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All the seasons are beautiful here in the northeast US, but there is a dark side to  nature - ticks. Tick numbers, types of ticks, and diseases (including Lyme disease) that people are getting from tick bites are all increasing. Nothing seems to stop their spread and their increasing numbers. While deer ticks have been a huge problem for years, now two new tick species are concerning us here in the northeast: the longhorned tick and the lone star tick.

The scary species of longhorned tick (or Haemaphysalis longicornis) was discovered in NJ in 2017, and now it appears that it is spreading rapidly (Virginia, West Virginia, Arkansas, North Carolina, NY). This tick is a native of east Asia (japan, New Zealand, Australia, etc.), and transmits a number of diseases and infests livestock in eastern Asia. It is especially worrisome because females can clone themselves - so they can appear on animals in really large numbers in varying stages. (The photos are horrifying.) The lone star tick is an aggressive tick that can march across the lawn and up onto the deck to get to humans. And its bite is linked to red meat allergies!

How are ticks spreading so rapidly in the US? Many researchers say that with a warming climate ticks are more active for longer periods of the year and can now live in places long thought that they couldn't live (e.g. at higher elevations). But there's more to it. Yes, tick species and tick-borne diseases are now spreading across the US due to warmer winters (climate change!), but research also shows that they spread  due to migratory birds carrying (and depositing) ticks along migratory paths. The huge, huge increase of deer populations in suburban areas is also spreading ticks. As well as small mammals (especially mice!). And on and on.

What to do? There are many pesticides available that can reduce tick populations (spray or apply to lawns and vegetation), but it is questionable whether it really helps. One good 2 year study found that pesticide treatments reduced the number of ticks, but not the number of human-tick encounters and it didn't reduce the number of tick-borne diseases (e.g. Lyme disease). Also, ticks like to live in "leaf litter" at the edges of the lawn and under bushes, in woods - all places hard to treat. Plus, animals and birds visiting the yard are constantly bringing more ticks to the property.

Basically the advice has generally been that it is up to the individual to prevent tick bites by applying an insecticide, or wearing clothes that have the insecticide permethrin on them, checking yourself after going outside and removing any ticks, showering after going outside (even if it's at the end of the day), changing and washing clothes (and put into the dryer to kill the little suckers) after going outside. But there is some concern about some insect repellents (e.g. DEET), especially if used frequently, and many people don't want to apply pesticides such as DEET daily on their children or themselves.

The one question that I hear the most is - are there nontoxic insecticides that are safe to use daily, especially for children? The answer is YES - a good one is Oil of Lemon Eucalyptus (OLE). My absolute favorite non-toxic insect repellent that I think is fabulous and also highly recommended by Consumer Reports as being effective against ticks (and mosquitoes) for at least 6 hours is: Repel Lemon Eucalyptus Natural Insect Repellent (comes in a pump spray). We found that it also repels other biting insects such as black flies, and washes well out of clothes, so a total win! My understanding is that the CDC (Centers for Disease Control) does not recommend it for children under the age of 3 at this time because studies on this age group have not been done.

Others also suggest some non-toxic possibilities for the yard: raise free range chickens (they eat ticks!) or guinea fowl (eat ticks, but very noisy), encourage the presence of foxes (they eat the mice, and a study found they really reduce tick populations), can throw tick tubes such as Damminix (contain cotton balls with permethrin that mice carry back to nests) into the bushes or woods around your property. And a large study in NY state is investigating a new possibility for non-toxic tick control (as described in the last post) - whether tick bait boxes (The Tick Control System) and/or applying a non-toxic tick killing fungus (the product Met52) will lower tick numbers and tick diseases. The researchers are hoping tick reductions of at least 90%! Finally some encouraging news.

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Summer is a wonderful season here in the northeast US, but there is a dark side - ticks. Tick numbers, types of ticks, and diseases (including Lyme disease) that people are getting from tick bites are all increasing. Nothing seems to stop their spread and their increasing numbers. But what if a fungus that kills ticks is the answer? The fungus is Metarhizium anisopliae, which occurs naturally in forest soils. It is sold as Met52 - a non-toxic to humans and pets product that anyone can now purchase.

