Iahi: 3.7 - Emerging Viruses

Front 1

What viral families are "emerging viruses"?

Back 1

- Bunyaviruses (Hantaviruses)
- Flaviviruses (West Nile Virus and Dengue Virus)
- Poxviruses (Monkeypox)

Front 2

What are the characteristics of Hantavirus? Type?

Back 2

- Bunyavirus (Hanta- hunter for bunnies)
- (-)ssRNA helical
- Hemorrhagic fever, pneumonia
- Fatality rate: 30-50%

Front 3

Which animal is associated with Hantavirus (Bunyavirus)?

Back 3

- Deer mouse
- Transmitted to humans by close contact or aerosolized virus from droppings or urine
- Emerged due to increased contact w/ mice d/t: high rainfall, plentiful food, increased mouse population

Front 4

How can you control infection of Hantavirus (Bunyavirus)?

Back 4

Decrease contact with rodents

Front 5

Which emerging viruses are in the Flavivirus family? Type?

Back 5

- West Nile Virus
- Dengue
- +ssRNA (icosahedral and enveloped
* ARthropod-BOrne = ARBOviruses = transmitted by mosquitoes, ticks)

Front 6

What are the symptoms of West Nile Virus? Type?

Back 6

- Flavivirus and ARBOvirus (transmitted by mosquitoes)
* Mild "fever" or serious encephalitis (may be asymptomatic)
- Fever, fatigue, swollen lymph glands, headache, skin rash on trunk, eye pain
- Severe: meningitis or encephalitis

Front 7

What are the symptoms of Dengue Virus? Type?

Back 7

- Flavivirus and ARBOvirus (transmitted by mosquitoes)
* "Fever" or more serious hemorrhagic fever and Dengue shock syndrome
- Breakbone fever - bone pain, joint pain
- Lymphadenopathy

Front 8

Why are West Nile Virus and Dengue virus emerging viruses?

Back 8

Increased range of vector (Dengue) or introduction of virus reservoir (mosquito) into a new area (West Nile)

Front 9

What is the natural reservoir of arboviruses (West Nile and Dengue)?

Back 9

- Birds - but mosquitos are the vector that transmits from bird to bird or human or horse
- Humans and Horses are dead-end hosts

Front 10

What features may help lead to a West Nile Virus diagnosis?

Back 10

- Clinical suspicion and lab tests
- WNV more likely in adults >50 yo, w/ unexplained encephalitis or meningitis in late summer/fall
- Local WNV activity (dead birds suggests may infect humans soon)

Front 11

How do you get Dengue Fever?

Back 11

** Individual with antibodies against one serotype is infected with another serotype
- Non-neutralizing Ab from 1st serotype reacts with 2nd serotype
- Increases infection of macrophages, release of inflammatory cytokines
- Leads to rupture of vasculature (hemorrhagic fever), internal bleeding, plasma loss, and shock (10-40% mortality)

Front 12

What features may help lead to a Dengue Hemorrhagic Fever / Virus diagnosis?

Back 12

- Positive tourniquet test --> leads to petechiae due to capillary fragility
- Virus antigen detection (immunofluorescence and ELISA)

Front 13

Why is Dengue virus spreading?

Back 13

Re-emergence of vector mosquito (vector control is key to prevention)

Front 14

What kind of virus is Monkeypox?

Back 14

Poxvirus (DS linear DNA - largest DNA virus)

Front 15

How do humans get infected with Monkeypox?

Back 15

Spread from monkeys to African squirrel
---> to African rats
---> to Prairie dogs (pets)
---> to Pet owners

Front 16

How long does Monkeypox incubate? Symptoms?

Back 16

- 12 day incubation
- Fever, headache, muscle aches, backache, swollen lymph nodes, fatigue
** 1-3 days after fever starts, rash develops (raised bumps filled w/ fluid, then crusts, scabs, and scab falls off
- Lasts 2-4 weeks

Front 17

How can Monkeypox be controlled? Why?

Back 17

- Smallpox vaccine
- Share antigenicity