RIO DE JANEIRO, Feb. 6 (Xinhua) -- The regional government of Minas Gerais, the second most populated state in Brazil, raised the number of deaths caused by an outbreak of yellow fever to 61 on Tuesday, 25 more than on Jan. 30.

According to a statement by the state health secretariat, there have been 164 confirmed cases of yellow fever, including 151 men and 13 women.

A total of 301 other potential cases are being investigated. Until now, there have been no confirmed cases among people that have been vaccinated against the disease.

Three of the deaths have come in Belo Horizonte, the state capital, and another 15 in its surrounding urban area. The secretariat also said the mortality rate of the disease stood at 37.2 percent.

Minas Gerais has been heavily affected along with Sao Paulo and Rio de Janeiro, leading federal, regional and municipal authorities to jointly roll out mass vaccination campaigns.

The mosquitoes spreading the yellow fever are of the "Haemagogus" and "Sabethes" varieties, different from the "Aedes ai", which has been spreading dengue, Zika and chikungunya in recent years.