Arboviruses (1) Flashcards
(44 cards)
What are arboviruses?
A group of viruses that are transmitted by arthropod vectors.
They are all RNA viruses
What are the 4 types of clinical syndromes of the mosquito- borne viruses?
1- Systemic febrile illness
2- Fever with arthritis
3- Encephalitis
4- Hemorrhagic fever
What are the 4 viruses that cause systemic febrile illness?
Chicungunya, O’nyong-nyong, Ross River, and Dengue
What are the 3 viruses that cause fever with arthritis?
Chicungunya, O’nyong-nyong, and Ross River
What are the 6 viruses that cause encephalitis?
JE, VEE, EEE, WEE, MVE, West nile virus
What 4 viruses cause hemorrhagic fever?
Yellow fever, Dengue, Rift Vally Fever, Chikungunya
What is the family and genera of the EEE virus?
Family= Togaviridae
Genera= alphavirus
What are the 4 members of the alpha virus family?
EEE (eastern USA), WEE (western USA), VEE (south america and north america), and everglades
Which alpha virus has the highest probability of developing encephalitis? The lowest probability?
EEE- highest
VEE- lowest
What are the mortality rate associated with EEE, WEE and VEE?
WEE: 5%
VEE: 35%
EEE: 50%
Describe the transmission cycle of EEE?
The host is birds, and the vector is mosquitos. Humans are horses are incidental hosts.
What are the symptoms of EEE?
Usually present in AUGUST. Fever, headache, mental status changes, stiff neck.
Family and genome of Japanese Encephalitis virus?
Family: Flavaviridiae
Genome: ssRNA (+)
T/F: There is more than 1 serotype for JE virus?
False…it circulates as 1 serotype but has 5 different genotypes.
What is the vector for JE? Also describe some characteristics of the vector.
Culex mosquitos.
Night feeders that live in rice fields, marshes and small collections of water. They are prevalent in the rainy season. They pass on their virus to other mosquitos vertically and sexually.
Natural hosts of the JE virus?
Pig and migrating birds and domestic fowl
What is special about the pig host of JE?
Prolonged and high titer viremia which is asymptomatic.
Accidental hosts of JE?
Humans and horses
What are the two transmission patterns of JE?
Seasonal transmission (april- july): prevalent in japan, china, taiwan, korea, n. vietnam, and thailand
Year round transmission: S. vietnam, thailand, india, indonesia, malaysia, philippines, sri lanka
Incidence and deaths per year of JE?
50,000 cases per year
10, 000 deaths per year.
These numbers are underreported though.
Incubation period of JE virus?
6-16 days
How long does the JE prodrome last and what are the symptoms?
2-3 days
Headache, fever, chills, anorexia, N/V, dizziness
How long does acute JE last and what are the symptoms?
3-4 days
High fevers, seizures, dull flat mask like faces, unblinking eyes, tremor, hypertonia, abnormal behavior, acute flaccid paralysis
How long does subacute JE and convalescence last? What are the symptoms?
Subacute: 7-10 days
Convalescence: 4- 7 weeks
Symptoms: tremors, paresis, incoordination, pathogenic reflexes, lip smacking, rapidly changing CNS