In February of last year, authorities confirmed the details of a grave medical accident.The US Centers for Disease Control and Prevention (CDC) diagnosed a fatal rabies infection in a patient from Michigan.The circumstances of transmission were unusual. The deceased man, an organ recipient, had received a donated kidney infected with rabies.The source of the kidney was a man in Idaho who had died only weeks earlier, donating his organs for others in need. At the time of his death, nobody realized his body was infected with the deadly virus.Subsequent investigations revealed the Idaho man had recently been scratched by a skunk on his rural property – an infectious encounter that ultimately claimed his own life, and that of the man to whom he gave his kidney.Records show it was only the fourth time in US history that an organ transplant procedure had transmitted the rabies virus (Lyssavirus rabies) from an initially undiagnosed donor.But what if these kinds of records are wrong?Colorized transmission electron micrograph of rabies virus particles. (NIAID/Wikimedia Commons/CC BY 2.0)A new analysis published in Communications Health suggests that official figures may dramatically underestimate how many human cases of rabies are actually circulating in the US each year.According to researchers from the Pandemic Sciences Institute at the University of Oxford, the extremely low count of confirmed human rabies cases in the US each year – just 2.4 cases annually on average from 2000 to 2024 – seems much lower than it should be.The reason why it seems low is that a relatively high number of rabies cases are subsequently confirmed after infected organ transplants, like the sad case of the kidney recipient from Michigan.