Which Vectors Drive Oropouche Fever Transmission in the Americas

The 2023-24 epidemic of Oropouche fever in the Region of the Americas suggests a potential change in the epidemiology of the disease, raising questions about which vectors are driving transmission.

In a pre-print study published on October 18, 2024, researchers systematically reviewed vector competence experiments with the Oropouche virus (OROV) published before the 2023-24 epidemic season.

Only seven studies were published by September 2024, highlighting the chronic neglect that OROV has been subjected to since its discovery in 1954.

Historically, OROV has been neglected compared to other arboviral diseases, such as dengue, chikungunya, or Zika, which have also reported upsurges in 2024.

Two species of midge (Culicoides paraensis and C. sonorensis), known as 'no-see-ums', consistently demonstrate a high competence to transmit OROV.

At the same time, mosquitoes exhibited an infection rate below 20% and showed limited OROV transmission.

These researchers stated, 'Further research is needed to establish which vectors are involved in the ongoing outbreak in Cuba and whether local vectors create any risk of establishment in regions with frequent travel to Latin America and the Caribbean.'

To alert travelers, the U.S. CDC has issued a Level 2 Health Notice regarding Cuba's Oropouche outbreak and a Level 1 for the entire region.

Symptoms of Oropouche virus disease begin four to eight days after an infective bite, says the U.S. CDC. Some people may develop more severe disease. In September 2024, Cuba reported three cases of Guillain-Barré syndrome associated with OROV.

This research is essential for the United States since Florida's southeast coast has already reported about 86 travel-related OROV cases near the city of Miami in 2024.

Moreover, no Oropouche vaccines have been approved for use.