Life After Lyme Disease

Vitamin C is one of the most commonly used supplements in the world and many people regularly take oral vitamin C pills to boost overall health and ward off viruses and bacterial infections. There is a wealth of medical evidence available which has documented the ability of vitamin C to cure a number of infectious diseases, including Lyme disease.

Medical experts are very interested in the powerful healing effects of vitamin C and many believe this supplement could be one of the most effective weapons we have against viral syndromes, even those that can be incurable with modern medicines.

Why is vitamin C not prescribed for Lyme disease?

Despite the potential for vitamin C to help Lyme disease sufferers some clinical failures have been recorded which have prevented medical authorities from considering this supplement in mainstream healthcare. However after reviewing the huge volume of medical evidence relating to vitamin C several leading experts concluded that there were some clear reasons for the clinical failures of vitamin C and that they appeared to occur only when ‘a large enough amount of vitamin C cannot be effectively delivered to the invading microorganisms.’ (Stone, 1972; Smith, 1988, Levy, 2002).

These conclusions where based on the necessity of delivering vitamin C in very high dosages directly to the main sight of the infection. Oral supplements were simply not effective enough at delivering the right quantities of vitamin C into the site of infection to combat the high concentrations of invading microorganism.

Tests on the clinical effectiveness of vitamin C showed that the majority of clinical failures resulted because of inadequate delivery methods (Casciari et al. 2001). Even administrating high dosages of vitamin C (as much as 60,000mg) using intravenous injections was not always successful This means that in order for vitamin C to be recommended as a standard treatment for infectious conditions such as Lyme disease the method of delivery has to be improved.

New techniques for vitamin C treatment

New techniques for delivering vitamin C have been developed and at the Colorado Integrative Medical Center (www.coloradomedicalcenter.com) medical staff have begun using a new form of vitamin C therapy. This is known as Pulsed Intravenous Vitamin C (PIVC) therapy and offers the ability to administrator a very rapid and intensive delivery of vitamin C to the body. PIVC works by getting blood levels of vitamin C as high as possible by administrating rapid dosages in order to deliver the maximum healing power to the site of infection. This method has been shown to be safe and effective at treating a number of different conditions.

The rapid administration of high levels of vitamin C can also induce side effects such as acute hypoglycemia. This can boost healing as acute hypoglycemia is well documented at assisting the absorption of drugs into specific areas of the body and this is known as Insulin Potentiation Therapy (www.iptq.org). This is essential for vitamin C treatment because glucose can compete with vitamin C for transport around the body. By lowering the glucose levels in the blood you can ensure that higher dosages of vitamin C are transported to the site of infection.

The future of vitamin C therapy for treatment of conditions such as Lyme disease is uncertain, but the positive results being documented from new techniques such as PIVC will go a long way to convincing health authorities that this can be a safe and effective treatment for infection conditions.

Prevention is better than the cure when it comes to Lyme disease, as this prevalent tick-borne condition can be difficult to diagnose and treat and can lead to some unpleasant and potentially harmful long term symptoms.

Experts have identified a number of strategies that have been shown to reduce tick abundance and therefore help to reduce the spread of Lyme disease, but there are currently no state-wide measures in place to deal with this growing problem.

Deer Population Control

Reducing the numbers of deer populations in high risk Lyme disease zones is a controversial strategy, but in many areas these animals are seen as one of the prime carriers of the infected ticks. This has been shown to be a potentially effective strategy as can be seen by examples such as Monhegan Island, Maine.  Here the populations of white tailed deer were totally eliminated during 1999 and 2000, and by 2004 no blacklegged ticks were found at all on the rodents on the island.  However it has not been shown conclusively that these techniques can have a significant effect on reducing the numbers of infected ticks in non-isolated areas such as mainland USA.

White Tailed Deer

Host-Target Methods

A more humane and potentially more effective method is currently being trialed, and this is called host-targeting.  This involves setting up deer feeding stations that are equipped with applicators that dispense pesticides, and also baited devices that can kill ticks feeding on rodents such as rats, mice and shrews, which are also prime carriers of infected ticks.  Host-targeted methods have performed well in testing, and initial trials have shown that the using pesticide treatments at deer feeding stations reduced populations of the known carriers of Lyme disease, the blacklegged tick ((Ixodes scapularis), by as much as 69%.  Rodent baited pesticide devices also showed well in the trials, and were also effective at reducing populations of blacklegged ticks.

