Tags: antigens, Arthritis, Borrelia, Chronic Lyme disease, health, Infectious Diseases Society of America, joints, Journal of Clinical Investigation, Lyme, Lyme Disease, medicine, mouse, research, spirochete, steroids, Yale
As you may be aware, there is a great deal of controversy about persistence of Lyme disease symptoms after treatment—even when treatment involves long-term antibiotics. There are many theories about this, and several of them may be true, depending on the patient. The Centers for Disease Control (CDC) and the Infectious Diseases Society of America (IDSA) say that once you’ve been treated with a month of antibiotics, you no longer have a Borrelia burgdorferi infection. If you’re still experiencing symptoms, they call it Post-Lyme or antibiotic-refractory arthritis. At the other end of the spectrum, some Lyme-literate medical doctors (LLMDs) believe that Lyme is a chronic disease, and once you have it, you’ll have it for life. Long-term (read: indefinite) antibiotic treatment, they maintain, is necessary to keep the organisms from multiplying, but you’ll never fully be rid of them.
My views fall somewhere between these two extremes. (Disclaimer: I am not a medical professional.) On the one hand, I don’t think that four weeks of antibiotics, whether oral or intravenous, is really enough to kill off a Borrelia infection in a patient who’s been infected for years. (And this view is supported by Embers et al’s study of Rhesus macaques.) On the other hand, I don’t think that antibiotics-for-life is the answer either. There are just too many people who have been on antibiotics for years who don’t seem to be getting better. Plus there’s the fact that antibiotics can cause a lot of damage if you take them long-term, which significantly lowers the quality of life for people on these treatment regimens.
So when patients have been treated and they’re still experiencing symptoms, I see several possible explanations:
1) The antibiotics didn’t kill off all the bacteria, and they are still hanging around somewhere—perhaps hidden in joints, cartilage, or the brain. This, as you can imagine, is very difficult to prove, especially in living human beings.
2) The antibiotics killed off all the bacteria, but the patient was bitten by another tick and re-infected. This is highly possible if the patient’s environment, lifestyle, and preventive measures have not changed. It’s also difficult to detect when patients are only being follow-up tested with Western Blots, and not something like the C6 antibody assay, which gives you a titer so you can see if your antibodies to the bacteria suddenly increase. (A study related to reinfection was just published on Wednesday in the New England Journal of Medicine. You can read about it in the NY Times here, or read the study abstract. I’ll be doing a run-down of that study next week.)
3) The antibiotics killed off the bacteria, but the body is still making an immune response, possibly attacking its own cells, causing inflammation and continuing symptoms.
When new research comes out, I like to pay attention to see which of these explanations is supported and why. In this post, I’ll take you through a study called “Spirochete antigens persist near cartilage after murine Lyme borreliosis therapy” that was conducted by some researchers at Yale and published in the Journal of Clinical Investigation back in June. (If you want to read along, you can access the full article here.)
The underlying question in this study is: what causes Lyme-associated arthritis in patients who have been treated with antibiotics? Is it that infectious spirochetes are still hiding somewhere in the body, or is it possible that antibiotics “kill” all the bacteria (read: disassemble them so they can’t multiply) but leave their building blocks (referred to as antigens because the body still detects them) behind, causing inflammation.
Let me explain how killing Borrelia in the human body works. The things you need to kill Borrelia are antibodies, first and foremost. If you don’t generate an IgM response, this infection can be fatal in the first 3 to 7 days. We know that IgM has a direct bactericidal effect. In other words, this antibody can kill Borrelia on its own in the absence of complement. IgG, by comparison, is very inefficient at killing Borrelia, but we make that, too. We also need phagocytes to kill Borrelia, and in order to generate antibodies, we need B cells that work. Another thing we need is toll-like receptors (TLRs). These are important for helping antibodies bind to pathogens or parts of pathogens. If we’re deficient in TLR2, or a certain molecule in TLR called myeloid differentiation antigen 88 (abbreviated MyD88), we can have an overwhelming infection.
What they did:
In this study, the researchers used a type of mouse in which this MyD88 protein has been knocked out—i.e. the mouse is totally deficient in MyD88. For that reason, they call it a Myd88-/- mouse. (No, that thing at the end is not an emoticon.) The problem with these mice is that they die quickly of opportunistic infection (specifically, Pneumocystis carinii), so in the lab, they have to give them an antibiotic called Sulfatrim or Septra, which is actually a combination of two antibiotics—sulfamethoxazole and trimethoprim. I’ll come back to why this is important a little later.
