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IAHI Block 3 > Emerging Viruses > Flashcards

Flashcards in Emerging Viruses Deck (31)
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1
Q

What percentage of human morbidity and mortality derive from infectious disease?

A

25%

2
Q

Factors contributing to the emergence of new virus disease

A
  • Increased population and population density
  • Increased travel
  • Changes in social behavior
  • Changes in environment
  • Changes in industry/technology
  • Changes in microorganisms (mutation)
3
Q

Changes in demographics - Population growth

A

World population reached 6 billion on Oct 11, 2000

300 million in US on Oct 17, 2006

4
Q

Production and distribution of _____ ______ broadened the distribution of HIV/AIDS

A

blood products

5
Q

____ and ____ are clear examples where travel was an important facilitator of disease spread

A

SARS; HIV

6
Q

Changes in behavior

A
  • Promiscuous sex
  • Intravenous drug use
  • Increased antibiotic/antiviral use
  • Increased use of day care
7
Q

Changes in the environment

A

Climate change
Population movement into new territories
Habitat destruction

8
Q

Changes in the virus

A
  • Mutation of surface molecules
  • Mutation to antigenic difference so prior immunity is no longer effective
  • Mutation to make it more pathogenic
  • Mutation to antiviral resistance
  • Change due to reassortment of segmented genomes
9
Q

Hantavirus - characterized by:

A
Fever
Hemorrhage
5-10% mortality
Headache
Acute renal failure
10
Q

Hantavirus in four corners area of US
Disease:
Emergence:
Host:

A

Disease: Pulmonary syndrome, pulmonary edema, shock, death
Emergence: due to High rainfall; plentiful food, increased mouse population
Host: deer mouse

11
Q

Number of cases of Hantavirus pulmonary syndrome
2012 cases:
Fatality rate:
Last noted outbreak:

A

2012 cases: 29
Fatality rate: 30-50%
Last noted outbreak: Yosemite Park

12
Q

Arbovirus (Arthropod Borne) cause three general types of disease…

A

Fever + maculopapular rash
Encephalitis
Hemorrhagic fever

13
Q

West Nile and Dengue (Arboviruses) characteristics

A
  • Flaviviruses
  • Enveloped ss (+)RNA, replicate similar to other such viruses
  • West Nile causes mild ‘fever’ or serious encephalitis
  • Dengue causes ‘fever’ or more serious hemorrhagic fever and dengue shock syndrome
14
Q

Emergence of Arboviruses:

A

Due to increased range of vector (dengue) or introduction of virus reservoir (bird, human, mosquito) into a new area

15
Q

Describe the origin of West Nile Virus starting in the Bronx Zoo…

A

In 1999, unusual deaths of exotic birds in Bronx Zoo
Crows/jays in NYC area
Birds and Culex Pipiens mosquitoes tested positive
Not long after, human cases noted

16
Q

Which year was the worst year in terms of West Nile Cases?

A

2003: 9862 cases; 264 fatalities

17
Q

Why did West Nile Virus increase in the US in 2012?

A
Unknown
Possibly weather (mild winter and hot summer)
Less water so more bird/bug interaction
18
Q

Transmission and Maintenance of Arboviral encephalitis

A

Virus reservoir in birds (in US, crows and Jays most affected by WNV)
Arthropod serves as vector to transmit from bird to bird
Horse or human - usually dead end hosts, viremia low and not transmitted back to vector

19
Q

Clinical features of West Nile Fever:

Severe Disease:

A

Clinical features of West Nile Fever: fever, fatigue, swollen lymph glands, headache, rash, eye pain
Severe Disease: Meningitis, Encephalitis, GI symptoms, Seizures, Change in mental status

20
Q

Diagnosis of WNV infection

A

High index of clinical suspicion and results of lab tests

  • Consider in adults > 50 years of age or older with unexplained encephalitis or meningitis in late summer/fall
  • Local WNV activity in area (dead birds)
  • Vaccine available for horses
  • Vaccine for humans in development
21
Q

Dengue virus - Hemorrhagic Fever

A

Dengue (a Flavivirus)

  • 4 serotypes
  • Mosquito transmission from human or monkey
  • Causes dengue fever or “breakbone fever” - muscle/bone pain, joint pain, lymphadenopathy
22
Q

Dengue hemorrhagic fever and Dengue shock syndrome

A
  • Occurs when individual antibodies against one serotype is infected with another serotype
  • Non-neutralizing Ab thought to increase infection of Macs, release of inflammatory cytokines
  • Causes rupture of vasculature, internal bleeding, plasma loss, and shock
  • DHF/DSS on rise due to import of serotypes in new areas
23
Q

Why are non-neutralizing antibodies to a first infection with Dengue virus harmful upon second infection

A

Cause inappropriate immune response to virus

Infected monocytes release vasoactive mediators and increase vascular permeability - hemorrhage

24
Q

Diagnosis of Dengue hemorrhagic fever

A

Positive tourniquet test (>20 petechiae/inch^2)
Virus antigen detection
- ELISA to detect antibodies
- Tetravalent vaccine being developed

25
Q

Dengue is spreading due to re-emergence of the ______ _______

A

vector mosquito

26
Q

Key to Dengue virus prevention

A

Vector control

27
Q

Monkeypox

A
  • Relatively rare disease occurring mostly in Africa
  • Monkeypox was first isolated in 1958 in lab monkeys - later shown in African squirrel
  • Virus a member of Poxvirus family
  • First human case in 1970 (not generally fatal)
28
Q

Path of transmission of Monkeypox (animals)

A

African squirrel → African Rats → Prairie Dogs → Transmission to pet owners

29
Q

Path of transmission of Monkeypox (states)

A

Texas → Iowa → Illinois → Wisconsin

30
Q
Monkeypox
Incubation time:
Symptoms:
Vaccine:
Reason for emergence:
A

Incubation time: about 12 days
Symptoms: fever, headache, muscle aches, backache
Vaccine: smallpox vaccine (shares antigenicity)
Reason for emergence: Change in behavior (pet choice) and movement of virus (and reservoir) into new areas as a result of commerce

31
Q
HIV emergence
Environment:
Population:
Lifestyle changes:
Poverty:
Travel:
Sex trade:
Technology:
A

Environment: transfer of HIV from chimp to human
Population: often spurred by war
Lifestyle changes: Loss of traditional cultures, more sex partners
Poverty: Commercial sex trade
Travel: The flight attendant who had 100s of sex partners
Sex trade: in Asia - exported exposures to other Countries
Technology: Infected blood products from US