Oropouche Fever: A Growing Threat in Latin America

Oropouche virus (OROV), which causes Oropouche fever (OROF), is an arthropod-borne virus (or arbovirus) that is maintained in a transmission cycle involving midges as the arthropod vector and multiple vertebrates as potential wildlife hosts. OROV was originally isolated in a village called Vega de Oropouche in Trinidad and Tobago and has since been detected in several South American countries but also in Central America. OROV is an enveloped virus and a member of the order Bunyavirales, genus Orthobunyavirus. As with other members of this genus, OROV has the typical tripartite, negative-sense RNA genome structure consisting of the large (L), medium (M), and small (S) segments, based on their molecular sizes. It is believed that genetic reassortment is a driving force in OROV evolution. Currently, the true public health impact of OROV remains poorly understood. The limited resources available for surveillance and diagnostics negatively impact the recognition of cases and outbreaks caused by OROV. The continuous recognition of novel OROV reassortants highlights the need to keep monitoring for their emergence, which might have increased pathogenicity in humans or enhanced transmission potential in arthropod vectors. Given the recognition of OROV in new geographic areas, it is also critical to include OROF as a potential clinical entity for diagnosis and to expand efforts for vector surveillance to recognize and incriminate vectors that can be contributing to the emergence and expansion of OROV as a growing threat in the Americas.