Now, an interesting thing is that this same group of researchers did a study back in 2002 using C3H mice, who don’t have the Myd88 protein knocked out—so essentially “normal” mice, in terms of their immune systems—and they showed that live Borrelia persist for 3 months after optimal treatment. These Borrelia that remained were sort of mutant Borrelia because they were missing a couple of proteins that they might need to infect other animals. The researchers knew this because the clean ticks that bit them got B. burgdorferi, but when they had those ticks bite healthy mice, those mice didn’t get infected.
Anyway, for some reason, these researchers didn’t want to use the C3H mice for this study, and they decided to use the Myd88-/- mice, who develop overwhelming infections. They also used a WT strain of mouse (which is not missing Myd88) for the sake of comparison. They infected both types of mice, and then they treated some of them with Doxycycline (through their water supply) and others with Ceftriaxone (via subcutaneous injection). Interestingly, they showed that after one day of Ceftriaxone therapy, they could kill all of the Borrelia. They also used an interesting microscopic technique which allows one to look real-time at tissue and watch an organism to see what it does. By cutting down to a mouse’s tendon, they can see what’s going on down there.
“B. burgdorferi DNA can be detected in B6 Myd88-/-, but not WT, mice after treatment with Doxycycline” (p. 2).
Translation: After treating the mice with Doxycycline, the researchers couldn’t find any B. burgdorferi DNA in the normal immune system mice, but they could find the DNA in the immune-compromised mice. One of those mice had a positive culture for B. burgdorferi, and ticks that fed on that mouse also tested positive for B. burgdorferi. HOWEVER, when they took samples from the knee joints of the mice, ALL of the mice tested positive for the ospA plasmid (B. burgdorferi DNA). In addition, ear-skin samples from half the immune-compromised mice and one of the normal mice tested positive for B. burgdorferi DNA (p. 2).
“Real-time imaging of B. burgdorferi in Myd88-/- mice reveals rapid spirochete elimination after antibiotic therapy” (p. 2).
Translation: The researchers used intravital 2-photon microscopy to observe the behavior of the B. burgdorferi spirochetes in the infected mice. Specifically, they looked at the dermis (skin) and the calcaneal (achilles) tendons. They say that 24 hours after beginning treatment with Ceftriaxone, the number of spirochetes had “diminished dramatically” in both the skin and tendons. The spirochetes left behind in the skin appeared to be moving, but the ones in the tendons did not. The following day, they were not able to see any spirochetes using this imaging technique, suggesting that they had all been destroyed.
“Spirochete antigens can be detected adjacent to ear cartilage in antibiotic treated Myd88-/- mice” (p. 3).
Translation: At the end of the study, the researchers took tissue samples from the ears of all the mice. They tested these samples for B. burgdorferi using both immunofluorescence staining (looking for antibodies) and culture techniques. The mice who were “sham treated” (not given antibiotics) tested positive. The mice who were treated with Ceftriaxone had negative cultures, but some “spirochete antigens” were detected in a deep layer of skin next to the ear cartilage. By “spirochete antigens,” they mean not live spirochetes but proteins (building blocks) left over from the bacteria that can cause the immune system to react. These antigens were found at a deeper level than where the imaging had earlier been peformed (which explains why they weren’t detected using imaging). The same antigens were detected in ear tissue from mice treated with Doxycycline. The researchers conclude that because the antigens were detected, but the bacteria could not be cultured (grown), it means whatever these spirochete remains were, they were incapable of multiplying because they had been too damaged by the antibiotics.
“Live imaging reveals antigen deposits but not motile spirochetes adjacent to cartilage of Myd88-/- mice after Doxycycline treatment for B. burgdorferi infection” (p. 3).
Translation: A separate experiment was conducted in which researchers studied mice between 2 and 10 weeks after finishing a 1 month course of Doxycycline. They used a technique called xenodiagnosis, where they let clean ticks bite the mice. They could find some B. burgdorferi DNA in the ticks that fed on the mice treated with Doxycycline, but when they studied the contents of the ticks’ guts, they could not find any spirochetes. By contrast, the ticks that fed on mice not treated with antibiotics had the bacteria in their bellies. In addition to using xenodiagnosis, they did the immunofluorescence test and cultures on this group of mice, and as before the cultures were negative and the immunofluorescence found antigens near the ear cartilage. This time, they used their imaging technique to look deeper under the skin, closer to the ear cartilage. In the sham treated mice, they found that there were motile (alive) spirochetes right next to the cartilage and large “deposits of nonmotile fluorescent material” where the skin meets the cartilage. In the antibiotic-treated mice, they saw no live spirochetes, but the same deposits were present next to the cartilage. So to see if these deposits would cause infection, the researchers transplanted skin from the infected mice (both those treated with Doxycycline and the sham-treated ones) into non-infected mice. Only the skin from sham-treated mice caused infection in the new mice. This shows that the antigens adjacent to ear cartilage in the mice treated with Doxycycline were not infectious.
