Epidemiology of Viral Diseases Flashcards
The study of determinants, frequency, dynamics, and distribution of viral diseases in populations is referred to as Virus _________.
Epidemiology
The risk of infection and/or disease in an animal or animal population is determined by what?
1) Characteristics of the virus (i.e. genetic variation)
2) The host and host population (i.e. passive, innate and acquired resistance)
3) Behavioral, environmental, and ecological factors that affect virus transmission from one host to another.
All of the following are roles of epidemiology in viral diseases EXCEPT:
A. To identify and/ or clarify the role of viruses in etiology of diseases
B. Understanding the interaction of viruses with environmental determinants of disease
C. Determining factors affecting host susceptibility
D. In unraveling modes of viral disease transmission
E. Studying the impacts of viral disease on health, economy and society
F. Studying role of infectious pathogens in the pathogenesis of chronic non- communicable diseases, such as oncogenic viruses in cancer
G. In large- scale testing of vaccines and drugs, i.e. clinical trials
H. All of the above are roles of epidemiology in viral diseases.
H. All of the above are roles of epidemiology in viral diseases.
How does Understanding Epidemiology of Viral Disease help?
A. Advances our understanding of the nature of diseases
B. Altering and directing disease treatments, control and prevention activities
C. Providing early warning systems and tracking of a disease
D. Assessment of the economic and social impacts of a disease
E. Assessment of the efficacy and cost of disease control and prevention programs
F. All of the above
F. All of the above
In an animal population of 100 there are 25 sick animals, 10 of the sick animals die, therefore, 40% of sick animals die. This is an example of which of the following? A. Mortality Rate B. Morbidity Rate C. Case Fatality Rate D. Morality Rate
C. Case Fatality Rate
–It is the number (%) of deaths among the clinically ill animals.
There is 100 animals in a population, of which 25 are sick, 10 animals die within the whole population in a 4 months period of time. Therefore, 10% of the population died. This is an example of which of the following? A. Mortality Rate B. Morbidity Rate C. Case Fatality Rate D. Morality Rate
A. Mortality rate
–The number (%) of animals in a population that die from a particular disease over a specified period of time.
There is 100 animals in a population, of which 25 are infected with the same virus. Of those 25 infected only 10 show clinical signs of the being infected over a 2 week period of time. This is an example of which of the following? A. Mortality Rate B. Morbidity Rate C. Case Fatality Rate D. Morality Rate
B. Morbidity Rate
–The morbidity rate is the percentage of animals in a population that develop clinical signs attributable to a particular virus over a defined period of time (commonly the duration of an outbreak)
It is the number (%) of deaths among the clinically ill animals.
Case Fatality Rate
The number (%) of animals in a population that die from a particular disease over a specified period of time.
Mortality rate
The percentage of animals in a population that develop clinical signs attributable to a particular virus over a defined period of time (commonly the duration of an outbreak)
Morbidity Rate
The number of new cases that occur in a population over a specified period of time.
Incidence
__________ = (number of cases x 10^n) / (population at risk) - IN A SPECIFIED PERIOD OF TIME
Incidence rate
___________ rate is the measure of the occurrence of infection or disease in a population over time. – for example, a month or a year, and is especially useful for describing acute diseases of short duration.
Incidence
T/F: The incidence rate not at a specific period of time
FASLE!!
– The incidence rate is in a specific period of time!
The number of occurrences of disease (old and new cases), infection, and or related attributes (antibodies) in a population, at a particular point of time.
