CDC issues warning as three die from Rocky Mountain spotted fever outbreak

US health officials have issued a warning after three people died from contracting the Rocky Mountain spotted fever on trips to Mexico.

The Centres for Disease Control and Prevention (CDC) announced a Level One warning urging people to practice usual precautions while travelling in affected areas.

The agency said that Rocky Mountain spotted fever had been found in urban areas of several states in northern Mexico, including but not limited to Baja California, Sonora, Chihuahua, Coahuila and Nuevo Leon.

The fever is spread through ticks, a tiny parasitic animal that can attach itself to the skin of a human or animal and suck out blood.

Dogs often carry the infected ticks which then come into contact and bite humans.

The fever is currently “endemic” across Mexico and areas of southwestern US, the US Embassy and Consulates in Mexico said in a statement.

Between July and December 2023, the California Department of Public Health said five patients had developed the disease within two weeks of travelling within Tecate in Mexico.

All five patients, four of whom were under 18 years old, were hospitalised, and three of them died.

“Seek medical attention if you or a family member has travelled to Tecate or another city in northern Mexico and develops symptoms during travel or within two weeks of returning to the United States,” reads the CDC website.

The CDC and the US embassy stressed the importance of treating Rocky Mountain spotted fever as early as possible – or the outcome could prove fatal.

“Half of all people who die from the disease succumb within eight days of illness onset,” the embassy said in their statement.

Most people who develop the illness begin suffering symptoms such as a fever, headache, nausea, vomiting, stomach and muscle pain and a lack of appetite, the CDC said.

A common sign that people are sick with the fever is a rash that will appear after around two to four days, sometimes looking like red splotches, other times like pinpoint dots.

People who experience a severe case of Rocky Mountain spotted fever may be left with long-term health problems such as amputation of appendages, hearing loss, paralysis or mental disability.

Most people who catch the fever early can be treated with the antibiotic doxycycline, preventing serious illness or death.

If travelling to affected areas, the CDC recommends using EPA-registered insect repellant on exposed skin and clothing and checking your body and clothing regularly for ticks.

If you do find a tick on your body, remove it as soon as possible.

Dogs can also be protected using tick preventatives.

Cases of Rocky Mountain spotted fever occur can also throughout the US and are most commonly reported in North Carolina, Tennessee, Missouri, Arkansas and Oklahoma.

There are upwards of 5,000 Rocky Mountain spotted fever cases recorded each year in the US, according to the CDC.