We are writing to alert you to a increase in cases of Oropouche fever (GeoSentinel code 848), which have been reported in various regions in in Brazil (Acre, Amazonas, Pará, Rondônia and Roraima), Peru (Loreto, Ucayali, Madre de Dios), and Bolivia (Pando) between epidemiological week (EW) 1 and EW 8 of 2024.
https://www.paho.org/en/documents/epidemiological-alertoropouche-region-americas-2-february-2024.
Oropouche virus – Bolivia: https://promedmail.org/promed-post?place=8715272,5]
Oropouche virus – Americas: PAHO/WHO 20240308.8715258
Oropouche virus – Brazil 20240305.8715188
Oropouche virus – Peru: (MD) 20240221.8714965
https://www.paho.org/en/documents/epidemiological-update-oropouche-region-americas-6-march-2024
Oropouche virus (OROV) belongs to the Simbu serogroup of the viral genus Orthobunyavirus in the Peribunyaviridae family, an arbovirus transmitted in urban epidemic cycles, through the bites of Culicoides paraensis midges, and Culex quinquefasciatus mosquitoes (but notably not Aedes aegypti or Ae. albopictus).
OROV frequently causes fever, that like dengue, may be accompanied by headache, rash, joint pain, or vomiting. It can also cause aseptic meningitis.
Because the clinical presentation is indistinguishable from dengue and illness due to other arboviruses and regions of exposure are overlapping, laboratory confirmation is crucial to make the diagnosis. Acute OROV infections are generally diagnosed by a positive PCR result, the identification of specific IgM, or the detection of seroconversion through paired acute and convalescent samples. In-house real-time RT-PCR and serological assays exist and include enzyme immunoassays, neutralisation tests, complement fixation tests, immunofluorescence tests, and haemagglutination inhibition tests.
Real-time RT-PCR in serum or plasma samples collected during the first 5 days of illness, when serum viral loads range from 10⁴ to 10⁸ genome copies/mL, has shown a high detection rate (93%).
The OROV genome consists of three single-stranded, negative-sense RNA molecules: small (S), medium (M), and large (L) segment. Based on high sequence distances of the M segments, which encodes the two glycoproteins Gc and Gn, and a non-structural protein (NSm), multiple OROV reassortants are likely to exist, three of which have been identified: Iquitos virus (IQTV), Madre de Dios virus (MDDV), and Perdões virus (PDEV). While antigenicity is shared among reassortants, cross-protection may not occur, and reinfection with another reassortant could potentially result in antibody-dependent enhancement (ADE).
We recommend that travelers should observe insect bite precautions; biting midges that transmit OROV can bite throughout the day but have increased activity in the late afternoon.
We are also reaching out to gauge the Network’s capacity to diagnose OROV (code 848). Please inform us if your site/ laboratory has OROV specific in-house or commercial molecular or serologic assays. If your site/laboratory does not have the diagnostic capacity, we would appreciate your cooperation in storing acute phase serum samples (within 7 days from symptom onset) of cases with suspected dengue or other arbovirus infections, that remain unconfirmed for diagnosis at a designated Network laboratory.
If your Site is participating in GeoSentinel’s PRESEVERE study, cases are likely captured and samples obtained by adhering to the protocol.
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FAQ
DOCUMENT LIBRARY (FOR MEMBERS)
We are writing to alert you to a increase in cases of Oropouche fever (GeoSentinel code 848), which have been reported in various regions in in Brazil (Acre, Amazonas, Pará, Rondônia and Roraima), Peru (Loreto, Ucayali, Madre de Dios), and Bolivia (Pando) between epidemiological week (EW) 1 and EW 8 of 2024.
https://www.paho.org/en/documents/epidemiological-alertoropouche-region-americas-2-february-2024.
Oropouche virus – Bolivia: https://promedmail.org/promed-post?place=8715272,5]
Oropouche virus – Americas: PAHO/WHO 20240308.8715258
Oropouche virus – Brazil 20240305.8715188
Oropouche virus – Peru: (MD) 20240221.8714965
https://www.paho.org/en/documents/epidemiological-update-oropouche-region-americas-6-march-2024
Oropouche virus (OROV) belongs to the Simbu serogroup of the viral genus Orthobunyavirus in the Peribunyaviridae family, an arbovirus transmitted in urban epidemic cycles, through the bites of Culicoides paraensis midges, and Culex quinquefasciatus mosquitoes (but notably not Aedes aegypti or Ae. albopictus).
OROV frequently causes fever, that like dengue, may be accompanied by headache, rash, joint pain, or vomiting. It can also cause aseptic meningitis.
Because the clinical presentation is indistinguishable from dengue and illness due to other arboviruses and regions of exposure are overlapping, laboratory confirmation is crucial to make the diagnosis. Acute OROV infections are generally diagnosed by a positive PCR result, the identification of specific IgM, or the detection of seroconversion through paired acute and convalescent samples. In-house real-time RT-PCR and serological assays exist and include enzyme immunoassays, neutralisation tests, complement fixation tests, immunofluorescence tests, and haemagglutination inhibition tests.
Real-time RT-PCR in serum or plasma samples collected during the first 5 days of illness, when serum viral loads range from 10⁴ to 10⁸ genome copies/mL, has shown a high detection rate (93%).
The OROV genome consists of three single-stranded, negative-sense RNA molecules: small (S), medium (M), and large (L) segment. Based on high sequence distances of the M segments, which encodes the two glycoproteins Gc and Gn, and a non-structural protein (NSm), multiple OROV reassortants are likely to exist, three of which have been identified: Iquitos virus (IQTV), Madre de Dios virus (MDDV), and Perdões virus (PDEV). While antigenicity is shared among reassortants, cross-protection may not occur, and reinfection with another reassortant could potentially result in antibody-dependent enhancement (ADE).
We recommend that travelers should observe insect bite precautions; biting midges that transmit OROV can bite throughout the day but have increased activity in the late afternoon.
We are also reaching out to gauge the Network’s capacity to diagnose OROV (code 848). Please inform us if your site/ laboratory has OROV specific in-house or commercial molecular or serologic assays. If your site/laboratory does not have the diagnostic capacity, we would appreciate your cooperation in storing acute phase serum samples (within 7 days from symptom onset) of cases with suspected dengue or other arbovirus infections, that remain unconfirmed for diagnosis at a designated Network laboratory.
If your Site is participating in GeoSentinel’s PRESEVERE study, cases are likely captured and samples obtained by adhering to the protocol.