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A new virus emerge from the Amazon Forest Basin and is spreading in Latin America text: Iani et al. medRXiV, 2024.08.02.24311415v2

A new virus emerge from the Amazon Forest Basin and is spreading in Latin America text: Iani et al. medRXiV, 2024.08.02.24311415v2

Brazil has experienced a significant surge in Oropouche virus cases, with over 7,000 reported by mid-2024. Recent genomic analyses reveal a rapid north-tosouth spread of the virus from the Amazon Basin into historically nonendemic regions. This study, conducted as part of the CLIMADE consortium, also reports the first fatal cases of Oropouche virus infection.

Oropouche virus, first identified in Trinidad and Tobago in 1955 and later in Brazil in 1960, has historically caused around 30 outbreaks, primarily within the Amazon Basin. The virus circulates among forest animals and is transmitted to humans by the midge Culicoides paraensis.

In collaboration with Central Public Health Laboratories across Brazil, researchers integrated epidemiological metadata with genomic analyses of recent cases. This effort resulted in the generation of 133 whole genome sequences from the virus’s three genomic segments (L, M, and S), including the first genomes from regions outside the Amazon and the first recorded fatal cases.

All 2024 genomes form a monophyletic group with sequences from the Amazon Basin sampled since 2022. The analyses revealed 21 reassortment events and a rapid viral movement from the Amazon Basin into new regions. However, it remains unclear if the virus’s genomic evolution has enabled it to adapt to local ecological conditions and evolve new phenotypes of public health importance.

The rapid spatial expansion and the first reported fatalities underscore the need for enhanced surveillance of this evolving pathogen. Factors such as viral adaptation, deforestation, and climate change may have contributed to the virus’s spread beyond the Amazon Basin.

The spread of Oropouche virus into regions more than 3,500 km from the Amazon Basin, coupled with genome reassortment events, suggests the virus is adapting to new environments. This evolution could lead to new viral phenotypes, affecting vector efficiency and disease outcomes, and highlights the need for robust surveillance systems at national and continental levels.

'We are not scared and are working to detect new pathogens before they emerge'

'Partering with FioCruz, and the Brazilian Navy to take genomics surveillance to the most remote forests and popultations'

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