Oropouche Virus: Reporting and Surveillance

Laboratory diagnosis is generally accomplished by testing serum. Cerebrospinal fluid can also be tested in patients with signs and symptoms of neuroinvasive disease. Diagnostic testing via CLIA-validated real-time reverse transcription polymerase chain reaction (RT-PCR) and plaque reduction neutralization test (PRNT) is currently available at CDC (Centers for Disease Control and Prevention).

All Oropouche virus testing must first be approved by an epidemiologist at the Wisconsin Department of Health Services, Bureau of Communicable Diseases. To request testing, contact the Bureau of Communicable Disease at dhsdphbcd@dhs.wisconsin.gov or 608-267-9003.

Who should be tested?

Clinicians should consider Oropouche virus diagnostic testing in patients who have been in an area with documented or suspected of Oropouche virus circulation in the 14 days before initial symptom onset (as patients may experience recurrent symptoms) and meet the following criteria:

• Acute onset of fever or chills or two or more of the following: headache, myalgia, arthralgia, retro-orbital pain, or generalized rash; or
• Meningitis, encephalitis, acute flaccid paralysis, or other acute signs of central or peripheral neurologic dysfunction, as documented by a physician; and
• Tested negative for other possible diseases, in particular dengue.ǂ

Outbreaks of dengue are also occurring in areas with reported Oropouche virus transmission. For patients with suspected Oropouche virus disease, it is important to rule out dengue virus infection because proper clinical management of dengue can improve health outcomes. Other diagnostic considerations include chikungunya, Zika, leptospirosis, malaria, or infections caused by various other bacterial or viral pathogens (for example, rickettsia, group A streptococcus, rubella, measles, parvovirus, enteroviruses, adenovirus, Mayaro virus).

What information is needed to obtain approval for Oropouche virus testing?

CDC (Centers for Disease Control and Prevention) and the Wisconsin State Laboratory of Hygiene (WSLH) require the following information before accepting specimens for Oropouche testing:

• Travel location and dates of travel
• Initial illness onset date
• Clinical features (patient signs, symptoms, and any notable lab findings)
• Negative dengue PCR and IgM testingǂ

ǂIn most circumstances, the WSLH will hold specimens for Oropouche virus testing until negative dengue PCR and IgM results are available or reported. However, if there is a strong clinical suspicion of Oropouche virus disease based on the patient’s clinical features (for example, recurrent symptoms or neurologic presentation) and travel to an area with documented virus circulation, then WSLH will not wait for negative dengue results to submit specimens to CDC for Oropouche virus testing.

Specimen collection guidance

A minimum of 1.0 mL of serum or CSF is needed for Oropouche virus testing. It is recommended that a specimen for Oropouche virus is collected at the time that a specimen is collected for dengue virus testing and other disease testing.

The timing of specimen collection after initial illness onset will affect which assay is performed.

A single positive PRNT result is generally considered adequate to diagnose Oropouche virus disease in a non-pregnant person with a clinically compatible illness and possible exposure to the virus. However, to confirm a recent infection using serologic testing, both acute and convalescent samples are needed to document a 4-fold or greater change in neutralizing antibody titers. If a specimen collected from a pregnant person is positive by PRNT only, acute and convalescent serum specimens collected optimally ≥2 weeks apart are preferred to confirm a recent infection. Specimens collected during the first two weeks of illness are considered acute.

Contact the Wisconsin Department of Health Services (DHS), Bureau of Communicable Disease at dhsdphbcd@dhs.wisconsin.gov or 608-267-9003 for Oropouche testing approval prior to sending specimen to WSLH.

For questions about Oropouche virus specimen collection, handling, and shipping, contact WSLH Customer Service at 800-862-1013.

Most people infected with Oropouche virus become symptomatic, with an incubation period of three to 10 days. Illness typically begins with the abrupt onset of fever, severe headache, chills, myalgia, and arthralgia. Other signs and symptoms include photophobia, dizziness, retroorbital or eye pain, nausea, vomiting, or maculopapular rash that starts on the trunk and spreads to the extremities.

Symptoms of Oropouche virus typically last less than a week, however, in up to 60% of patients, similar symptoms can reoccur a few days or even weeks later.

Oropouche virus can also cause neuroinvasive disease, such as meningitis or encephalitis, in up to 4% of patients. It’s possible that some patients may develop Guillain-Barré syndrome (GBS) following Oropouche virus infection.

Vertical transmission of Oropouche virus can occur, and infection during pregnancy has been associated with birth defects and fetal or infant death. For more information on clinical management of pregnant patients, visit CDC’s Interim Clinical Considerations for Pregnant People with Confirmed or Probable Oropouche Virus Disease. For more information on the clinical management of infants at risk for congenital Oropouche virus infection, visit CDC’s Interim Guidance for Evaluating and Managing Infants Born to Pregnant People with Confirmed or Probable Oropouche Virus Disease.

No specific antiviral treatments or vaccines are available for Oropouche virus disease. Treatment for symptoms can include rest, fluids, and use of analgesics and antipyretics. Acetaminophen is the preferred first-line treatment for fever and pain. Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) should not be used to reduce the risk of hemorrhage. Patients who develop more severe symptoms should be hospitalized for close observation and supportive treatment.

Pregnant people with laboratory evidence of Oropouche virus infection should be monitored during pregnancy and live-born infants should be carefully evaluated.