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General Virology- Exam 4 > Virus Epidemiology > Flashcards

Virus Epidemiology Flashcards

1
Q

Incidence or attack rate

A

frequency of disease over time in a population at risk

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2
Q

Prevalence

A

number of cases in a population at risk at a particular time

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3
Q

Death rates

A

given by cause-specific mortality rate (deaths per year per population at mid-year) or by case-fatality rate (percentage of those with a disease who die from it)

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4
Q

Prevalence of Cytomegalovirus

A

50% approximately

CMV is a very common infection, esp among populations that have poor hygiene.
infects between 50% and 85% of adults in the United States by 40 years of age.

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5
Q

Which place has high CMV prevalence?

A

Barbados have very high rates of cytomegalovirus

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6
Q

What does a positive CMV IgG test indicate?

A

The person has had CMV

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7
Q

Calculate cause-specific mortality rate

A

that die from the disease/ population

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8
Q

Calculate case-fatality rate

A

that die from the disease/ # sick

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9
Q

Hepatitis B prevalence

A

low in the US as a whole, but depends on where you live
intermediate in Russia and parts of Africa
high in most of Africa and east Asia/china

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10
Q

HIV Prevalence

A

Compared with the hepatitis B and C viruses, the human immunodeficiency virus is much less infectious

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11
Q

Prevalence of HIV by transmission type and race

A

48%- men who have sex with men (MSM)
18%- heterosexual females

46%- Black
35%- white

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12
Q

Endemic

A

multiple or continuous transmission within in a population of a limited region.

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13
Q

Epidemics

A

peaks in the occurrence of disease above the endemic or normal level

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14
Q

Incubation period

A

time between infection and presentation of symptoms

The interval between the time of contact and/or entry of the agent and onset of illness (latency period)

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15
Q

Period of infectivity (communicability)

A

usually short in acute viruses and long in chronic infections

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16
Q

Peak incidence of occurrence of severe RSV disease is observed at what age?

A

age 2-8 months

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17
Q

Rhinovirus (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Respiratory
  2. 1-3 days
  3. short
  4. moderate
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18
Q

Respiratory Syncytial Virus (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Respiratory
  2. 2-5 days
  3. short
  4. moderate
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19
Q

Dengue (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Mosquito bite
  2. 5-8 days
  3. short
  4. moderate
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20
Q

Herpes Simplex (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Saliva, Sexual
  2. 6-12 days
  3. long
  4. moderate
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21
Q

Poliomyelitis (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Enteric, Respiratory
  2. 9-12 days
  3. long
  4. low
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22
Q

Parvovirus (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Respiratory, Congenital
  2. 4-20 days
  3. moderate (years in immunosuppressed)
  4. unknown
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23
Q

Adenovirus (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Respiratory, Enteric
  2. 2-14 days
  3. moderate
  4. moderate
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24
Q

Measles (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)

