CDC Warns Travelers: Brain-Bleeding Virus Detected in Americas, Urgent Alert Issued

Travelers heading to various countries are being urgently cautioned about escalating outbreaks of a mosquito-borne illness known for causing brain hemorrhages.

The Centers for Disease Control and Prevention (CDC) has raised a level 1 global travel alert following an unusual rise in dengue fever cases worldwide.

Specifically, the CDC has highlighted 16 countries where the risk of contracting this disease is notably higher, advising travelers to adopt protective measures against mosquito bites.

The CDC has noted an unexpected increase in dengue cases among US travelers returning from countries including Afghanistan, Bangladesh, Bolivia, Colombia, the Cook Islands, Cuba, Guyana, Maldives, Mali, Mauritania, New Caledonia, Pakistan, Samoa, Sudan, Timor-Leste, and Vietnam.

Health experts recommend that travelers use insect repellent, wear long-sleeved clothing and pants when outside, and sleep in air-conditioned rooms or those equipped with window screens to minimize exposure to mosquitoes.

Dengue fever often causes an asymptomatic infection, but in some patients it can trigger life-threatening internal bleeding, respiratory distress and heart failure.

It can also lead to shock and organ failure, especially of the liver, brain and heart. 

Patients may also develop dengue shock syndrome, a condition where severe bleeding leads to a rapid drop in blood pressure and causes the body to go into shock.

Children under five, adults over 65 and pregnant women are considered to be most at risk from the virus.

The CDC has issued a travel alert for travelers heading to 16 countries over dengue fever (stock image of the Maldives)

Dengue was virtually eradicated from the US in the 1970s, but sporadic outbreaks have been recorded since, particularly in warmer states, including Florida and California. Most cases recorded in the US are linked to international travel. 

A level 1 travel advisory urges Americans to practice usual precautions because of the presence of an outbreak. It is the lowest level travel alert out of the four levels that can be issued. Level four is advice to avoid all travel.

The Americas recorded a major dengue fever outbreak in 2025, with Brazil alone registering nearly 200,000 cases. Today, cases are still above normal, although well below this peak.

Samoa has been battling a dengue outbreak since April last year, that has already sickened 16,800 people and been linked to the deaths of eight individuals, including a seven-month-old baby. 

Dengue is present in more than 100 countries globally and is a year-round threat to travelers and local people. Outbreaks occur every two to five years.

So far this year, no locally acquired cases of dengue fever have been detected in the mainland US. 

A total of 55 cases have been detected, but these were all linked to travel outside the US. Florida had the most, at 16 cases, followed by New York, at eight cases.

In 2025, 67 cases of locally acquired dengue fever were reported in the US, including 60 in Florida, six in California and one in Arizona. There were also 1,128 cases that were linked to travel.

People are being urged to use insect repellent and wear long-sleeve tops and pants (stock image)

Health officials say about 40 to 80 percent of people infected with dengue fever do not develop any symptoms. If symptoms do develop, they appear abruptly about five to seven days after infection.

Warning signs include a fever above 100F (38C), severe headache, pain behind the eyes, bone, joint or muscle pain, and bleeding in the gums. 

Some patients also develop redness of the skin on the face within the first 24 to 48 hours of symptoms emerging.

In severe cases, patients may also suffer from severe abdominal pain, persistent vomiting and lethargy.

There is no specific cure for dengue fever and treatment consists of supportive care and therapies to manage symptoms and complications.

Doctors recommend patients with mild symptoms drink plenty of fluids and take Tylenol to ease pain. 

In severe cases, patients may be admitted to the hospital for supportive care, an IV, blood pressure monitoring and a transfusion to replace lost blood.

To protect against dengue fever, there is a three-dose vaccine available, which is recommended for children aged nine to 16 years. It slashes the risk of a symptomatic infection by about 80 percent.