Oropouche virus

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Classification

belongs to the Simbu serogroup of the genus Orthobunyavirus in the Peribunyaviridae family.

endemic areas in the Amazon basin
spread to people primarily by the bite of infected biting midges (Culicoides paranesis)
Some mosquitoes can also spread the virus

incubation period is 3-10 days
typically presents as an abrupt onset of fever, severe headache, chills, myalgia, & arthralgia
other signs & symptoms include photophobia, dizziness, retroorbital pain or eye pain, nausea/vomiting, or centrifugal maculopapular rash that starts on the trunk & goes to the extremities
less common symptoms can include conjunctival injection, diarrhea, severe abdominal pain, & hemorrhagic symptoms (epistaxis, gingival bleeding, melena, menorrhagia, petechiae)
symptoms typically last less than a week (2-7 days)
in < 60% of patients, symptoms can reoccur a few days or even weeks later with similar symptoms on relapse

CBC: lymphopenia, leukopenia, thrombocytopenia less common
elevated serum CRP
mildly elevated serum transaminases
CSF pleocytosis, elevated CSF protein with neuroinvasive disease
viral culture during first few days of infection, not detected after 5 days
Oropouche virus RNA detectable for several days after virus is no longer present
convalescent IgM & IgG
CDC can perform plaque reduction neutralization tests (PRNTs) to detect virus-specific neutralizing antibodies in serum & CSF
to confirm a recent infection using serologic testing, both acute & convalescent samples are needed to document a >= 4-fold change in antibody titers

↑ Centers for Disease Control & Prevention Increased Oropouche Virus Activity and Associated Risk to Travelers CDC Health Alert Network. August 16, 2024 https://emergency.cdc.gov/han/2024/han00515.asp