The product is now being tested in a multiyear study (led by R. Ostfeld & F. Keesing) in 24 neighborhoods with a high incidence of Lyme disease in New York state. Studies show that ticks die within 3 to 7 days after being exposed to Met52 (a spray made up of the fungal spores and water). Personally, I am very excited by this natural product and hope that it works well. The researchers are hoping for a 90% reduction of ticks (or more!) in areas and yards where it is applied! That is better control than the insecticides typically used. The researchers feel that if this works well, then municipalities or neighborhoods could do it on a large scale for tick control.

I first read about the study in this July 2018 article by M. Molteni in Wired: WE HAVE NO IDEA HOW BAD THE US TICK PROBLEM IS

Together, these efforts are helping to change the way people and government agencies think about ticks as a public health threat. ...The trouble is that scientists also know very little about which interventions actually reduce those risks. “There’s no shortage of products to control ticks,” says Ostfeld. “But it’s never been demonstrated that they do a good enough job, deployed in the right places, to prevent any cases of tick-borne disease.” In a double-blind trial published in 2016, CDC researchers treated some yards with insecticides and others with a placebo. The treated yards knocked back tick numbers by 63 percent, but families living in the treated homes were still just as likely to be diagnosed with Lyme.

Ostfeld and his wife and research partner Felicia Keesing are in the middle of a four-year study to evaluate the efficacy of two tick-control methods in their home territory of Dutchess County, an area with one of the country’s highest rates of Lyme disease. It’s a private-public partnership between their academic institutions, the CDC, and the Steven and Alexandra Cohen Foundation, which provided a $5 million grant.  ...continue reading "Is A Tick Killing Fungus The Answer to Tick Control?"

A new study provides evidence for what so many people complain about - that after being treated for Lyme disease with several weeks of antibiotics - they feel that they are not cured, but instead still suffer from Lyme disease. Lyme disease is caused by the bacterium Borrelia burgdorferi, which is transmitted to a person during a tick bite. However, many medical professionals deny that a person can still have Lyme disease after antibiotic treatment, and instead call the lingering symptoms post-treatment Lyme disease syndrome (PTLDS). It is thought that between 10 to 20% of persons treated with antibiotics for Lyme disease have symptoms of PTLDS.

Hah! The Tulane University researchers found that yes, the live bacteria (B. burgdorferi spirochetes) can still be there in different organs of the body even after 28 days of antibiotic treatment. They studied late Lyme disease in both treated (with antibiotics) and untreated rhesus macaques - primates in which Lyme disease has effects similar to humans. Other studies have also found that the Lyme disease bacteria can evade treatment (here and here). From Medical Xpress:

Lyme bacteria survive 28-day course of antibiotics months after infection

Bay Area Lyme Foundation, a leading sponsor of Lyme disease research in the US, today announced results of two papers published in the peer-reviewed journals PLOS ONE and American Journal of Pathology, that seem to support claims of lingering symptoms reported by many patients who have already received antibiotic treatment for the disease. Based on a single, extensive study of Lyme disease designed by Tulane University researchers, the study employed multiple methods to evaluate the presence of Borrelia burgdorferi spirochetes, the bacteria that cause Lyme disease, before and after antibiotic treatment in primates.

The data show that living B. burgdorferi spirochetes were found in ticks that fed upon the primates and in multiple organs after treatment with 28 days of oral doxycycline. The results also indicated that the immune response to the bacteria varied widely in both treated and untreated subjects. "It is apparent from these data that B. burgdorferi bacteria, which have had time to adapt to their host, have the ability to escape immune recognition, tolerate the antibiotic doxycycline and invade vital organs such as the brain and heart," said lead author Monica Embers, PhD, assistant professor of microbiology and immunology at Tulane University School of Medicine.

"In this study, we were able to observe the existence of microscopic disease and low numbers of bacteria, which would be difficult to 'see' in humans but could possibly be the cause of the variable and nonspecific symptoms that are characteristic of post-treatment Lyme disease syndrome. Although current antibiotic regimens may cure most patients who are treated early, if the infection is allowed to progress, the 28-day treatment may be insufficient, based on these findings," Embers said.

The findings also demonstrated: All subjects treated with antibiotics were found to have some level of infection 7 - 12 months post treatment. Despite testing negative by antibody tests for Lyme disease, two of 10 subjects were still infected with Lyme bacteria in heart and bladder. Lyme bacteria which persist are still viable.

To better elucidate previous animal studies demonstrating that some B. burgdorferi bacteria survive antibiotics, the study explored Lyme disease infection in rhesus macaque primates treated with antibiotics and a control group who were also infected but not treated. 