Pesticides

Pesticides, in particular acaricides (targeted at the Acari group which includes mites and ticks), have been used effectively to suppress tick populations in residential areas.  This works well in combination with efforts to remove brush, dense landscaping, leaf litter and woodpiles around domestic dwellings, and in general open up areas to reduce habitats for both ticks and the prey they feed on such as deer and rodents.  The pesticides cyfluthrin, deltamethrin and carbaryl have been shown to be particularly effective at killing the nymph stage of the blacklegged ticks (Ixodes scapularis), but homeowners are not always willing to use pesticides heavily around their own properties.  There are also some concerns that pesticides could be overused and this could affect fragile ecosystems.

Landscape Management

Landscape management practices can also be used to reduce tick abundance, and strategic one year intervals of controlled wild grassland and brush burning were found to reduce the populations of tick adults and larvae significantly.  Burnings scheduled for the spring time were found to be particularly effective.

There is no way of completely eliminating the presence of ticks in wild and residential environments, but there are a number of strategies available that could help to significantly reduce tick abundance, and help to in turn reduce the risks of Lyme disease being passed to humans and domestic animals.

Lyme disease is a condition prevalent in many parts of the US, Canada and Europe and is caused by the bacteria known as Borrelia burgdorferi, which is spread from animals to humans by the bites if infected ticks.  Once Borrelia burgdorferi has invaded the host’s body it can spread throughout the system via the blood and lymph nodes, and can infect the major organs, skin and joints causing a number of problems from minor skin lesions through to potentially debilitating conditions such as heart disease and Lyme arthritis.

Lyme Arthritis

Although Lyme disease can be treated with standard antibiotics this can be a difficult condition to diagnose in the early stages as the symptoms can be generalized, and there are no reliable tests available to healthcare professionals as yet that can confirm the presence of Borrelia burgdorferi in the first few weeks of infection.   This means that a vast number of Lyme disease sufferers are misdiagnosed, and nearly 60% of them then go on to develop more serious symptoms such as Lyme arthritis, which can cause swelling and inflammation in the joints (in particular the knee joints) and can cause severe pain and mobility problems.  In many cases despite the correct treatment being applied Lyme arthritis can persist for months or even years after the initial infection and this is a rare condition known as antibiotic-refractory Lyme arthritis. 

Lyme Arthritis can cause severe knee joint pain

Different Strains of Lyme Bacteria

The main problem with antibiotic-refractory Lyme arthritis is that in many cases tests carried out on the joint fluid of the affected areas actually show negative for the Borrelia burgdorferi bacteria, which indicates that the arthritis is persisting even when the bacteria has been successfully eradicated from the system.  Researchers at the Massachusetts General Hospital and Harvard Medical School, led by Allen Steere, have been looking into this problem and analyzing joint fluid samples from over 120 patients who have received treatment for Lyme arthritis in the last 30 years.  The research has revealed that different strains of the B. burgdorferi bacteria may have a significant impact on the severity and duration of Lyme arthritis.  It was shown that a particular strain of B. burgdorferi known as RST1 was most commonly found in patients that suffered from the rare and more serious condition of antibiotic-refractory Lyme arthritis.  At first researchers considered that this may have indicated a greater resilience in RST1 to survive in the joint fluid despite treatment with antibiotics, but then further tests showed that in fact the RST1 strain seemed to be more virulent than other strains of B. burgdorferi, and caused a much more severe immune response in the infected host. This meant that those patients that had become infected with the RST1 strain were much more likely to suffer from severe joint inflammation and develop persistent antibiotic-refractory Lyme arthritis, especially if they were genetically susceptible to joint conditions in the first instance.

The results of this study have been valuable in ascertaining why some individuals seem to develop persistent Lyme arthritis despite being successfully treated for Lyme disease with antibiotics, and also adds to the growing body of evidence examining the differential pathogenicity of the known strains of B. burgdorferi.

Genetic engineering has always been a controversial issue, but researchers at the Centers for Disease Control and Prevention in Fort Collins, Colorado have been testing ways in which advanced genetic engineering techniques could help to prevent the spread of the potentially debilitating insect-borne condition known as Lyme disease.

Microscopic image of tick

Lyme disease is transmitted by the bite of infected blacklegged ticks and is a major problem throughout many parts of Europe and the mid and eastern United States, and has recently been shown to be spreading across the border into southern Canada. Lyme disease is difficult to detect in the early stages as the symptoms are often generalized and similar to a number of other common conditions, and although this disease can be cleared up quickly with a course of oral or injected antibiotics, if left untreated it can become very serious, resulting in a number of painful and potentially debilitating symptoms including Lyme arthritis and heart problems.

