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.