This year, nearly 100,000 people in Bangladesh have contracted dengue fever, a mosquito-borne viral disease common in tropical and subtropical regions of the world. The number of infected patients is overwhelming the fragile hospital system there. More than 450 people have died so far, the deadliest dengue outbreak in the nation of approximately 170 million since record keeping began in 2000. Sri Lanka, nearby, is also experiencing a sharp spike — more than 40,000 cases of dengue this year alone.

Similar dengue-driven crises are unfolding in other parts of the globe. The Americas are in a “public health emergency,” according to the World Health Organization, or WHO: Peru experienced its largest dengue outbreak ever this summer; Brazil, Bolivia, and Argentina are also reporting alarmingly high numbers of cases.

In the United States, five cases of locally acquired dengue have been reported in Florida this month alone, prompting local health officials to put Miami-Dade and Broward counties on alert. The state has reported a total of 11 cases of locally transmitted dengue so far in 2023.

These outbreaks are concerning, but they’re not particularly surprising to experts who have been tracking dengue for the past several decades. Cases of dengue — which can cause fever, rashes, vomiting, and, in severe instances, internal bleeding, organ failure, and death — have been rising for years.

Since the beginning of the century, global cases of the disease, carried by the Aedes genus of mosquitoes, have skyrocketed, from roughly 500,000 in 2000 to more than 5 million in 2019. In the first seven months of 2023, worldwide cases spiked to more than 3 million, and over 1,500 deaths have been reported — numbers that are expected to rise as the summer continues.

There are likely hundreds of millions more unreported incidents each year, as dengue produces mild or no symptoms in most people. But as more people get infected, the percentage who end up developing the severe form of the disease will increase, too. Experts say a tangled web of factors is driving the surge, but one culprit stands out: climate change.

Read the full article about dengue fever by Zoya Teirstein at Grist.