“Spirochete antigens can be detected in joints of antibiotic-treated C3H Myd88-/- mice” (p. 4).
Translation: Here, the researchers decided to look at the knee joints of the mice to see if the same antigen deposits exist in antibiotic-treated mice. They looked at the knees of mice that had been infected for 4 months (which is a long time considering mice only live for about a year). When they treated these mice with Ceftriaxone, intravital microscopy showed that the spirochetes died off, but debris was left behind. They are pretty sure the spirochetes died off because the cultures were negative.
“Tissues from antibiotic-treated mice contain immunogenic and inflammatory B. burgdorferi antigens” (p. 4).
Translation: Finally, they wanted to test whether the deposits left behind in the knees of the mice actually contained B. burgdorferi antigens. They did this by immunizing new mice with knee tissue from the infected mice. They found that both the tissue from sham-treated and antibiotic-treated mice caused an IgG immune response to several B. burgdorferi proteins in the new mice.
Problems with the study:
1. It’s in mice. If you follow the research on B. burgdorferi, you’ll see that many of the studies are done in mice. That’s because it’s much less expensive to study disease in mice than in other animals. However, if we really want to learn about arthritis and B. burgdorferi in the human body, it would be better to do a study like this in Rhesus monkeys, which are much more similar to humans. Hopefully, this study will make it possible for some researchers to try to replicate this work in a primate model so that we can learn more.
2. The use of a “lab” strain of B. burgdorferi. They used a 297 strain of Borrelia burgdorferi which is “stable”–in other words, it’s not changing. It’s old and predictable. The problem is that most Borrelia in the wild are likely mutating and changing. They could even be developing resistance to antibiotics. After all, these organisms have been around for thousands of years; they are masters of adaptation. It would be much more interesting to do a study like this using a “wild” strain of B. burgdorferi, as this would more closely mimic the average patient’s experience.
3. The ambiguous blot analysis. The researchers used their own immunoblot to look at the antigens in the patellas (knees) of the mice. It’s not clear to me why they didn’t just use a Western Blot (since that’s the test used on us humans). Another odd thing they did was use a dilution of 1:1,000 for the blot, which is ten times the dilution used for other blots. Perhaps a lower dilution showed too many similarities between the sham group and the antibiotic group? In any case, for a study like this, I would expect more justification for these unusual choices.
4. The study’s “lack of heart” (and brain). I’m referring to the fact that the researchers failed to examine the effect of B. burgdorferi in the hearts of the mice. We know that, in addition to knee problems, patients with B. burgdorferi infections are at risk for a variety of heart problems, including myocarditis. The researchers were so bent on showing that antibiotics could kill the bacteria near joints, but what does that matter if the heart is still infected? If they truly believe that 24 hours of Ceftriaxone in mice eliminates B. burgdorferi, they missed a golden opportunity to show it by neglecting to examine the hearts–and the brains, for that matter. Not only did they ignore the heart, but they wasted valuable word space in their discussion section attacking the research design of Embers et al’s 2012 study of B. burgdorferi infection in Rhesus macaques. Now, the infamous monkey study is far from perfect, but they did do one thing right, which was to look at the heart tissue of the monkeys post-mortem–and guess what they found? In 3 out of 12 monkeys who were treated with antibiotics (that’s 25%), B. burgdorferi RNA could be detected in the heart. That’s despite the fact that in all 12 of the treated animals, C6 antibody titers decreased steadily over the course of treatment.
