Arboviruses Flashcards
What are the two families of Arboviruses?
Family Togaviridae and Family Flaviviridae
Arboviruses=
Arthropod Borne
Describe the structure of a family togaviridae virus
Enveloped, icosahedral capsid symmetry, ssRNA genome
Family Togaviridae contains which virus?
Equine encephalitis viruses
What is the reservoir of infection for equine encephalitis viruses?
Birds, small mammals, and horses
How are equine encephalitis viruses transmitted?
Via Aedes and Culex mosquitos
Are humans a good host for equine encephalitis viruses?
No, because they are a dead end host
What are the symptoms of equine encephalitis viruses? and who can have more serious symptoms?
Many cases result in flu like symptoms but children are more likely to have severe clinical symptoms than adults
Can the Equine encephalitis virus cause death?
Death results frequently when there is clinical disease
Family Flaviviridae has which 4 viruses/(fevers)?
West nile virus
Yellow fever
Dengue fever
Dengue Hemorrhagic fever
What are the symptoms of 75% of people who beocme infected with West Nile Virus?
They show no symptoms and mount a successful immune attack against the virus
What happens to 20% of people who decome infected with West Nile Fever?
They have symptoms such as fever, headache, and body aches, nausea, vomiting
What happens to 1 in 150 people who become infected with West Nile virus?
They develop severe meningoencephalitis
What is the natural reservoir for West Nile virus?
Birds
How is West Nile virus transmitted?
By mosquitoes
Where does Yellow fever occur?
Africa and South America
How is Yellow Fever transmitted?
Aedes aegypti mosquito
In some cases there is involvement of which internal organs with a Yellow fever infection?
Liver, kidneys, and the heart
Describe the progression of Yellow Fever in terms of symptoms
- Hemorrhage from the digestive tract, later the disease is sometimes complicated by jaundice with liver failure and/or renal insufficiency
- Then delirium, seizures, and coma ensure
- Mortality is around 5%, historically it has been much higher
What did Walter Reed do in regards to Yellow Fever?
He proved the theory, first set forth by Dr. Carlos in 1881, that yellow fever is transmitted by mosquitoes rather than direct contact
What is the treatment for Yellow fever?
None
How is Yellow Fever controlled?
Eradicate(control) mosquito population
Live attenuated vaccine- a single dose confers immunity lasting 10yrs or more
What is Dengue fever caused by?
4 different arboviruses
How is dengue fever transmitted?
By the bite of the Aedes aegypti(yellow fever mosquito)
What does a person with Dengue fever under go?
The fever is generally self limited and although uncomfortable is not fatal
How does Dengue Hemorrhagic fever occur?
When someone with immunity to one type of Dengue virus is infected by a different type
Dengue Hemorrhagic fever serious?
Yes, it is a severe potentially fatal infection
