National Park Service officials are investigating a series of illnesses among individuals who recently rafted along the Colorado River in the Grand Canyon. Reports indicate that some rafters have experienced flu-like symptoms, including fatigue and fever, alongside infections from minor injuries.
One rafter, Matthew Wappett of Utah, recounted his experience on social media. Wappett, who rafted the river in late May and early June, developed a severely swollen knee with intense joint pain and fever within days of completing his trip. Doctors initially suspected a staph infection and began antibiotic treatment, but Wappett continued to experience fevers and severe aches, and was later diagnosed with pneumonia. He has also undergone testing for mosquito-borne illnesses like dengue fever and fungal diseases such as Valley Fever.
Wappett stated that he feels "horrible" and has been contacted by National Park Service epidemiologists. He shared a warning on a Grand Canyon rafting Facebook group, urging others to "be careful."
The National Park Service confirmed it is aware of the reported illnesses and is leading an investigation in coordination with public health partners. As of this report, the agency has not released details on the number of cases or potential diagnoses, stating that more information will be shared as it becomes available.
Speculation on social media includes potential diagnoses such as Dengue fever, Chikungunya, Valley Fever, and Legionnaires' disease. Dengue and Chikungunya are mosquito-borne illnesses that can cause severe joint pain, fever, and other symptoms, with Chikungunya-related arthritis sometimes persisting for months or years. Valley Fever is a fungal infection contracted by inhaling spores from disturbed soil, common in Arizona. Legionnaires' disease is a severe form of pneumonia transmitted through contaminated water vapor.
