The fatality rate for H5N1 highly pathogenic avian influenza in humans historically has been high, with more than half of people dying. Why, then, is the current H5N1 bird flu outbreak — which has caused massive die-offs in wild birds, farmed poultry and even wild mammals — causing mostly mild symptoms in the people it has infected? New research, led by scientists at Penn State and the University of Pittsburgh and published today (July 23) in the journal Science Translational Medicine, indicates that immunity to a seasonal influenza virus known as pandemic H1N1 that began circulating in 2009, provides protection from severe illness from H5N1 in a laboratory animal model.

A USC proof-of-concept study found that OCT imaging can measure fluid levels in the inner ear, which correlate with a patient’s degree of hearing loss. The Keck School of Medicine of USC team used the tool to scan the inner ears of 19 patients undergoing ear surgery. Six patients had normal inner ear function, four had Ménière’s disease, and nine had vestibular schwannoma (a benign tumor on a nerve that connects the inner ear to the brain). During surgery, a thick outer bone known as the mastoid was temporarily removed, allowing researchers to use OCT to collect images of the fluid compartments in the inner ear. OCT images showed that patients with Ménière’s disease or vestibular schwannoma had higher levels of a fluid called endolymph, compared to those with normal inner ear function. Increased endolymph levels were linked to greater hearing loss, indicating that measuring these fluid levels could help predict the severity of symptoms. The researchers are working to develop a smaller, more affordable version of the tool that they plan to distribute and test with surgeons and are working to adapt the technology for clinical use outside of surgery by improving the software and image-processing techniques.