Prevalence
_____________ = (number of cases x 10^n) / (population at risk) AT A PARTICULAR POINT OF TIME
Prevalence
Viral disease occurring occasionally, singly, or in scattered instances, and in an irregular and haphazard manner. This is the definition of: A. Panzootic Viral Diseases B. Enzootic Viral Diseases C. Epizootic Viral Diseases D. Sporadic Viral Diseases
D. Sporadic Viral Diseases
The CONSTANT presence of a viral disease within a given geographic area or population group. This is the definition of: A. Panzootic Viral Diseases B. Enzootic Viral Diseases C. Epizootic Viral Diseases D. Sporadic Viral Diseases
B Enzootic Viral Disease
–Endemic in humans
The occurrence of more cases of viral diseases than expected in a given area or among a specific group of people/ animals over a PARTICULAR period of time. Refers to peaks in desease incidence that exceed the endemic/ enzootic baseline or expected incidence of disease. This is the definition of: A. Panzootic Viral Diseases B. Enzootic Viral Diseases C. Epizootic Viral Diseases D. Sporadic Viral Diseases
C. Epizootic Viral Disease
–Endemic in humans
A virus epidemic occurring over a very WIDE AREA (several countries or continents) and usually affecting a large proportion of the population. This is the definition of: A. Panzootic Viral Diseases B. Enzootic Viral Diseases C. Epizootic Viral Diseases D. Sporadic Viral Diseases
A. Panzootic Viral Diseases
– Pandemic in humans
Animals that have contracted an infectious viral disease, but display no clinical symptoms. They shed virus, transmitting disease to others, and the shedding of the virus may be continuous or intermittent. This all describes a _____________ carrier.
Asymptomatic
_____________ disease= a disease that is spread form one person or organism to another by direct or indirect contact.
Contagious
Period _____________ refers to the time during which an infected animal sheds the virus.
Contagiousness
__________ disease= a disease not known to occur in a particular country or geographical area.
Exotic
In a(n) __________ host the level of virus can become high enough that an insect vector such as a mosquito that feeds on it will probably become infectious.
Amplifying
____A_______ host or ____B______ host: A host from which infectious agents are not transmitted to other susceptible hosts. They do not develop sufficient viremia to be picked up by the insect vectors.
A. Dead- end Host
B. Incidental Host
______________ is a method that simply denies the use of serological data as the basis of epidemiological investigation, as determined by diagnostic serological techniques.
Seroepidemiology
T/F: Molecular epidemiology of viruses uses molecular biological data as the basis of of epidemiological investigation of viral diseases.
True
Which of the following is NOT a way viruses can be transmitted? A. Horizontal B. Zoonotic C. Vertical D. Lateral
D. Lateral
__________ transmission is defined as the spread of an infectious agent from one person/ animal or group to another person/ animal or group.
Horizontal
Contact trasmissione is the spread of infectious agent by ____A____ or ___B_____ contact.
A. Direct
B. Indirect
________ contact: involves actual physical contact between an infected animal and a susceptible animal. This category also includes sexual contact.
Direct
Bites, Coitus, Licking and droplet transmission are examples of what kind of contact?
Direct
Transmission of virus in droplet nuclei (saliva or mucus) that travel less than _____ meter, from the source to the susceptible host is considered to be direct contact.
One
What are the two ways in which viruses are spread via indirect contact?
1) Airborne transmission—spread of infectious agent by droplet nuclei in DUST that travels more than one meter, sometimes for miles, from the source to the susceptible host.
2) Fomites (Inanimate objects)
An inanimate object or substance that is contaminated with the infectious agent and is capable of transmitting infectious organisms from one individual to another, is the definition of ?
Fomites
All of the following are routes of horizontal transmission EXCEPT:
A. Contact transmission (direct or indirect)
B. Vector transmission (aka arthropod - borne transmission)
C. Vehicle- borne transmission (aka common- vehicle transmission)
D. Iatrogenic Transmission
E. Transmission from Dam to embryo
F. Nosocomial Infection
E. Transmission from Dam to embryo
— transmission from dam to embryo is an example of vertical transmission not horizontal transmission.
Arthropods vectors carry the viruses from the infected host to susceptible host in _______ transmission.
Vector
What are the two types of vector transmission?
1) Biological
2) Mechanical
Passive transport of the infectious agent on the feet or other body parts of the arthropod vector. Is this Biological or Mechanical vector transmission?
Mechanical
Infectious agent undergoes either a necessary part of its life cycle, or multiplication, in the vector before transmission to susceptible host. Is this Biological or Mechanical vector transmission?
Biological
Arboviruses are a class of virus transmitted to humans by arthropods such as mosquitoes and ticks. The vector is needed to transmit the virus, therefore this is an example of what type of transmission?
Biological Vector Transmission
All of the following are types of transmission cycles of arboviruses EXCEPT?
A. Enzootic Cycle (Sylvatic or Jungle Cycle)
B. Epizootic Cycle (Rural Cycle)
C. Sporadic Cycle
D. Urban Cycle
C. Sporadic cycle
The natural transmission of virus between wild animals/ birds (vertebrate hosts) and primary insect vectors. This is what type of Arbovirus transmission cycle?
