Oropouche virus

Classification

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

Epidemiology

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

Clinical manifestations

• 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

Laboratory

• 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

Complications

• neuroinvasive disease (meningitis, encephalitis)
• most patients recover without long-term sequellae, death uncommon
• can be transmitted from a pregnant woman to her fetus
  • fetal deaths & congenital abnormalities have been reported in pregnant women

Differential diagnosis

• other arboviruses
  • dengue, chikungunya
  • Zika virus
• malaria

Management

• no vaccines to prevent Oropouche infection
• no medicines to treat Oropouche infection
• prevention: personal protective measures to avoid bites

More general terms

• Orthobunyavirus; bunyavirus