Scientists have discovered that a small group of neurons in the airway plays a vital role in alerting the brain about a flu infection. In a study published in Nature, researchers explored the brain-body connection during a respiratory infection by studying mice. The researchers identified a small population of neurons in the glossopharyngeal nerve, which runs from the throat to the brain, that signals to the brain that a flu infection is present. These neurons have receptors for lipids called prostaglandins, which are made by both mice and humans during an infection and are targeted by drugs such as ibuprofen and aspirin. The team found that cutting the glossopharyngeal nerve, eliminating the neurons, blocking the prostaglandin receptors in those neurons, or treating the mice with ibuprofen reduced influenza symptoms and increased survival.

The researchers also discovered evidence of another potential sickness pathway, this one traveling from the lungs to the brain, which appears to become active in the second phase of infection as the virus infiltrates deeper into the respiratory system. This additional pathway doesn’t involve prostaglandins, and mice in the second phase of infection didn’t respond to ibuprofen. The findings suggest an opportunity for improving flu treatment if scientists can develop drugs that target the additional pathway.

The study provides a foundation for future research into the brain-body connection during respiratory infections. Although mice and humans share a lot of basic sensory biology, researchers need to conduct further genetic and other experiments to confirm that humans have the same neuron populations and pathways seen in the mouse study. If the findings can be replicated in humans, it raises the possibility of developing treatments that address both the prostaglandin- and nonprostaglandin pathways of flu infection. Deeper understanding of these pathways can help scientists learn how to manipulate them to better treat a range of illnesses.