After a tick bite, how long for disease transmission?

tick-disease-transmission

A single tick bite can transmit several diseases. But investigators continue to debate how long a tick must be attached before it can transmit the Lyme disease bacterium. While many believe a tick must be attached for at least 36 to 48 hours before transmission can occur, others say it can happen within several hours.

 

People often ask: How long does it take for disease transmission to occur after a tick bite? According to investigators, Lyme disease may be transmitted faster if the tick previously fed on another host.

In a 2014 article entitled “Lyme borreliosis: a review of data on transmission time after tick attachment,” Michael J Cook explored the topic. “It is frequently stated that the risk of infection is very low if the tick is removed within 24 to 48 hours with some claims that there is no risk if an attached tick is removed within 24 hours or 48 hours.”

However, in animal models, Cook found, “transmission can occur in less than 16 hours, and the minimum attachment time for transmission of infection has never been established.”

Have you been bitten by a partially fed tick?

Investigators suggest that transmission time may be shorter if a tick has already fed on a host. A study by Shih and colleagues, found that, “Partially fed nymphal ticks transmit spirochetal infection more rapidly than do ticks that have never been attached to a host.”¹

So, how quickly a tick can transmit Lyme disease may depend on whether the tick had been partly fed BEFORE it attached to its second host.

Shih et al. demonstrated that partially fed nymphal ticks (84%) were capable of transmitting spirochetes to a non-infected mouse within 24 hours. The authors discovered it took less time for an infected nymphal deer tick to transmit Lyme spirochetes to a mouse if the tick was partially fed.

Ticks spontaneously detach from hosts

Individuals may mistakenly believe that once a tick bites it will remain attached throughout the entire feeding or until it is removed. But this isn’t the case.

In the mouse study, Shih found that ticks can spontaneously detach during the feeding process. And this action can profoundly impact the time it takes for spirochetes to infect the host.

“Virtually all nymphal ticks that previously had fed for 16 hours reattached efficiently.”¹

“We found that nymphs do detach spontaneously from free-ranging mice in the laboratory, perhaps as frequently as 15% of the time,” the authors report.

“Indeed, about [one tenth] of questing nymphs in nature seem to be distended, and reattachment by partially fed sub-adult ticks commonly occurs.”

In the laboratory, partially fed ticks would reattach to a second host and commence feeding. “Virtually all nymphal ticks that previously had fed for 16 hours reattached efficiently.”

What happens in partially fed ticks?

The tick attaches to a host, feeds and the Lyme bacteria multiply rapidly in the tick’s mid-gut. Normally, the tick eliminates all of the bacteria, leaving behind only those spirochetes that survive in the mid-gut before they molt into an adult.

But, in a partially fed tick, spirochetes multiply in the mid-gut and then move to the salivary glands.

If the tick bites again, the spirochetes residing in the salivary glands can be transmitted more quickly. “Partially fed nymphs [ticks] are able to reattach to another host and Lyme disease spirochetes may be transmitted by partially fed nymphs more rapidly than by nymphs that have not already fed.”

Pet owners: be wary

Their findings are particularly relevant to people who own pets. “These partially fed ticks may already have acquired spirochetal infection and avidly seek other hosts,” writes Shih.

“Pet ownership appears to be a risk factor for human Lyme disease, and this may reflect contact with ticks that have detached from a cat or dog within the household.”

If an unfed tick attaches it can take up to 36 hours to transmit the Lyme spirochetes to a mouse, Shih claims. “The chain of events that culminates in migration of the spirochetes from the gut of the tick to its salivary apparatus begins within the first day of attachment and requires at least another day for completion.”

Note: The study by Shih and colleagues was conducted only with mice and has not been replicated with humans.

UPDATED: June 22, 2021

References:
  1. Shih CM, Telford SR, 3rd, Pollack RJ, Spielman A. Rapid dissemination by the agent of Lyme disease in hosts that permit fulminating infection. Infect Immun, 61(6), 2396-2399 (1993).
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7 Replies to "After a tick bite, how long for disease transmission?"

