Infectious Disease Chapter 2 Quiz

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Questions and Answers

What characteristic defines tissue trophism?

A microbe's preferential infection of specific cells. (correct)

A microbe's resistance to antibiotics.

A microbe's capability to cause systemic infection.

A microbe's ability to reproduce rapidly.

Which measure is used to define virulence?

The quantity of microorganisms in a sample.

The ability of a pathogen to infect a host.

The duration of an infection.

The degree of harm caused by a pathogen. (correct)

What does the term 'invasiveness' refer to?

The ability of a pathogen to spread through tissues. (correct)

The survival rate of a pathogen in different environments.

The length of time a pathogen remains dormant.

The resistance of a pathogen to the immune system.

What does a narrow host range signify in terms of a pathogen?

The pathogen is limited to infecting a specific host species. Signup and view all the answers

How is disease defined in the context of human health?

A disruption of normal body structure or function. Signup and view all the answers

What is the purpose of pathogens changing their molecular shape?

To confuse the immune system Signup and view all the answers

During which phase of an infectious disease may a person appear healthy but still be contagious?

Incubation Phase Signup and view all the answers

What typically characterizes the Illness Phase of an infectious disease?

Typical signs and symptoms appear Signup and view all the answers

Which stage of an infectious disease begins when symptoms start to decline?

Decline Phase Signup and view all the answers

What role do siderophores play for pathogenic organisms?

To steal iron from the host's body Signup and view all the answers

In the Prodromal Phase, which symptom can often occur?

Malaise Signup and view all the answers

What is a potential outcome when pathogens secrete proteins that induce apoptosis in immune cells?

Increased pathogen replication Signup and view all the answers

What physiological change typically occurs during the Decline Phase?

Normalization of body temperature Signup and view all the answers

What term describes the ability of a microbe to stay attached to the body surface and replicate?

Colonization Signup and view all the answers

Which of the following statements is true regarding opportunistic pathogens?

They are less likely to cause disease in healthy hosts. Signup and view all the answers

What is the primary difference between acute and chronic infections?

Acute infections resolve rapidly while chronic infections resolve slowly. Signup and view all the answers

What is the term for a state when a microorganism cannot be cultured but may still lead to symptoms?

Latent state Signup and view all the answers

Which of the following is an example of a primary pathogen?

Tuberculosis Signup and view all the answers

How are ectoparasites defined?

Parasites that live on the surface of the host. Signup and view all the answers

What term is used for the ability of an organism to cause disease?

Pathogenicity Signup and view all the answers

Which of the following best describes mutualism?

Both organisms benefit from the interaction. Signup and view all the answers

What is the primary characteristic that defines an infectious disease?

It results from pathogens that can be transmitted between hosts. Signup and view all the answers

Which of the following describes 'signs' in the context of disease?

They can be measured or observed objectively. Signup and view all the answers

What role do adhesins play in the infection process?

They facilitate the adherence of microbes to host cells. Signup and view all the answers

Which of the following best defines 'syndrome'?

A combination of signs and symptoms that result from a specific condition. Signup and view all the answers

What can result from the immune response after an infection is resolved?

Pathological consequences known as sequelae. Signup and view all the answers

What is the primary characteristic of the convalescence phase of a disease?

Symptoms have completely disappeared Signup and view all the answers

What does morbidity refer to in public health terms?

Rate of illness due to a disease Signup and view all the answers

What is immunopathology in relation to infectious diseases?

The impact of the immune response on host tissue during infection. Signup and view all the answers

What is the purpose of immune avoidance strategies employed by pathogens?

To evade the host's immune response. Signup and view all the answers

Which transmission method involves the transfer of an infection directly from one person to another?

Horizontal transmission Signup and view all the answers

Which of these is an example of indirect transmission?

Touching a contaminated surface Signup and view all the answers

What happens during the attachment phase of an infection?

Microbes bind to specific receptors on host cells using adhesins. Signup and view all the answers

An endemic disease is defined as:

A disease that is consistently present in a community at a low rate Signup and view all the answers

What distinguishes a pandemic from an epidemic?

Widespread distribution worldwide Signup and view all the answers

What is a zoonotic disease?