In the study, ticks carrying B. burgdorferi spirochetes fed on ten primates. Four months post infection, half of the primates (five) received the antibiotic doxycycline orally for 28 days at a proportional dose to that used in human treatment...... The results show: Few subjects displayed a rash. Although all subjects were infected, only one of the 10 displayed a rash with central clearing, the classical "bulls-eye" rash. ... Organs may be infected even if antibody tests are negative...... Intact spirochetes were found in three of five treated and four of five untreated subjects based on xenodiagnosis results 12 months after the tick bite.

Immune responses to B. burgdorferi varied greatly posttreatment .... This is significant because it demonstrates that subjects infected with the same strain of B. burgdorferi may have different immune responses to the same antigen. And, because humans, like primates, are genetically diverse, it underscores that testing antibody responses may be inherently unreliable as a singular diagnostic modality for Lyme disease.

Widespread and variable microscopic disease was observed in all infected subjects, despite antibiotic treatment. Compared to uninfected subjects of the same age, infected subjects in this study (treated and untreated) demonstrated inflammation in and around the heart, in skeletal muscles, joints, and the protective sheath that covers the brain, and near peripheral nerves. Rare, but intact B. burgdorferi spirochetes were found in the tissues of both the treated and untreated subjects. In two subjects treated with doxycycline, multiple Lyme bacteria were observed in the brain tissue [Original study.]

Another article was published this month raising the issue of whether Alzheimer's disease is caused by a microbe - which can explain why all the medicines and experimental drugs aimed at treating the "tangles" or amyloid plaques in the brain are not working as a treatment (because that's the wrong approach). The microbe theory of Alzheimer's disease has been around for decades, but only recently is it starting to be taken seriously. Some of the microbes found in patients with Alzheimer's disease (from analyses of both normal brains and Alzheimer patient brains after death): fungi, Borrelia burgdorferi (Lyme disease), herpes simplex virus Type 1 (HSV1), and Chlamydia pneumoniae.

The general hypotheses seem to be that Alzheimer’s disease is caused by infection, but it isn't linked to any one pathogenic microbe.  Instead, the evidence seems to support that "following infection, certain pathogens gain access to brain, where immune responses result in the accumulation of amyloid-β, leading to plaque formation". So the microbes act as "triggers" for Alzheimer's disease - the microbes get into the brain, and immune responses somehow eventually result in the amyloid plaques and Alzheimer's disease. From The Scientist:

Do Microbes Trigger Alzheimer’s Disease?

In late 2011, Drexel University dermatology professor Herbert Allen was astounded to read a new research paper documenting the presence of long, corkscrew-shape bacteria called spirochetes in postmortem brains of patients with Alzheimer’s disease. Combing data from published reports, the International Alzheimer Research Center’s Judith Miklossy and colleagues had found evidence of spirochetes in 451 of 495 Alzheimer’s brains. In 25 percent of cases, researchers had identified the spirochete as Borrelia burgdorferi, a causative agent of Lyme disease. Control brains did not contain the spirochetes.

Allen had recently proposed a novel role for biofilms—colonies of bacteria that adhere to surfaces and are largely resistant to immune attack or antibiotics—in eczema....  Allen knew of recent work showing that Lyme spirochetes form biofilms, which led him to wonder if biofilms might also play a role in Alzheimer’s disease. When Allen stained for biofilms in brains from deceased Alzheimer’s patients, he found them in the same hippocampal locations as amyloid plaquesToll-like receptor 2 (TLR2), a key player in innate immunity, was also present in the same region of the Alzheimer’s brains but not in the controls. He hypothesizes that TLR2 is activated by the presence of bacteria, but is locked out by the biofilm and damages the surrounding tissue instead.

Spirochetes, common members of the oral microbiome, belong to a small set of microbes that cross the blood-brain barrier when they’re circulating in the blood, as they are during active Lyme infections or after oral surgery. However, the bacteria are so slow to divide that it can take decades to grow a biofilm. This time line is consistent with Alzheimer’s being a disease of old age, Allen reasons, and is corroborated by syphilis cases in which the neuroinvasive effects of spirochetes might appear as long as 50 years after primary infection.

