Dengue fever has killed at least 273 people and infected more than 156,000 others across Peru in what has become the worst outbreak of the disease in the country’s history — with little relief in sight. The fever, also known as “breakbone fever” because of the intense bone pain it inflicts, kills as many as 13% of those unable to receive treatment and hospitals across the country are currently stretched far beyond their capacity. The mosquitoes that carry the dengue fever virus flourish in the wet conditions brought on by El Niño and a cyclone that dumped heavy rain on the northern part of the country earlier this year — conditions that aren’t expected to improve anytime soon. (Washington Post $, CBC, Forbes, Reuters, BBC, USA TODAY; Climate Signals background: Vector-borne disease risk increase)