A new study in PLoS Pathogens sheds light on why a mosquito-borne virus has been linked to serious neurological problems during an ongoing outbreak in South and Central America.
Known as Oropouche virus (OROV), it has caused tens of thousands of infections since 2023, including cases of Guillain-Barré syndrome and, in pregnant people, babies born with microcephaly — a birth defect in which a baby’s head and brain are significantly smaller than expected, often leading to developmental delays and other neurological problems.
The research was conducted in the laboratory of Amy Hartman, PhD, associate professor of infectious diseases and microbiology at Pitt Public Health, and led by former graduate researchers Kaleigh Connors, PhD, and Maris Pelow, MS. The team studied how both historical and newly emerging strains of the virus behave in brain and nerve cells.
They found that a strain from 1960 could infect and multiply in several types of central nervous system cells, including neurons and brain immune cells. Using lab-grown models that closely mimic developing brain tissue, the researchers also showed that early-stage human and rat brain cells were vulnerable to infection.
The team then tested two strains collected during the 2024 outbreak. These newer strains infected cells somewhat less efficiently but still spread across multiple types of brain cells.
Building on Connors’ earlier work with another mosquito-borne virus, Rift Valley fever virus, the researchers developed a brain-based infection model maintained outside the body to observe how the virus interacts with intact neural tissue. All three strains triggered local inflammation, including immune responses typically seen when the brain detects viral infection.
Taken together, the findings show that both historical and newly emerged strains of OROV can invade and replicate in a wide range of brain cell types. The new models developed in Hartman’s lab will help researchers better understand how the virus causes neurological disease and could support future work on treatments or vaccines.
-Clare Collins