Ixodes (Hard-Bodied) Ticks
Of the 84 species of ticks found in the U.S., at least a dozen can infect humans. Ixodes (hard-bodied) ticks are the biggest culprits, known to transmit a large number of bacteria, parasites, and viruses.
According to the CDC, seven out of the 18 reportable tick-borne diseases in the U.S. are attributable to Ixodes ticks.
The main vectors are Ixodes scapularis (blacklegged tick or deer tick) found east of the Rockies, and Ixodes pacificus (western blacklegged tick) found west of the Rockies.
Known pathogens transmitted by Ixodes ticks include:
- Anaplasma phagocytophilum,
- Borrelia burgdorferi,
- Borrelia miyamotoi,
- Borrelia mayonii,
- Babesia microti,
- Ehrlichia muris, and
- Powassan virus.
Co-infections Are the Rule
To better understand how many microbes can be carried by ticks, scientists are going straight to the source—the tick. One such study took a deep dive into the pathogens carried by Ixodes ticks. While this research was conducted in France, I believe the conclusions are applicable to Ixodes ticks found throughout the world. Basically, ticks carry lots of bad stuff!
This study was the first to simultaneously test for 38 pathogens (bacteria, parasites, and viruses) and four symbionts (other microorganisms that may affect the transmission of disease). Some symbionts may make it harder for the tick to transmit pathogens, while others may make it easier.
The results were astonishing! Every tick carried at least one symbiont, and 45% were co-infected with up to five different pathogens. When you include symbionts in the count, some ticks carried as many as eight microorganisms. The study’s findings are summarized in the chart below:
Ticks Are Toxic Soup
In conclusion, if you are bitten by a tick, know that you may have been exposed to more than just Lyme disease, and that multiple infections increase the severity of illness.
LymeSci is written by Lonnie Marcum, a licensed physical therapist and mother of a daughter with Lyme. Follow her on Twitter: @LonnieRhea. Email her at lmarcum@lymedisease.org.