4th exam part 1

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Questions and Answers

Which type of epidemic is characterized by spread from one person to another?

Propagated epidemic (correct)

Cyclical epidemic

Point source epidemic

Common source epidemic

What is a key characteristic of a common source epidemic?

Origins from contaminated food or water (correct)

Multiple exposure over time

Transmission during seasonal changes

Person-to-person spread

Which type of epidemic arises due to seasonal activities?

Seasonal epidemic (correct)

Common source epidemic

Cyclical epidemic

Propagated epidemic

What can be a reservoir of infection for seasonal diseases?

Human carriers Signup and view all the answers

In the context of disease severity, which term best describes an outbreak that occurs suddenly and affects many individuals rapidly?

Epidemic Signup and view all the answers

Which of the following represents a point source epidemic?

Outbreak from a contaminated food item Signup and view all the answers

How can cyclical epidemics best be described?

They repeat patterns over time Signup and view all the answers

What characterizes a common-source epidemic?

A rapid rise in cases suggesting exposure to a single source Signup and view all the answers

Which of the following describes a propagated epidemic?

It shows a slow rise in cases from person to person. Signup and view all the answers

How can seasonal epidemics be best described?

They are linked directly to changes in climate or environmental factors. Signup and view all the answers

What is the first case in a propagated epidemic referred to as?

Index case Signup and view all the answers

Which of the following statements regarding the pathogen-host relationship is accurate?

All pathogens require a host for transmission. Signup and view all the answers

Which of the following best describes reservoirs of infection?

Reservoirs can include animals, humans, and environmental sources. Signup and view all the answers

What is a significant factor in differentiating between types of epidemics?

The nature of the transmission method used by the pathogen. Signup and view all the answers

Which of these best describes how a common-source epidemic can be identified?

By identifying a sudden surge in cases related to a single exposure. Signup and view all the answers

What type of epidemic is characterized by cases that are contagious and spread from person to person?

Propagated epidemic Signup and view all the answers

What type of disease is characterized by being easily spread from one host to another?

Communicable disease Signup and view all the answers

How is an epidemic disease defined?

A disease that appears above normal endemic levels Signup and view all the answers

What is the key difference between incidence and prevalence in epidemiology?

Incidence refers to the rate of disease spread in a population over time. Signup and view all the answers

Which term describes a disease that is constantly present in a specific population?

Endemic disease Signup and view all the answers

What distinguishes a contagious disease from a communicable disease?

Contagious diseases are easily spread between hosts. Signup and view all the answers

What is a characteristic of an outbreak?

It is localized and affects many hosts in a short time. Signup and view all the answers

In the context of disease classification, what best defines a pandemic?

A disease that spreads across multiple countries or continents Signup and view all the answers

What is an example of a noncommunicable disease?

Diabetes Signup and view all the answers

What defines a syndrome in the context of disease?

A specific group of signs and symptoms associated with a disease. Signup and view all the answers

Study Notes

Viral Epidemiology

Viruses reproduce within host cells—either productively or latently.
Productive infection leads to the production of more viruses and cell lysis, releasing the virions.
Latent infection involves the viral genome becoming part of the host cell's DNA, replicating as a plasmid.
Viral infectiousness often categorized by transmission route.

Classification of Animal Viruses

Enteric viruses are typically transmitted via the fecal-oral route and often cause gastroenteritis.
Respiratory viruses spread through inhaled infected respiratory droplets, commonly remaining localized in the respiratory tract.
Zoonotic viruses spread from animals to humans through animal vectors.
Sexually transmitted viruses can cause genital lesions or systemic infections.

Interactions of Animal Viruses with Their Host

The outcome of viral infection depends on factors independent of the host's cell defense mechanisms.
Viruses can establish balanced pathogenicity with the host, causing no obvious disease or damage.
Acute infection is characterized by a brief duration, potential for long-lasting immunity, and the production of large numbers of viruses.
- Disease symptoms arise from tissue damage, infection of new cells, and viral reproduction.
- Viral reproduction cycle is similar to virulent bacteriophages, with steps including attachment, entry, targeting reproduction sites, uncoating, nucleic acid replication, protein coat removal, maturation, cell lysis and spreading through host.
Persistent infections are characterized by the continuous presence of the virus in the host. These infections can be categorized as latent, chronic, or slow.
- Latent infections involve a period of dormancy, the virus typically lying dormant in the host until reactivation.
- Chronic infections involve the continuous presence of the infectious virus in the host throughout the infection period. Presence of disease symptoms can be present or absent during the infection.
- Slow infections are characterized by a gradual increase in the amount of infectious agent, with a long asymptomatic period before symptoms become significant.

Epidemiology Tools

Notifiable diseases are tracked through national surveillance systems like the CDC.
Active and passive surveillance methods involve systematic surveys of populations and disease presence. Active surveillance establishes sentinel sites and observes animals and vectors.

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Description

This quiz covers key concepts in viral epidemiology, including how viruses reproduce within host cells, the classification of different animal viruses based on transmission routes, and the interactions between viruses and their hosts. Test your understanding of these fundamental topics related to viral infections and their spread.