  • Katie Bull
    07/07/2021 (1:22 am)
    Reply

    Hello! Last night I felt a strange almost burning sensation on my waist and when I looked down there was a small rash but no tick. There was a hardness to the center and no Red ring. My Visiting friend took a photo and said she thought it looked like a spider bite. The hair follicles seemed raised and bumpy. This morning it had a very bright redness around it and small blisters forming inside. I went to my doctor who had a cancellation/free time to see me on short notice (miracle!) and she was visibly and verbally perplexed. To her 1.) it didn’t appear to be Lymes as I have no other symptoms at all and don’t recall a tick (I do tick checks every day.) “But it could be.” 2.) she was thinking – maybe a spider bite (which is what I thought it was.) 3.) then she said – possibly shingles – but then she changed her mind and said it didn’t look like shingles.
    So she put me on two weeks of doxy in case it is Lymes which I took starting tonight. And she gave me a steroid cream for the blistery burning sore. It’s very strange. I have researched Lymes because my former husband had it years ago. I managed to avoid it for 22 years and so have my kids – by dressing properly, using tick sprays and not ever going into the high grass or wooded tick areas of our property. No bare feet either. Ever. But I do have a hound dog who sometimes gets into tall grasses for a moment or two. The suddenness of this coupled with zero other symptoms makes me think it’s a spider bite. Are there spider bites that look somewhat like tick bites? I was thinking maybe a brown recluse or woof spider bite… But meanwhile I’m being preventatively treated for Lymes just in case- with the doxy. Thoughts? I have photos. I feel very scared because I saw a neighbor with undiagnosed Lymes really spiral down. But I’m keeping my chin up for this immediate antibiotic prescription my doctor gave me. From the Catskills mountains

    • Dr. Daniel Cameron
      07/07/2021 (7:36 am)
      Reply

      I have faced the diagnostic uncertainty in some of my patients. I also find it difficult to make diagnosis based on a picture. I have patients with rashes without symptoms. I have treated with antibiotics if Lyme disease is a consideration even if the diagnosis is uncertain. I also follow them to be sure there is no other diagnosis.

  • Nancy Zamboni
    07/04/2021 (6:59 pm)
    Reply

    When treatment is started early (1-2 weeks after a tick bite), is it soon enough to avoid later immunity issues?
    (Are there timing factors for this in the progression of the disease?)
    Can this affect the effectiveness of Covid vaccines, or the preferred timing?

    • Dr. Daniel Cameron
      07/05/2021 (8:57 am)
      Reply

      My patients are more likely to stay well if treated early. I advise followup to assess for chronic illness. You would have to work with your doctor to determine the best time for a vaccine if you are ill.

  • Betty Scanlon-Neal
    03/04/2018 (12:27 am)
    Reply

    Interesting findings about partially fed ticks DR C. It makes sense. The tick that infected me was only attached for 7-8 hours tops. A red-raised ring developed in 24 hours and the classic flu-like symptoms hit 4 days later with the classic stiff neck symptom on the 5th morning. Did my GP believe the tick that bit me gave me those symptoms? -no. He said the tick was “not a deer tick and we do not have Lyme in our area of the mountains.” Months passed as the symptoms escalated into the next stages. My verbal concern for myself and Lyme ignored and he became hostile towards me. Month 3, He told me I was being paranoid and that I was extremely depressed and had Fibromyalgia; he prescribed Paxil and Valium. Did he finally believe me after I demanded a blood test for Borrelia that returned a positive via ELISA? He said, “how did you know?” Put me on 2 weeks doxy….the rest is history. 18 years later still sick. Not a unfamiliar story anymore is it Dr C. Thank you for all you do for us. Physicians reading this stop denying Lyme, your’e killing us.

    • Ellen Marshall
      06/23/2021 (6:10 am)
      Reply

      Pretty much my story too. Except I was pronounced Bipolar and spent 20 years on an array of psych meds that kept changing after each of four hospitalizations for suicidal ideation. All that attributed to PTSD for trauma history. And “attention seeking behaviors.”

      Tick, red ring, same progression of symptoms. When the crippling arthritis started after ten years, that was attributed to hard living as a cave explorer and a UPS driver in my youth.

      Wake up doctors, CDC, psychiatric professionals. Follow up with your patients who have these symptoms.

  • Alicia
    04/28/2017 (4:07 pm)
    Reply

    Thank you for this important information, Dr. Cameron.
    https://madisonarealymesupportgroup.com/2017/04/14/transmission-time-for-lymemsids-infection/
    In this link is a helpful video by Microbiologist Holly Ahern who does a great job interpreting this information.


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