Microbiology-Viral Bioterroism Agents

Question 1

What type of viruses are most of the viral hemorrhagic fevers?

Answer 1

RNA

Question 2

Reservoirs of most viral hemorrhagic fevers

Answer 2

Rats, bats for ebola and Marburg. Note that the host usually does not become ill even though humans do.

Question 3

A patient presents with fever, bruising on his arms, muscle aches and GI hemorrhage. What is your differential diagnosis?

Answer 3

VHF (arena, bunya, filo and flaviviruses), Bacterial (typhoid, rickettsioses, leptospirosis, meningococcemia, N. meningitides. E. coli 0157 H7), Protozoa (falciparum malaria) and other (Hemolytic uremic syndrome, vasculitis, heat stroke).

Question 4

Treatment for viral hemorrhagic fever

Answer 4

Limit needle sticks, supportive care, correct coagulopathies, ribavirin (arena and bunyaviruses).

Question 5

Vaccines for VHFs?

Answer 5

Junin (weaponized Argentine hemorrhagic fever) and yellow fever virus.

Question 6

Ebola and Marburg virus types

Answer 6

-ssRNA: needs RNA-dependent RNA polymerase to make mRNA.

Question 7

Bunyavirus transmitted by ticks and humans that causes VHF. What type of virus is it?

Answer 7

Crimean-Congo Hemorrhagic Fever (CCHF). Circular ambisense segmented RNA virus.

Question 8

1/2 of genome is +ssRNA and 1/2 of genome is -ssRNA

Answer 8

Ambisense

Question 9

Arenaviruses transmitted by aerosolized rodent urine/saliva/feces that cause VHF.

Answer 9

Lassa fever and South American Hemorrhagic Fever. Note that Lassa is particularly concerning because there is clear human to human transmission (secretions).

Question 10

How did the arenaviruses get their name?

Answer 10

When they bud from the host cell they bring ribosomes with them and look sandy.

Question 11

Common complications of Lassa virus

Answer 11

3rd trimester abortion and hearing loss

Question 12

Treatment for Lassa virus

Answer 12

Ribavirin

Question 13

A patient presents with fever, chills and multiple joint pain. He spent 5 days in a village in Africa with dead rats around. On day 5 oral, conjunctival and petechial hemorrhages are present. 2 other patients in the ward are affected. What is the likely agent?

Answer 13

Lassa fever virus.

Question 14

Largest virus there is

Answer 14

Poxvirus (small pox)

Question 15

Small pox features

Answer 15

Complex, dsDNA, resistant to inactivation and replicates in CYTOPLASM.

Question 16

Host of small pox

Answer 16

Human only

Question 17

What distinguishes small pox blisters from any other vesicular lesion?

Answer 17

No region is spared (chicken pox spares hands/feet) and all lesions are at same stage of disease (chicken pox has all at different stages of disease)

Question 18

Key factors that enabled eradication of small pox

Answer 18

No animal reservoir, no recurrent infection, one serotype, effective vaccine, no subclinical infection

Question 19

Treatment for adverse reactions associated with small pox vaccines

Answer 19

hVIG (human Vaccinia Immune Globulin)

Question 20

Absolute contraindication for receiving the small pox vaccine

Answer 20

Eczema