Coinfections & Diseases
Lyme rarely travels alone
A single tick can carry several pathogens at once. These deep-dive guides cover the coinfections and tick-borne diseases that matter most — including the ones patients say get missed.
Different regions, different ticks. See which diseases are carried where you live.
Common Lyme coinfections
Bartonella
A stealthy bacterium many Lyme-literate doctors consider one of the most common — and most disruptive — coinfections.
Learn moreBabesiosis
A malaria-like parasite that infects red blood cells — think night sweats and 'air hunger.'
Learn moreMycoplasma
One of the most frequently cited Lyme coinfections in the Lyme-literate community.
Learn moreAnaplasmosis
A bacterial coinfection carried by the same tick as Lyme, often with high fevers and abnormal blood counts.
Learn moreEhrlichiosis
A lone-star-tick infection common across the Southeast and south-central US.
Learn moreRocky Mountain Spotted Fever
A fast-moving, potentially fatal rickettsial infection — doxycycline can't wait for test results.
Learn morePowassan Virus
Rare but rising — a virus that can transmit in minutes and cause serious neurological illness.
Learn moreAlpha-gal Syndrome
A tick bite that can leave you allergic to red meat — with delayed, sometimes severe reactions.
Learn moreTick-borne Relapsing Fever
Recurring cycles of fever, classically after a stay in a rustic mountain cabin.
Learn moreTularemia
A serious bacterial infection spread by ticks and by contact with infected animals.
Learn moreOther tick-borne illnesses
Rickettsia parkeri Rickettsiosis
A milder spotted-fever cousin of RMSF, marked by an eschar at the bite site.
Learn moreHeartland & Bourbon Viruses
Emerging lone-star-tick viruses with no specific treatment — supportive care only.
Learn moreColorado Tick Fever
A high-elevation Western virus with a characteristic two-phase fever.
Learn moreSTARI
A Lyme-like bull's-eye rash in the South — its cause is still an open question.
Learn moreNot sure what you're dealing with?
Start with the symptom checker to organize what you're experiencing, then bring it to a Lyme-literate clinician.
Educational information only — not medical advice. Read our disclaimer.