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Virology > Week 3 - Lecture 9 > Flashcards

Week 3 - Lecture 9 Flashcards

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1
Q

Epidemiology =
Demos =
Logos =

A

epi= on/upon, people, knowledge
demos = state
logos = word/thought/principle

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2
Q

Zoonotic = ?
Most zoonoses are ?

A

Backzoonoses = binary direction of virus (from human to animal and animal to human).
RNA viruses

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3
Q
A
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4
Q

Each vector has a certain virus that they transmit.
E.g. mosquito –> west nile virus, Equine encephalitis, etc.
Mode of transmission types: ?

A

Direct contact, vector, food, etc.

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5
Q
  1. Secretion from animal
  2. Transfer to susceptible host
  3. Replication within new host
  4. Excretion from new host
A
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6
Q
A
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7
Q
A
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8
Q

List the host factors that impact viral diseases

A

-Age, Gender
-Immune status
-Vaccination status
-Reproductive status
- Genetics

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9
Q

List the environmental factors that impact viral diseases

A

-Geography
-UV light
-Climate
-Organic matter
-Season
-Ammonia concentration
-Water activity

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10
Q

List the agent/pathogen factors that impact viral diseases

A

-Dose
-Virulence
-Infectivity
-Pathogenicity

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11
Q

What are the objectives of studying viral epidemiology??

A

To identity the causative agent of viral disease and the relevant risk factors
• To assess the severity of viral disease appeared in certain animal/human population
• To study the natural history and outcomes of some viral disease of interest
• To evaluate the efficacy and potency of some preventive and therapeutic strategies against
some viral diseases

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12
Q

What is the benefit of using epidemiology in viral diseases?

A

• To study the cause (or etiology) of disease(s), or conditions, disorders, etc.
• To determine the primary agent responsible for some viral diseases
• To determine the characteristics of the viral diseases or and other causative factors
• To determine the mode of transmission of viral diseases
• To determine the contributing factors to viral infection
• To identify and determine geographic patterns of the viral diseases

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13
Q
A

Asymptomatic person could be the most important chain in the transmission cycle b/c you do not know if you are shedding the pathogen into the environment and that pathogen is then transmitted to immunocompromised.

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14
Q
A
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15
Q

• Endemic = _______:
Presence of ____ or _____ chains of transmission resulting in ______ occurrence of diseases in a
population over a period of time.

A

Enzootic, several, continuous, continuous

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16
Q

• Epidemic = _____:
The peaks in diseases incidences which ______ the endemic ____ ____ or expected incidence of diseases

A

Epizootic, exceed, base line

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17
Q

• Pandemic = _____
Very extensive _____ ____ (SARS-CoV-2, H1N1, etc)

A

Panzootic, worldwide, epidemic

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18
Q

Incubation period: the ___ intervals between the _____ and the appearance of the _____ ____ on the affected
host

A

time, infection, clinical signs

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19
Q

Sero-epidemiology: using ______ ____ as basis for epidemiologic investigations.

A

serological data

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20
Q

Molecular epidemiology: using ______ ___ as basis for epidemiologic investigations

A

molecular data

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21
Q

Morbidity rate: the percentage of animals in population that develop ______ ____ out of the total number of the population

A

clinical signs

100 animals, 20% of them develop clinical signs while the rest are not. 20% morbidity rate.

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22
Q

Mortality rate: the percentage of ____ animals from viral infection in relation to the _______ number of _____

A

dead, total, population

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23
Q

What is descriptive epidemiology?

A

-Studies that generate hypotheses and
answer the following questions
-Who?
-What?
-When?
-Where?
is the disease or infection

-Person, Animal, Place, and time

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24
Q

What is analytical epidemiology?

A

-Studies that carried out to test for
hypotheses and to generate conclusions
on the particular disease.
-answer the following questions
-Why
-How
is the disease or infection

-Use to identify the cause of a viral
disease or an outbreak with virus

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25
Epidemiology Surveillance Cycle
All countries monitor "hot" diseases so they can strategize how to deal with these viruses in event of an outbreak.
26
What does this image demonstrate?
Curve starting from 0 --> peak --> declining = epidemic curve After treatment, curve declines
27
What are the aims of epidemiological surveillance in viral diseases?
• To help in the discovery and controlling the transmission of viral infectious diseases • To help in the prevention and control programs for the viral infectious diseases
28
Describe active public health surveillance types
Local or state health departments initiate the collection of information from laboratories, physicians, health care providers, or the general population. Achieves more complete and accurate reporting than passive surveillance Ex: Youth Risk Behavior Surveillance surveys
29
Describe passive public health surveillance types
Laboratories, physicians, or others regularly report cases of disease or death to the local or state health department Examples -A doctor’s office reports 2 cases of measles -A nursing home reports an unusual number of older patients with unexplained rashes
30
Describe syndromic public health surveillance types
The ongoing, systematic collection, analysis, interpretation, and application of real-time indicators for disease that allow for detection before public health authorities might otherwise identify them Example: Hospital admittance records
31
List the types of epidemiologic investigations
Case-control studies (retrospective) Cohort studies (prospective or longitudinal) Cross-sectional studies Long-term herd studies
32
Describe case-control studies (?)
retroperspective -Investigation starts after the diseases episode starts -Used to identify the cause of disease outbreak -Use the existing data and less expensive -Requires careful selection of the control groups matching the subject group -Unit of interest is individual animals or aggregates (herds/flocks)
33
Describe cohort studies (?)
prospective or longitudinal -Investigation starts with a presumed diseases episode -Requires creation of new data and records -Requires careful selection of control group to be as similar/close to the exposed group with absence of any contact with the causative agent -Very expensive due to long term followup until disuses is detected in the population -Proof of cause-effect relationship is very strong -It may progresses into cross sectional or longitudinal studies
34
Describe cross-sectional studies
-The cause of specific diseases is known -Can be carried out relatively quickly by the serology or virus identification -Provides data on the prevalence of virus infection in a population in specific area
35
Describe long-term herd studies
-Provides info about presence and continued activity of virus in given area -Could be run as series of cross sectional studies -Can be designed to produce data on the efficacy of some vaccines and drugs
36
E.g. you have a case of the flu, you develop symptoms such as coughing, sneezing. Siblings and parents will eventually develop similar symptoms. Body is shedding the virus --> spread. **Don't be worried about examples.** Some organisms can be carriers but show no clinical signs. Carriers that have virus forever pose a risk to everyone around them. Some carriers act as a reservoir host.
37
Name the routes of viral shedding
Oral Fecal Milk Skin Urogenital tract Respiratory
38
Oral -Rabies execrated in **saliva** of infected animal. Saliva rich in virus Either as a source of infection or ideal sample site collection.
39
Fecal - Especially Enteric viruses that cause GI disturbance execrated in high titters in feces Ex: BCoV
40
Milk -Some viruses excreted in milk during viremia EX-1 FMDV EX-2 BLV
41
Skin -Scabs from skin lesions very rich with virus in case of Poxvirus -Feather follicles of chickens are very rich with MDV
42
Urogenital tract -Some viruses excreted in urine and genital secretions during viremia Ex: Herpesviruses, vulvovaginitis, etc. - Virus is shed in urogenital tract - Splashing of fluids into mucosa can infect you or other animals around.
43
Respiratory Coughing, sneezing, halation of discharges from nose and mouth of infected animal
44
Particles larger than ____ um fall out of suspensions and contaminate the environment. Smaller particles rapidly dehydrated to form droplet nuclei of 10 um or less, which remain airborne which can be inhaled by a susceptible animal
100
45
visualization using light refraction caused by differences in air density) of a human cough
46
Flash photo of a human sneeze Droplet size helps us determine size of virus and what organs they will affect in the body, how far they will travel, etc. Each droplet has billions of viral particles. In case of COVID, wear mask/PPE to reduce transmission.
47
Know difference between direct or indirectly.
Carry virus on clothes/shoes = Example of indirect vehicle borne? Mechanical?: insect or fly injects sucks blood of infected animal and injects healthy animal.
48
Vertical transmission: parent to offspring through germ plasma, placenta, milk, eggs. Horizontal transmission: direct, indirect, vector borne
49
List the epidemiological based antiviral control strategies
1. Quarantine procedures 2. Sanitation procedures 3. Wildlife control 4. Vector control 5. Vaccines
50
Quarantine procedures: restriction of the _____ of virus infection including: ?
source A- Prohibition/restrictions importation of livestock and animals from certain areas where exotic diseases spread B- Quarantine and testing of the imported livestock at the portal of entry C- Restrictions of the animal movements during the epidemics D- Keep the closed herds strategies to avoid the introduction of any viral infections
51
What are the common methods of viral inactivation?
Heat UV irradiation Ionizing irradiation pH extremes Desiccation
52
Explain how heat can inactivate a virus
- High temp has deleterious effects on most viruses - protein impacted by temperature; envelope, core protein, etc. - Low temp has preservation effects on viruses
53
Explain how UV irradiation can inactivate a virus.
Some viruses destroyed when exposed to sunlight while UV irradiation has weak penetration effects
54
Explain how ionizing irradiation can inactivate a virus.
Inactivates viruses rapidly and has very strong penetration Ex: Gamma irradiation used to sterilize disposable syringes and needles
55
Explain how desiccation can inactivate a virus.
Most viruses rapidly destroyed by drying except Poxvirus
56
Explain how pH extremes can inactivate a virus.
Most viruses inactivated by pH less than 4 and greater than 9. Ideal pH = neutral Viruses that can grow in stomach, GI tract can tolerate pH extremes.
57
List the common chemical viral disinfectants
Chlorine and iodine Formaldehyde Phenolic compounds Caustic Soda 70% alcohol Chlorohexidine hibitane Detergents
58
How does chlorine and iodine kill viruses
-Hypochlorite: cheap but rapidly inactivated by organic matters -Iodophores: more stale, less corrosive, more expensive
59
How does formaldehyde kill viruses?
Reliable antiviral but hazardous due to toxicity -Glutraldhyde: useful but more expensive
60
How do phenolic compounds kill viruses?
-Although widely used commercial disinfectants, it is not reliable in case of enveloped viruses
61
How does caustic soda kill viruses?
-Effective against many viruses -Relatively inexpensive -Corrosive
62
How does 70% alcohol kill viruses?
-Good antiviral disinfectant -its use restricted by the coast to small scale procedures as disinfection of instruments
63
How does chlorohexidine hibitane kill viruses?
-Unreliable against nonenveloped viruses
64
How do detergents kill viruses?
-Useful as cleaning agents but are effective against enveloped viruses only
65
What are the objectives of sanitation procedures?
Objectives: To reduce the spread of viral infections including A- Slaughtering then safe disposal of the carcases by incineration or burial of the infected animals B- Hygienic disposal of the foodstuffs, bedding and animal manures C- Disinfection of buildings and surfaces
66
What are the objectives of wildlife control?
Objectives: To restrict the sources of infection by reducing the risk of exposure of domestic animals to the reservoir hosts A- Keeping the live stocks in houses B- Fencing of pastures C- Destruction/vaccination of the wildlife (Ex: Rabies virus)
67
What are the objectives of vector control?
Objectives: To reduce the potential risk of spread of viral infections by insect vectors A- Apply insect proofing an control barns B- Dipping or spraying of animals with appropriate insecticides to control ticks, fleas, and lice C- Environmental spraying with larvicides to control mosquitoes
68
Surveillance of animal diseases provides ?
information about the diseases (prevalence, incidence, epizootic spread etc)
69
What is a notifiable disease?
-Veterinarians have to report the prevalence of some viral disease to the local veterinary authorities. -Local veterinary authorities/country must inform the World Organization for Animal Health (OIE) about the prevalence of some viral diseases - The OIE may notify the neighbouring countries and the world community about the prevalence of some diseases in certain region/country • The OIE has listed the notifiable diseases on its website and in regular brochures
70
What are sources of surveillance data?
-Notifiable diseases reports -Laboratory based surveillance -Population based surveillance
71
Describe the early phase of the discover to control continuum.
-Identify the major parameters of epizootic potential (mortality rates, severity, transmissibility) -Discovery of new diseases in its host population -Zoonotic diseases handled by Vet Practitioner -Epidemiologic field investigation -Etiologic investigation: to identify the causative virus of the outbreak -Diagnostic development: to develop some laboratory tests that enable the sensitive, accurate and specific detection of the causative virus
72
Describe the intermediate phase of the discover to control continuum.
-Expansion of many elements Focusing research about the etiology of this outbreak (vector biology, zoonosis) -Training, outreach, continuing education and public education -Risk communication using the common methods as internet, TV, radio, media Technology transfer (diagnostic, vaccine sanitation and vector control) vaccine sanitation and vector control) -Commercialization of diagnostic and vaccines from research to production in large scale
73
Describe the late phase of the discover to control continuum.
-Animal health development system -Special clinical system -Development of public infrastructure system -Largest epidemic may require test and slaughtering, restrict movement -Involvement of international agencies
74
What are the steps of a viral disease outbreak investigation
75
Surveillance, control measures, vaccines --> reduce number of cases. Measles mostly belongs to paramyxovirus Millions of cases at first, then ided causative agent, vaccinated people, cases dropped in the 80s and 90s and now there are no active cases.
76
same pattern as measles also present in mumps
77
Infected Zone: Minimum __ ___ radius of the infected premises
3 km
78
Buffer Zone: The area between ___ ___ and __ ____ of the infected premises will be considered the buffer zone
3 km, 10 km
79
Control Zone: _____ and ____ zone
Infected, buffer
80
Surveillance Zone: at least __ ___ and may be wider
10 km
81
What are the recommended measures for the control of HPAI-Farm level?
• Keep poultry away from areas frequented by wild fowl • keep control over access to poultry houses by people and equipment • Maintain sanitation of property, poultry houses and equipment • Appropriate disposal of manure and dead poultry • Generally ‘stamping out’ (culling) to eradicate the disease • Appropriate disposal of carcasses and all animal
82
Describe HPAI-Control Poultry Carcass Management
Burial : fast and cheap, but concerns about environment increasing -Burry the dead carcasses and overlaid with lime stone Incineration: several types of incineration units were used with varying degrees of success
83

Virology (17 decks)

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