Rabies and Other Zoonotic Viruses Flashcards
What type of virus is rabies?
- family: rhabdovirus
- -ssRNA
- helical
- enveloped
How is rabies transmitted?
- saliva in bite or scratch of an infected mammal (also if in contact with neuronal matter)
T/F: Rabies cross species easily
True!
- different mammals have different strains of rabies virus but they easily cross species
What is the fatality of rabies?
- 100% fatal
What are the primary carriers of rabies in the US?
- raccoons, bats, skunks and some feral house cats
How long is the incubation time for rabies?
- depends where it was bitten: the further the virus needs to travel in PNS, the longer the incubation time
- once it reaches the DRG, the faster it can move
incubation time: 20-90 days
What to do for post exposure prophylaxis of rabies?
- wash wound for 15 min with soap and water and with dilute iodine solution
- go to the doctor
- post exposure prophylaxis: human rabies immunoglobulin is injected into bite and intramuscularly
- rabies vaccine is given at a different site than the rabies immunoglobulin
- vaccine is repeated on ays 3, 7, and 14
close to 100% effective
What to do for post exposure prophylaxis
Why is post-exposure prophylaxis important to prevent virus from transferring to nerves?
- once the virus is nerve, it is hidden from immune system and can travel to the brain
What is the rabies vaccine?
- killed virus vaccine
- given to vets, people working in wild animal preserves, cavers (due to bats)
- if these people are bitten, they don’t need the human rabies immunoglobulin, but they still need to wash the wound and get re-vaccinated
What type of virus is the hantavirus?
- family: bunyavirus
- –ssRNA
- segmented
- helical
- enveloped
How is hantavirus transmitted?
- virus is excreted in rodent’s urine, feces, and saliva
- most transmission events occur by being in areas where there are rodent dropping and breathing in these droppings, touching face with contaminated hands, or a bite from an infected rodent
What should you do when cleaning rodent droppings?
- wet them down with disinfectant and use gloves to clean up
T/F: Hantavirus doesn’t cause disease in their rodent hosts
True!
- the rodent sheds virus sporadically throughout life
What is Hantavirus Pulmonary Syndrome?
- acute respiratory distress, causing rapid fatal edema of lungs
- high fatality rate (60-70%)
- some can also cause hemorrhagic fever with renal disease too
What type of virus is arenavirus?
- -ssRNA
- segmented
- helical
- enveloped
What can Arenavirus cause?
- lymphocytic choriomeningitis virus
- lassa virus
What is lymphocytic choriomeningitis virus?
- found in some house mice
- can cause meningitis
- can cause miscarriages or severe congenital disabilities if infected while pregnant
- transmitted from mouse using and droppings, or bites and saliva
Exposure to which animal causes most rabies cases in the US and the world?
US: bats
world: dogs
What is Lassa virus?
- rat found in Africa spreads Lassa fever
- most people have mild illness or are asymptomatic
- if severe, high fatality
- common is hearing loss
What type of virus is Filovirus?
- -ssRNA
- helical
- enveloped
What are the 2 different viruses of Filovirus?
- ebola
- marburg
- both can cause hemorrhagic fevers and both can cause outbreaks with high mortality
- all outbreaks occur in Africa
T/F: Ebola is infectious before symptoms
False!
- Ebola is NOT infectious before symptoms
- the level of infectiousness increases with illness and body is very infectious after death (only 1 to 10 virus particles required to cause infection)
How is Ebola transmitted?
- must enter mouth, eye, nose, or break in the skin
- must have direct contact with body or fluids… NOT aerosolized
- virus is also found in semen for at least 3 months and can cause infection through sex
What is the fatality of Ebola?
- pretty high (39% for last outbreak but can go up to 90%)
- larger number of Ebola survivors but can have lingering problems
T/F: There is no vaccine for Ebola
False!
- there is a vaccine: Zaire strain and appears to be highly effective