Viral Hemorrhagic Fevers

Question 1

3 main symptoms of VHF

Answer 1

1. Fever and other non specific symptoms (headache, malaise, myalgia, arthralgias, ab pain, nausea, diarrhea)
2. Shock (life threatening, body is not getting enough blood flow)
3. Hemorrhage (itself is rarely life threatening)

Question 2

4 virus families that cause VHF

Answer 2

Arenaviruses (ex: Lassa)
Filoviruses (ex: Ebola)
Bunyaviruses (ex: Hanta)
Flaviviruses (ex: Dengue)

Question 3

2 common features of all VHF virus families

Answer 3

Enveloped

RNA

Question 4

3 Arboviruses that cause hemorrhagic fever

Answer 4

Dengue
Rift Valley fever
Yellow fever

Question 5

Bats are a common vector for which 2 VHF families?

Answer 5

Filoviruses

Bunyaviruses

Question 6

Primary transmission

Answer 6

When activities of infected reservoir hosts or vectors and humans overlap

Question 7

Secondary transmission

Answer 7

Human to human

Question 8

2 VHF families where there is human to human transmission

Answer 8

Filoviruses
Arenaviruses
Mostly droplet or contact

Question 9

Hantavirus

Answer 9

Transmission via aerosol or direct contact
Occasionally seen in Canada
Amplifies in the rodents, its urine and stool gets in the environment, gets dried out and particles can get into the air and inhaled
Indirect transmission
Pulmonary syndrome is the worst

Question 10

Ebola transmission

Answer 10

Direct contact with blood or secretions (urine, feces, seme, breast milk contaminated objects)
Mucosal, breaks in skin, parenteral
Must wear adequate personal protective equipment

Question 11

How do we stop VHFs?

Answer 11

Early diagnosis
Contact tracing
Isolation
Infection prevention and control
Safe burial practices

Question 12

Do patients transmit ebola when they are asymptomatic?

Answer 12

No

Question 13

Ebola non-specific symptoms

Answer 13

Fever
Fatigue
Loss of appetite
Vomiting
Diarrhea
Red Eyes
Unexplained bleeding
Rash (rare)
Cough
Hiccups
Everyone does not get everything

Question 14

Antibody-dependent enhancement

Answer 14

Dengue fever
Antibodies from infection by one serotype can bind and help the virus of a second serotype get into the cell and start replicating faster
Causes a worse disease (hemorrhagic component)

Question 15

VHF diagnosis

Answer 15

Initially based on clinical criteria and judgement, with lab testing used to confirm/exclude diagnosis
RT-PCR and serology available, but have to know what you’re testing for
Test with a panel depending on what is common in the area
Immunohistochemistry in post mortem

Question 16

VHF treatment

Answer 16

In general, no cure or treatment
Supportive care to manage symptoms (rehydration using IV fluids)
Antivirals not effective
Convalescent phase plasma has some success

Question 17

Why are aerosolized VHFs potentially suitable for biological weapons?

Answer 17

Low infectious dose
High morbidity and mortality
Potential for person to person transmission
Effective therapy and vaccines are not available