

    <p>An epidemic that spreads worldwide</p> Signup and view all the answers

    What is a characteristic of zoonotic diseases?

    <p>They can be transmitted from animals to humans</p> Signup and view all the answers

    In the context of disease transmission, what is a common feature of spillover events?

    <p>The pathogen does not cause disease in the animal but can in humans</p> Signup and view all the answers

    Which of the following describes the fecal-oral portal of entry for microbial pathogens?

    <p>Entry through the mucosa of the gastrointestinal tract</p> Signup and view all the answers

    What role do animal and insect reservoirs play regarding infectious diseases?

    <p>They may serve as incubators for new infectious diseases</p> Signup and view all the answers

    Which of the following pandemics is noted for killing more than a third of Europe’s population in the fourteenth century?

    <p>The Black Death</p> Signup and view all the answers

    What is the primary method by which the bacterium Yersinia pestis is thought to be transmitted to humans?

    <p>Flea vectors from infected animals</p> Signup and view all the answers

    What does the term 'parenteral' refer to regarding portals of entry for infectious agents?

    <p>Entry via breaks in the skin</p> Signup and view all the answers

    Which of the following is NOT a part of standard precautions designed to protect medical personnel?

    <p>Avoid patient isolation precautions</p> Signup and view all the answers

    What biosafety level (BSL) is associated with high-virulence pathogens that can cause lethal exposure?

    <p>BSL 4</p> Signup and view all the answers

    Among the following factors, which one significantly increases susceptibility to infectious diseases based on age?

    <p>Individuals under 3 and over 60</p> Signup and view all the answers

    Which of the following host factors can impact susceptibility to disease due to inherent biological features?

    <p>Host genetic makeup</p> Signup and view all the answers

    What dietary factors can enhance the immune system's ability to resist infections?

    <p>Good nutrition and moderate exercise</p> Signup and view all the answers

    Which occupation is at higher risk for exposure to infectious agents?

    <p>Agricultural workers</p> Signup and view all the answers

    How does immune status influence the course of infections in hosts?

    <p>It can cause collateral damage to healthy tissues.</p> Signup and view all the answers

    Study Notes

    Chapter 2: Basic Concepts of Infectious Disease

    • The chapter cover infectious diseases, focusing on basic concepts like pathogenicity, virulence, and transmission.
    • The objectives are: describe relationships among a host, microbiome, and pathogens; apply concepts of pathogenesis to specific infections; discuss how infectious diseases impact communities and emerging pathogens.
    • Case study of Brandon, a stockbroker with symptoms of a sexually transmitted disease, syphilis.
    • Syphilis symptoms: small lesion, fluid leakage at the tip of the penis.
    • Diagnostic test: clinical lab found corkscrew-shaped bacteria (Treponema pallidum).
    • Treatment: long-acting penicillin, quick lesion resolution.
    • Contact tracing of Brandon's sexual partners.

    2.1 Normal Microbiota versus Pathogens

    • Objectives: describe differences between normal microbiota and pathogens; relationship between infection and disease, and virulence vs. pathogenicity; infectious dose vs. lethal dose; and attributes of a successful pathogen.
    • Microbes colonize many areas of the human body. This collection is known as human microbiota.
    • Microbes colonizing body surfaces remain attached and replicate.
    • Adhesins allow microbes to attach to host cells.
    • Parasites are microbes that cause harm inducing infections. Two types are ectoparasites and endoparasites.
    • Pathogen: a bacterium, virus, fungus, protozoan, or worm that causes disease in humans.
    • Pathogenicity: a pathogen's ability to cause disease.
    • Infection occurs when a pathogen/parasite enters and begins to grow in a host. Not all infections cause disease.
    • Disease occurs when the infection results in symptoms.
    • Acute infection: rapid symptom development and resolution.
    • Chronic infection: gradual symptom development and resolution. Tuberculosis is an example.
    • Primary pathogens: likely to cause disease after infection.
    • Opportunistic pathogens: less likely to cause disease in a healthy host.
    • Low virulence is a trait of some opportunistic infections.

    2.1 Pathogenesis

    • Virulence describes the severity of harm caused by pathogens.
    • Methods to measure virulence include: Lethal dose (LD50) and Infectious dose (ID50).

    2.1 Pathogenesis

    • Invasion is when a pathogen enters a living cell and lives there.
    • Invasiveness is the ability of a bacterial pathogen to rapidly spread through tissues.

    2.1 Host Range

    • Host range refers to the specific animals a pathogen can infect and cause disease in.
    • Some organisms can infect only one type of host, producing disease in that one host. Salmonella enterica serovar Typhi infects only humans.
    • A broad range of organisms infects many species. Salmonella enterica serovar Typhimurium infects animals but also humans.

