I travelled to Brasil last Jan and it is really hot just now as it's their summer - the mosquitoes were really mad and the most fustrating thing ever. I was on the east coast and didn't need any vaccinations, however you will need to check the local news in your destination for possible outbreaks of yellow fever. Take plenty of very strong mosquitoe repellant. Have a great time it really is a beautiful country and the beaches are fantastic. Factor 50 sunblock is a must.