Epidemiology of viral diseases

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What is the primary focus of virus epidemiology?

The molecular structure of viruses

The determinants, frequency, dynamics, and distribution of viral diseases in populations (correct)

The genetic evolution of viruses

The immune response of individual hosts

Why is the study of viral epidemiology important?

To determine viral taxonomy

To enhance viral replication in laboratory settings

To increase viral mutation rates

To predict and control virus transmission in populations (correct)

The risk of viral infection in a population is influenced by which of the following factors?

Characteristics of the virus

The host and host population

Environmental and ecological factors affecting virus transmission

All of the above (correct)

Which of the following is NOT a factor that influences virus transmission?

The number of mitochondria in host cells (D) Signup and view all the answers

What is one of the primary roles of epidemiology in viral diseases?

Identifying the role of viruses in disease etiology (A) Signup and view all the answers

How does epidemiology help in understanding viral diseases?

By determining factors affecting host susceptibility (A) Signup and view all the answers

Which of the following is NOT a function of viral epidemiology?

Modifying viral genetic material for medical purposes (D) Signup and view all the answers

What is a key benefit of epidemiological studies in viral disease outbreaks?

Providing early warning systems and tracking disease spread (A) Signup and view all the answers

What does case fatality rate measure?

The number of deaths among clinically ill animals (B) Signup and view all the answers

How does mortality rate differ from case fatality rate?

Mortality rate counts deaths among all animals (sick or healthy), while case fatality rate considers only those that were clinically ill (B) Signup and view all the answers

What does morbidity rate measure?

The percentage of animals with clinical signs of disease (B) Signup and view all the answers

What is the key difference between incidence and prevalence?

Incidence counts the number of new cases that occur over a specific period of time, while prevalence includes all infected individuals (old and new cases) at a particular point in time (C) Signup and view all the answers

Which type of carrier sheds the virus during the incubation period before symptoms appear?

Incubatory carrier (D) Signup and view all the answers

Why are inapparent carriers considered the worst type of carriers?

They shed virus without any signs of illness, making detection and control difficult (B) Signup and view all the answers

A viral disease that occurs occasionally, randomly, and in scattered instances is classified as

Sporadic (C) Signup and view all the answers

Which term describes a viral disease that is consistently present in a specific geographic area or population group?

Enzootic (C) Signup and view all the answers

A disease that is not known to occur in a particular country or region is classified as:

Exotic (A) Signup and view all the answers

What defines a contagious disease?

A disease that spreads from one organism to another by direct or indirect contact (B) Signup and view all the answers

What does the "period of contagiousness" refer to?

The time when an infected animal sheds the virus and can infect others (B) Signup and view all the answers

What is the primary focus of seroepidemiology?

Using serological data to investigate epidemiology (B) Signup and view all the answers

What is the key distinction between droplet transmission and airborne transmission?

Droplet transmission occurs at a distance of less than 1 meter, while airborne transmission occurs at a distance of more than 1 meter (D) Signup and view all the answers

What is the term for viral transmission via arthropods?

Arbovirus transmission (C) Signup and view all the answers

A sneeze or a cough is considered airborne

False (B) Signup and view all the answers

What is the main characteristic of an enzootic (sylvatic or jungle) transmission cycle?

Viral transmission between wild animals and insect vectors (B) Signup and view all the answers

Which transmission cycle involves viral transmission between domestic animals and insect vectors?

Epizootic cycle (B) Signup and view all the answers

What defines an "urban cycle" of viral transmission?

Virus transmission between humans and insect vectors (A) Signup and view all the answers

What is an "amplifying host" in viral transmission?

A host that increases viral concentration to a level where an insect vector can spread the virus (B) Signup and view all the answers

What is a "dead-end host" in viral transmission?

A host that cannot transmit the virus to another organism (A) Signup and view all the answers

What is the role of a "bridge vector" in viral transmission?

It acquires a virus from an infected wild animal and transmits it to humans or other secondary hosts (A) Signup and view all the answers

What are the stages of illness in virology?

Incubation period, prodromal, acute, decline, convalescent Signup and view all the answers

What occurs during the incubation period of an illness?

The infection has entered the body, but no clinical signs have appeared yet (A) Signup and view all the answers

During which stage of illness do the first non-specific symptoms appear?

Incubation period (A) Signup and view all the answers

What characterizes the acute period of illness?

Severe and specific clinical signs are at their peak (C) Signup and view all the answers

What happens during the decline stage of illness?

Clinical signs begin to subside (C) Signup and view all the answers