Allen’s work contributes to the revival of a long-standing hypothesis concerning the development of Alzheimer’s. For 30 years, a handful of researchers have been pursuing the idea that pathogenic microbes may serve as triggers for the disease’s neuropathology..... In light of continued failures to develop effective drugs, some researchers, such as Harvard neurobiologist Rudolph Tanzi, think it’s high time that more effort and funding go into alternative theories of the disease. “Any hypothesis about Alzheimer’s disease must include amyloid plaques, tangles, inflammation—and, I believe, infection.”

Herpes simplex virus type 1 (HSV1) can acutely infect the brain and cause a rare but very serious encephalitis. In the late 1980s, University of Manchester molecular virologist Ruth Itzhaki noticed that the areas of the brain affected in HSV1 patients were the same as those damaged in patients with Alzheimer’s disease. Knowing that herpes can lie latent in the body for long periods of time, she began to wonder if there was a causal connection between the infection and the neurodegenerative disorder.

Around the same time, neuropathologist Miklossy, then at the University of Lausanne in Switzerland, was detailing the brain damage caused by spirochetes—both in neurosyphilis and neuroborrelia, a syndrome caused by Lyme bacteria. She happened upon a head trauma case with evidence of bacterial invasion and plaque formation, and turned her attention to Alzheimer’s. She isolated spirochetes from brain tissue in 14 Alzheimer’s patients but detected none in 13 age-matched controls. In addition, monoclonal antibodies that target the amyloid precursor protein (APP)—which, when cleaved, forms amyloid-β—cross-reacted with the spirochete species found, suggesting the bacteria might be the source of the protein.

Meanwhile, in the U.S., a third line of evidence linking Alzheimer’s to microbial infection began to emerge. While serving on a fraud investigation committee, Alan Hudson, a microbiologist then at MCP-Hahnemann School of Medicine in Philadelphia, met Brian Balin.... Soon, Balin began to send Hudson Alzheimer’s brain tissue to test for intracellular bacteria in the Chlamydia genus. Some samples tested positive for C. pneumoniae: specifically, the bacteria resided in microglia and astrocytes in regions of the brain associated with Alzheimer’s neuropathology, such as the hippocampus and other limbic system areas. Hudson had a second technician repeat the tests before he called Balin to unblind the samples. The negatives were from control brains; the positives all had advanced Alzheimer’s disease. "We were floored,” Hudson says.

Thus, as early as the 1990s, three laboratories in different countries, each studying different organisms, had each implicated human pathogens in the etiology of Alzheimer’s disease. But the suggestion that Alzheimer’s might have some microbial infection component was still well outside of the theoretical mainstream. Last year, Itzhaki, Miklossy, Hudson, and Balin, along with 29 other scientists, published a review in the Journal of Alzheimer’s Disease to lay out the evidence implicating a causal role for microbes in the disease.

The microbe theorists freely admit that their proposed microbial triggers are not the only cause of Alzheimer’s disease. In Itzhaki’s case, some 40 percent of cases are not explained by HSV1 infection. Of course, the idea that Alzheimer’s might be linked to infection isn’t limited to any one pathogen; the hypothesis is simply that, following infection, certain pathogens gain access to brain, where immune responses result in the accumulation of amyloid-β, leading to plaque formation.

  Finally some good news regarding ticks and the diseases they can transmit to humans. Currently ticks in the US are known to transmit at least 14 diseases, including Lyme disease. But a recent study done in the Netherlands found that the presence of predators such as foxes resulted in mice and voles having fewer ticks on them. A really big reduction in both tick numbers and the percentage of ticks infected with a disease. The researchers  thought that this was due to the mice and voles being less active when predators were nearby, and also that mice and voles that did venture further were preyed upon and eaten by the predators. So be happy if you see foxes in your neighborhood - they're beneficial. Excerpts from the NY Times:

Lyme Disease’s Worst Enemy? It Might Be Foxes

It is August, the month when a new generation of black-legged ticks that transmit Lyme disease and other viruses are hatching. On forest floors, suburban estates and urban parks, they are looking for their first blood meal. And very often, in the large swaths of North America and Europe where tick-borne disease is on the rise, they are feeding on the ubiquitous white-footed mice and other small mammals notorious for harboring pathogens that sicken humans.

But it doesn’t have to be that way. A new study suggests that the rise in tick-borne disease may be tied to a dearth of traditional mouse predators, whose presence might otherwise send mice scurrying into their burrows. If mice were scarcer, larval ticks, which are always born uninfected, might feed on other mammals and bird species that do not carry germs harmful to humans. Or they could simply fail to find that first meal. Ticks need three meals to reproduce; humans are at risk of contracting diseases only from ticks that have previously fed on infected hosts.

