Lyme disease is an illness caused by bacteria, primarily Borrelia burgdorferi. This article explains how Lyme disease is transmitted and addresses common misunderstandings about its spread.
How Lyme Disease Spreads
Lyme disease is primarily transmitted through the bite of infected blacklegged ticks. In the United States, these include Ixodes scapularis in the eastern and central regions and Ixodes pacificus on the West Coast. Other Ixodes species are responsible for transmission in Europe and Asia.
Ticks acquire the Borrelia bacteria when they feed on infected small mammals and birds during their larval and nymphal stages. Nymphs, which are immature ticks about the size of a poppy seed, are particularly significant vectors. Their small size makes them difficult to notice, increasing the likelihood of prolonged attachment to a host.
For transmission to occur, an infected tick generally needs to be attached for more than 24 to 36 hours. The bacteria, initially in the tick’s midgut, must migrate to its salivary glands before they can be transmitted to a human during a blood meal. Prompt removal of an attached tick can significantly reduce the chances of infection. However, some research suggests that transmission can occur in shorter periods, with some studies indicating it might happen in under 16 hours.
Common Misconceptions About Transmission
There is no credible scientific evidence that Lyme disease spreads through direct person-to-person contact. This means the infection cannot be transmitted through touching, kissing, or sexual contact. The bacteria causing Lyme disease have not been found in bodily fluids involved in sexual acts, nor are there documented cases of sexual transmission.
Lyme disease is also not spread through blood transfusions, although the bacteria can survive in stored blood. For this reason, individuals undergoing antibiotic treatment for Lyme disease are advised not to donate blood. Furthermore, Lyme disease cannot be transmitted through casual contact, from pets (though pets can bring infected ticks into a home), or through the bites of other insects like mosquitoes or fleas.
Transmission During Pregnancy
While rare, untreated Lyme disease during pregnancy can potentially lead to infection of the placenta. In such cases, spread from the mother to the fetus is possible. However, receiving appropriate antibiotic treatment during pregnancy prevents adverse birth outcomes.
The Centers for Disease Control and Prevention (CDC) states there are no reports of Lyme disease being transmitted to infants through breast milk. Mothers diagnosed with Lyme disease who are undergoing antibiotic treatment can generally continue breastfeeding. Healthcare providers can recommend antibiotics that are safe for use while breastfeeding.