General Risk Statement
Taking into account the alert issued by the Pan American Health Organization / World Health Organization (PAHO/WHO) on February 2, 2024, due to the increase in cases of detection of Oropouche virus (OROV) infection in several countries of the Americas Region recently. month (1), the Rapid Risk Assessment (RRA) for public health in the region was introduced.
This ARH aims to assess the current regional risk related to OROV, taking into account the potential risk to human health (clinical-epidemiological behavior of the disease, severity indicators, risk factors and more detailed determinants at the country level), the risk of spread ( vector activity, cross-border geographical expansion) and, the risk of insufficient capacities for prevention and control with available resources (including capacities to support the response, surveillance capacities, diagnostic technique, readiness of health services and supplies).
Since the first identification of OROV in 1955 in Trinidad and Tobago, cases and outbreaks of OROV have been identified in Brazil, Colombia, Ecuador, French Guiana, Panama, Peru, Trinidad and Tobago, and Venezuela. The reported eruptions occurred mainly in the Amazon basin region. These are associated with the presence of the mule vector, Culicoides paraensis (C. paraensis) (1, 2) maintained in a sylvatic cycle involving the reservoir host such as sloths and non-human primates. Given that its clinical presentation is similar to other arboviral infections, that there is no systematic surveillance of cases and that laboratory diagnosis is not widespread, it is possible that the true burden of the disease in the countries of the Region is underestimated. Outbreaks are generally identified from retrospective population-based or laboratory epidemiological studies.
Several factors are related to the increased risk of the spread of the C. paraensis vector, among which are: climate changes leading to increased rainfall and increased temperatures; deforestation due to the expansion of the agricultural frontier in the area of influence of the Amazon Basin Region; increased urbanization; among other human activities that favor the spread of the vector and create a favorable environment for the vector-host interaction, and consequently, the possibility of increasing the transmission of OROV. The same factors greatly affect reservoir host habitats, forcing them to move closer to urban and peri-urban regions where vectors are proliferating.
Fragile health systems amid political and financial instabilities in countries facing complex humanitarian crises and high population movements are also determinants to consider in the face of a growing risk of disease spread.
Although scientific evidence and data on the surveillance of the event are currently limited, the outbreaks that have occurred in the last decade have allowed a partial characterization of the clinical-epidemiological behavior of OROV disease, as well as an assessment of its size and severity. . In terms of documented severity, most cases have mild to moderate symptoms. They are self-limited (recover within 7 days) and in rare cases complications such as aseptic meningitis develop and there is no evidence of human-to-human transmission. No related deaths have been reported (3).
Based on the criteria established for this assessment, the overall risk at the level of the Americas Region is classified as “moderate” with a “moderate” level of confidence in the available information.