For the study, Tim R. Hofmeester, then a graduate student at Wageningen University in the Netherlands and the lead researcher of the study, placed cameras in 20 plots across the Dutch countryside to measure the activity of foxes and stone martens, key predators of mice. Some were in protected areas, others were in places where foxes are heavily hunted. Over two years, he also trapped hundreds of mice — and voles, another small mammal — in the same plots, counted how many ticks were on them, and tested the ticks for infection with Lyme and two other disease-causing bacteria. To capture additional ticks, he dragged a blanket across the ground.

In the plots where predator activity was higher, he found only 5 to 10 percent as many newly hatched ticks on the mice as in areas where predators were scarcer. Thus, there would be fewer ticks to pass along pathogens to the next generation of mice. In the study, the density of infected “nymphs,” as the adolescent ticks are called, was reduced to 6 percent of previous levels in areas where foxes were more active.“The predators appear to break the cycle of infection,’’ said Dr. Hofmeester, who earned his Ph.D. after the study.

Interestingly, the predator activity in Dr. Hofmeester’s plots did not decrease the density of the mouse population itself, as some ecologists had theorized it might. Instead, the lower rates of infected ticks, Dr. Hofmeester suggested in the paper, published in Proceedings of the Royal Society B, may be the result of small mammals curtailing their own movement when predators are around. [Original study.]

Many of us who who spend time outdoors worry about ticks. Just about everyone in the Northeast knows someone who has struggled with Lyme disease or one of the other diseases spread by ticks. An earlier post from June 8, 2015 noted that the CDC says that there are 14 known tick-borne diseases in the United States, and possibly 15 (if recently discovered Bourbon virus is included). Lyme disease is the most common, but people can be infected with more than one tick-borne illness at a time. [POST on Some Ways  To Get Rid of Ticks]

But recently I've seen news reports about a rare and scary tick borne disease called Powassan virus which is spread by deer ticks. News stories reported that an infant that developed the disease was the first case ever in Connecticut, and that the tick had been attached less than 3 hours on the child.

What is Powassan virus and should I be concerned? The good news is that it is very rare, but the bad news is that it's very scary: the virus can be transmitted in less than 2 hours (even as little as 15 minutes!) from an attached tick, and is fatal in about 10% of cases. It can cause encephalitis. And among those who recover, there is about a 50 percent chance of permanent neurological damage.  On the other hand, the CDC also says: "Many people who become infected with POW virus do not develop any symptoms." - But note that we don't know how many people get it and don't get serious symptoms, or any symptoms at all.

Powassan virus (POWV) is a tick-borne flavivirus that was first discovered in Ontario, Canada in 1956. At this time we don't know how prevalent it is in the US. From 2006 to 2015, an average of 7 cases of POWV were reported each year in the United States - only 77 cases in total. Although the virus is mostly found in the Northeast and Great Lakes region of the United States, some states outside of this area have been reporting their first cases.  One recent study found that the Powassan virus was in 1 to 2% of the ticks studied in Long Island in NY and Connecticut.

The Centers for Disease Control (CDC) states that: "Signs and symptoms of infection can include fever, headache, vomiting, weakness, confusion, seizures, and memory loss. Long-term neurologic problems may occur. There is no specific treatment, but people with severe Powassan virus illnesses often need to be hospitalized to receive respiratory support, intravenous fluids, or medications to reduce swelling in the brain. One study of 14  Powassan virus cases in NY state (2004-20012) reported that all of the hospitalized patients who received corticosteroids during their illness survived (looks like something helps).

From CNN: Experts warn of increases in tick-borne Powassan virus

Summer is nearly here, and it's bringing fears of a rare tick-borne disease called Powassan. This potentially life-threatening virus is carried and transmitted by three types of ticks, including the deer tick that transmits Lyme disease. Over the past decade, 75 cases have been reported in the northeastern states and the Great Lakes region, according to the US Centers for Disease Control and Prevention. Though no one can say how many infections will occur this year, warmer winters have led to an increased tick population, so experts predict rising tick-borne infections of many types.

Everyone is at risk for Powassan: Newborns, 20-somethings, the middle-aged, the elderly and the immunocompromised. Anyone bitten by an infected tick can get it, said Dr. Jennifer Lyons, chief of the Division of Neurological Infections and Inflammatory Diseases at Brigham and Women's Hospital in Boston. Infections are most likely during late spring, early summer and mid-fall, when ticks are most active.