5. The use of septra/Sulfatrim. This one is a doozy. Earlier, I mentioned that the researchers added the antibiotic sulfamethoxazole-trimethoprim (Sulfatrim) to the mice’s drinking water “to reduce opportunistic infection”(p. 7). They claim that this drug has “no effect on B. burgdorferi infection or disease”(p. 7). I’m guessing they think that because of this 1996 study done in Austria. In that study, several species of Borrelia were evaluated to see whether they were susceptible to amoxicillin, azithromycin, cefotaxime, ceftriaxone, doxycycline, penicillin G sodium, roxithromycin, and trimethoprim-sulfamethoxazole (Sulfatrim) in vitro. The researchers used 30 different strains of Borrelia, but only 4 of those were Borrelia burgdorferi, and they were European B. burgdorferi at that. They found that B. burgdorferi was resistant to trimethoprim-sulfamethoxazole. Now, even though both ceftriaxone and trimethoprim-sulfamethoxazole were studied, the Austrian researchers didn’t investigate what would happen if you used both of these drugs on the Borrelia at the same time (which is what was done in the Yale study). In fact, after scouring PubMed, I was unable to find any synergistic Borrelia studies using ceftriaxone and trimethoprim-sulfamethoxazole. I did, however, find this study, also from Austria, published in 1997. They found that “trimethoprim was more active against Borrelia burgdorferi than against a sensitive strain of Escherichia coli, but sulfamethoxazole was not active against Borrelia burgdorferi.” In other words, one of the drugs that makes up Sulfatrim kills Borrelia, and the other doesn’t. The question is, if you add Ceftriaxone, does Sulfatrim start killing the Borrelia? To actually know whether or not Sulfatrim has an effect on B. burgdorferi when combined with Ceftriaxone, our Yale researchers would have had to do a synergy study, to see what would happen if you took the 50% kill rate of Doxycycline and Ceftriaxone, and add Sulfatrim. But they didn’t show that adding Sulfatrim didn’t affect the kill. So when they’re saying that “Ceftriaxone rapidly [within 24 hours] reduces pathogen burden in the skin,”(p. 5) they’re not taking into account that the Sulfatrim in the drinking water is also probably helping kill off spirochetes. It’s ironic how critical they are of other studies when their own study isn’t exactly “clean.”
6. The way Doxycycline was administered. Doxycycline was given to the mice in their drinking water. This means that the amount of Doxycycline in each mouse’s system depended on how much water it drank. The researchers said their reason for doing the Doxy in the water instead of force-feeding it to the mice twice a day was that when it was given twice daily, serum drug levels fell too low and they were not able to kill all the bacteria (p. 5). When I read this, I thought to myself, “Well, let’s see, how many humans do I know who are taking their Doxycycline through their drinking water? Oh, that’s right. None.” So here we have a study of Borrelia burgdorferi infection in mice in which the researchers choose not to give oral antibiotics because they believe not that the drug doesn’t work, but that the drug delivery system doesn’t work because it can’t get a high enough level of the drug into the blood stream. Yet, these are the same doctors who are saying that one month of oral Doxycycline should be enough to treat the same infection in humans. Curious, isn’t it? They even admit that one mouse may have stayed sick “due to a drinking pattern that led to inconsistent Doxycycline levels” (p. 5). So I guess either that mouse just wasn’t as thirsty as all the other mice, or he was eating his food and drinking his water in one sitting, and the food interfered with the drug absorption (as it can in people!).
7. They didn’t treat the arthritis. Okay, I get that the researchers were having lots of fun with their innovative real-time imaging technique. They tried to accomplish a lot with this study, and it already appears that they may have spread themselves a little thin. However, it bothers me that they spent no time examining ways to treat the arthritis caused by the deposits left behind by B. burgdorferi. In the world outside the laboratory, it doesn’t so much matter to people whether their arthritis is caused by live spirochetes or dead ones. They want to know what’s going to make them feel better. The study’s authors suggest that more antibiotics likely won’t work, but they don’t explore any alternatives, like steroids, for treating Lyme arthritis.
Some interesting (and some unexpected) implications:
1. Cool pictures. Intravital microscopy, the real-time imaging technology used in this study, is pretty nifty, and could be used in better-designed studies to find out a lot of useful information. The researchers in this study could even see some of the spirochetes changing into spherical forms, but they didn’t really investigate or discuss this in detail, beyond saying they don’t think those forms are bacterial cysts. It might be useful to have an entire study dedicated to investigating that.
