West Nile virus: Difference between revisions
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+ | == Background == |
+ | * Single-stranded positive-sense enveloped virus in the family [[Flaviviridae]] and genus [[Flavivirus]] |
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+ | * Essentially worldwide distribution |
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+ | * Vector is [[Vector::mosquitoes]] |
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+ | * Main reservoir is birds |
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+ | * As well as being vector-borne, can also be transmitted by blood transfusion, solid organ transplantation, and vertically |
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+ | == Clinical Manifestations == |
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+ | * Incubation period of [[Usual incubation period::3 to 14 days]] |
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+ | * Up to 80% of infections are asymptomatic; of those with symptoms, [[fever]] is most common |
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+ | * Some form of CNS disease develops in 1:150 people |
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+ | ** [[Meningoencephalitis]] |
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+ | ** [[Acute flaccid paralysis]] |
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+ | ** 10% mortality, with about half of survivors having neuropsychiatric sequelae |
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+ | == Differential Diagnosis == |
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+ | * Other causes of [[meningitis]], [[encephalitis]], and [[acute flaccid paralysis]] |
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+ | ==Diagnosis== |
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+ | == Management == |
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+ | * Supportive care |
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[[Category:Flaviviridae]] |
[[Category:Flaviviridae]] |
Revision as of 06:44, 18 August 2020
Background
- Single-stranded positive-sense enveloped virus in the family Flaviviridae and genus Flavivirus
- Essentially worldwide distribution
- Vector is mosquitoes
- Main reservoir is birds
- As well as being vector-borne, can also be transmitted by blood transfusion, solid organ transplantation, and vertically
Clinical Manifestations
- Incubation period of 3 to 14 days
- Up to 80% of infections are asymptomatic; of those with symptoms, fever is most common
- Some form of CNS disease develops in 1:150 people
- Meningoencephalitis
- Acute flaccid paralysis
- 10% mortality, with about half of survivors having neuropsychiatric sequelae
Differential Diagnosis
- Other causes of meningitis, encephalitis, and acute flaccid paralysis
Diagnosis
- Serology
- Serum or CSF for IgM antibodies is the standard test; usually positive by 3 to 8 days, and persist for 2 to 3 months
- If submitted CSF, must also submit serum
- May cross-react with other flaviviruses
- Can be seronegative if immunosuppressed (e.g. rituximab), therefore may need to do PCR
- Serum or CSF for IgM antibodies is the standard test; usually positive by 3 to 8 days, and persist for 2 to 3 months
- PCR
- RNA virus, therefore needs reverse transcriptase step (RT-PCR)
- Can be done on serum, CSF, and tissue
- On MRI, may have a slight preference for thalamus
Management
- Supportive care