Dengue virus cases are rising, especially in New Jersey and New York, CDC says

According to the CDC, the number of dengue virus cases has increased, especially in New York and New Jersey.

Officials say 41 cases of the mosquito-borne disease have been reported in the Garden State.

Pennsylvania has reported 25 cases, while Delaware has only reported four.

There have been more than 2,500 infections in the U.S. so far, with most people getting sick while traveling, officials said.

What is dengue and where is it common?

Dengue is a mosquito-borne virus that is primarily spread by the Aedes aegypti mosquito. According to the CDC, this mosquito also carries several other viruses, including yellow fever, chikungunya, and Zika.

According to WHO, dengue is endemic in more than 100 countries with tropical and subtropical climates, mainly in urban and semi-urban areas.

The disease is also endemic in the U.S. territories of Puerto Rico, the U.S. Virgin Islands, and American Samoa.

According to CDC data, more than 34,000 locally acquired cases were reported in the U.S. between 2010 and 2023. A handful of outbreaks of locally transmitted cases have been reported in states with warmer climates, including Florida, Texas, Hawaii and Arizona. California reported its first locally transmitted case last year in Pasadena.

But nearly all of the cases in the U.S. are being reported in Puerto Rico, Dr. Gabriela Paz-Bailey, chief of the Dengue Branch in the Division of Vector-Borne Diseases at the CDC’s National Center for Emerging and Zoonotic Infectious Diseases, previously told CNN. And that’s no surprise.

“The climate is perfect for it. It’s a tropical island,” she said. “There are indeed efforts by the health department and other organizations like the Puerto Rico vector control unit to combat dengue in the area.”

This includes public education and integrated mosquito management, such as “removing mosquito breeding sites, through community engagement as well as clean-up campaigns,” Paz-Bailey said.

She noted that similar efforts are also recommended in the rest of the US and its territories.

Dengue symptoms

Only about 1 in 4 people infected with dengue experience symptoms.

The most common symptom is fever. It can also cause nausea, vomiting, a rash or pain, usually behind the eyes, or muscle, joint or bone pain.

There are four strains of the virus, or serotypes, according to the World Health Organization. Once someone contracts one of the strains, they cannot be infected again. But the more times someone is infected with different strains, the greater the chance that they will become seriously ill.

Severe dengue is less common, affecting about 1 in 20 people. But the symptoms are more disturbing. It can cause shock, internal bleeding and even death.

According to the CDC, approximately 100 million people worldwide become ill and 40,000 people die from severe dengue each year.

Dengue vaccine and treatment

The U.S. Food and Drug Administration approved a dengue vaccine in 2019, and the CDC recommends it for children ages 9 to 16 who have laboratory-confirmed evidence of dengue infection and who live in areas of the United States where dengue is endemic or frequently occurring. The vaccine requires three doses, given six months apart.

However, Sanofi-Pasteur has indicated that it will stop production of the Dengvaxia vaccine due to a lack of demand in the global market.

There is no dengue vaccine available for adults in the U.S. The CDC said two other dengue vaccines have been approved or are in development, but they are not currently available in the United States.

There is also no specific medication to treat dengue, the CDC says. Over-the-counter medications such as acetaminophen can help relieve fever or pain, but experts say you should not take aspirin or ibuprofen because they can increase the risk of bleeding that sometimes occurs with dengue.

Protecting yourself against dengue

Preventing mosquito bites and controlling mosquitoes in and around the home are the most important ways to prevent dengue. If you do go outside, the CDC recommends using insect repellents registered with the U.S. Environmental Protection Agency to prevent bites from mosquitoes that can transmit dengue. Wearing long-sleeved shirts and long pants is another option, along with treating your clothing with 0.5 percent permethrin, an insecticide.

The Aedes aegypti mosquito, which spreads dengue and other viruses, doesn’t like to travel far and prefers to breed in our backyards, said Dr. Isik Unlu, acting director and operations manager of the Miami-Dade County Mosquito Control Division.

“They prefer to be around people. That’s the problem,” she said, adding that the species is often found in containers that collect rainwater, especially during the summer months.

According to Unlu, almost anything you see in your backyard can become a breeding ground, including bird baths, plant saucers, tires, extension gutters and kiddie pools.

Unlu and Paz-Bailey recommend removing standing water around your home as often as possible to prevent mosquitoes from gathering and breeding.

CNN Wire contributed to this report.