FLICKR, KENNY HOLSTONBetween 1988 and 1997, an anesthesiologist from Valencia, Spain, infected 275 of his patients with the hepatitis C virus, according to Spanish courts. Earlier this month (July 19), researchers from University of Valencia who helped establish the timing and victims of the outbreak for the courts published their account of the case in BMC Biology.
The anesthesiologist, Juan Maeso, is believed to have been infected with the blood-borne virus himself and then to have spread the infection by injecting himself with painkillers from the same needles he used to inject his patients.
Epidemiological data linked the anesthesiologist to 322 hepatitis C-positive patients. The researchers sequenced a rapidly evolving area of the hepatitis C genome, the E1-E2 region, in samples from the anesthesiologist and his putative victims. As a control, they also sequenced hepatitis C samples from 44 hepatitis C-infected people who were believed not to have been involved in the outbreak.
A phylogenetic tree of the viral sequences suggested that the majority of the patients’ viruses were derived from the anesthesiologist, excluding viruses from the control group and 47 additional patients. The courts determined that these 47 patients had not been infected by the anesthesiologist.
The researchers then used molecular clocks to calculate when the patients had been infected, based on the expected rate of viral evolution and calibrated using information from the few patients whose dates of infection were known. They determined that the anesthesiologist had likely been infected in 1988, around the time the first patient infections were estimated to have occurred.
“In the case described here, we used the fast evolutionary rate of HCV to disentangle a large and complex transmission process from a single source to almost 300 recipients spanning over a decade, a period during which the infecting viral population underwent evolutionary changes itself,” the researchers wrote in the paper.
The anesthesiologist was sentenced in 2007 to 1,933 years in prison and ordered to make extensive payments to victims.
(Hat tip to Genome Web)