Rising Threat of Exotic Ticks Hitchhiking into the US via Travelers and Public Health Implications

Exotic tick species are increasingly appearing in the United States, transported across borders by travelers returning from various parts of the world. A recent study highlights the introduction of seven non-native tick species into Connecticut between 2019 and 2023. These ticks originate from countries including Germany, Guatemala, Costa Rica, Poland, Scotland, Tanzania, and Belize. The research, published in iScience, underscores the expanding range of invasive tick species in the US, fueled by the rise in international travel and animal trade.

Scientists scrutinized ticks collected from travelers and identified their species through microscopic examination and DNA analysis. Among these, two nymphs of Amblyomma mixtum from Guatemala and Costa Rica tested positive for Rickettsia amblyommatis. While the pathogenic role of this bacterium remains uncertain, related bacteria are known to cause Rocky Mountain spotted fever, indicating potential health risks.

The proliferation of non-native ticks raises concerns about the spread of tick-borne pathogens, which can lead to diseases such as Lyme disease and others. An estimated 476,000 cases of Lyme disease are diagnosed annually in the US, primarily transmitted through infected Ixodes ticks. Some ticks, like the lone star tick, can also trigger Alpha-gal syndrome, an allergic reaction to red meat, which can sometimes escalate to severe anaphylaxis.

This situation emphasizes the need for enhanced surveillance programs that include tick identification and pathogen screening to monitor and manage the risk of invasive ticks establishing permanent populations. Public awareness efforts are crucial to educate travelers about avoiding tick bites, inspecting for ticks, and understanding potential health hazards.

Efforts by public health officials to update clinicians on various tick species and their associated risks can help prevent disease transmission. As global connectivity increases, the risk of exotic ticks and the pathogens they carry being imported into the US is expected to rise, necessitating proactive measures to safeguard public health.

Source: https://medicalxpress.com/news/2025-08-exotic-hitchhiking-health.html