2. Rethinking oral Doxycycline. It’s been my belief for a while now that oral antibiotics are just not as effective at killing Borrelia as IV antibiotics like Ceftriaxone. I’m not expecting everyone to agree with me on this, but let me tell you why I think so. While Doxycycline is by far the best choice among oral antibiotics for killing Borrelia (as it’s better at crossing the blood-brain barrier than many other drugs), there is an inherent disadvantage to all oral drugs because they have to be delivered through our digestive system. As a patient who took Doxy for a month, I can tell you that no matter how responsible and organized you are, it is very difficult to eat meals at the same time every day, to space the doses 12 hours apart, and to avoid ingesting things like milk that interfere with drug absorption. Reading Bockenstedt et al’s article made me further question the effectiveness of oral Doxy, as the researchers decided that oral Doxy twice per day would not be enough to keep serum drug levels consistent. Instead, they opted to deliver the drug through the mice’s water supply, which poses other problems with consistency. In any case, if it’s not good enough for lab mice, I don’t see how it’s good enough for humans.
3. A new drug combo? The study shows that in the presence of trimethoprim, you can rapidly kill Borrelia with Ceftriaxone. That means we should be doing more studies on how this works and whether it is safe for humans. There is always concern with killing off bacteria too rapidly because macrophages need time to clear the debris (which we think causes arthritis). However, this drug combination seems worth examining in other laboratory studies.
4. Location, location, location. The study doesn’t show that cartilage can be infected with Borrelia burgdorferi, but it does show that deposits are left over near cartilage after the bacteria have been disassembled by antibiotics. If the infection is in cartilage, that’s bad news, because there is no blood flow to cartilage, so it’s very difficult to eradicate an infection there. We need more studies that examine how this bacterium acts around cartilage.
5. Chronic Lyme? Contrary to what Yale alum and journalist Carole Bass would have you believe (Thanks to Becki from Bloody Lymey for opening my eyes to that one.), this study neither proves nor disproves the existence of Chronic Lyme disease, so despite the agenda that may underlie this study, patients need not see it as a threat. The study authors themselves admit in their Discussion section that they’re not quite sure what all their data mean: “The significance of B. burgdorferi DNA in xenodiagnostic ticks and in mouse tissues after antibiotic therapy is unclear” (p. 5). One possibility is that “Some B. burgdorferi DNA could remain intact if it is sequestered in cellular debris such as the GFP deposits.” They’re saying they think that the B. burgdorferi DNA they detected is just remnants of dead spirochetes that were preserved because they were stuck in the debris left behind by the antibiotics. However, they also admit to another possibility: “Alternatively, spirochete DNA could represent a minor subpopulation of B. burgdorferi that is not killed by the antibiotic treatment.” It’s a one-sentence admission in a 9-page paper, but it’s there–and it means that despite what these researchers think is going on, they still can’t say with 100% certainty that the antibiotics completely eradicated the infection.
What the study does show is that there are deposits in mouse tissue that the researchers insinuate are dead organisms (they have Borrelia antigens, are immunogenic, and don’t appear to be infectious). Because they don’t examine all of the tissue–including the cartilage, the heart, and the brain–it’s difficult to say whether they have completely eliminated the bacteria with antibiotics. What Embers et al showed in their primate model is that there seems to be persistence of spirochetes following 4 weeks of IV Ceftriaxone treatment and 8 weeks of Doxycycline. Until somebody does another study in Rhesus monkeys and proves that they’re wrong, that study stands.
6. Treating the arthritis. We know that reactive arthritis caused by Borrelia infections is a real phenomenon, and this study suggests that the cause is the debris left behind by spirochetes following antibiotic treatment. However, what patients and doctors alike need is access to information about how best to treat this unique form of arthritis. I’ve heard anecdotes from patients and doctors about the helpfulness of steroids like prednisone during or following antibiotic treatment, but there really isn’t enough research being done on this. It would be nice if researchers on both sides of the Chronic Lyme debate would pool their resources for the sake of better patient care.
I hope you enjoyed this installment of Tick-Lit Tuesday. It’s good to be back.
What has been your experience with Lyme or Tick-borne Relapsing Fever and reactive arthritis? What questions would you like to see addressed in future research?
Well, Babs, you’re trickier than I thought 05/01/2012Posted by thetickthatbitme in Diagnosis, Peer-Reviewed, TBI Facts, Tick-Lit.
Tags: Babesia, Blood donation, Blood transfusion, health, IFA, labs, Lyme, medicine, PCR, smear, tick
1 comment so far
Welcome to the second installment of Tick-Lit Tuesday, where I comb through PubMed so you don’t have to. Today’s topic: Babesia and Blood Transfusions. Now, I know I posted about Babesia in the blood supply just a few days ago, but an interesting study has since come to my attention (thanks, Dr. W), and the implications are a bit scary. Okay, get your popcorn and let’s begin.
