Powassan virus: Difference between revisions
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* Transmitted by a number of ''Ixodes'' and ''Dermacentor'' ticks |
* Transmitted by a number of ''Ixodes'' and ''Dermacentor'' ticks |
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** ''[[Ixodes cookei]]'', ''[[Ixodes scapularis]]'', ''[[Ixodes marxi]]'', ''[[Ixodes spinipalpus]]'', ''[[Dermacentor andersoni]]'', and ''[[Dermacentor variabilis]]'' |
** ''[[Ixodes cookei]]'', ''[[Ixodes scapularis]]'', ''[[Ixodes marxi]]'', ''[[Ixodes spinipalpus]]'', ''[[Dermacentor andersoni]]'', and ''[[Dermacentor variabilis]]'' |
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* Transmission only requires 15 minutes of tick attachment |
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== Clinical Manifestations == |
== Clinical Manifestations == |
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* Incubation period 1 to 3 weeks |
* Incubation period [[Usual incubation period::1 to 3 weeks]] |
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* Fever, headache, confusion, weakness, encephalopathy, focal neurological deficits, and vomiting |
* [[Causes::Fever]], [[Causes::headache]], [[Causes::confusion]], [[Causes::weakness]], [[Causes::encephalopathy]], [[Causes::focal neurological deficits]], and [[Causes::vomiting]] |
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* Progresses to severe encephalitis |
* Progresses to [[Causes::encephalitis|severe encephalitis]] |
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== Diagnosis == |
== Diagnosis == |
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* Serology with hemagglutination assay (HI) for IgM + IgG |
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* Serologic with IgM, using screening ELISA followed by confirmatory PRNT |
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**Fourfold or greater increase or decrease in titre between the acute phase and convalescent phase serum is considered to be diagnostic |
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**Cross-reacts with other flaviviruses, including [[dengue]] |
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*Molecular testing available at NML |
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== Management == |
== Management == |
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Latest revision as of 16:26, 8 July 2023
- Tick-borne viral infection that can cause encephalitis
- Closely related to deer tick virus
- Named for Pawassan, Ontario, but endemic in Eurasia and North America
Background
Microbiology
- Single-stranded positive-sense RNA virus in the genus Flavivirus, family Flaviviridae
- Two genotypes: lineage 1 and lineage 2
Epidemiology
- Transmitted by a number of Ixodes and Dermacentor ticks
- Transmission only requires 15 minutes of tick attachment
Clinical Manifestations
- Incubation period 1 to 3 weeks
- Fever, headache, confusion, weakness, encephalopathy, focal neurological deficits, and vomiting
- Progresses to severe encephalitis
Diagnosis
- Serology with hemagglutination assay (HI) for IgM + IgG
- Fourfold or greater increase or decrease in titre between the acute phase and convalescent phase serum is considered to be diagnostic
- Cross-reacts with other flaviviruses, including dengue
- Molecular testing available at NML
Management
- Supportive
Prognosis
- Mortality is 10%, with survivors having permanent neurologic sequelae
