July 18, 2024 Vertical transmission of Oropouche virus in Brazil.

July 18, 2024

The Pan American Health Organization (PAHO) and the World Health Organization (WHO) have issued an epidemiological alert following the detection of possible cases of vertical transmission of Oropouche virus (OROV) in BrazilThis report is based on the latest data provided by the National Communication Center (CNE) for the International Health Regulations (IHR) of Brazil and reveals alarming cases in the state Pernambuco.

The first case has been investigated

The first documented case is a pregnant woman living in Rio Formoso, Pernambuco, who presented with symptoms of ARVI, including fever, headache and epigastric pain, at 30 weeks of pregnancy. Laboratory tests confirmed the presence of the virus in serum and placental samples using RT-PCR. Unfortunately, the patient gave birth to a stillborn child, and analysis of fetal tissue confirmed vertical transmission of the virus.

Second suspicious case

The second suspected case was a 33-year-old pregnant woman from Jaqueira, Pernambuco, who presented with similar symptoms. This patient had a spontaneous abortion at 8 weeks of gestation. Serum tests were positive for OROV, although fetal samples could not be obtained for further analysis.

Retrospective analysis and additional cases

Retrospective analysis of samples stored at the Instituto Evandro Chagas (IEC) revealed microcephaly and the presence of IgM antibodies against OROV in four newborns, suggesting a possible link between OROV infection and neurological malformations, although a definitive causal relationship has not yet been established.

Cases reported in the Americas region

As of 16 July 2024, there have been 7,688 confirmed cases of OROV reported in five countries in the Americas, with the highest number of cases reported in Brazil (6,976). The Amazon region of Brazil has been particularly affected, accounting for 78% of cases.

Guidance for Member States

PAHO/WHO calls on Member States to strengthen surveillance of pregnant women and to report any cases of abortion or fetal death associated with OROV infection. Recommendations for laboratory diagnosis and surveillance are outlined, as well as vector prevention and control measures to reduce vector populations and personal protection.

Measures for prevention and control of infection vectors

Measurements include:

• Strengthen entomological surveillance.
• Map urban and rural areas with conditions for vector development.
• Promote advanced agricultural practices.
• Eliminate breeding grounds and swamps.
• Use appropriate mosquito nets and repellents.
• Take additional measures such as fumigation in transmission areas.

This report highlights the importance of ongoing surveillance and preventive measures to control the spread of OROV, particularly among vulnerable populations such as pregnant women. International cooperation and information sharing are essential to address this public health issue.

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