The Other Lab Leak Hypothesis: Is Lyme Disease Caused by an Escaped Bioweapon?

Practically everyone has heard of the tick-borne infection known as Lyme disease, even if they don’t live in a high-risk area. Some are aware of long-standing controversies about the consequences of infection or how best to treat it. Our concern here is for a newly emerging controversy about Lyme disease—namely, the theory that it originated as part of a bioweapons program. As U.S. Representative Chris Smith of New Jersey is heard to say while participating in a Department of Health and Human Services roundtable on Lyme disease: “They were weaponizing Ixodes burgdorferi [sic], as we all know.”¹

Part of this theory is that Lyme disease’s origins can be traced to the United States Department of Agriculture’s (USDA) Plum Island Animal Disease Laboratory, where it allegedly was developed as a biological weapon, either as a genetically modified organism or by “weaponizing” native ticks to carry a secret pathogen. Plum Island, in fact, would seem to be a good place to center these hypothetical activities, because it has exclusively been the site of a restricted-access USDA facility since 1954. The facility has long conducted research on foreign animal diseases that would devastate the livestock industry in the United States if they were ever introduced accidentally or purposefully as a biological weapon. This research is essential for developing vaccines and measures to prevent potential outbreaks of animal diseases, such as foot-and-mouth disease, African swine fever, and other diseases of domesticated animals. 

Plum Island is located off the eastern end of Long Island and about seven miles across the water from the town of Lyme, Connecticut, where what seemed (at the time) to be a new tick-borne disease was identified in the 1970s. Over the past five decades, Lyme disease—as that illness is now called—has been documented in several other states in the northeastern, mid-Atlantic, and north-central U.S., as well as parts of states in the Far West. It is a tick-borne infectious disease affecting tens of thousands of people each year and at an enormous cost to the public’s health and people’s well-being. 

Nature poses a greater threat than human design or error as a source of new infectious diseases and epidemics for humans and other animals. 

The issue of whether the emergence of Lyme disease is the consequence of natural processes or might have originated from humans—namely, as a designed bioweapon, subsequently inadvertently or intentionally released—has become a hot topic in the news, social media, and podcasts. It has prompted calls for an investigation from members of Congress, where an amendment from Representative Smith is now part of the recently passed and White House-signed defense authorization bill. It would seem more convenient to have somebody or some government institution to blame for an emerging infectious disease, rather than natural events. But in reality, nature poses a greater threat than human design or error as a source of new infectious diseases and epidemics for humans and other animals. 

Plum Island is a high-containment facility only reachable by boat from Long Island and Connecticut for the daily transport of authorized personnel. Visitors are not allowed, and any intruders are promptly escorted off the island. Deer and other wildlife that may be susceptible to infections and occasionally swim to the island are immediately culled by sharpshooters from helicopters. Such high security has long led to rumors and suspicion among neighboring communities that something nefarious must be going on at Plum Island. The island had undeservedly gained notoriety in the Silence of the Lambs book (1988) and film (1991) in Hannibal Lecter’s telling as “Anthrax Island.” 

One of us (DF) worked on Plum Island during the 1990s, conducting research on African swine fever under a USDA research contract with Yale University. African swine fever is a tick-borne disease native to Africa, and it is highly infectious among pigs even without ticks. Access to infected animals required two changes of clothing and a shower before passing through each of two air-tight chambers. But there was no protection for personnel, as these animal diseases do not have the capacity to infect humans. If they did, self-contained spacesuits would be required, as are used for Ebola and other dangerous human pathogens in BSL-4 labs. The Plum Island facility had no capacity to work with human pathogens, and there is no evidence that scientists there ever worked on Lyme disease. 

The second of us (AGB) participated in the early 1980s in the discovery and then isolation of the bacterium that causes Lyme disease. The team accomplished this from ticks that were collected at the far end of Long Island, so not far from Plum Island. This sounds suspicious for an escape from the Plum Island lab. But Long Island and Lyme, Connecticut, were not the only places where Lyme disease was occurring at the time. The availability of cultured bacteria led to diagnostic assays that were quickly developed and implemented. Application of these blood tests for laboratory diagnosis in many other places in the United States revealed that the infection was not limited to a small area near Plum Island and had not been so restricted for many years. 

Besides New York and Connecticut in the early 1980s, cases were soon identified in other northeastern states, north-central states like Minnesota and Wisconsin, and even across the country in northern California. This is a disease only transmitted by ticks, which crawl and, unlike mosquitoes, do not fly. Even if attached to a deer, mouse, or bird, it would have been decades for the infection to spread so widely if it had been released from a single place at the continent’s end. 

Evidence that the bacteria were already present in the area long before any theorized release from Plum Island was finding their presence in museum specimens of preserved ticks and field mice that had been collected in the northeastern U.S. in the 19th or early 20th century. In retrospect, cases of Lyme disease in different parts of the country had been described by physicians in medical case reports from the 1960s. 

If the Lyme disease agent were some kind of Frankenstein germ, malignly created and released upon the world, one might as well invoke space aliens.

Further justification for rejecting a Plum Island bioweapon release theory was recognition that Lyme disease, under other names, had clearly been occurring in Europe since at least the early 20th century, decades before it was first named as a new disease in North America. In Sweden, the Lyme disease agent was recovered from chronic skin rashes that had started years before it was found in some New York ticks. Subsequently, the causes of Lyme disease were identified in ticks and mammals, as well as in patients in China, Japan, Korea, and Russia. Why would there be a need for a new bioweapon delivered by ticks if the infection was already occurring in many parts of the world? 

The bacterium that was isolated from those ticks from Long Island was the first example of what was soon recognized to be a species meriting its own name. But there was nothing strange about it at the time or since, even after intensive study. There is nothing to indicate that it was a genetically modified organism or was constructed from parts of other bacteria, as has been suggested. Genetic analysis of Lyme disease bacteria shows that they originated on the Eurasian continent and spread to North America thousands of years ago. 

That first isolate was representative of but one strain out of several that were occurring then and now in the northeastern U.S. There are other strains in the Midwest and another set in the Far West. Europe has its own strains of the bacteria. This pattern of differences is what would be expected for bacteria that have been widely distributed for millennia and evolved to adapt to their unique local circumstances over time. If the Lyme disease agent were some kind of Frankenstein germ, malignly created and released upon the world, one might as well invoke space aliens that had visited the Earth thousands of years ago. 

What’s the more plausible explanation for the increase in numbers and distribution of Lyme disease that began in the last half of the 20th century? It is clear to us that Lyme disease is a product of nature and has been present for millennia throughout the continents of Eurasia and North America. What has changed to cause it to become recently epidemic is the reestablishment of forests and deer, which has led to a proliferation of ticks over the past half-century. Massive deforestation in the Northeast and upper Midwest before 1900 for agriculture and manufacturing resulted in the near extermination of deer, the natural host of the deer tick that is responsible for transmitting Lyme disease in these areas. Long Island is the only known location in the Northeastern U.S. where white-tailed deer and deer ticks have persisted since colonial times. 

Lyme disease is a product of nature and has been present for millennia throughout the continents of Eurasia and North America.

Another refuge occurred in northern Wisconsin, where a case of Lyme disease occurring in the 1960s was retrospectively identified. From these two ancient refugia, Lyme disease has slowly spread to neighboring states as forests regenerated, and as deer and ticks returned to their former ranges. This spread has been well documented since the original discovery of the Lyme disease agent more than 40 years ago. The same history of reforestation of areas previously used for agriculture and industry accounts for the increase and spread of the Lyme disease bacteria and the ticks that transmit them in Europe. 

Can we call this increase in Lyme disease in various parts of the world the result of “human activities”? Of course. Without the human population growth and concomitant advances in agriculture and industry, Lyme disease would be but one of many infections transmitted among mammals, birds, and reptiles by ticks in woodlands for eons. But the resurgence of the Lyme disease story is just one aspect of a broader process of demographic, environmental, and social change occurring in developed countries of North America, Europe, and parts of Asia. We need not attribute it to the intentional or inadvertent actions of some government workers in a high biosafety level laboratory off the coast of Long Island.