"About 15% of patients who are infected and have symptoms are not going survive," said Lyons, who is also an assistant professor of neurology at Harvard Medical School. "Of the survivors, at least 50% will have long-term neurological damage that is not going to resolve." Although most infected people will never show symptoms, those who do become sick usually do so a few days to about a week after the tick bite, she said. The most common symptoms will be fever and headache. "You basically feel nonspecific flu-like stuff," Lyons said, including "muscle aches and pains; maybe you have a little rash on your skin, but almost certainly, you'll have a fever and the headache."The unlucky few who develop a more serious illness will do so "very quickly over the next couple of days," she said. "You start to develop difficulties with maintaining your consciousness and your cognition. ....

Just as there are no vaccines to prevent infection, there are also no treatments for Powassan. There are some experimental therapies we try when somebody comes in and they get here early enough and we get the therapy started early enough, but we have no idea if any of that works," Lyons said. Standard treatment includes intravenous fluids, though antiviral medications, systemic corticosteroids and other drugs have been tried in some patients.

Scientists also believe Powassan is on the rise based on studies that have identified an increasing number of infections in deer. Similarly, Lyme is showing increasing numbers. ....To make the matter more complicated, we are seeing greater number of ticks infected with other tick-associated pathogens, including babesiosis and anaplasmosis," Molaei said. Both babesiosis and anaplasmosis usually don't have symptoms, just like Powassan, though both may cause severe or even life-threatening illnesses.

Medical story about the Connecticut infant who developed Powassan virus. From Contagion Live: Connecticut Reports Its First Human Case of Powassan Virus

 Lyme disease is caused by the bacterium Borrelia burgdorferi and is typically treated with antibiotics. This study may go a long way in explaining why some people do not seem to respond to Lyme disease treatment, and why they continue to feel sick even after prolonged antibiotic therapy. The researchers discussed how, in addition to the familiar spirochete form, B. burgdorferi can transform from spirochetes into round body forms in the presence of various unfavorable environmental conditions, including the presence of antimicrobial agents (antibiotics). And that the different forms respond to different antibiotic treatments!

But now they found that this bacterium has an additional form, which they refer to as biofilm, and which may be resistant to even very aggressive antibiotic (antimicrobial) treatments. They say this is the first study that demonstrates the presence of Borrelia biofilm in infected human skin tissues. From Medical Xpress:

Lyme disease 'Biofilm' eludes antibiotics: report

In many cases, Lyme disease returns after a patient has completed antibiotic treatment, and this finding may help explain why that occurs, the researchers said. University of New Haven researchers determined that Lyme disease-causing Borrelia burgdorferi bacteria produces a biofilm that makes it up to 1,000 times more resistant to antibiotics than other bacteria.

The discovery may lead to new ways to treat Lyme disease, said study author Eva Sapi, head of biology and environmental sciences at the university. "These findings could change the way we think about Lyme disease, especially in patients where it seems to be a persistent disease, despite long-term antibiotic treatment," she said in a news release from the Connecticut-based university.

"This recent finding could help to better understand how Borrelia can survive treatment and ... will provide novel therapeutic targets for chronic Lyme disease, with the hope of eradicating Borrelia in these patients," Sapi added. (original study)

 Borrelia burgdorferi  Credit: CDC

Another microbe that causes Lyme disease! Lyme disease is the most common tick-borne disease in the northern hemisphere, and it is caused by the bacteria Borrelia burgdorferi. Recently Mayo Clinic researchers found a new bacteria, which they named Borrelia mayonii, in the fluids and tissues of some people diagnosed with Lyme disease in the upper midwestern USA. The symptoms are different from typical Lyme disease: with nausea and vomiting, diffuse rashes (rather than a single bull's-eye rash), and a higher concentration of bacteria in the blood. Same treatment as with the original bacteria , but it may not show up in tests for Lyme disease.

