Oropouche Virus More Widespread Than Previously Thought

Recent research has revealed that the Oropouche virus, a tropical pathogen associated with febrile illnesses, is far more prevalent in South America than previously estimated. The findings were presented by a team of German researchers at the European Congress of Clinical Microbiology and Infectious Diseases (ESCMID) in Vienna.

Originally identified in Latin America during the 1950s, the Oropouche virus has been underreported for decades, with only a handful of cases officially documented annually across various countries. The study, led by a research team from the Charité - Universitätsmedizin Berlin and directed by Jan Drexler, focused on the actual distribution of the virus.

According to the study, the Oropouche virus is significantly underdiagnosed throughout Latin America. In certain regions, at least one in ten inhabitants has been infected with the virus. The comprehensive study involved the analysis of over 9,400 blood samples from both healthy and ill individuals collected from 2001 to 2022 across Bolivia, Brazil, Colombia, Costa Rica, Ecuador, and Peru.

The results indicated that approximately six percent of these samples contained antibodies against the Oropouche virus, suggesting previous infections. However, there were notable regional differences; Costa Rica showed an average of two percent positivity, while Ecuador had five percent, and areas within the Amazon rainforest reported over ten percent.

Currently, there is an ongoing outbreak of Oropouche fever in Latin America and the Caribbean, marked by symptoms such as fever, chills, headaches, and body aches. Although the disease has historically been considered mild, recent reports indicate a rise in severe cases, including instances of meningitis and fatalities among otherwise healthy individuals. Since late 2023, over 20,000 infections have been reported, including two deaths among young women.

Additionally, there have been documented cases of miscarriage and fetal malformations potentially linked to infections during pregnancy, raising concerns about the virus's impact on maternal and fetal health.

Despite the emerging threats posed by the Oropouche virus, there is currently no vaccine or specific treatment available. The researchers utilized artificial intelligence systems and machine learning techniques to explore the environmental and demographic factors influencing the frequency of infections. Their analysis suggested that climatic conditions, such as rainfall and stable temperatures, significantly affect the virus's prevalence.

Jan Drexler noted that the ongoing outbreak may be exacerbated by weather phenomena like El Niño. The study did not find evidence indicating altered viral characteristics that could explain the recent surge in cases. However, there are concerns that climate change could facilitate the virus's further spread.

The researchers produced a risk assessment map for Oropouche infections throughout Latin America, identifying the Amazon rainforest as the primary area of concern. Other high-risk regions include parts of Central America, the Caribbean, and southern Brazil.

In Germany, two cases of imported Oropouche virus infections were reported in 2024, both linked to travelers returning from Cuba, with additional reports from Italy. The virus is primarily transmitted by small biting midges, which are not effectively blocked by regular mosquito nets due to their size.

Given the current situation, it is advisable for pregnant women traveling to regions with high infection rates to seek medical advice and take precautionary measures to minimize their risk of exposure to the Oropouche virus and other tropical diseases.