New Research

Researchers in the Vector-Borne Infectious Diseases team at Fort Collins have been analyzing exactly how the bacteria responsible for Lyme disease, Borrelia burgdorferi, is transmitted and have been testing ways in which genetic engineering could interfere with this process and halt the spread of this disease. Recent laboratory research into genetic engineering and insect-borne diseases has revealed some breakthrough results, which could hold the key to developing an effective vaccine against the potentially debilitating disease caused by Borrelia burgdorferi infections.

Deactivating Genes

Genetic engineering has allowed researchers to analyze Lyme disease on a genetic level, and research has shown that deactivating specific genes in the Borrelia burgdorferi bacteria makes it much less likely for hosts to contract Lyme disease. The gene isolated for this treatment is known as bba64, and is expressed by those ticks responsible for the spread of Lyme disease, and scientists believe this gene plays a key part in the infection process, facilitating the transmission of the bacteria from tick bites to the animal host by somehow repressing the host’s immune response and allowing the bacteria to pass unchallenged into the system. Researchers deactivated gene bba64 and then used this to inoculate mice test subjects in a laboratory environment, and found that when the mice were exposed to infected ticks they were much less likely to become infected with the Borrelia burgdorferi bacteria compared to those mice that had not been inoculated.

Close up image of tick mouth parts

Researchers believe that by deactivating the bba64 gene which naturally facilitates the infection process, they can effectively create a laboratory stage vaccination and it is thought this works by making it much more difficult for the Lyme disease bacteria to survive in the tick’s mouth and gut, meaning that there are not enough bacteria to pass along in the ticks saliva when it feeds in order to infect the host animal.

Future Vaccination

Although this genetic testing is only in its early stages scientists are hopeful that this breakthrough research on the bba64 gene may hold the key to developing an effective Lyme disease vaccination for the future, and may also be useful in developing vaccinations for other insect-borne diseases.

Insects that feed on animals are primary carriers of a number of unpleasant diseases, and many of these can be transmitted from animals to humans such as Lyme disease, which is caused by the bacteria Borrelia burgdorferi.

Humans have a significant impact on fragile ecosystems all around the world, and research suggests that increasing urbanization and modern forest management techniques can all have a significant impact on the spread of tick-borne disease.  We often think of dramatic environmental disruptions happening in far away places such as the rainforests or Arctic glaciers, but similar problems are occurring with ecosystems right in our own backyards, and this can result in a number of problems such as an increased risk of exposure to infected ticks carrying the bacteria which causes Lyme disease.

Urbanization spreading into wild areas

Urbanization

Ticks mostly feed on woodland mammals such as mice, rabbits and deer, and because their chosen prey is more abundant at woodland and forest edges this is also where the population densities of ticks are the most concentrated.  Spreading urbanization has put woodland and forests under threat and pushed the boundaries between residential and wild areas even closer, and this means that there are more and more people living and working in high risk areas for Lyme disease.

Forest Management

Both ticks and their prey need certain habitats in order to survive, and researchers at the Washington University’s Tyson Research Center discovered that in the Missouri Ozarks (predominantly oak and other hardwood forests) those areas which were managed by the Missouri Department of Conservation and the Nature Conservancy were actually more at risk from tick-borne diseases crossing to humans and domestic animals, as selective logging and managed burns of the woodland created much more sustainable habitats for the prey ticks fed from, in particular deer and small mammals such as rabbits which both prefer the tender fresh green growth that is abundant in newly cleared woodland areas.

Woodland management can create ideal habitats for ticks

Researchers were keen to determine exactly which species were the main feeders of infected ticks in a typical woodland enviroment, and so collected ticks from a variety of sites in the managed woodland and wilder areas, and analyzed the DNA in the blood the ticks had fed on to identify which animal the blood came from, and whether or not any pathogenic bacteria were present.  This research provided some interesting results and it was found that stable deer populations did not significantly effect the spread of tick-borne diseases, but that concentrated populations brought about by plentiful food and protected habitats caused a dramatic increase in the impact and spread of tick-borne diseases such as Lyme disease.

