What type of viruses are most of the viral hemorrhagic fevers?
Reservoirs of most viral hemorrhagic fevers
Rats, bats for ebola and Marburg. Note that the host usually does not become ill even though humans do.
A patient presents with fever, bruising on his arms, muscle aches and GI hemorrhage. What is your differential diagnosis?
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).
Treatment for viral hemorrhagic fever
Limit needle sticks, supportive care, correct coagulopathies, ribavirin (arena and bunyaviruses).
Vaccines for VHFs?
Junin (weaponized Argentine hemorrhagic fever) and yellow fever virus.
Ebola and Marburg virus types
-ssRNA: needs RNA-dependent RNA polymerase to make mRNA.
Bunyavirus transmitted by ticks and humans that causes VHF. What type of virus is it?
Crimean-Congo Hemorrhagic Fever (CCHF). Circular ambisense segmented RNA virus.
1/2 of genome is +ssRNA and 1/2 of genome is -ssRNA
Arenaviruses transmitted by aerosolized rodent urine/saliva/feces that cause VHF.
Lassa fever and South American Hemorrhagic Fever. Note that Lassa is particularly concerning because there is clear human to human transmission (secretions).
How did the arenaviruses get their name?
When they bud from the host cell they bring ribosomes with them and look sandy.
Common complications of Lassa virus
3rd trimester abortion and hearing loss
Treatment for Lassa virus
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?
Lassa fever virus.
Largest virus there is
Poxvirus (small pox)
Small pox features
Complex, dsDNA, resistant to inactivation and replicates in CYTOPLASM.
Host of small pox
What distinguishes small pox blisters from any other vesicular lesion?
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)
Key factors that enabled eradication of small pox
No animal reservoir, no recurrent infection, one serotype, effective vaccine, no subclinical infection
Treatment for adverse reactions associated with small pox vaccines
hVIG (human Vaccinia Immune Globulin)
Absolute contraindication for receiving the small pox vaccine