Other researchers say that other Borrelia species found throughout the US and Europe also cause Lyme disease. This may explain why Lyme diseasse sufferers are not always diagnosed with Lyme disease, even though they have it. From Scientific American:

New Cause for Lyme Disease Complicates Already Murky Diagnosis

Tick-borne Lyme disease in the U.S. has long been thought to be caused by a single microbe, a spiral-shaped bacterium called Borrelia burgdorferi. Last week this notion was challenged when a team led by scientists at the Mayo Clinic discovered that Lyme could be caused, albeit rarely, by a different bacterial species that may incite more serious symptoms ranging from vomiting to neurological issues. Scientists working in the contentious field of Lyme disagree, however, as to what this information means for public health and if these findings are truly the first of their kind. For years, they say, research has pointed to the notion that the spirochete that causes Lyme disease in the U.S. is more heterogeneous than many have acknowledged ...continue reading "Another Microbe That Causes Lyme Disease"

Bad news about ticks: the blacklegged ticks (Ixodes scapularis and the western Ixodes pacificus) that spread Lyme disease, are now reported in almost half of the counties in the U. S. Researchers found blacklegged ticks in 1,420 out of 3,110 counties in the continental U.S., or about 46% of counties, and found western blacklegged ticks in 111 counties, or about 4%. Combined, this is a 45% increase from 1998 when ticks were reported in 1,058 counties.Of course the tick-dense northeast is where Lyme disease is most common. Although the blacklegged tick is found from Florida to Minnesota, 95% of confirmed Lyme disease cases come from just 14 states in the northeast and upper Midwest. 

One interesting study that looked at reasons for these differences was published in PLOS ONE last year by parasitologist Isis Arsnoe and colleagues . They found that populations of blacklegged ticks behave differently in the north and the south United States. Nymphs of the blacklegged tick in the north are bolder and more active in seeking out hosts, a behavior known as questing. Arsnoe found that that tick nymphs originating from Wisconsin and Rhode Island were 20 times more likely to emerge from leaf litter, putting them in the path of passing humans, than nymphs from North or South Carolina. "Questing behavior is a key factor affecting the risk of tick bites." From Science Daily:

Ticks that transmit Lyme disease reported in nearly half of all US counties

Lyme disease is transmitted by the blacklegged tick (Ixodes scapularis) and the western blacklegged tick (Ixodes pacificus), and the range of these ticks is spreading, according to research published in the Journal of Medical Entomology.

Some symptoms of Lyme disease include fever, headache, and fatigue, all of which can be mistaken for the common flu, so medical personnel need to know where these ticks are found in order to make a correct diagnosis. Unfortunately, the range of blacklegged ticks had not been re-evaluated in nearly two decades, until now.

The team used surveillance methods similar to those used in 1998 so that they would be able to accurately judge the degree to which the distribution of these ticks had changed. Using the gathered data, they figured out which counties had established populations, which ones had one or more reports of a blacklegged ticks, and which ones had none.

They found that the blacklegged tick has been reported in more than 45% of  U.S. counties, compared to 30% of counties in 1998. Even more alarming, the blacklegged tick is now considered established in twice the number of counties as in 1998. Most of the geographic expansion of the blacklegged tick appears to be in the northern U.S., while populations in southern states have remained relatively stable. The range of the western blacklegged tick only increased from 3.4% to 3.6% of counties. (The study in J. of Medical Entomology)

I recently posted on ways the number of  ticks can be reduced in a backyard. Now an article on vaccines being developed to battle tick borne diseases, especially Lyme disease. However, the bad news is that ticks now transmit 16 diseases in the US (including anaplasmosis, babesiosis, ehrlichiosis), while vaccines typically only focus on one disease at a time. Tick borne diseases are on the rise throughout the world.

We all know about Lyme disease (which is also a problem in Europe, China, and Mongolia), but in parts of Africa, the Middle East, Asia and southern Europe, ticks can spread Crimean–Congo haemorrhagic fever, which is fatal 40% of the time! And while some researchers are focusing on human vaccines, some are focusing on vaccines for mice. Big problem: would we really be able to give the vaccine to enough mice to make a difference? I really like the idea of a vaccine that hampers the ability of ticks to feed on humans. From Nature:

The new war on Lyme and other tick-borne diseases

Williams is testing whether vaccinating mice against Borrelia burgdorferi, the bacterium that causes Lyme disease in the United States, can reduce the proportion of ticks that are infected. ....Borrelia burgdorferi infects an estimated 329,000 people in the United States each year, according to the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia. And although most people who get prompt treatment recover quickly — Williams has had Lyme three times — up to one in five develops long-term and potentially life-threatening symptoms, including heart, vision or memory problems, or debilitating joint pain. ...continue reading "Vaccines to Battle Tick Diseases?"