Jan. 26 (UPI) -- Brazil's Ministry of Health said it ordered 11.5 million doses of yellow fever vaccine following an outbreak that killed at least 40 people.
Most cases occurred in the state of Minas Gerais, but about 360 cases are also under investigation in the states of Espírito Santo, Rio de Janeiro, Bahia and São Paulo.
The Centers for Disease Control and Prevention said yellow fever, found in tropical and subtropical areas in Africa and South America, is transmitted to people through the bite of infected mosquitoes.
"The Ministry of Health strengthens the strategic stock of the yellow fever vaccine with 11.5 million more doses," Brazil's ministry said in a statement on Wednesday, adding that 6 million doses would be delivered "immediately" while the remaining 5.5 million will be "delivered as requested by the ministry."
The CDC said illness ranges in severity from a self-limited febrile illness to severe liver disease with bleeding, adding that from 20 percent to 50 percent of people whose yellow fever infection becomes serious die.
"The measure of focusing vaccination in areas considered at risk, taken by the Ministry of Health together with the states, is the best way to contain the current situation, offering efficacy and safety for the population," Eduardo Hage, director of Brazil's Department of Surveillance of Communicable Diseases, said in a statement.