Exam #7: Zoonotic/ Exotic Viruses Flashcards
What is a zoonoses?
Disease of vertebrate animals that can be transmitted to man
- Can be direct or through an insect vector
What is an arboviral disease?
Disease that has an insect vector i.e. arthropod borne viruses
What is the general lifecycle of the arboviruses?
- Bird natural host
- Mosquito intermediate
- Mosquito bites humans & infects
What is the most common arbovirus in the US?
West Nile Virus
What does WNV cause?
- Febrile illness
- Encephalitis in man & horses
~50% lead to encephalitis
When are WNV most commonly seen?
Summer-Fall when mosquitoes are most prevalent & people are outside
When has person-to-person transmission of WNV been seen?
- Blood transfusion & organ transplant
- Breast feeding
What is West Nile Fever?
A summertime flu-like illness seen in ~20% of those infected with WNV
*Most infections are asymptomatic
What percentage of the population develops WNV neurological disease? What patient population is this most common in?
<1% of individuals & mostly elderly
*Thus, the greatest risk factor for WNV encephalitis or noninvasive disease is age
How is WNV diagnosed?
History–WNV or other arboviral disease should be strongly considered in adults >50 years who develop unexplained encephalitis or meningitis in the summer or early fall
- CSF
- Serology
What is the treatment for WNV?
Supportive therapy
Is there a vaccine for WNV?
NOT in humans, but there is one for horses
What is St. Louis Encephalitis Virus?
- Prior to WNV, considered a major cause of arbovirus encephalitis in the US
How is SLE transmitted?
Mosquitoes
What symptoms are caused by SLE?
- Mild disease with fever & headache
- Severe disease with more typical meningitis symptoms, paralysis, and fatality
How is SLE prevented & supported?
No vaccine
Supportive treatment
What is Japanese Encephalitis Virus?
Leading cause of viral encephalitis in Asia
What are Eastern, Western, & Venezuelan Encephalitis Viruses?
Togaviruses/ alphaviruses
When is EEV most common?
Summer & fall, maybe precipitated by horse endemic
What are the symptoms of EEV?
Sudden onset fever Myalgia Headache Seizures Coma
How does WEV differ from the other arboviruses?
Most severe in young children instead of adults
What is LaCrosse encephalitis virus?
Bunyavirus (Hantavirus)
What is the unique feature of the Lacrosse encephalitis virus?
Most common in rodents & tree squirrels
Where is Rabies not seen?
Australia
Great Britain
Hawaii
How is rabies transmitted?
Via saliva of infected animals
- Bite
- Contamination of mucous membranes
- Aerosol
- Transplant
Describe the mechanism of action of Rabies.
- Inoculation
- Virus enters peripheral nerve & is transported to the CNS
- Flu-like symptoms
- Dissemination
- Behavioral change
- Hydrophobia
- Coma & death
How is Rabies prevented? How is it treated?
Vaccination of animals and high risk individuals (post-exposure prophylaxis & IgG)
How is Rabies diagnosed?
- Virus isolation or serology
- Negri bodies in infected neurons
What is LCMV?
Lymphocytic Choriomeningitis Virus
How is LCMV transmitted?
Inhalation of infectious aerosolized particles in rodent urine, feces, or saliva
- From common house mouse
- Person-to-person transmission has not been reported
What are the symptoms of LCMV?
Biphasic:
1) Febrile illness
2) Remission
3) Febrile illness
*Greatest concern in pregnant females
What are prion diseases?
Slowly developing neurodegenerative diseases that are thought to be caused by a family of viruses known as “slow viruses,” now known to be caused by prions–small infectious proteins
List the prion diseases.
Kuru
CJD
GSS
FFI
What is the mechanism of prion disease?
Prions induce abnormal aggregation
