Researchers from North Carolina State University and UNC-Greensboro have discovered a bacterium in North Carolina that causes scrub typhus, a disease not previously reported in the United States. Scrub typhus can lead to fever, headache, body aches, and can be fatal if untreated with antibiotics. However, the disease has not yet been found in animals or humans in the state.
The researchers conducted tests on free-living, larval trombiculid mites, commonly known as chiggers, in various recreational parks in North Carolina. They found a high frequency of the bacterium, Orientia, which belongs to the Rickettsiaceae family, in the chiggers. These mites become parasitic during their larval stage and bite vertebrate hosts, including humans.
The team collected chiggers by placing a black tile on the ground in ten different state parks and observing the mites as they crossed the tile. Microbiome studies helped identify the bacteria present in the chiggers. Some parks showed a positivity rate of 90% or 80% for the Orientia bacterium, while others had rates as low as 10%.
Scrub typhus symptoms resemble those of Rocky Mountain spotted fever, a disease typically associated with tick bites. While scrub typhus is more commonly found in Asia and the Pacific, it has been detected in Africa and the Middle East in recent years. The exact cause of its spread to different regions is still uncertain.
The researchers have not determined whether the bacterium is a recent introduction or if it has been present in the state for an extended period. It is also unclear whether the infected chiggers found in North Carolina will cause disease, which requires further investigation.
The team plans to resample chiggers in the recreational park sites to validate their initial findings. The study was published in the journal Emerging Infectious Diseases and involved researchers from North Carolina State University, UNC-Greensboro, and the Georgia Museum of Natural History.
Source: North Carolina State University