The Importance of Tracking Emerging Diseases

With Lyme disease and other insect-borne diseases it is important we fully understand under what conditions the carriers of these pathogens can multiply and spread, as this will help health authorities and governments to identify and track emerging patterns of these potentially harmful diseases and put measures in place quickly to minimize the impact on humans.  For example the research from the Ozarks showed that managed environments caused explosions in deer populations, which in turn led to the increased risk of Lyme disease passing to humans and other animals, and this could be a significant piece of evidence to drive measures against the spread of ticks in the future, particularly when you consider that some state agencies actually encourage deer populations by planting out food for them.  In Missouri alone it was estimated that there were over 1.4 million deer, and this seems to be a similar pattern in woodland across the US, and researchers have estimated that there could be as many as 30 million deer currently living wild in the the mid and eastern United States.  It is likely that alongside these increasing deer and rabbit populations levels of other small mammals such as squirrels, shrews and mice are also booming, which can also be key prey sources for ticks, and all of this could explain why tick-borne diseases are spreading despite many efforts to hold them in check.

White footed mouse - Peromyscus leucopus

The Borrelia burgdorferi bacterium responsible for Lyme disease can infect humans, birds and mammals, and is transmitted to different hosts by tick bites. There are a number of animals that can carry the Borrelia burgdorferi bacterium and they can pass this on to uninfected ticks, but in many cases of zoonotic diseases (those transmitted from wild animals to domestic animals and humans) there is one natural animal host in particular responsible for incubating the bacterium. In the case of Lyme Disease researchers had historically considered mice (in particular white-footed mice) to be the main animal reservoir for this disease in North America, as past studies have shown that almost 90% of all ticks feeding on infected mice pick up the Borrelia burgdorferi bacterium, which is an infection rate almost double of any other species. Also mice are very common animals that occupy diverse habitats from woodland to residential districts, which would increase the spread of this disease across a larger area and this combined with the high infection rate would support the assumption that mice were the primary reservoir of Lyme disease.  Current vaccination strategies aimed at bringing Lyme disease under control throughout northern America have been based on the assumption that white footed mice are the main source of the Borrelia burgdorferi infection cycle.

New Studies

However new evidence from studies undertaken by biologists from the University of Pennsylvania have revealed that Lyme disease may have a much more complicated host pattern than first thought, and that there are actually a wide number of vertebrate species that contribute to transmitting the Borrelia burgdorferi bacterium. In a recent in-depth study carried out in the high risk tick infection area of the Hudson Valley, researchers discovered that both mice and deer (another species that is commonly linked to Lyme disease), did not actually factor very highly in the cycle of transmitting the Borrelia burgdorferi bacterium infection. The research revealed that just 25% of infected ticks were fed by mice, much less than the 55% of infected ticks discovered to have been fed by shrews in the same area. This evidence indicates that other factors such as animal population density had a huge influence on the spread of the Borrelia burgdorferi bacterium, and that focusing on just one species such as the white-footed mouse was not an effective way to combat the spread of this disease.

Combating Lyme Disease

Zoonotic pathogens (such as the Borrelia burgdorferi bacterium that causes Lyme disease) that can cross easily between human and animal species are a major threat to ecological systems all around the world, and areas where residential and wild land converge such as at forest and woodland boundaries are particular high risk zones. It is very important that researchers understand exactly how the diseases spread to

Woodland edges are high risk areas for Lyme Disease

different species and across to humans, so that they can work with governments and health authorities in finding new strategies to help protect the public and minimize the spread of infection both in wild and domestic animals. Identifying the main animal host or hosts of pathogens such as Lyme disease can be a key weapon in combating the impact of zoonotic emergences, as strategies can be implemented that interrupt the transmission of infection such as between the ticks and the primary animal hosts, thereby breaking the infection cycle and preventing the disease from spreading to new areas.

Microscopic Image of a Tick

Bacteria are some of the oldest forms of life on earth, and all life is thought to have developed from these simple but highly effective organisms.  During Earth’s turbulent history bacteria and other basic life forms have survived many natural disasters from devastating global forest fires to volcanic eruptions, glacial ages and meteor strikes, of all which saw billions of other species become extinct, and one of the greatest mass extinctions in history during the Permian Period 248 million years ago saw so many animal species wiped out (including 90-95% of all marine life) that Earth very nearly returned to a similar state as the Precambrian eon 3–4 billion years ago, where the only life on earth were microorganisms.

Pre-Ice Age Europe

It is not surprising to learn then that researchers have now discovered that the bacterium responsible for Lyme disease (Borrelia burgdorferi) is incredibly old and could actually predate the Ice Age, and was also thought to have originated in the continent we now know as Europe, rather than North America.

