Rabies & other Zoonosis Flashcards
Describe the structure of Rabies
Rhabdovirus family, -ssRNA virus, helical, enveloped
How is Rabies transmitted
By the saliva in the bite or scratch of an infected mammal
Does rabies cross species?
Yes, rabies virus easily crosses species
-Different mammals have different strains of the rabies virus
Is rabies fatal?
Rabies is nearly 100% fatal; only a few cases have survived
Who are the primary carriers of rabies in the US?
Racoons, bats, and skunks. Feral house cats cam also have rabies.
What is the incubation time for rabies?
The further the virus needs to travel in the peripheral nervous system, the longer the incubation time. Once it reaches the dorsal root ganglion, it can move faster
-So, the closer the bite is to your brain, the shorter the incubation time
-On average, 20-90 days but can be years
What is the first thing you should do when exposed to rabies?
-First, wash the wound for 15 min with soap and water and, if possible, a dilute iodine solution
(Goal is to get as much of the virus as possible out of the wound)
-Next, go to the dr right away
If post-exposure prophylaxis is needed, what is that proccess?
-Human Rabies Immunoglobulin (HRIG) is injected into the bite site. If there’s solution remaining, it’s given intramuscularly
-The same day you get HRIG, a shot of rabies vaccine is given at a different site. This vaccine is given on days 3, 7, and 14
-Rabies PEP is close to 100% effective
Where does the rabies virus replicate?
In the muscle near the bite site and then enter the nerves.
-PEP is designed to prevent the virus from transferring to the nerves. Once the virus is in the nerve, it is hidden from the immune system, will travel to the brain, and cause rabies
What kind of vaccine is the rabies vaccine?
Killed virus vaccine
If someone who was previously vaccinated gets exposed to rabies, what should be done?
-Wound needs to be washed and re-vaccination must occur immediately
-HRIG does NOT need to be given. Re-vaccination will cause a substantial boost in antibodies, quickly replacing the HRIG
Describe the structure of Bunyavirus Family-Hantavirus
-ssRNA virus, segmented, helical, enveloped
What animal caries Hantavirus
Different wild rodents
Where is Hantavirus excreted?
-In the rodent’s urine, feces, and perhaps saliva.
How is Hantavirus transmitted?
-Being in areas where there are rodent droppings.
-Breathing in these droppings, contaminated hands touching the face, or by a bite from an infected rodent
-Virus is NOT transmitted from person to person
-This is why you should never sweep up or vacuum rodent droppings but instead wet them down with a disinfectant and use gloves to clean them up
Does Hantavirus infect their rodent hosts?
No, the rodent sheds virus sporadically throughout their life
What syndrome can Hantavirus cause in the US?
-Hantavirus Pulmonary Syndrome (HPS)
Who does HPS affect?
Any age group
-Has a high fatality rate
-Virus can cause rapid fatal edema of the lungs
What syndrome does Hantavirus cause in Asia and Europe
Hemorrhagic Fever with Renal Syndrome (HFRS)
List the different Arenaviruses and their structure
-Lymphocytic choriomeningitis virus (LCMV)
-Lassa virus
-Filovirus
-ssRNA, segmented, helical, enveloped viruses
What animal is LCMV found in?
Some house mice. IT can also be found in pet mice and hamsters if colonies had LCMV infection or they were in contact with wild mice
What can LCMV cause?
-Meningitis
-Miscarriages
-Severe congenital disabilities is infected while pregnant
How is LCMV transmitted?
From mouse urine and droppings, or bites and saliva
What should you do if you see mouse droppings to avoid LCMV exposure?
Treat it the same way as for Hantavirus, do not sweep or vacuum. Instead, wet down with disinfectant for 5 minutes and use gloves to clean up
What animal carries Lassa virus?
Rat found in Africa
What are symptoms of Lassa virus?
-Most people have a mild illness or are asymptomatically infected
-In severe illness, there can be high mortality
-A common sequela is hearing loss
Describe the structure of Filovirus
-ssRNA virus, helical, enveloped
List the two different viruses of Filovirus
Ebola
Marburg
What can both viruses of Filovirus cause?
-Hemorrhagic fevers
-Outbreaks with high mortality
Where do all outbreaks of Ebola and Marburg occur?
Africa
T/F: Ebola is infectious before symptoms begin
False - Ebola is NOT infectious before symptoms
The level of infectiousness increases with illness. The body is very infectious after death
How many Ebola virus particles are needed for infection?
Only 1 to 10
How is Ebola transmitted?
-Ebola needs to enter the mouth, eye, nose, or break in the skin
-Ebola is not aerosolized; you need to have direct contact with the body or fluids from the body
Can you survive Ebola?
-The death rate is very high
-There are now a large number of Ebola survivors, and they can have lingering problems from the infection
The ebola virus is found in the ______ for at least three months and in some much longer
semen
-Infection through sex has occurred
Is there a vaccine for Ebola?
-There is now an FDA-approved vaccine
-It appears to be highly effective
