Oropouche: Cases of mother-to-child transmission under investigation in Brazil – PAHO/WHO
Washington, DC, July 18, 2024 (PAHO) – The Pan American Health Organization (PAHO) issued an epidemiological alert informing its Member States about the identification of possible cases of transmission from pregnant mother to child of the Oropouche virus (OROV) under investigation in Brazil. The alert calls for increased surveillance to monitor the possible occurrence of similar events in other countries with circulation of OROV and other arboviruses.
The OROV virus, a member of the Peribunyaviridae family, is transmitted to humans mainly through the bites of an insect commonly known as a mosquito, as well as by the Culex Mosquito. It was first detected in Trinidad and Tobago in 1955 and sporadic outbreaks have since been documented in several countries in the Americas, including Brazil, Ecuador, French Guiana, Panama and Peru. Recently, an increase in cases has been observed in the region.
Between January and mid-July 2024, nearly 7,700 confirmed cases of Oropouche have been reported in five countries in the Americas, with Brazil reporting the highest number (6,976), followed by Bolivia, Peru, Cuba and Colombia. The identification of suspected cases of mother-to-child transmission of the virus occurs in the context of this increase in reported cases.
In a recent case, a pregnant woman, resident in the state of Pernambuco, presented symptoms of Oropouche during the 30th week of gestation. Following laboratory confirmation of OROV infection, fetal death was subsequently reported. A second suspected case was reported in the same state, in which similar symptoms were observed in an expectant mother, leading to a spontaneous abortion.
“The possible vertical transmission and consequences for the fetus are still under investigation,” PAHO states in its epidemiological alert. “However, this information is being shared with Member States to raise awareness of the situation and at the same time to ask them to be alert to the occurrence of similar events in their territories,” it adds, with the aim of increasing understanding of this possible route of transmission and its implications.
On July 17, 2024, PAHO issued guidelines to assist countries in the detection and surveillance of Oropouche and possible cases of mother-to-child infection, congenital malformation, or fetal death. The Organization is working closely with countries where cases have been confirmed to share knowledge and experiences.
Symptoms of the disease include sudden onset of fever, headache, joint stiffness, aches and pains, and in some cases persistent photophobia, nausea and vomiting that may last five to seven days. Although severe clinical presentation is rare, it may progress to aseptic meningitis. Full recovery may take several weeks.
To control Oropouche, PAHO calls on countries to implement vector prevention and control actions, including strengthening entomological surveillance, reducing mosquito and other transmitting insect populations, and educating the population, especially pregnant women, on personal protection actions to prevent bites.
Recommended measures include protecting homes with fine-mesh screens on doors and windows; wearing clothing that covers arms and legs, especially in homes where people are sick; applying repellents containing DEET, IR3535 or icaridin; and using mosquito nets around beds or furniture where people rest.
Since the increase in cases in the region, PAHO has provided technical support to affected countries to strengthen their capacity to detect and confirm OROV. This effort includes the distribution of reagents for molecular testing and a protocol that is currently available in 23 countries to facilitate early detection.
In addition, PAHO has organized various activities such as an international workshop on molecular surveillance of emerging and re-emerging arboviruses, which brought together health experts and researchers from Bolivia, Ecuador, Guyana, Paraguay, Peru, Suriname, Venezuela and Brazil.