A
  1. Respiratory
  2. 12-14 days
  3. moderate
  4. high
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25
Smallpox (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Respiratory 2. 13-17 days 3. moderate 4. high
26
Mumps (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Respiratory, Saliva 2. 16-20 days 3. moderate 4. moderate
27
Rubella (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Respiratory, Congenital 2. 17-20 days 3. moderate 4. moderate
28
Mononucleosis (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Saliva, parenteral 2. 30-50 days 3. moderate 4. moderate
29
Hepatitis A (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Enteric 2. 15-40 days 3. long 4. low
30
Hepatitis B (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Parenteral, sexual, perinatal 2. 50-150 days 3. very long 4. low
31
Rabies (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Animal bite 2. 30-100 days 3. - 4. high
32
Warts (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. contact, sexual 2. 50-150 days 3. long 4. high
33
AIDS (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Sexual, Parenteral, Congenital 2. 1-10 years 3. very long 4. high
34
Influenza (mode of transportation, incubation period, period of infectivity, clinical to subclinical ratio)
1. Respiratory 2. 1-2 days 3. short 4. moderate
35
Modes of Transportation
1. Person-to-person (respiratory, orogenital, skin) Examples: HIV, measles, HSV 1-2 2. Vector (animals, insects) Examples: rabies, yellow fever 3. Common vehicle (food, water) Examples: Hepatitis 4. Mechanical vectors (personal effects) such as doorknobs, or toothbrushes are called FOMITES
36
Fomites
mechanical vectors
37
Which disease has the longest incubation period?
Rabies
38
Iceberg concept of infection
Clinical disease: moderate severity/mild illness or clinical and severe disease or fatal Subclinical disease: exposure without infection or infection without clinical illness
39
Subclinical to Clinical Ratio of Human Viral Infections
No Symptoms versus clinical symptoms
40
Poliomyelitis (clinical features)
paralysis
41
Epstein barr (clinical features)
Heterophile-positive infectious mononucleosis
42
Hepatitis A (clinical features)
jaundice
43
Rubella (clinical features)
Rash
44
Influenza (clinical features)
fever, cough
45
Measles (clinical features)
rash, fever
46
Rabies (clinical features)
CNS symptoms
47
Sources of Statistical Health Data
Physicians participate in National Disease and Therapeutic Index Hospitals, Public Health Departments and diagnostic laboratories Morbidity and Mortality Weekly Report (MMWR) and Weekly Epidemiology Record Seroepidemiology: obtained using sera from volunteers or "captive volunteer" groups Molecular epidemiology
48
Neuraminidase Inhibitor Resistance Testing Results
Oseltamivir (tamiflu) = 4 resistant viruses in Influenza A (H1N1) Zanamivir= 0 resistant viruses Peramivir= 4 resistant viruses in Influenza A (H1N1)
49
Which hepatitis disease is most reported?
Hepatitis B
50
Types of Epidemiological Investigations
Cross-sectional studies Case-control studies Cohort studies Koch's postulates
51
Cross-sectional studies
prevalence of a virus
52
Case-control studies
determine cause of disease after the case infections have started and therefore it is retrospective also used for drug testing
53
Cohort studies
prospective because a cause has already been identified Volunteers prove viruses cause a disease
54
Koch's postulates
revised by Thomas Rivers showed seroconversion of mice and guinea pigs produced protective antibodies.
55
Types of epidemiological investigations: Vaccine and Drug Trails
Phase 1- determines safety in humans. Phase 2- investigates the immune response. Phase 3- is a large-scale field trial (case vs. controls) Followed by monitoring vaccination effects
56
Virus Horizontal Transmission
``` Direct contact transmission Indirect contact transmission Common vehicle transmission Airborne transmission Arthropod-borne transmission Iatrogenic transmission from instruments Nosocomial transmission from hospital ```
57
Indirect contact transmission
ex: sneezing (respiratory)
58
Vehicle transmission
ex: food or water (hepatitis A)
59
Airborne transmission
ex: influenza
60
Arthropod-borne transmission
ex: dengue, west nile virus
61
Iatrogenic transmission
from instruments | ex: hepatitis B
62
Nosocomial transmission
from hospital | ex: norovirus, measles
63
Which viruses are associated with this mechanism of transmission: Human-to-human, direct droplet, respiratory
Measles, Variola, Varicella, Influenza, Cytomegalovirus
64
Which viruses are associated with this mechanism of transmission: fecal- oral
Polio, Rotavirus, Hepatitis A, Adenovirus, Norovirus
65
Which viruses are associated with this mechanism of transmission: shellfish, water
Hepatitis A, Norovirus
66
Which viruses are associated with this mechanism of transmission: surgical, needle
Rabies, Hepatitis B, HIV
67
Which viruses are associated with this mechanism of transmission: sexual contact
Hepatitis B, Herpesvirus-2, Human T-cell lymphoma, HIV
68
Which viruses are associated with this mechanism of transmission: hand-mouth, hand-conjunctiva
Rhinovirus, Enterovirus
69
