The phrase "widespread outbreak" means that a disease or a problem is spreading rapidly over a large area, affecting a lot of people or things. Full definition
The academies added that more cooperation is needed to cut the risk of widespread outbreaks of infectious diseases. (dotearth.blogs.nytimes.com)
Zika was known for 60 years as a mild virus that appeared sporadically, but since 2007, two troubling shifts have taken place, Dye said: Zika virus now results in widespread outbreaks of hundreds or thousands of cases, and it is associated with neurological disorders like microcephaly and Guillain - Barre syndrome, a disorder in which the body's immune system attacks the nerves. (aaas.org)
Viruses and parasites pose a threat to the blood supply as evidenced by the recent widespread outbreaks of Chikungunya and Zika viruses. (bsrisf.org)