LOS ANGELES, Sept. 1 (UPI) -- Elimination of the smallpox vaccine in 1980 because the disease had ended has allowed a related virus -- human monkeypox -- to thrive, U.S. researchers say.
Anne Rimoin of the University of California, Los Angeles, School of Public Health and colleagues report that 30 years after the smallpox vaccination ceased, rates of monkeypox have increased dramatically in the rural Democratic Republic of Congo, with sporadic outbreaks in other African nations and even the United States.
Until 1980, the smallpox vaccine provided cross-protective immunity against monkeypox -- a "zoonotic orthopoxvirus," meaning it can be passed from animals to humans -- for which there is no treatment, Rimoin says.
"All you can do is provide supportive care," Rimoin says in a statement. "There are no antibiotics. If you survive, the illness eventually runs its course."
Rimoin and colleagues conducted a population-based surveillance in the central region of the Democratic Republic of Congo from 2006 to 2007, gathering epidemiologic data and biological samples obtained from suspected cases. They compared the data gathered in similar regions from 1981 to 1986.
Rimoin describes the findings as "startling," saying the study "shows a 20-fold increase in human monkeypox in the DRC since smallpox vaccinations were ended in 1980."