HARD SCIENCE ON LYME: Ticks can transmit infection the first day
A new article has resurrected the old myth about disease transmission being impossible before a certain time after the tick bites. In the New Haven (CT) Register this week, Dr. David Katz writes: “Ticks need to be embedded for 24 hours or more to transmit Lyme.” This is an improvement on the usual 36-48-hour minimum we usually see, but it is still misleading. See the science and judge for yourself.
By Phyllis Mervine
The CDC claims on their website: “In most cases, the tick must be attached for 36-48 hours or more before the Lyme disease bacterium can be transmitted.” Dr. Katz says 24 hours are enough. What does the science say?
Nymphal ticks are implicated in most human cases of Lyme disease. (Clover 1995) Promptly and properly removing embedded ticks is key to preventing transmission of disease agents. In one study, experimentally infected Ixodes pacificus nymphs do not EFFICIENTLY [emphasis added] transmit Borrelia burgdorferi (Bb) to mice until ticks have been attached for 3-4 days, HOWEVER 11% of mice became infected after only 2 days of tick attachment (<=48hrs.) (Peavy 1995)
Matuschka and Spielman reported that about 5% of infected Ixodes dammini (i.e. scapularis) nymphs transmit Bb in the first day (24hr), about 50% after 2 days. (Matuschka 1995) J. Piesman et al. reported that Ixodes ticks transmitted Lyme disease to 1 of 14 rodents exposed for 24 hours, 5 of 14 rodents exposed for 48 hours, and 13 of 14 rodents exposed for 72 or more hours. The authors concluded that prompt removal of ticks is important.(1987)
Patmas and Remora reported on a case of Lyme disease that was transmitted after only 6 hours of attachment by a deer tick. The authors concluded that, “The current recommendation against treatment of shortduration tick bites may need reconsideration.”(1994)
It is impossible to remove a tick promptly if one does not even know it is there. According to some experts, only 14-32 % of patients who have Lyme disease recall a tick bite. (Nadelman, 2002) Durland Fish, associate professor in the Department of Epidemiology and Public Health at Yale University, wrote this letter to the New York Times (6-14-01):
You report on a new study showing that Lyme disease is very difficult to catch, even from a deer tick in a Lyme-infested area (front page, June 13). But the 3 percent chance of getting Lyme disease from a tick bite cited in the New England Journal of Medicine article that I co- authored pertains only to people who have found and removed a tick, which greatly decreases the chance of infection. Most people never notice the tick that gave them Lyme disease [emphasis added]. About 25 to 30 percent of nymph-stage deer ticks in the Northeast are naturally infected with the Lyme disease bacterium. Nearly all of these infected ticks will cause Lyme disease if they are not removed [emphasis added]. Ticks in this stage are about the size of a poppy seed, making them very difficult to find. People who live in Lyme disease areas should take the risk of tick bites seriously and do all they can to prevent them, keeping in mind the 25 percent chance of infection if they miss a tick, instead of the 3 percent chance if they find one.
UC Berkeley entomologist Robert Lane reports that one of his team of researchers was fed upon by infected nymphal ticks for at least 1-2 days after exposure to tick-infested habitat, despite “extreme personal preventive measures.” He advises people who work or recreate in endemic areas to check themselves frequently and carefully for several days following exposure, since unfed nymphs are very difficult to spot and may be easier to detect when partially replete.(Lane 2004)
Maybe the CDC claim “in most cases, ” turns on the word “most.” But is it really smart to discount those first 35 hours so emphatically when so much is at stake?
To read Dr. David Katz’s otherwise good article, click here.
Phyllis Mervine is the founder and president of LymeDisease.org, as well as Editor-in-chief of The Lyme Times. Contact her at pmervine@lymedisease.org.
Dear Phyllis,
Thank for once again trying to clarify this important issue. In my families experience, in a highly endemic area of the Hudson Valley, at least 50% of our known tick-bites have resulted in an active case of Lyme disease plus coinfections (usually Babesia duncani). One of my neighbor’s children is now fighting for her life because when she received a tickbite and rash at the age of 2, she was not treated. According to her doctor, because the tick was attached for less than 24 hours, it couldn’t be Lyme. I now insist that our family physician treat every tick-bite prophylacticly with a month of antibiotics.
I’ve been telling this self-described researcher on CNN, “Chris Olson”, that Piesman found a tick could transmit Lyme disease within 24 hours. Olson claims that a process has to take place within the tick in order for activated spirochetes to leave the midgut and move to the salivary glands and it requires a certain minimum timeframe.
Last I looked, he didn’t respond to my question about whether or not a tick which had been interrupted from feeding on a different host could still carry spirochetes in its salivary glands – which could mean quick transmission in the next host mammal – including people.
Thank you for the additional references. Patmas and Remora… 6 hours? Really? That’s awful. Transmission time for Powassan Virus, if I recall correctly, is 15 minutes. No one knows for sure how long Borrelia miyamotoi takes, far as I know – have not come across transmission times and don’t know if the issue has been studied. What I do know is that in soft bodied ticks, other relapsing fever Borrelia are located all throughout the tick and not just the midgut, and such RF Borrelia are transmitted in minutes to the host. Being a soft bodied tick may play more of a role in that than the spirochete type, though.
It’s no longer just about Lyme disease. But then, it hasn’t been for some time. Look at how many people get coinfections…
I know mine was only a couple of hours, NOT even 24 hours… black tick tiny like the head of a pin.
Since have been bitten total 4 and the last with a reaction & recurring the original symptoms, is another tiny head of pin black tick. (the others were brown)
The last one did have reaction and again only a couple of hours with recurrant reactions (red around bite area) and symptoms of flu like & joint pain tired headaches returning over a month after.
I KNOW it’s the black one for me and much less then the 24 hr period.
Last summer, my brother-in-law found a tick on his inner thigh on the drive home from a tubing trip. There is no way that tick was on him more than 4 hours and yet a bullseye came up a week later and he was diagnosed. The CDC contacted him, but never asked how long the tick was on him. The 24 hour incubation theory gives people a false sense of security.
We hiked on a Tuesday afternoon. I had my 4 year old strip down naked and checked her for ticks (she’s super white so it’s easy). Nothing. I didn’t, however, check her boots or wash her coat – which she put back on later. 12 hours after that check, I find tick embedded in her chest. I remove it & its head. Now 10 days later she’s got a rash at the bite. Not a bullseye (yet).
This 24-48 hour stuff is not true. My 5 year old son had a deer tick on him for no more than 4 hours. It was barely attached. I plucked it off & called the Dr. They told me not to worry bc I caught it very early. One week later he developed a high fever & the classic bullseye rash. The 24-48 thing is 100% not true. I have him a bath at 1:00 PM, went to the park for a few hours, even coated him with bug spray (mosquito, gnat & tick). At 6:00 PM I checked him as I usually do & there it was on the side of his stomach. He’s pale so it was as clear as day & was not there during the 1:00 bath. Be smart, be aware, ask questions & don’t believe everything you read about these timeframes.