Here are a few natural ways to rewrite this title in Swedish, depending on the style you prefer:

Option 1 (Most direct and news-style):

Minst åtta döda i bussolycka i Rio de Janeiro-området

Option 2 (Using a dash for a dramatic headline):

Bussolycka i Brasilien – minst åtta döda i Rio-området

Option 3 (More explanatory/present tense):

Minst åtta omkommer i svår bussolycka i Rio de Janeiro-området

The first option is the most common and concise way a Swedish news outlet would headline this story.