At a glance
- This document provides updated testing guidance for patients with suspected Oropouche virus disease, an interim case definition, and guidance for case reporting to ArboNET.
- Updates to the guidance will be made, as needed, based on new information about Oropouche virus.
Overview
CDC can provide clinical diagnostic testing for patients meeting the suspect case definition for Oropouche virus disease. Clinical diagnostic testing consists of CLIA-validated molecular and neutralizing antibody testing of serum or CSF. Patients meeting the suspect case definition are eligible for testing. However, State, Tribal, and Local Territorial (STLT) health departments can request a consultation with CDC for an exception if an asymptomatic pregnant person who lived in or traveled to an area with documented or suspected Oropouche has fetal findings concerning for congenital Oropouche (e.g., microcephaly, structural brain anomalies) or experiences a stillbirth. More details on the testing algorithm are described below.
Suspect case definition
A suspect case is a patient who has been in an area with documented or suspected Oropouche virus circulationA within two weeks of initial symptom onset (as patients may experience recurrent symptoms) and the following:
- Abrupt onset of reported fever, headache, and one or more of the following: myalgia, arthralgia, photophobia, retroorbital/eye pain, or signs and symptoms of neuroinvasive disease (e.g., stiff neck, altered mental status, seizures, limb weakness, or cerebrospinal fluid pleocytosis); AND
- Tested negative for other possible diseases, in particular dengueB; AND
- Absence of a more likely clinical explanation.
Other diagnostic considerations
In many countries, outbreaks of dengue are 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 (e.g., rickettsia, group A streptococcus, rubella virus, measles virus, parvovirus, enteroviruses, adenovirus, Mayaro virus).
Specimen requirements
All specimens should be submitted to CDC through state health departments. For after-hours contact information for health departments please visit: https://www.cste.org/page/EpiOnCall.
All specimens should be submitted according to CDC's routine arboviral testing submission protocol. Please note in CSTOR or on the 50.34 Specimen Submission Form dates and results of commercial and state laboratory testing for other arboviruses, in particular dengue.
For questions about specimen requirements or submission, contact ADBClinicalTeam@cdc.gov.
Clinical diagnostic testing
For patients meeting the suspect case definition, CDC can perform CLIA-validated Oropouche virus testing using real-time reverse transcription-polymerase chain reaction (RT-PCR) to detect viral RNA and/or plaque-reduction neutralization test (PRNT) to detect neutralizing antibodies on serum and/or CSF specimens.
Clinical diagnostic test results will be sent to public health partners in the jurisdictional health department where the case resides. These results can be shared with the treating physician and can be used for clinical decision making.
Oropouche virus disease clinical diagnostic testing algorithm
The specific assay(s) used will depend on timing of specimen collection in relation to initial symptom onset in most patientsC as follows:
| Day of specimen collection post symptom onset | Assay |
|---|---|
| 0–7 | RT-PCR |
| 6–7 | PRNT, if RT-PCR is negative |
| >7 | PRNT |
Based on current knowledge of Oropouche virus disease epidemiology, if a patient meets the suspect case definition, a single PRNT result is generally considered adequate to diagnose Oropouche virus disease. However, 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 by demonstrating a ≥4-fold change in neutralizing antibody titers. Specimens collected during the first two weeks of illness are considered acute.
Infant testing guidance is provided in Interim Guidance for Evaluating and Managing Infants Born to Pregnant People with Confirmed or Probable Oropouche Virus Disease.
Reporting cases to ArboNET
Oropouche virus disease is not currently a nationally notifiable condition. However, CDC encourages voluntary reporting to ArboNET, the national arboviral surveillance system. CDC has incorporated two new condition (event) codes for reporting:
- 50290: Oropouche virus disease, non-congenital
- 50291: Oropouche virus disease, congenital
For jurisdictions entering data directly into ArboNET via web or XML: These codes are already available for use. If you utilize the ArboNET Desktop Application for XML and need the latest version, please email us at dvbid2@cdc.gov.
For jurisdictions onboarded to the Arboviral MMG: CDC is aware that jurisdictions will need a transition period to modify their systems to transmit these new codes. While transitioning, CDC encourages jurisdictions to continue using condition code 10072 (Other arboviral disease, not otherwise specified) and 'Oropouche' for arbovirus. If you cannot report the arbovirus variable as 'Oropouche' then please report as 'Other Arbovirus'.
The interim case definition below should be used for classification of non-congenital Oropouche virus disease cases. CDC is working on establishing an interim case definition for congenital Oropouche virus disease. Once established, CDC will notify jurisdictional partners and update this page. For questions or further guidance on reporting, please contact dvbid2@cdc.gov.
Interim case definition for non-congenital disease
Current testing is limited to the assays described above; however, the interim case definition for non-congenital Oropouche virus disease incorporates additional assays and testing on specimen types that may become available in the future.
Confirmed case
A case that meets the suspect case definition and one or more of the following laboratory criteria:
- Isolation of virus from, or demonstration of specific viral antigen or nucleic acid in, tissue, blood, CSF, or other body fluid
- Four-fold or greater change in virus-specific quantitative antibody titers in paired sera
- Virus-specific IgM antibodies in CSF or serum with confirmatory virus-specific neutralizing antibodies in the same or a later specimen
Probable case
A case that meets the suspect case definition and one of the following laboratory criteria:
- Virus-specific IgM antibodies in CSF or serum
- Virus-specific neutralizing antibodies in a single CSF or serum specimen
- If concern exists for local transmission in a non-endemic area, consider if the patient shared an exposure location with a person with confirmed Oropouche virus infection, lives in an area where travel-related cases have been identified, or has known vector exposure (e.g., mosquitoes or biting midges).
- If strong suspicion of Oropouche virus disease exists based on the patient's clinical features, history of travel to an area with virus circulation, or other potential exposures, do not wait on negative testing before sending specimens to CDC.
- If a patient is immunocompromised from an underlying illness or medication or has another condition that might impact their immune response, RT-PCR can be conducted on samples collected after the first week of illness. Please indicate if a patient is considered immunocompromised in CSTOR or on the 50.34 Specimen Submission Form.