Health officials issued a warning on Tuesday alerting authorities, health care providers, and the public of the increased risk of dengue fever infections in the US. The virus, which is spread by mosquitoes, has been surging worldwide, helped by climate change. In barely six months, countries across the globe have broken calendar-year records for dengue cases. A total of 2,241 dengue cases have been reported so far this year in the US, including 1,498 cases in Puerto Rico, where a public health emergency was declared in March after cases exceeded historical figures. Florida has the most reported cases in the continental US, with most of those cases in Miami-Dade County and at least 13 cases in Palm Beach County.