It has been well-documented that the tick-borne protozoan parasite Babesia can be contracted through blood transfusions. Blood centers aren’t required to test donated blood for Babesia, but this may change in the future, as Babesia infections contracted through transfusions are on the rise. So if we were to test all donors for Babesia prior to donation, which tests should we rely on to detect this pesky parasite? Let’s look at the candidates.
IFA: IFA is an abbreviation for indirect fluorescent antibody test. This type of test can also be referred to as serologic (as in blood serum) testing. If you’ve had one of these tests for Babesia, it’s probably titled something like “WA1 IGG ANTIBODY IFA” (for B. duncani) or “BABESIA MICROTI ABS IGG/IGM” on your lab results. If you’ve had Babesia in the past and been treated for it, your antibody test might still read positive because your body is still making antibodies to the parasite. This is one of the reasons why most insurance companies refuse to pay for treatment for Babesia if your only positive test is the IFA. They think maybe you had a past infection that you got over, so you don’t need treatment. (The other reason they refuse to pay is that they’re jerks, to put it nicely.) I’ll talk more about why this is such a problem later in this post.
Smear: When we talk about a smear for Babesia, we mean a Giemsa-stained thin blood smear. This test involves looking at blood samples under a microscope to see if there are any parasites hanging around. The problem with this test is that Babesia can infect fewer than 1% of your circulating red blood cells, so it could take many, many smears before any Babesia show up under the microscope. For more information about that phenomenon, read this.
PCR: This stands for polymerase chain reaction. It’s basically a DNA test that tries to identify whether a gene associated with Babesia is present in the blood. PCR has been found to be “as sensitive and specific” as blood smears for Babesia (see this study), which is not saying much, considering the tendency of Babesia to go undetected with smears.
Hmmm, for whom shall I cast my ballot, the antibody test insurance companies don’t trust, the inaccurate smear, or the inaccurate PCR? Choices, choices…
Can the donated blood of someone with a negative PCR and negative blood smear still be infected with Babesia and cause Babesia infection in transfusion recipients?
(Hint: This is a leading question.)
Let’s talk about a study published in the journal Transfusion in December of 2011 called “The third described case of transfusion-transmitted Babesia duncani.”
Here’s what happened:
In May 2008, a 59 year-old California resident (I’ll call him Cal) with sickle-cell disease had some red blood cell transfusions. Cal’s only risk factor for Babesia was the transfusions; he didn’t have any tick exposure. In September of 2008, Cal was diagnosed with a Babesia duncani (WA-1) infection. The parasites were visible on a blood smear, the indirect fluorescent antibody (IFA) test was positive, and the PCR was positive for the Babesia gene. This launched a transfusion investigation in which doctors tracked down 34 of the 38 blood donors whose blood could have infected Cal with Babesia. One donor, a 67-year-old California resident (who I’ll call Don) had a B. duncani titer of 1:4096 (on the IFA test). What does a titer of 1:4096 mean? Well, if the antibody test for B. duncani is negative, the titer will be < 1:256. That means that Don’s antibody test was positive.
What the article abstract doesn’t tell you, which the full article does, is that both Don’s PCR and blood smear were negative for Babesia. How did the researchers prove definitively that Don had Babesia in his blood? They injected the blood into Mongolian gerbils, and were later able to isolate the parasite from the gerbils. Conclusion: Even though Don showed no symptoms of Babesia and both his PCR and smear were negative, his donated blood caused Babesiosis in both Cal and the gerbils.
Here’s why the study’s findings are important:
1. Clearly, blood smears and PCRs are not good indicators of whether someone is infected with Babesia. Why insurance companies think these tests need to be positive before they’ll pay for treatment is a mystery to me. There are probably a lot of people out there who’ve had positive IFAs but negative smear and/or PCR who were then not treated for Babesia because either the doctor, the insurance company, or both said they didn’t have an infection.
2. As far as the blood donation goes, if we don’t start screening out donors with positive Babesia IFAs, we’re going to continue to contaminate the blood supply with Babesia. It should be as simple as that. Been bitten by a tick? No blood donation for you. Positive IFA? No blood donation for you.
