The United States Does Not Know How Many People Have Alpha-Gal Syndrome. That Is the Problem.

Alpha-gal syndrome is a tick-borne condition that turns the people who develop it into late-night emergency cases. The lone star tick carries a sugar molecule called galactose-alpha-1,3-galactose in its saliva, and when the tick bites a person, the bite can trigger the immune system to produce antibodies against the molecule. After that, eating beef, pork, lamb, or sometimes dairy or gelatin can cause hives, vomiting, abdominal cramps, or anaphylaxis. The reaction is delayed by several hours, which is why clinicians have started calling it “the midnight allergy”. Patients eat dinner, fall asleep, and wake to a full-body reaction whose connection to a hamburger they ate at six o’clock is not obvious to anyone who has not seen the condition before. The CDC has documented more than 110,000 suspected cases since 2009 and estimates the true number could be three to four times higher. The United States does not actually know how many people have this condition, and the gap between what the surveillance data shows and what the disease burden likely is has consequences that compound every year the gap remains uncorrected.

Why counting matters

The foundation of any public health response to a disease is the ability to count it. This is not an abstract principle; it is the operational reality on which every downstream intervention depends. If you cannot count cases, you cannot tell communities how common the disease is. You cannot tell clinicians who in their patient population is likely to be at risk. You cannot allocate resources to the regions where the burden is highest. You cannot evaluate whether any prevention effort is working. Public health agencies that cannot see a disease cannot manage it, and clinicians who do not know a disease is common in their area are less likely to consider it when a patient presents with symptoms that could be explained by it. The patient bounces between specialists, accumulates medical bills, and eventually arrives at a diagnosis through trial and error, often after months or years of unexplained reactions.

For alpha-gal, the surveillance gap is striking. Arkansas became the first state to make alpha-gal a reportable condition in 2023. More than 15 states now track cases to some degree. New York, which contains one of the country’s most concentrated hot spots in Suffolk County, does not track cases statewide. New York City does track them, and has documented 280 suspected cases since 2024, even though the lone star tick is not common in the five boroughs themselves. The implication is that some portion of the New York City cases are people who were bitten on Long Island or in the Hudson Valley and developed symptoms after returning home. The statewide surveillance system that would connect these dots does not exist.

What a patchwork surveillance system actually produces

The lone star tick is not waiting for state public health departments to catch up. It is expanding its range northward, driven by the same warming temperatures that are pushing all tick populations into regions they did not previously occupy. In April, the CDC reported last month that emergency department visits for tick bites had risen roughly three-fold since March, with the Northeast leading the country at nearly 50 visits per 100,000. The tick is also notable for actively crawling toward people rather than waiting passively for a host to brush past, which makes it more efficient at finding hosts and more likely to produce the bites that lead to alpha-gal sensitization.

A surveillance system that operates in some states but not others, and that captures cases inconsistently within states, produces a picture of the disease that systematically underestimates how common it is in the places where it is most common. The CDC’s estimate that the true case count could be three to four times the documented number is not a wild guess; it is the kind of estimate epidemiologists generate when they know the surveillance system is missing cases and can do rough math on the size of the gap. The actual number could easily be higher than that, particularly in the corridors where the tick’s range is expanding and where clinicians have not yet learned to consider alpha-gal in their differential diagnosis.

The clinical consequence of bad surveillance

The cost of inadequate surveillance shows up in patient experience in ways that are easy to overlook until you talk to people who have lived through it. A patient who develops nighttime hives and gastrointestinal symptoms after dinner does not arrive at an alpha-gal diagnosis quickly. They see their primary care physician, who treats the symptoms as a generic allergy. They see a gastroenterologist for the cramps and an allergist for the hives. They try elimination diets. They are told their reactions are stress-related, or food-sensitivity-related, or psychosomatic. The right test, an IgE assay for alpha-gal antibodies, is straightforward and inexpensive, but it is not ordered routinely because most clinicians have not been told that the disease is common enough in their population to warrant testing. The surveillance gap and the diagnostic gap are the same gap, and they reinforce each other. A condition that public health does not track is a condition that medicine does not learn to recognize.

This is a recurring pattern in how the United States handles diseases that fall outside the standard infectious-disease surveillance categories. When public health infrastructure is cut or never built in the first place, the work that would have happened in a clinic or a health department gets transferred to the patient, who pays in time, in money, and in the prolonged uncertainty of going years without knowing what is wrong. The savings to the government look small on a budget spreadsheet. The costs to patients are substantial, and they accumulate across hundreds of thousands of people.

What an actual response would look like

The fix for alpha-gal surveillance is not technically complicated. It requires making the condition reportable in every state where the lone star tick has established a population, which at this point includes most of the eastern half of the country. It requires laboratory reporting of the IgE test results that confirm the diagnosis, so that cases get into the surveillance system without depending on busy clinicians to remember to file the paperwork. It requires public health communication to clinicians about when to consider the diagnosis. And it requires a sustained federal role in coordinating across state systems, because the lone star tick does not respect state boundaries and a surveillance system that operates state by state will always undercount cases in regions where the tick is expanding.

None of this is happening at the scale the disease requires. The federal capacity for vector-borne disease surveillance has been reduced rather than expanded, even as the geographic range of the relevant ticks has grown. The states that are taking the problem seriously are doing so largely on their own initiative, and the states that are not have no federal incentive pushing them to start. The result is a national surveillance system that is blind in the places where it most needs to see, and a clinical workforce that is operating without the information it would need to diagnose patients in real time.

Alpha-gal syndrome is not a rare disease anymore, if it ever was. It is a tick-borne condition spreading through a changing climate, affecting an unknown but substantial number of Americans, and it is being managed by a public health system that has chosen not to count it. The choice not to count is itself a policy. It produces the patients who spend two years bouncing between specialists. It produces the clinicians who do not consider the diagnosis. It produces the public that does not know which ticks to worry about. The first step toward a serious response is the simplest one: see the disease, and let the count drive everything that comes next.