Previously experts had believed that the Borrelia burgdorferi bacterium originated in North America, but new studies from researchers at the University of Bath, which combined findings from both the UK and USA, have revealed a fascinating evolutionary history to this bacterium that charts its emergence and spread all the way back to pre-Ice Age Europe.  This research was gathered by extracting samples from infected ticks and humans and studying the sequence of a number of ‘housekeeping genes’ (a code for proteins which are essential for basic cell functions and present under any conditions), which evolve very slowly over a long period of time.  Because these housekeeping genes are so fundamental to the survival of the cell they are passed down through history largely unchanged, and contain valuable information dating back to the origins of the cell, and from this scientists can track the evolutionary path of the bacterium.

Results from Studies

From the results of the study carried out by the University of Bath’s Department of Biology & Biochemistry, researchers found 33 different combinations of these housekeeping genes in just 64 samples, and from this they were able to construct a ‘family tree’ based on actual molecular information, which is the first time this technology has been applied to tick-borne disease.  This family tree revealed that the oldest molecular information charted the origins of the Borrelia burgdorferi bacterium back to pre-Ice Age Europe, but did also show that it has been present in North American for a very long time as well.  The research also suggested that the geographic territory of the tick species that carry the Borrelia burgdorferi bacterium spread in the 1970’s, which can explain the re-emergence of Lyme disease during this time, and this may have been linked to efforts to restore woodland in North America that created new sustainable habitats for insects such as ticks to breed and spread.

The importance of this research cannot be underestimated as by understanding more about how this bacterium has spread throughout history, experts can predict more accurately just how it will develop into the future, and find more effective ways in which to combat and contain it.

New studies published in the November 2009 issue of Cell Host & Microbe (a leading scientific journal published by Cell Press) have shown some possible ways forward for scientists who are working hard to develop an effective vaccine for Lyme disease, which is caused by the bacterium Borrelia burgdorferi and transmitted through tick bites.  Researchers at the Yale School of Medicine and the Howard Hughes Medical Institute have discovered evidence that suggests a vaccine could be developed from a protein in the tick’s salvia (the pathogen’s transmitting agent), which could confer immunity to those people living in areas affected by this disease.

Developing the Vaccine

The interaction between the Borrelia burgdorferi bacterium and ticks is highly complex, and lead author Erol Fikrig, M.D. of Yale University stated that the recent studies have shown that the bacterium actually uses a protein in the tick’s saliva to ‘facilitate infection of the mammalian host’.  This means that the bacteria effectively ‘wraps’ itself in a coating of these proteins (which it stimulates the tick into producing in excess quantities), which masks its presence from the host’s immune system and allows it to pass into the system unnoticed.  Researcher believe that this interaction between the protein in the tick’s salvia and the bacterium is absolutely key to the infection process, and by interfering with this process an effective protective vaccine could be developed against Lyme disease.

Previous vaccines have been developed against Lyme disease but these have subsequently been removed from the market following unsuccessful field trials, and as yet no other antigens have been released for testing in phase III clinical trials.  These previous vaccinations targeted just the outer surface proteins of the pathogen itself, but the new research suggests that by adopting a different strategy and targeting the transmitting agent (in this case the tick’s salvia) instead of the pathogen a much more effective form of defense could be developed, which could have far reaching effects in the fight against not just Lyme disease, but other harmful insect-borne pathogens that as yet we are unable to vaccinate against such as dengue fever, West Nile virus and even one of the most deadly killers in the world, malaria.

As yet the research on tick’s saliva is still only in the laboratory stages, but the initial studies on animals at the Howard Hughes Medical Institute have shown that mice test subjects responded well to a basic antiserum produced to interfere with the protein in the tick saliva identified as being essential to the Borrelia burgdorferi bacterium infection of the host, which significantly reduced the risks of the mice becoming infected with Lyme disease after being exposed to this tick-borne pathogen.

Hope for the Future

These results are encouraging for the future of vaccination against not just Lyme disease but other insect-borne diseases, and can certainly bring a measure of hope for all those living in areas affected by the Borrelia burgdorferi bacterium.  Ticks produce anesthetics in their salvia that stop the bite from stinging, so in many cases the host does not even realize they have been attacked by the insect, and Lyme disease is an insidious condition and can be difficult to diagnose in the early stages as symptoms are wide ranging and include rashes (that can go unnoticed), fever and chills, tiredness, weakness and joint pain, and if left untreated can result in serious conditions such as heart problems and chronic fatigue.

