The Centers for Disease Control and Prevention has issued a Level 2 alert in multiple states of Brazil due to a large, ongoing outbreak of yellow fever.
A Level 2 alert means travelers should take extra precautions before going to infected areas, such as getting vaccinated against certain diseases.
According to the CDC, since the end of 2017, yellow fever has been reported in the states of Rio de Janeiro, Minas Gerais, and São Paulo, including areas close to the city. The organization strongly recommends travelers and locals be vaccinated before going to any of these areas.
Source: Travel+Leisure