A disease transmitted from animals to humans Signup and view all the answers

Which organism acts as a vehicle for indirect transmission?

Fomites Signup and view all the answers

Study Notes

Normal Microbiota versus Pathogens

The human microbiota consists of all microbes residing on the human body, primarily through commensalism or mutualism.
Commensalism benefits one organism without affecting the other, while mutualism benefits both.
Colonization is the ability of microbes to attach and replicate on host surfaces via adhesins.
Pathogens include bacteria, viruses, fungi, protozoa, or helminths that can cause diseases in humans.
Pathogenicity refers to a microbe's ability to cause infection or disease, while parasites always harm the host.
Ectoparasites live on the host's surface (e.g., Trichophyton rubrum), while endoparasites reside within the host (e.g., cause of elephantiasis).

Pathogenesis Terminology

Infection occurs when pathogens enter a host and grow, often without immediate symptoms.
Disease is characterized by recognizable symptoms arising from infections.
Acute infections present rapid onset and resolution of symptoms (e.g., common cold).
Chronic infections develop gradually with prolonged symptoms (e.g., tuberculosis).
Latent infections exist when pathogens remain dormant until symptoms re-emerge (e.g., herpes virus).

Pathogen Types

Primary pathogens are likely to cause disease in healthy hosts (e.g., tuberculosis).
Opportunistic pathogens are usually harmless but may cause illness in immunocompromised individuals.
Virulence measures the severity of disease caused by pathogens, often assessed by lethal dose (LD50) and infectious dose (ID50).

Microbial Interaction with Host

Invasion involves a pathogen entering host cells for survival.
Invasiveness is the ability of a pathogen to spread rapidly within tissues (e.g., Streptococcus pyogenes).
Host range indicates the diversity of potential hosts a pathogen can infect.

Disease Definition and Symptoms

Disease disrupts normal bodily structure/function, identifiable by specific signs and symptoms.
Signs are observable indicators (e.g., rash, fever), whereas symptoms are felt (e.g., pain, fatigue).
Syndromes represent a collection of signs and symptoms indicating a specific condition.

Host Immune Response

Immunopathology refers to host tissue damage resulting from the immune response against pathogens.
Sequelae are long-term consequences after disease resolution, like heart damage post-streptococcal infection.

Pathogen Strategies

Attachment is aided by adhesins binding to host cell receptors.
Immune avoidance strategies can include changing pathogen structure or secreting deceptive signals.
Nutrient theft, such as siderophores capturing iron, is a strategy utilized by some pathogens.

Stages of Acute Infectious Disease

Incubation Phase: Initial infection until symptoms appear; host may be contagious.
Prodromal Phase: Mild non-specific symptoms occur; host can still spread the microbe.
Illness Phase: Characteristic symptoms manifest; pathogens peak in numbers.
Decline Phase: Symptoms subside as host defenses prevail; body temperature normalizes.
Convalescence Phase: Complete recovery and strength restoration.

Epidemiology of Diseases

Morbidity reflects the illness rate while mortality indicates death rates from diseases.
Modes of transmission encompass both horizontal (person-to-person) and vertical (parent-to-offspring) transmission routes.
Direct contact transmission involves direct physical transfer (e.g., touching, kissing).
Indirect transmission may occur via airborne routes, vehicles (food/water), fomites (inanimate objects), or vectors (e.g., mosquitoes).

Disease Reservoirs and Carriers

Reservoirs are environments or organisms that support pathogen survival without necessarily showing symptoms.
Asymptomatic carriers, like Neisseria meningitidis, can transmit diseases without exhibiting symptoms.

Disease Classification

Endemic disease: Consistently low prevalence within a community, often linked to animal reservoirs.
Epidemic disease: A sudden increase in disease cases within a community.
Pandemic disease: An epidemic that spreads globally (e.g., influenza, HIV, COVID-19).
Zoonotic diseases: Infection cycles involving animal reservoirs that can transmit pathogens to humans.

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Description

Test your knowledge on the basic concepts of infectious diseases as discussed in Chapter 2. Explore the differences between normal microbiota and pathogens, including their interactions and colonization abilities. This quiz will challenge your understanding of these fundamental concepts.