Oropouche Virus: A New Threat to Monitor During Pregnancy?

By Ana Espino | Published on June 26, 2026 | 4 min read

Long overshadowed by other arboviral diseases such as dengue, chikungunya, and Zika, Oropouche virus (OROV) is now attracting increasing attention from public health authorities. Responsible for recurrent outbreaks across Latin America, particularly in Brazil, this virus is primarily transmitted by biting midges of the Culicoides genus. Until recently, Oropouche infection was generally considered a mild, self-limiting febrile illness.

However, several recent reports have raised a major concern: the virus may be capable of crossing the placental barrier and affecting fetal development. This hypothesis echoes the early observations made during the emergence of the Zika virus. In light of these new findings, researchers conducted a literature review to assess the current evidence regarding Oropouche infection during pregnancy, its transmission pathways, and its potential perinatal consequences.


   Read next : Pregnancy and Malaria : A High-Risk Combination

Growing Evidence for Mother-to-Child Transmission

The authors analyzed data from clinical studies, case series, surveillance reports, and scientific publications focusing on Oropouche infection during pregnancy. Their review identified several documented cases of vertical transmission, confirmed through the detection of viral genetic material in the placenta, amniotic fluid, umbilical cord blood, and even fetal tissues.

The most concerning observations involve fetal outcomes. To date, several cases of intrauterine fetal death have been associated with maternal Oropouche virus infection. Other pregnancies have been complicated by the development of congenital abnormalities, including microcephaly, ventriculomegaly, corpus callosum abnormalities, cerebral atrophy, posterior fossa malformations, and arthrogryposis.

The authors emphasize that these abnormalities predominantly affect the central nervous system, suggesting a degree of neurotropism comparable to that observed with other teratogenic arboviruses.

The analysis also suggests that infections occurring during the first trimester of pregnancy may carry the highest risk of severe complications, corresponding to critical stages of organogenesis. However, adverse outcomes have also been reported following infections acquired later in pregnancy.

Researchers further note that diagnosis remains challenging. Symptoms—including fever, headache, muscle and joint pain, nausea, and vomiting—closely resemble those caused by many other arboviral infections circulating in the same regions. Laboratory confirmation relies primarily on RT-PCR during the acute phase, followed by serological testing at later stages.


   Read next : Zika: A Latent Threat or a Past Danger?

Toward Recognition of a Congenital Oropouche Syndrome?

This review highlights the emergence of a previously underrecognized risk associated with Oropouche virus infection. Current evidence suggests that vertical transmission is possible and may lead to severe fetal complications, particularly involving the nervous system.

However, the authors caution that knowledge remains limited. Most available evidence comes from isolated cases and small observational series, making it difficult to accurately estimate the frequency of complications or establish a definitive causal relationship. The precise mechanisms of placental transmission and the long-term neurodevelopmental consequences for exposed children also remain poorly understood.

Despite these uncertainties, the findings support increased vigilance in regions affected by Oropouche outbreaks. The authors advocate for the inclusion of Oropouche virus in the differential diagnosis of febrile illnesses during pregnancy, enhanced maternal-fetal surveillance, and the implementation of large-scale prospective studies.

As occurred following the Zika epidemic, such research could help characterize a potential congenital Oropouche syndrome and guide the development of appropriate prevention and management strategies for pregnant women at risk of exposure.


About the author – Ana Espino
PhD in Immunology, specialized in Virology  
As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions.