As you get to know Lyme disease, you come to appreciate that the illness is much more complicated than an infection with a bacteria called Borrelia burgdorferi. Since 1981, many other species of Borrelia bacteria have been discovered worldwide, and many of those microbes have the potential to cause Lyme disease-like syndromes.

This has led to the terms, Borrelia burgdorferi sensu stricto and Borrelia burgdorferi sensu lato. The former refers to microbes that are similar enough genetically and structurally to the microbes discovered by Dr. Burgdorfer in 1981 to be called the same species. The latter are species of Borrelia that cause Lyme-like syndromes, but are not similar enough to be defined as the same species¹.

As of 2015, there are over twenty known species of Borrelia worldwide² and an uncountable number of different strains of each species. At least a dozen of them can cause Lyme disease-like syndromes. (Though current medical textbooks still only provide an outdated discussion of three species; most doctors have received little education about Lyme Disease.)

And this may just be scratching the surface; the more researchers look, the more they find.

If you consider the nature of the microbe, this shouldn’t be surprising. Borrelia is an extremely adaptable microbe. It has been adapting to a wide range of different hosts and different environments over millions of years. With each adaptation, it changes ever so slightly. The potential for new variations is almost infinite.

If one group of Borrelia is only slightly different than another group, then the two are considered different strains of the same species. If differences are more significant, then they are considered different species³.

Note that “newly discovered” does not necessarily imply that any of them are just emerging (coming onto the scene and rapidly expanding). The species present today have likely been present for a long time, it’s simply that researchers are looking harder and getting better at looking.

Before 1981, no one was aware of any of them. Gradually other species were identified worldwide and it became apparent that Borrelia is much more widespread in tick populations than originally thought.

Now, thirty-five years later, it is well accepted that Borrelia is widely distributed worldwide⁴. And that’s just the Borrelia species that we know about. With every year that goes by, new species of borrelia are identified.

Despite all the species and all the variations, however, the modus operandi for all Borrelia microbes causing Lyme disease is the same: transmit to a susceptible host via a tick bite, adapt to that host, fool the host’s immune system enough to persist in low concentrations, wait for another tick to come along, spread to new host… do it all over again.

In other words, Lyme disease is Lyme disease, but because Lyme disease can be caused by different species and strains of Borrelia, it can vary in presentation. Some people with chronic Lyme disease have more pronounced neurological symptoms and some people have more arthritis… or possibly a different presentation altogether.

Also, Lyme disease can vary geographically. Contracting Borrelia in Europe can be slightly different than contracting it in Australia or in the United States. And Lyme in California may be slightly different than Lyme in Wisconsin or the Southeast.

Other Borrelia Associated Illnesses

Borrelia infections are not limited to Lyme disease. Certain species of Borrelia are associated with illnesses that share many symptoms with Lyme disease, but also have unique differentiating features.

Even so, the basic mode of operation is still the same: infect by way of an insect bite, reproduce inside a susceptible host, spread to other hosts via an insect. The twist is in how the unique species of Borrelia fools the host’s immune system, resulting in odd symptoms.

STARI, standing for Southern Tick Associated Rash Illness, is a Lyme-like syndrome presently limited to the southeastern and south central United States (it may be spreading, but no one really knows for sure). It is specifically associated with bite from the lone star tick (Amblyomma americanum).

The illness commonly presents with a bull’s eye rash (erythema migrans) and a flu-like syndrome that is similar to, but typically milder than classic Lyme disease. Though an absolute causative agent has not been defined, a species of Borrelia (no surprises here), called Borrelia lonestari has been isolated from some cases.

Relapsing Fever is a form of Borrelia infection defined by abrupt onset of shaking chills, high fever, severe muscle aches, and headache. Associated enlargement of the spleen and liver are common. The acute phase resolves after 3 to 7 days, only to recur about a week later. Multiple recurrences are possible (varies with the species of borrelia).

There are two types of relapsing fever, one transmitted by soft ticks⁶ (tick-borne relapsing fever) and the other by lice⁷ (louse-borne relapsing fever). Each is associated with different species of Borrelia, which are also different than those that cause Lyme disease.

Morgellons disease is a peculiar illness that is getting a lot of attention (though it is relatively rare). The illness is characterized by skin lesions containing filaments of varying colors (white, black, red, blue, purple, and green) and sensations of things crawling under the skin. Analysis of the filaments has shown that they are comprised of abnormal keratin and collagen. Other symptoms include fatigue, neurological symptoms, and joint pain. Recently an association has been made with spirochetes identified as Borrelia species (though other tick-borne microbes may also be part of the syndrome).

Beyond Borrelia

To complicate matters even more, chronic Lyme Disease is rarely Borrelia alone.

Ticks are nature’s perfect vehicle for transmitting microbes (certainly as good as mosquitos, and possibly better because they feed longer) and many different types of microbes take advantage of this extraordinary opportunity.

A search on PubMed will reveal citations for hundreds of different tick-borne microbes that have the potential to cause illness in humans and other animals. The list includes viruses, bacteria, protozoan, and even fungi.

In his 2015 book on Lyme Disease, Stephen Buhner points out that “depth examination of Ixodes ticks has found they can carry up to 237 genera of microorganisms that are infectious to vertebrates” (and that’s just one type of tick). A genus is a group of organisms with similar characteristics. For microbes, a genus can include many species. Tallied up, the list of tick-borne microbes adds up into the hundreds or even thousands.

This really shouldn’t be surprising; all creatures harbor a wide variety of microbes. Humans are capable of harboring thousands of different microbe species. While we are a permanent host for these microbes, many microbes found in ticks are just using the tick as a vector to transfer from host to host.

Just like humans, or any other creature, the spectrum of microbes present in different ticks is highly variable. Certain microbes are more prevalent in certain geographic regions. Certain microbes are also more prevalent in certain tick species or tick populations. But one thing is for certain: all ticks carry a variety of microbes.

It is nature as intended. Microbes harbored by ticks are in the process of searching for a host. Every tick bite is an opportunity for tick-borne microbes to infect and colonize a new host. Microbes (usually more than one variety) always enter the host’s bloodstream when a tick bite occurs.

If you have ever been bitten by a tick, tick-borne microbes have entered your bloodstream.

Tick-borne Microbe Sampler (Roundup)

The most commonly described tick-borne microbes associated with Lyme disease include Borrelia, Mycoplasma, Bartonella, Babesia, Ehrlichia, Anaplasma, Rickettsia, and more recently Chlamydia. Just like Borrelia, however, each one of these groups (genera) of microbes consists of many species and an almost unlimited number of different strains (and these are just the ones we know something about – who knows how many tick-borne microbes are still yet to be identified?).

Next to Borrelia, Mycoplasma is thought to be the most common microbe associated with chronic Lyme disease (about 75% of cases, but possibly even more; Mycoplasma is also very hard to diagnose). It is also widespread in the general population. Virtually everyone has been exposed to Mycoplasma and somewhere between 30 and 70% of different populations harbor it chronically without having symptoms.

Mycoplasma is the smallest of all bacteria. There have been over 200 species of Mycoplasma classified and at least 23 of them can infect humans (some are considered normal flora, but many can cause illness). Mycoplasma can be spread by ticks, but it also commonly occurs as respiratory and genital infections. Acute infections generally resolve without consequence in healthy individuals, but, like Borrelia, chronic Mycoplasma infections can occur. The symptoms of chronic infection are nonspecific and very different from those of the acute infection.

Like most tick-borne microbes, Mycoplasma lives inside cells. It commonly infects white blood cells, which allows it to hitch a ride to every part of the body. The microbe must scavenge everything it needs to survive; favorite sites include collagen-rich areas (joints, skin, brain) and myelin covering nerves. To do this, it manipulates the immune system to generate inflammation to break down tissues. Is this story starting to sound familiar?

Chlamydia is an extremely small bacteria with characteristics similar to Mycoplasma. Presently, there are nine recognized species of Chlamydia, but others will likely be uncovered. Chlamydia can be spread by ticks, but it is more commonly spread by respiratory infections (C. pneumoniae) and intimate contact with other people (C. trachomatis). More than half of people have been exposed to the more common species of Chlamydia and chronic subclinical infection (chronic infection without overt symptoms) is very common. How often it is present with chronic Lyme disease is unknown (but possibly very commonly).

Bartonella, the next most common chronic Lyme player, occurs widely in nature. All mammal populations harbor Bartonella (including whales and dolphins) and more than a dozen species of Bartonella can infect and cause illness in humans. As a Lyme coinfection, it occurs in an estimated 25-50% of cases. Like the other microbes discussed so far, most people have been exposed to some form of Bartonella and a third of people carry it without having symptoms.