A. Enzootic Cycle (Sylvatic or Jungle Cycle)
B. Epizootic Cycle (Rural Cycle)
C. Sporadic Cycle
D. Urban Cycle
A. Enzootic Cycle (Sylvatic or Jungle Cycle)
The virus is transmitted between non- wild or domestic animals and the primary or accessory insect vectors. This is what type of Arbovirus transmission cycle?
A. Enzootic Cycle (Sylvatic or Jungle Cycle)
B. Epizootic Cycle (Rural Cycle)
C. Sporadic Cycle
D. Urban Cycle
B. Epizootic Cycle (Rural Cycle)
The virus cycles between humans and insect vectors. This is what type of Arbovirus transmission cycle?
A. Enzootic Cycle (Sylvatic or Jungle Cycle)
B. Epizootic Cycle (Rural Cycle)
C. Sporadic Cycle
D. Urban Cycle
D. Urban Cycle
What type of horizontal transmission includes fecal contamination of food and water supplies (fecal- oral transmission) and virus- contaminated meat or bone products.
Vehicle- borne Transmission aka Common- vehicle transmission.
What type of horizontal transmission is an infection that is transferred during medial or surgical practice?
Iatrogenic Transmission
In which two ways can Iatrogenic Transmission occur?
1) Introduction of pathogens by CONTAMINATED INSTRUMENTS (non- sterile surgical instruments, syringes), or CONTAMINATED BODY SURFACE (inadequate handwashing)— example spread of equine infectious anemia virus via multiple use syringes and needles.
2) Introduction of pathogen through CONTAMINATED PROPHYLACTIC or THERAPEUTIC PREPARATIONS.
If you use the same syringes and needles over and over causing the spread of equine infectious anemia virus- this is an example of what type of transmission?
Iatrogenic Transmission
What type of horizontal transmission can occur while an animal is in a veterinary hospital or clinic?
Nosocomial Infection
_________ transmission is used to describe infection that is transferred from dam to embryo, or fetus, or newborn before, during, or shorty after parturition.
Vertical
All of the following are examples of Vertical transmission EXCEPT: A. Milk B. Mosquito C. Colostrum D. Fecal contamination of teats
B. Mosquito
–mosquito is apart of horizontal transmission.
_________ transmission describes infections that are transmissible from animals to humans.
Zoonotic
T/F: Viruses transmitted by the RESPIRATORY ROUTE have LOW environmental STABILITY, whereas those transmitted by the FECAL- ORAL ROUTE have a HIGHER STABILITY in the environment.
True.
–If a virus can last long enough in fecal matter to wait for an animal to come consume it, it has higher environmental stability then a virus that need to get into a host very quickly via respiratory route.
_________ immunity is a form of immunity that occurs when the vaccination of a significant, large, portion of a population (or herd) provides a measure of protection for individuals who have not developed immunity.
Herd
What is the course of a typical infectious disease?
1) Incubation Period
2) Prodromal Period
3) Acute Period
4) Decline Period
5) Convalescent Period
Which period refers to the interval between infection and the onset of clinical signs? (in many diseases there is a period of during which animals are infectious before they become sick). A) Incubation Period B) Prodromal Period C) Acute Period D) Decline Period E) Convalescent Period
A) Incubation Period
Which period refers to the first signs and feeling of illness after incubation period? (The period of early symptoms of a disease occurring after the incubation period and just before the appearance of the characteristic symptoms of the disease). A) Incubation Period B) Prodromal Period C) Acute Period D) Decline Period E) Convalescent Period
B) Prodromal Period
Which period refers to when the disease is at its height and there are severe clinical signs? A) Incubation Period B) Prodromal Period C) Acute Period D) Decline Period E) Convalescent Period
C) Acute Period
Which period refers to when clinical signs begin to subside? A) Incubation Period B) Prodromal Period C) Acute Period D) Decline Period E) Convalescent Period
D) Decline Period
Which period refers to when the body gradually returns to its pre-disease state, and health is restored? A) Incubation Period B) Prodromal Period C) Acute Period D) Decline Period E) Convalescent Period
E) Convalescent Period
