The U.S. Centers for Disease Control and Prevention has issued a health advisory warning the public and health care officials about the increasing risk of dengue virus infections in the United States.

The U.S. territory of Puerto Rico has declared a public health emergency with almost 1,500 cases.

There has also been a record 745 cases among U.S. travelers this year, the CDC said.

The CDC advisory issued on Tuesday said the 9.7 million dengue cases reported in the Americas this year are more than twice the 4.6 million recorded last year.

The 2024 global incidence of dengue, a disease spread by bites of the Aedes aegypti mosquito, is the highest on record, according to the CDC. That trend is being fueled by the warmer temperatures brought about by climate change, officials say.

Dengue is usually more common in tropical and subtropical climates.

The CDC urged health care providers to be increasingly suspicious of people with fevers who have recently visited areas known to have frequent or continuous dengue transmissions.

The CDC also called for health care providers to order the appropriate detection tests and report the results promptly to public health authorities.

In addition, the U.S. agency advised health care workers “to promote mosquito bite prevention measures” among people and also travelers who live or visit areas where there is “frequent or continuous dengue transmission.”

Dengue infections are often asymptomatic or can sometimes produce a mild illness. However, dengue can sometimes manifest as a severe illness that can cause death.

The World Health Organization says that after a fever from dengue has subsided, other symptoms can emerge, including severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, fatigue, restlessness, blood in vomit or stool, severe thirst, pale and cold skin and weakness.

While there is no specific treatment for dengue, WHO said most cases are treated with pain medication, but recuperation can take several weeks.

In 2000, WHO reported 505,430 global dengue cases. Nineteen years later, that figure jumped to at least 5.2 million cases.

WHO cautioned that figure was likely an underestimation of the cases, as dengue is often underreported and misdiagnosed.

Some information for this report came from Reuters and The Associated Press.