The Oropouche fever It is an infection transmitted by insects which was classified by the World Health Organization (WHO) with a “high” risk at the regional level” in the Americas, for his rapid spread.
The virus that causes the disease is transmitted to humans mainly through the bite of the Culicoides paraensiscommonly known as at the signwhich is why it is considered “vector transmission”. But this year it was detected that there is another way of transmitting the pathogen: vertical. That is, from mother to child during pregnancy.
in the magazine New England Journal of Medicine (NEJM), researchers of Brazil reported evidence of the first confirmed case of vertical transmission of the Oropouche virus. The research was carried out by 23 experts from eight Brazilian institutions and marks a significant advance in the understanding of the disease.
“Given the confirmation that there is a way to vertical transmissionwarning should be given to people who are pregnant and who visit areas with outbreaks of Oropouche fever. In countries like the Argentinathey could also register sprouts because the midge insect that can transmit the virus is found within the territory,” he commented to Infobae the doctor Silvia González Ayalapresident of the Argentine Society of Pediatric Infectology.
Oropouche virus was described in 1955 from the case of a coal worker with high fever on the Caribbean island of Trinidad. Since then, it has caused sporadic outbreaks of fever in humans in South America and in the Caribbean.
In 2024, infections spread to previously non-endemic regions in all five regions of Brazil. This expansion is linked to emerging genetic variants.
In the journal NEJM, researchers reported on cases of Oropouche fever that were diagnosed in Cearáa historically free state of the Oropouche virus (OROV).
One notable case involved a 40-year-old pregnant woman, in her 30th week of gestation. The symptoms were fever, chills, muscle pain and a severe headache.
Gestational diabetes had been identified in her routine prenatal care, and metformin was administered. Four routine obstetric ultrasounds were performed. On July 27, a medical evaluation revealed mild vaginal bleeding and dark discharge, with an ultrasound indicating fetal macrosomia.
By August 5, persistent symptoms and decreased fetal movements led to confirmation of fetal death.
Molecular diagnoses confirmed an acute Oropouche infection, and dengue, Zika, chikungunya and Mayaro were ruled out. The analysis of fetal tissues, through minimally invasive techniques, detected RNA from the virus and this allowed us to establish that it was a case of vertical transmissionthat is, from the infected mother to the fetus.
Phylogenetic analysis indicated that the result was consistent with the current outbreak strains. These findings directly link fetal death to the active spread of the virus in Brazil, and highlight the potential risks of infection during pregnancy.
“These findings emphasize the risks of Oropouche infection in pregnancy and the need to consider this infection in pregnant women with fever or other suggestive symptoms who live in or visit regions where the virus is endemic or emerging,” the researchers stated in the article published as “Correspondence” in NEJM.
Recently, an investigation in Italia had postulated the possibility that the virus could be transmitted through unprotected sex, as reported Infobae last October 27.
This work was carried out by Concetta Castilletti and colleagues from Hospital IRCCS Sacred Heart Don Calabriaalong with Federico Gobbi, de the University of Brescia.
The team documented the case of a 42-year-old Italian man who presented symptoms of Oropouche fever after having traveled to Cuba last July. It was detected ARN of the virus in the patient’s blood, serum, urine and semen.
Sixteen days after the onset of symptoms, they managed to isolate a replicating virus in a semen sample, suggesting the possibility of sexual transmission, they commented in the journal of the Centers for Disease Control and Prevention (CDC).
Given the epidemic outbreaks, PAHO recommended control and prevention measures in areas with outbreaks of Oropouche fever:
- Surveillance must be strengthened to detect insects, especially Culicoides paraensiswhich is the main transmitter of the virus. It is recommended to identify and eliminate breeding sites where water accumulates.
- Implement agricultural practices that prevent the accumulation of waste and maintain areas clean of weeds to reduce refuge sites for insects.
- Use fine mesh on doors and windows of homes to avoid bites.
- Apply approved repellents, such as DEET, to exposed skin and clothing.
- Wear clothing that covers the legs and arms, especially for people in contact with the outside.
- Use insecticide-impregnated mosquito nets for people who rest during the day, such as pregnant people and babies.