Which viruses are associated with this mechanism of transmission: human-to-human from carriers
Hepatitis B, Varicella-zoster
70
Which viruses are associated with this mechanism of transmission: Arthropod to human to arthropod
dengue
71
Which viruses are associated with this mechanism of transmission: Arthropod from animal cycle to human
``` Yellow fever Japanese encephalitis Venezuelan encephalitis St. Louis encephalitis West Nile encephalitis ```
72
Which viruses are associated with this mechanism of transmission: Transovarial in Mosquito
La Crosse encephalitis
73
Which viruses are associated with this mechanism of transmission: Transovarial in Tick
Tick-borne encephalitis
74
Which viruses are associated with this mechanism of transmission: Animal to animal, human is accidental host Droplet (feces, urine, aerosol) Bite
Hantaan virus, rabies, arenavirus | Rabies
75
Which viruses are associated with this mechanism of transmission: Human reservoir transmitted with another virus which is required for replication
Delta agent
76
Specifically Human Infections
Respiratory/salivary: influenza, measles, rhinovirus Fecal-Oral: enterovirus, rotavirus Contact (sexual): herpes simplex 2, genital warts, HIV
77
Zoonoses
Vector (biting arthropod): sandfly fever, dengue Vertebrate reservoir: rabies, cowpox vector-vertebrate: most arbovirus infections
78
Zoonotic Transmission: Orthomyxoviridae- Influenza
Reservoir Host: bird, pigs | Mode of Transmission to Humans:
79
Zoonotic Transmission: Herpesviridae- Herpesvirus B
Reservoir Host: Monkey | Mode of Transmission to Humans: Animal bite
80
Zoonotic Transmission: Poxviridae- Cowpox
Reservoir Host: rodents, cats, cattle | Mode of Transmission to Humans: contact through abrasions
81
Zoonotic Transmission: Poxviridae- Monkeypox
Reservoir Host: squirrel, monkeys | Mode of Transmission to Humans: contact through abrasions
82
Zoonotic Transmission: Poxviridae- Pseudocowpox
Reservoir Host: cattle | Mode of Transmission to Humans: contact through abrasions
83
Zoonotic Transmission: Poxviridae- Orf
Reservoir Host: sheep, goats | Mode of Transmission to Humans: contact through abrasions
84
Zoonotic Transmission: Rhabdoviridae- rabies
Reservoir Host: various mammals | Mode of Transmission to Humans: Animal bite, scratch, respiratory
85
Zoonotic Transmission: Rhabdoviridae- vesicular stomatitis
Reservoir Host: cattle | Mode of Transmission to Humans: contact with secretions
86
Zoonotic Transmission: filovirirda- ebola, marburg
Reservoir Host: ?, Monkey | Mode of Transmission to Humans: Contact- iatrogenic (injection)
87
Zoonotic Transmission: bunyaviridae- hantaan
Reservoir Host: Rodents | Mode of Transmission to Humans: contact with rodent urine
88
Zoonotic Transmission: arenaviridae- Lymphocytic choriomeningitis, Junin, Machupo, Lassa
Reservoir Host: Rodents | Mode of Transmission to Humans: Contact with rodent urine
89
Major Arthropod-Borne Viral Zoonoses: Togaviridae- Alphavirus
``` Diseases: Chikungunya fever Eastern equine encephalitis Western equine encephalitis Venezuelan equine encephalitis Ross River polyarthritis Highlands J virus Sindbis virus O'nyong-nyong virus ``` Arthropod Vector: Mosquitos
90
Major Arthropod-Borne Viral Zoonoses: Flaviviridae- Flavivirus
``` Diseases: Japanese encephalitis St. Louis encephalitis West Nile fever Murray Valley encephalitis Yellow fever Dengue Powassan virus Tick-borne encephalitis ``` Arthropod Vector: mosquitos (expection: tick-borne encephalitis --> ticks)
91
Major Arthropod-Borne Viral Zoonoses: Bunyaviridae- Phlebovirus
Diseases: Rift Valley Fever Sandfly Fever Arthropod Vector: Sandflies Sandflies & midges
92
Major Arthropod-Borne Viral Zoonoses: Bunyaviridae- Orthobunyavirus
``` Diseases: California encephalitis La Crosse encephalitis Bunyamwera virus Oropouche fever ``` Arthropod Vector: mosquitos
93
Major Arthropod-Borne Viral Zoonoses: Reoviridae- Coltivirus
Disease: Colorado tick fever Arthropod Vector: Ticks
94
Major Arthropod-Borne Viral Zoonoses: Reovidirdae- Orbivirus
Diseases: Bluetongue of sheep African Horse Sickness Arthropod Vector: Culicoides, biting midges Culicoides midges, ticks, sandflies and mosquitoes Biting midges Culicoides
95
Virus Vertical Transmission
- Mother to embryo: fetus or newborn child. - Rubella and cytomegalovirus: transplacental to the fetus - Herpes simplex type 2: transmitted through birth canal. - Hepatitis B: transmitted perinatally or postnatally via saliva or milk
96
Acute Self-Limiting Infections
maintained in large and dense populations - Transmissibility - Seasonality - Community size - Effects of immunity types - Antigenic drift, shift, and reassortment
97
Transmissibility
related to virion release from the patient and quantity
98
Seasonality
affects the survival of viruses
99
Community size
determines if acute or persistence infections are perpetuated
100
Persistent Infections
``` Herpesviridae, Adenoviridae, Papillovaviridae, Hepadnaviridae, Arenaviridae, Togaviridae, Flaviviridae, Retroviridae ```
101
Mechanism of Survival
Vertical Transmission: Arenaviruses, herpesviruses, retroviruses and some togaviruses
102
Transovarial transmission
allows arboviruses to persist in insect hosts

General Virology- Exam 4 (1 decks)

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