Washington, DC, July 18, 2024 (OPS) – The Pan American Health Organization (PAHO) has issued aepidemiological alert informing its Member States of the identification of possible cases in pregnant women Child-to-child transmission of Oropouche virus (OROV) is under investigation in Brazil. The alert calls for enhanced surveillance to monitor the potential occurrence of similar events in other countries where OROV and other arboviruses are circulating.
The OROV virus, a member of the family Peribunyaviridae is transmitted to humans mainly by the bite of an insect commonly called a midge, as well as by Culex mosquito It was first detected in Trinidad and Tobago in 1955 and since then sporadic outbreaks have 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 were reported in five countries in the Americas, with Brazil having the highest number (6,976), followed by Bolivia, Peru, Cuba, and Colombia. The identification of suspected 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 of 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, where similar symptoms were observed in a pregnant woman and resulted in a miscarriage.
"The possible vertical transmission and its consequences on the fetus are still under study," PAHO states in the epidemiological alert. "However, this information is shared with Member States to raise awareness of the situation and at the same time ask them to be attentive to the occurrence of similar events in their territory," it adds, with the aim of better understanding this possible transmission route and its implications.
On July 17, 2024, PAHO issued guidelines to help countries detect and monitor 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 its knowledge and experience.
Symptoms of the disease include sudden onset of fever, headache, joint stiffness, body aches, and in some cases, photophobia, nausea, and persistent 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 populations of mosquitoes and other transmitting insects, and raising awareness among the population, especially pregnant women, about individual 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; using 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 currently available in 23 countries to facilitate early detection.
In addition, PAHO 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.
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