The Pan American Health Organization (PAHO) today issued another alert urging countries to bolster their surveillance, medical management, and vector-control activities in ongoing battles against chikungunya and Oropouche viruses.
Fourteen countries in the Americas have reported more than 212,000 cases this year, a decline from last year. Cases have been concentrated in South America, especially Bolivia, Brazil, and Paraguay, as well as parts of the Caribbean.
The agency said the outbreaks are linked to a shift in the circulating genotypes. Since 2014, cases in the Americas region have mainly involved the Asian genotype, but this year the most affected countries are also seeing circulation from the East/Central/South African (ECSA) genotype.
Presence of the ECSA genotype in at least four countries is concerning, because cocirculation enhances the risk of adaptation. “Understanding chikungunya’s genetic lineages is essential to predict transmission dynamics and tailor public health responses,” PAHO said.
Also, it warned that cases linked to ongoing outbreaks in the Indian Ocean, Europe, and Asia also raise the risk of reintroduction and further spread into new areas with conditions conducive to transmission.
Extra vigilance for Oropouche illness
For Oropouche virus, mainly spread by biting midges, about 12,700 cases have been reported in 11 Americas countries in the first 7 months of the year, with local cases reported in Brazil, Colombia, Cuba, Panama, Peru, and Venezuela. Continuing a trend that began in 2024, the virus continues to spread to previously unaffected areas.
PAHO urged countries to focus on early case detection and to include Oropouche infection in the differential diagnosis for suspected dengue infections and be alert for possible neurologic complications. It added that community engagement is crucial for reducing populations of insects that spread the two diseases.