Beyond the Lone Star Tick? Two Patient-Reported Alpha-gal Cases Following Asian Longhorned Tick Exposure

When most people think about Alpha-gal Syndrome (AGS), they think about one tick: the Lone Star Tick.

And for good reason. The Lone Star Tick remains the species most strongly associated with AGS in the United States.

But as researchers continue to study Alpha-gal Syndrome and as invasive tick species expand into new regions, questions are beginning to emerge about whether other species may also play a role in alpha-gal sensitization.

One species attracting growing attention is the Asian Longhorned Tick (Haemaphysalis longicornis).

An Invasive Tick That Wasn't Supposed to Be Here

The Asian Longhorned Tick is native to East Asia and was first officially identified in the United States in August 2017after a sheep in Hunterdon County, New Jersey was found carrying a massive infestation. More than 1,000 ticks were reportedly collected from the animal, leading investigators to confirm the presence of this invasive species in the U.S.

Source: CDC, Multistate Infestation with the Exotic Disease–Vector Tick Haemaphysalis longicornis — United States, August 2017–September 2018 (MMWR, 2018)https://www.cdc.gov/mmwr/volumes/67/wr/mm6747a3.htm

Since that discovery, the Asian Longhorned Tick has continued to spread throughout the

United States, prompting concerns among public health officials, veterinarians, livestock producers, and researchers.

Adding to the interest, scientific studies have identified alpha-gal-containing material within Asian Longhorned Ticks, raising questions about whether the species could potentially contribute to alpha-gal sensitization. While no definitive causal relationship has been established, the topic remains an active area of research.

What We Found in the TickBiteData Registry

Among more than 3,000 patient-reported survey responses collected by TickBiteData, two respondents identified the tick responsible for their exposure as an Asian Longhorned Tick.

Reported Locations

• Arkansas

• Georgia

Shared Characteristics

Interestingly, both respondents reported:

• Female

• Age 50–59

• Exposure occurring in their backyard

• Symptom onset within weeks of the reported bite

• Persistent joint pain or arthritis

• Tremors or shaking

Arkansas Case

The Arkansas respondent reported:

• Asian Longhorned Tick exposure

• Bite occurring in August 2011

• More than 10 lifetime tick bites

• Symptom onset within weeks

• Persistent joint pain

• Tremors

No additional narrative details were provided.

Georgia Case

The Georgia respondent reported:

• Asian Longhorned Tick exposure

• Bite occurring in June 2015

• Rash and infection at the bite site

• Symptom onset within weeks

• Persistent arthritis and joint pain

• Tremors

• Negative Lyme disease testing

• Laboratory-confirmed Alpha-gal Syndrome through blood testing

• More than three years before receiving an AGS diagnosis

• Additional tick bites after diagnosis with worsening symptoms

The respondent described years of ongoing health challenges before eventually requesting Alpha-gal testing from an allergist.

Why This Matters

To be clear, two cases do not establish causation.

Patient-reported surveys are valuable for identifying patterns and generating hypotheses, but they cannot determine whether a particular tick species caused a person's Alpha-gal Syndrome.

What these cases do show is that some patients who developed AGS do not always identify the Lone Star Tick as the tick responsible for their exposure.

As awareness grows and more patients participate in research, understanding these reports may help guide future scientific investigation.

It's Not Just the Asian Longhorned Tick

One of the most interesting findings from the TickBiteData registry is the diversity of tick species reported by respondents.

While the Lone Star Tick remains by far the most commonly reported exposure, survey participants have identified numerous other tick species from around the world.

Tick Species Reported by Survey Respondents

Reported Exposure	Number of Respondents
Lone Star Tick	1,662
Seed Ticks (species unknown)	142
Deer Tick	83
Blacklegged Tick	37
Brown Dog Tick	13
American Dog Tick	12
Australian Paralysis Tick	10
Rocky Mountain Wood Tick	10
Asian Longhorned Tick	2

Important: Not all survey respondents were able to identify the species of tick involved in their exposure. Many respondents left this field blank or reported being unsure of the tick species. As a result, the totals shown below represent only respondents who selected a specific tick type and should not be interpreted as the total number of AGS cases in the registry.

In addition, respondents have reported exposures occurring throughout:

• The United States

• Australia

• Canada

• South Africa

• Sweden

• Multiple European countries

These reports do not prove that each species is capable of causing Alpha-gal Syndrome.

Tick identification is self-reported, and many respondents have experienced multiple tick bites throughout their lives.

However, the findings highlight an important reality:

Patients around the world continue to report AGS following exposure to a wider variety of tick species than is commonly discussed.

As researchers work to better understand Alpha-gal Syndrome, continued investigation into regional tick species, alpha-gal sensitization pathways, and geographic patterns remains important.

The Bottom Line

The Asian Longhorned Tick was first officially identified in the United States in 2017 on a sheep in New Jersey, and it continues to expand its range across the country.

Within the TickBiteData registry, two respondents identified the Asian Longhorned Tick as the tick involved in their exposure history. One of those individuals later reported a laboratory-confirmed Alpha-gal Syndrome diagnosis.

While these observations cannot establish cause and effect, they add to a growing body of questions about whether AGS may involve a broader range of tick species than currently recognized.

As always, more research is needed—but patient-reported data can help identify where researchers may want to look next.

References

Beard CB, Occi J, Bonilla DL, et al. Multistate Infestation with the Exotic Disease–Vector Tick Haemaphysalis longicornis — United States, August 2017–September 2018. MMWR Morb Mortal Wkly Rep. 2018;67(47):1310–1313.https://www.cdc.gov/mmwr/volumes/67/wr/mm6747a3.htm

Centers for Disease Control and Prevention (CDC). Asian Longhorned Tick (Haemaphysalis longicornis).https://www.cdc.gov/ticks/asianlonghornedtick/

Disclaimer: Findings presented are based on patient-reported survey responses submitted to TickBiteData.com and have not been independently verified. These observations are intended to identify emerging patterns and generate hypotheses for future research. They should not be interpreted as evidence of causation.