    2.2 Basic Concepts of Disease

    • Objectives: distinguish between signs and symptoms of a disease; explain the role of immunopathology in infectious disease; describe the five basic stages of infectious disease.
    • Disease: disruption of normal structure or function of a body part, organ, or system that has recognized symptoms and signs.
    • Infectious disease: a disease caused by a pathogen that can spread from one host to another.
    • Signs of disease are objective markers; symptoms are subjective markers

    2.2 Signs, Symptoms, and Sequelae

    • Diseases are identified by characteristic signs and symptoms. Signs are examined objectively; symptoms are expressed subjectively.
    • Many of the signs and symptoms of a disease are caused by the host's response to infection (immunopathology).
    • Cells can cause damage to nearby host tissue when killing the microbe.
    • Sequelae are pathological consequences after a disease resolves.

    2.2 Stages of Infectious Disease

    • Characteristic stages of acute infectious disease include: incubation phase; prodromal phase, illness phase; decline phase; convalescence phase; and long-term phase.

    2.2 Disease Transmission

    • Public health agencies track disease rates and severity.
    • Morbidity: rate of illness due to a disease.
    • Mortality: rate of death due to a disease.
    • The CDC publishes the Morbidity and Mortality Weekly Report.

    2.3 Infection Cycles and Disease Transmission

    • Objectives: describe complex vs. simple infection cycles; differentiate between endemic, epidemic, and pandemic disease, and animal reservoirs and incubators.
    • Infection cycle: route of transmission between hosts.
    • Horizontal transmission: transfer between hosts.
    • Vertical transmission: transfer from parent to offspring.
    • Endemic disease occurs at a low rate continuously in a community, often in an animal reservoir.
    • Epidemic disease: an increase in the number of cases in a community in a short period.
    • Pandemic disease: a worldwide epidemic.

    2.3 Case Study: Emma Katherine and Rocky Mountain Spotted Fever

    • Emma Katherine developed sickness following a hiking and camping trip to North Carolina.
    • Emma noticed a rash, and the PA suspected RMSF.
    • The tick bite may have been the cause.

    2.4 Zoonotic Diseases

    • Pathogens impacting animals, potentially spreading to humans.
    • Transmission: Direct or indirect "spillover."
    • Lyme disease: pathogen spreads to humans after the tick bite.
    • Ebola: virus present in animals and humans.
    • Animal and insect reservoirs are "incubators" for new diseases. Two different strains of the influenza virus can infect an animal at the same time. The pathogens swap segments of their genomes and develop into a new more dangerous virus.

    2.4 Disease Portals and Biosafety

    • Portals of entry and exit (e.g. respiratory, fecal-oral, skin, urogenital, or parenteral).
    • Biosafety precautions (e.g., proper hand hygiene and PPEs).
    • Different lab settings use various levels of agent containment (BSL 1-4) to protect medical personnel, and others.

    2.5 Host Factors in Disease

    • Host Factors: biological features of humans impacting infections' course.
    • Lifestyle impacting susceptibility to disease (e.g. age, hygiene, diet, and exercise).
    • Existing conditions (e.g., chronic infections, other diseases).
    • Immune status impacting susceptibility to and the outcome of infection.
    • Occupation and exposure increase risk of infection (e.g., healthcare workers, agricultural workers).

    2.6 Global Change and Emerging Infectious Diseases

    • Objective: Explain how civilization has impacted emerging infectious diseases and how climate change alters infectious patterns.
    • Emerging diseases: new diseases recently appearing in populations
    • Reemerging diseases: known diseases increasing in incidence.
    • Human activities bring humans closer to disease reservoirs and vectors, impacting disease increases.

    2. Case Study: The Third Pandemic

    • A historical case study of the Third Pandemic of Bubonic Plague during 1884.
    • Symptoms of the Bubonic Plague: a swollen, dark lesion or "bubo" appeared at first.
    • Spread: through the blood stream in individuals.
    • Transmission: rats housed the bacterium via flea vectors.
    • Several pandemics of plague have occurred over the centuries, including the Black Death.

    2. Are All Infectious Diseases Known to Us?

    Emerging/re-emerging diseases are continually being discovered. Global increases in disease are caused by human activities and interaction with disease vectors and reservoirs. Deforestation may play a role in the spread of infectious diseases.

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    Related Documents

    Lecture 2 Slides: Basic Concepts of Infectious Disease PDF

    Description

    Explore the fundamental principles of infectious diseases in this quiz based on Chapter 2. Understand concepts such as pathogenicity, virulence, and transmission through case studies, including syphilis. Analyze the relationships between the host, microbiome, and pathogens, and how these diseases affect communities.

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