Epidemiology of viral diseases

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Questions and Answers

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

Identify the risk group that’s at risk of infection from the microorganisms

Risk Group 1 = No or low individual and community risk Risk group 2 = Moderate individual risk, low community risk Risk group 3 = High individual risk, low community risk Risk group 4 = High individual risk, high community risk Signup and view all the answers

Describe what a BSL-4 laboratory is

It’s the maximum containment laboratory. They handle dangerous and exotic pathogens belonging to the highest risk group Signup and view all the answers

Which of the following is NOT a requirement for a BSL-4 containment laboratory?

Sterilization through a single door autoclaving system (D) Signup and view all the answers

What is the primary purpose of maintaining negative air pressure in a BSL-4 laboratory?

To prevent the escape of potentially hazardous microorganisms from the lab (B) Signup and view all the answers

Which risk group do pathogens handled in a maximum containment laboratory belong to?

Risk group 4 (D) Signup and view all the answers

Match the term to the definition

Biohazard = Biological substance that poses a threat to health Biosafety = Containment principles, technologies, and practices implemented to prevent unintentional exposure or realize a pathogen Biosecurity = Protection, control and accountability for valuable biological materials to prevent unauthorized access, loss, theft etc. Aerosol = Very small droplets of fluid that spread via the air Signup and view all the answers

What are the requirements needed to isolate a virus? Why?

The specimen should be collected ASAP after the onset of symptoms (3days). This is when the maximum titer of the virus is present Signup and view all the answers

What are the timing requirements in order to collect the pathogen for serological tests?

Two blood samples are collected. One during the acute and one during the convalescence period (10-14days after first sample) Signup and view all the answers

As a general rule, specimens collected for molecular diagnostics (such as PCR), should be collected during the _ part of the illness.

ASAP; early Signup and view all the answers

What is the function of the Viral transport medium (VTM)?

To keep the swabs in sterile vials Signup and view all the answers

In order to prevent spillage, we need to follow the basic ______ system

Triple packing system Signup and view all the answers

Flashcards

Virus epidemiology

The study of determinants, frequency, dynamics, and distribution of viral diseases in populations.

Importance of viral epidemiology

To predict and control virus transmission in populations.