Arbovirus Flashcards
What is arbovirus?
Virus that spread by arthropod vectors
Humans can serve as…
dead-end host, accidental host, or they can be maintenance reservoir
What are the three types of arboviruses?
Flavivirus, Togavirus, and Bunyavirus
What are the tests used to diagnose arbovirus infections?
Serology: ELISA, Complement Fixation Test (CFT)
Culture
Animal Inoculation
Direct detection test: detection of antigen and nucleic acids (PCR)
What is the treatment for arbovirus infection?
Treatment for most infections is supportive only.
In haemorrhagic fevers, bleeding may require phytonadione (vitamin K1)
Transfusion of packed RBCs or fresh frozen plasma
Why are aspirin and other NSAIDs contraindicated (avoided)?
Because of antiplatelet activity
What are the preventions?
Surveillance
Vector control: proper clothing, using insect repellents
Vaccine: only available for JE and YF
Flavivirus. Humans are dead-end hosts, as they do not develop high concentrations of the virus in their bloodstream to infect feeding. Transmission: The virus is maintained in a cycle between mosquitoes and vertebrate hosts, primarily pigs and wading birds.
Japanese Encephalitis (JE)
Initial symptoms: fever, headache, vomiting, encephalitis
Mental status changes, neurologic symptoms, seizures are common, especially among children, neck stiffness, and paralysis or muscle weakness.
JE
What is the diagnosis and treatment for JE?
Detection of IgM antibodies in serum or cerebrospinal fluid. Positive IgM antibodies indicate past infection or vaccination.
No treatment is available, and hospitalization for supportive care and close observation is generally required.
Inactivated Vero cell culture-derived JE vaccine is mainly used. It is recommended for travellers who plan to spend 1 month or more in endemic. Two dose series will be given 28 days apart. The last dose should be given at least 1 week before travel.
Belongs to Flavivirus, mainly found in West Africa and South America. Is transmitted by mosquitoes.
Yellow Fever
What are the two cycle forms in YF?
The jungle cycle: Transmission between non-human primates (monkey) and mosquito species found in the jungle. The virus is transmitted by mosquitoes from monkeys to humans in the jungle.
The urban cycle: Transmission is between humans and urban mosquitoes, primarily Aedes. The virus is usually brought to the urban setting by a viremic human who was infected in the jungle.
Viremic means infected people are infectious to mosquitoes.
Initial symptoms: Sudden onset of fever chills, severe headache, back pain, body aches, nausea, vomiting, fatigue, and weakness.
Severe: high fever, jaundice, bleeding, and eventually shock and failure of multiple organs.
YF
What is the diagnosis of YF?
Serology test
What is the treatment for YF?
There are no specific treatments. Hospitalization for supportive care and close observation.
Plenty of rest, fluids, and use of pain relievers.
Avoid aspirin or other nonsteroidal anti-inflammatory drugs as they may increase the risk of bleeding
Protection from further mosquito exposure