Tags: Borrelia burgdorferi, Borrelia hermsii, Borrelia persica, CDC, doxycycline, health, Israel, Lyme Disease, medicine, NEJM, prevention, prophylaxis, research, TBRF, tick bite, treatment
Today is Tuesday, and I’ve made an executive decision that from now on, every Tuesday I will be covering peer-reviewed research related to tick-borne infections. We in academia call this a “review of the literature,” even though it’s not what normal people think of as literature–no Shakespeare, just dry prose littered with scientific jargon–which is why most people don’t want to read it. Lucky for you, I am a super-nerd and enjoy this kind of reading, at least when it’s about TBIDs (tick-borne infectious diseases). I’ve even come up with an affectionate name for it: “tick-lit”. So every Tuesday from here on out will be Tick-Lit Tuesday, the day on which I read the literature so you don’t have to. Enjoy!
Today’s question: Does prophylaxis work for tick bites?
While a lot of patients with tick-borne infections don’t remember a tick or a tick bite (which is why it takes so long to get diagnosed), there are also people who do notice being bitten and go to a doctor right away because they are concerned about TBIDs. So what happens to these patients?
I’ve heard stories from patients with TBIDs, particularly patients with Borrelia burgdorferi (Lyme) and Borrelia hermsii (Tick-borne Relapsing Fever), about how when they went to a doctor within 48 hours of being bitten, they were told “Oh, we don’t have Lyme in this state, so you don’t have to worry.” Following this logic, ticks carrying Borrelia burgdorferi must be so smart that 1) they know which bacteria they are carrying; 2) they know which state they are in; and 3) they have the decency to respect state lines. I can really imagine a deer tick saying, “Oh, no, I can’t go over there. I’m a California tick. They don’t let dirty ticks like me out of California.” I suppose some doctors imagine that there is some kind of tick parole system that keeps them from traveling anywhere where the CDC and state health departments have not documented them to exist.
Some of these delusional doctors probably can’t be reasoned with, but what about doctors who want to do the right thing? What should they do when a patient comes to them within 48 hours of a tick bite?
Let’s take a look at the research.
One of my favorite tick-lit studies is one that was published in the New England Journal of Medicine way back in July 2006. The study took place in Israel, where Ornithodoros tholozani ticks infect people with a bacterium called Borrelia persica. Borrelia persica, like Borrelia hermsii, causes Tick Borne Relapsing Fever (TBRF). You can think of Borrelia persica as B. hermsii‘s brother. The researchers wanted to find out whether prophylaxing soldiers (giving them antibiotics right away) who had recently been bitten by ticks would prevent the infection from spreading and causing the symptoms of TBRF.
Here’s how they did it (Methods). They studied 93 healthy soldiers with suspected tick bites. Some of these people had evidence of a tick bite (like a rash) and others didn’t, but had been in the same places that the people with bites had, so they had the same risk of exposure. They randomly picked half of the soldiers who would receive antibiotics (Doxycycline for 5 days), and the other half would receive a placebo (which means they would think that they were taking antibiotics, but they were really taking a sugar pill). The study was double-blind, which means that neither the soldiers nor the researchers knew which patients were given the real antibiotics at the time of the study. This makes the study more credible.
Here’s what happened (Results):
All 10 cases of TBRF identified by a positive blood smear were in the placebo group of subjects with signs of a tick bite (P<0.001). These findings suggested a 100 percent efficacy of preemptive treatment (95 percent confidence interval, 46 to 100 percent). PCR for the borrelia glpQ gene was negative at baseline for all subjects and subsequently positive in all subjects with fever and a positive blood smear. Seroconversion was detected in eight of nine cases of TBRF. PCR and serum samples were negative for all of the other subjects tested. No major treatment-associated adverse effects were identified.
In English, this means that 10 of the 46 people who did not get treated with antibiotics got sick with TBRF, and their blood tests showed that they were making antibodies to Borrelia persica. (Their PCR test (a DNA test) was also positive for the borrelia gene.) However, none of the 47 people who were treated with antibiotics developed any symptoms of TBRF. When their blood was tested, it was negative for antibodies to Borrelia persica and their PCR was negative for the borrelia gene. That means that prophylaxing with Doxycycline prevented 100% of cases of TBRF (Borrelia perica infection).
Now you may say to yourself, “Oh, that’s only one study. The sample size was fairly small, and it’s not necessarily generalizable to all Borrelia infections.” At least, that’s what I imagined you (or your skeptical primary doctor) saying as I was rooting around on PubMed. Then I dug up this study from *gasp* 2001: “Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite” (!!!)
