Ticks can carry multiple pathogens and these are generally referred to as “Co-Infections” of a tick bite. Below are some of the “common” co-infections of the Borrelia bacteria that causes Lyme borreliosis. The co-infections can be worse than Borrelia and just as hard to treat, many times complicating the recovery of Lyme Borreliosis.


Babesiosis is an infection caused by a malaria-like parasite (Babesia microti and B. duncani are two examples), that infects red blood cells. If ticks are infected with the Lyme bacterium, Borrelia burgdorferi and Babesia, this is a co-infection. Although rare, it’s possible to contract babesiosis from a contaminated blood transfusion. Babesiosis is often so mild it goes unnoticed, but it can be life-threatening to people with no spleen, the elderly, and people with weak immune systems.
Symptoms of babesiosis are similar to those of Lyme disease, often starting with a high fever and chills. Some symptoms of babesiosis can be very low blood pressure, liver problems, severe hemolytic anemia (a breakdown of red blood cells), and kidney failure.


Bartonella are bacteria that live inside cells that can infect humans and a wide range of other animals. Not all Bartonella species cause disease in humans. It is mainly carried by cats and causes cat-scratch disease, endocarditis, and several other serious diseases in humans.
Fleas, body lice and ticks carry Bartonella. Scientists suspect that only ticks can transmit the infection to humans; however, more research is needed to establish the role of ticks in spreading the disease.


Rocky Mountain Spotted Fever is caused by bacteria called Rickettsia rickettsii. The disease is treatable with antibiotics (often doxycycline); however, 30% of untreated patients die. Symptoms may include: high fever, rash, headache, and bleeding problems.


Ehrlichiosis is caused by various types of Ehrlichia and Anaplasmosis is caused by Anaplasma phagocytophilum. Ehrlichiosis was formerly called HME, human monocytic ehrlichiosis and Anaplasmosis used to be called HGE, human granulocytic ehrlichiosis. Some studies suggest that, in endemic areas, as many as 15 – 36% of the human population has been infected, although many people may not be aware that they are infected.


Borrelia Miyamotoi is a new species of Borrelia found across Canada that we do not have testing for and its symptoms present very similarly to Borrelia burgdorferi.


Powassan (POW) virus is transmitted to humans by infected ticks. Most cases have occurred in the Northeast and Great Lakes region. Signs and symptoms of infection can include fever, headache, vomiting, weakness, confusion, seizures, and memory loss. Long-term neurologic problems may occur. There is no specific treatment, but people with severe POW virus illnesses often need to be hospitalized to receive respiratory support, intravenous fluids, or medications to reduce swelling in the brain.

You can reduce your risk of being infected with POW virus by using tick repellents, wearing long sleeves and pants, avoiding bushy and wooded areas, and doing thorough tick checks after spending time outdoors. If you think you or a family member may have POW virus disease, it is important to consult your healthcare provider.


Mycoplasmas can be transmitted through insect bites, open wounds, inhalation, ingestion, and sex.
There are many species of Mycoplasmas – over 200, and they are tiny Gram-positive bacteria lacking cell walls, which allows them to take on many shapes; they exist intracellularly. The primary mycoplasmas that cause human disease are: M. pneumoniae, M. genitalium, M. Hominis, M. Fermentans, and included in the family are – Ureaplasma urealyticum, U. parvum, as well as M. penetrans. They can infect any organ in the body and can be at the root of many chronic diseases whose origins have been confusing.

Mycoplasma: Often Overlooked In Chronic Lyme Disease by Scott Forsgren

Please see the tick identification page to see which pathogens the various tick species carry.
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