New Haven, Conn. — Yale researchers have discovered that a protein found in the saliva of ticks helps protect mice from developing Lyme disease. The findings, published in the November 19th issue of Cell Host & Microbe, may spur the development of a new vaccine against infection from Lyme disease, which is spread through tick bites .

Traditionally, vaccines have directly targeted specific pathogens. This is the first time that antibodies against a protein in the saliva of a pathogen’s transmitting agent (in this case, the tick) have been shown to confer immunity when administered protectively as a vaccine.

The Lyme bacterium known as Borrelia burgdorferi is transmitted by ticks. When it moves through the tick, it is coated with a tick salivary protein known as Salp15. The Yale research team injected Salp15 into healthy mice and found that it significantly protected them from getting Lyme disease. When combined with outer surface proteins of B. burgdorferi , the protection was even greater.

Lead author Erol Fikrig, M.D. of Yale School of Medicine and Howard Hughes Medical Institute said, “The interaction between the Lyme disease agent and ticks is very complex, and the bacteria uses a tick salivary protein to facilitate infection of the mammalian host. By interfering with this important interaction, we can influence infection by the Lyme disease agent.”

Several years ago there was a Lyme vaccine on the market that utilized just the outer surface proteins of the bacteria. It was taken off the market in 2002, and to date no other antigen has been tested in phase III clinical trials.

The authors believe this new strategy of targeting the saliva – the “vector molecule” that a microbe requires to infect a host – may be applicable not just to Lyme disease but to other insect-borne pathogens that cause other human illnesses.

“We believe that it is likely that many arthropod-borne infection agents of medical importance use vector proteins as they move to the mammalian host,” Fikrig explained. “If so, then this paradigm, described with the Lyme disease agent, is likely to be applicable to these illnesses. Currently, we are working to determine if this strategy is likely to be important for West Nile virus infection, dengue fever, and malaria, among other diseases.”

Other researchers were Jianfeng Dai, Penghua Wang, Sarojini Adusumilli, Carmen J. Booth and Sukanya Narasimhan of Yale School of Medicine, and Juan Anguita of the University of Massachusetts. This work was support by grants from the National Institutes of Health.

Contact: Helen Dodson , 203-436-3984

Source: Yale University

Using a powerful microscopic live imaging technique, a research team led by Dr. Justin Radolf, professor in the Departments of Medicine and Genetics and Developmental Biology at the University of Connecticut Health Center, has discovered that how ticks transmit Lyme disease to humans is different than was previously thought. His research is published online in the Journal of Clinical Investigation .

It has been known for some time now that Lyme disease is caused by the transmission of the spirochete bacterium Borrelia burgdorferi from ticks to humans, but the transmission process has been difficult to study for a number of technical reasons.

Dr. Radolf and researchers Star Dunham-Ems and Melissa Caimano tried a novel approach at solving this mystery. They genetically modified a virulent strain of B. burgdorferi with a green fluorescent protein (GFP). “This bacterium glows and can be followed in the living state as it migrates through the tick to the mouse during feeding,” explains Radolf. “Then using a powerful microscopic technique called confocal microscopy, we discovered that the transmission process unfolds quite differently than previously believed.”

Spirochetes in culture are highly motile, and it is widely believed that during feeding, the spirochetes in the mid-gut rapidly move through the wall of the mid-gut. But Radolf and his team discovered that during much of the feeding period, the spirochetes do not move. They actually divide and surround the cells of the mid-gut lining or epithelium, forming tight networks. “We also found that the reason they don’t move is that the tick mid-gut secretes molecules that actually inhibit the motility of the spirochetes,” explains Radolf.

Eventually, spirochetes in the networks reach the base of the epithelium by completely surrounding the epithelial cells. At this point, they become motile, detach, and completely penetrate the mid-gut, although in very small numbers. These bacteria then swim to the salivary glands, which they penetrate en route to the mouse. “So rather than being entirely motility-driven, dissemination of spirochetes within ticks actually happens in two phases,” says Radolf, “which is something we didn’t know before.”

Lyme disease is the most prevalent vector-borne infection in the United States with more than 25,000 new cases reported annually. “The improved understanding of the transmission process revealed by our study could lead to novel strategies for controlling the spread of Lyme disease,” says Radolf.