The 2001 study was conducted in an area of New York with a high incidence of Borrelia burgdorferi (Lyme) infection. Like the Israeli study, it was also a randomized, double-blind, placebo-controlled trial, but unlike the Israeli study, they only gave patients a single dose of doxycycline. The results? One out of the 235 people treated with doxycycline got Erythema migrans, the bull’s-eye rash that indicates a Borrelia burgdorferi infection. In the placebo group (people who didn’t get antibiotics) 8 out of 235 developed the rash and tested positive for infection. Their conclusion: a single dose of doxycycline can prevent Lyme if given within 72 hours of the tick bite.
If these two studies are not convincing or current enough, the doctors from the Israeli Medical Corps published another study in 2010. First, they inform us that “Since 2004, the Israel Defence Forces (IDF) has mandated the prophylaxis of tick-bitten subjects with a five-day doxycycline course.” (That has me thinking the Israelis are pretty smart.) Just to make sure they were doing the right thing, in this study, they decided to analyze all the tick bite and TBRF cases in their records from 2004-2007.
Here’s what they say:
Of those screened, 128 (15.7%) had tick-bite and were intended for prophylaxis, of which four TBRF cases occurred-3.13% attack rate compared with an expected rate of 38.4% in these bitten individuals without prophylaxis (RR = 0.08, number needed to treat = 3). In all cases in which screening and prophylaxis were provided within 48 h of tick bite, complete prevention of TBRF was achieved. No cases of Jarisch-Herxheimer reaction (JHR) was recorded.
What does that mean? Only 4 of the 128 people who were treated with doxycycline developed TBRF, a rate of 3.13%. The expected attack rate was more than 10 times that, 38 percent, so without the doxycycline policy, it would likely have been 48 people with TBRF instead of 4. One more thing. There was a reason those four people got sick: they were given the doxycycline later than 48 hours after being bitten!
The Big Picture
How does this research affect you as a patient who has been bitten by a tick and contracted an infection or as a patient who could potentially be bitten by a tick in the future?
The research shows us that, if treated within 48 hours with 5 days of Doxycycline, most–if not all–cases of Borrelia infection and resulting symptoms can be prevented. If you could get an appointment with an infectious disease specialist who recognizes this fact within 48 hours of being bitten, you could probably avoid a lot of potential suffering. The problem is that to see a specialist, you usually need to be referred by your primary care doctor. Some of us can’t even get an appointment to see our primary care doctors within 48 hours, and some of the primary care doctors don’t even know how to spell Borrelia (no offense to primary care doctors who can spell it), let alone diagnose it with a simple blood test. And most of them certainly don’t know that the best thing to do would be to prophylax you with doxycycline.
Let’s put the numbers in perspective. In 2010, the CDC reported over 20,000 confirmed cases of Lyme (Borrelia burgdorferi) and an additional 10,000 probable cases. The CDC’s number of cases (which I believe, as with burgdorferi, are severely underreported) for 1990-2011 for Borrelia hermsii (TBRF) is 483. If 35% of those Borrelia cases had been prevented with prophylaxis, that would mean 10,669 fewer sick people.
So what can you do? Here’s a list of my suggestions:
- If you’ve been diagnosed with a tick-borne illness, make sure that every one of your doctors knows it, even the ones you don’t like and the ones you don’t go to very often. All doctors, not just infectious disease doctors, need to be aware of how prevalent these infections are.
- If you are bitten by a tick, insist that your primary care doctor prophylax you with doxycycline for five days. You can even print out these PubMed article abstracts and bring them to your appointment. Many doctors can be reasoned with, and if they won’t listen to you, sometimes they’ll listen to the New England Journal of Medicine.
- If you are bitten by a tick, try your best to save the little beast. You can store it in an old prescription bottle or a jar. (Labs like Quest Diagnostics also distribute collection containers to some doctors’ offices.) Inform your doctor that you are brining the tick to your appointment and you want to have it tested. Having ticks tested helps with more accurate CDC reporting about which areas have infected ticks.
- Getting the tick tested doesn’t mean that you don’t need to get tested. The tick testing takes longer than the people testing. On the off-chance that prophylaxis doesn’t work for you, you’ll need to get more treatment if you test positive.
- As always, the best way not to get a tick bite is not to be in areas where ticks live and not to be around animals that carry ticks. Follow tick-exposure prevention best practices. This includes keeping your home and yard free of mice and rats (on which the hermsii-carrying ticks feed) as well as deer (on which the burgdorferi-carying ticks feed).
That’s all for Tick-Lit Tuesday. Stay informed and stay well!