Recently Discovered “Sister” Bacteria to Lyme disease Highly Prevalent in New England

A team of researchers from Yale School of Public Health, including Dr. Peter Krause, Dr. Durland Fish, Demerise Johnston, and others, have published a study in the journal Clinical Infectious Diseases documenting a bacteria similar to the one which causes Lyme disease. This bacteria was found in human blood from samples taken from individuals living in New England.

The Bacteria

The bacteria found was of the Borrelia miyamotoi species. This species has only recently been discovered as capable of infecting humans, through a study also conducted by Krause and Fish. Borrelia miyamotoi has been found to cause relapsing fevers and meningoencephalitis.

Further, this species is carried by deer ticks, just like those which transfer Lyme disease to humans.

Since the species itself is so new, researchers in this study didn’t expect the bacteria would be widespread. However, they found it at each and every site they tested.

The Study

This study was a collaboration between Yale, the FDA (led by Sanjay Kumar), and L2 Diagnostics (led by Michel Ledizet). The team tested over 1100 samples from New England States in 2018.

  • About 3% of participants had antibodies to Borrelia miyamotoi.
  • At some sites in New England, 5% of participants had antibodies to the bacteria.
  • For Lyme disease and for babesiosis, we know the origin is southeastern New England. The antibodies found were so dispersed for this new bacteria that the origin of the infection couldn’t be determined.
  • There were many more people with the Lyme disease pathogen (up to 15% at some sites) than those with the Borrelia miyamotoi antibodies.


These researchers also tested the blood samples for another organism called Babesia microti. This microorganism causes human babesiosis and like Lyme disease and Borrelia miyamotoi, it can be spread via ticks.

About 10% of the sample had antibodies to Babesia microti.

While Lyme disease is more common, what is so dangerous is that co-infection can occur. People can get sick from Babesia microti and Lyme disease at the same time, worsening outcomes.

What This Means

Although Borrelia miyamotoi was found to be less prevalent than both Lyme disease and babesiosis, the prevalence of Borrelia miyamotoi is worrisome. Physicians who see patients with Lyme disease symptoms should not rule out other infections.

An average of 3% at each trial site means there are possibly tens of thousands of people who are becoming infected with Borrelia miyamotoi in New England.

Thankfully, there are treatments for those diagnosed with this kind of infection. Most of the treatments are the same as those for Lyme disease (typically antibiotics).

The research team suggests that we should continue to track the geographic spread of this bacteria in order to monitor transmission.

You can read more about this study and its findings here.

Share this post