Bartonella is spread by ticks, but also by other biting insects, especially fleas. The most well known acute Bartonella infection is cat-scratch fever, but there are many other variations. It infects and reproduces inside specialized white blood cells that line blood vessels (slight variation on the theme). Symptoms arise from damage to small blood vessels (small vessel disease). Typical organs that can be affected include the liver, spleen, bone marrow, eyes, skin, and the entire vascular system, including the heart. This is important to note when vascular symptoms are part of the chronic Lyme complex.

While all of this sounds highly threatening, most people exposed to Bartonella do not get severely sick. After a brief flu-like illness, the person is back to full health; care from a doctor is rarely required and a formal diagnosis of Bartonella is often never made. Antibiotic therapy is generally not required to overcome a Bartonella infection.

If immune function falters, however, chronic symptomatic infection can occur. Symptoms of chronic illness are nonspecific and very different than those of the acute illness. (This story should be sounding really familiar by now – it is common to a wide variety of microbes, each microbe using a slightly different strategy for success).

Babesia, the next microbe on the list, is a protozoan. Protozoa are one-celled organisms with a nucleus surrounding their DNA (bacteria do not have a true nucleus). It is a distant cousin of malaria. Though it is much less threatening than malaria, it is more threatening than aforementioned tick-borne microbes. Fortunately, it is also less common than other tick-borne microbes and is associated with Lyme disease in only about 5-20% of cases.

There are more than a hundred different species of Babesia, and at least a dozen are known to cause human illness. Babesia species, however, are more like groups of very similar organisms than distinct species; it has a near infinite ability to continually change its genotype (genetic presentation).

People bitten by a tick carrying Babesia may hardly get sick at all, or they may get very sick very suddenly. This may be a function of the strain or species of the microbe, the reaction of the person to the microbe, or both. In this way, it is very different than Borrelia and other tick-borne microbes.

Like malaria, it causes symptoms by infecting and destroying red blood cells. It does this to scavenge essential nutrients from the cell. It can infect anything with red blood cells (mammals, birds, reptiles, amphibians). It also infects white blood cells and can live inside different types of cells.

When people do get sick, they often get very sick. Common acute symptoms include high fever (105 F), severe fatigue and malaise, shaking chills and sweats, severe headache, muscle aches, joint pain, abdominal pain, jaundice, and a range of other symptoms. Severe infection can last weeks to months.

Also unlike Borrelia and previously mentioned tick-borne microbes, chronic illness with Babesia, when it occurs, is defined by relapses of acute symptoms (though some species may cause less severe recurrent symptoms).

The tick-borne microbes least commonly associated with Lyme disease include Ehrlichia, Anaplasma, and Rickettsia (5% or less of cases). The primary way these closely related microbes differ is by the cell type they infect. Ehrlichia and Anaplasma each infect different types of white blood cells and are carried throughout the body (ehrlichia causes more severe infections than anaplasma). Rickettsia infect cells that line blood vessels.

Similarly to Babesia, infections with these microbes are either all or nothing: two-thirds of people will experience a mild illness that resolves without medical therapy, but some people will become very ill, very acutely. Acute symptoms include high fever, malaise, headache, confusion, joint pain, muscle aches, and a characteristic rash (more common with ehrlichia than anaplasma).

Rickettsia rickettsiae, the microbe causing Rocky Mountain Spotted Fever, differs from the other two in that it infects cells lining blood vessels (endothelial cells). This causes severe inflammation in blood vessels with obstruction. In addition to the symptoms above, it can cause loss of fingers and toes, and organ failure.

These last three microbes are not ones to mess around with. When suspected, they should be treated aggressively with conventional antibiotics.

Diagnosis is based on clinical signs and symptoms and confirmed by labs after treatment initiated. Labs are not helpful for the first two weeks when acute symptoms are most pronounced.

Chronic infection with these three microbes typically presents as recurrence of acute symptoms. Symptom-free phases can last months or even years.

Note that the above discussions are generalizations about the most well understood species of tick-borne microbes; there are many different species and strains of each microbe. Each strain and species can have widely varying tendencies to cause illness. Milder species of Ehrlichia, Anaplasma, Rickettsia, and Babesia may be more commonly associated with chronic Lyme disease than once thought – making absolute conclusions about any microbe can be misleading.

Search Dr. Rawls’ blog for a complete monograph on each of these microbes.

Dr. Rawls is a physician who overcame Lyme disease through natural herbal therapy. You can learn more about Lyme disease in Dr. Rawls’ new best selling book, Unlocking Lyme.

You can also learn about Dr. Rawls’ personal journey in overcoming Lyme disease and fibromyalgia in his popular blog post, My Chronic Lyme Journey.