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Co-Infection Guide

Comprehensive guide to tick-borne co-infections commonly found alongside Lyme disease. Understanding co-infections is critical for accurate diagnosis and effective treatment.

Common Co-infections

Tick-borne organisms frequently found with Lyme

40%

Co-infection Rate

Of Lyme patients have at least one co-infection

2.3

Avg Co-infections

Average number of co-infections per chronic Lyme patient

2+ yrs

Delayed Diagnosis

Average time to co-infection diagnosis after initial Lyme

Babesiosis

Babesia microti

15-40% of Lyme patients in endemic areas

Transmission Vector

Ixodes scapularis (black-legged tick), blood transfusion, transplacental

Geographic Distribution

Northeastern and upper Midwestern United States (Connecticut, Massachusetts, New York, Wisconsin, Minnesota)

Key Symptoms

Malaria-like cyclical fevers and chills

Drenching night sweats

Air hunger (dyspnea without exertion)

Hemolytic anemia

Dark urine from hemoglobin breakdown

Severe fatigue and malaise

Splenomegaly (enlarged spleen)

Jaundice in severe cases

Distinguishing Features

Parasitizes red blood cells (intra-erythrocytic)

Air hunger is a hallmark symptom unique to Babesiosis

Can be fatal in immunocompromised or asplenic patients

Does not respond to standard Lyme antibiotics

Diagnostic Tests

Giemsa-stained thin blood smear

Microscopy

Sensitivity: ~50% (low parasitemia may be missed)

Look for "Maltese cross" tetrad formation inside red blood cells; distinguishes from Plasmodium

Babesia PCR (polymerase chain reaction)

Molecular

Sensitivity: 95-100%

Most sensitive test; can detect low-level parasitemia; recommended for acute infection

Babesia IFA (Indirect Fluorescent Antibody)

Serology

Sensitivity: 88-96%

IgM rises first (1-2 weeks); IgG peaks at 2-4 weeks; titers >= 1:256 considered positive

Babesia FISH (Fluorescent In Situ Hybridization)

Molecular

Sensitivity: ~93%

Rapid test (under 2 hours); offered by IGeneX; detects ribosomal RNA in blood

Treatment Protocols

Atovaquone + Azithromycin

7-10 days (mild); 6+ weeks (chronic/relapsing)

First-line for mild-to-moderate disease; better tolerated than quinine regimen

Clindamycin + Quinine

7-10 days

Reserved for severe disease or treatment failures; significant GI side effects

Exchange transfusion

As needed

For life-threatening cases with parasitemia > 10%, severe hemolysis, or organ failure

Critical Notes

Can be life-threatening in asplenic, elderly, or immunocompromised patients

Relapses are common, especially in immunosuppressed individuals

Standard Lyme treatment (doxycycline alone) does NOT treat Babesiosis

Blood supply screening for Babesia became mandatory in the US in 2024

Explore Related Modules

Treatment Guide

Evidence-based treatment info

Lab Test Guide

Diagnostic test interpreter

Symptom Screener

Clinical pre-screening tool

Tick Prevention

Bite prevention & response guide

Data Sources (6)

Centers for Disease Control and Prevention (CDC). Tick-Borne Disease Surveillance and Epidemiology Data. 2024-2026.
International Lyme and Associated Diseases Society (ILADS). Evidence-Based Guidelines for Management of Lyme Disease. 2014-2024.
Infectious Diseases Society of America (IDSA). Clinical Practice Guidelines for Tick-Borne Diseases. 2020-2025.
Galaxy Diagnostics / Dr. Ed Breitschwerdt Research. Bartonella Diagnosis and Treatment Protocols. 2018-2026.
National Institutes of Health (NIH). Human Babesiosis: Clinical Implications of Emerging Parasite. 2021-2025.
Centers for Disease Control and Prevention (CDC). Rocky Mountain Spotted Fever: Diagnosis and Treatment. 2023-2026.

Co-Infection Guide

Comprehensive guide to tick-borne co-infections commonly found alongside Lyme disease. Understanding co-infections is critical for accurate diagnosis and effective treatment.

Common Co-infections

Tick-borne organisms frequently found with Lyme

40%

Co-infection Rate

Of Lyme patients have at least one co-infection

2.3

Avg Co-infections

Average number of co-infections per chronic Lyme patient

2+ yrs

Delayed Diagnosis

Average time to co-infection diagnosis after initial Lyme

Babesiosis

Babesia microti

15-40% of Lyme patients in endemic areas

Transmission Vector

Ixodes scapularis (black-legged tick), blood transfusion, transplacental

Geographic Distribution

Northeastern and upper Midwestern United States (Connecticut, Massachusetts, New York, Wisconsin, Minnesota)

Key Symptoms

Malaria-like cyclical fevers and chills

Drenching night sweats

Air hunger (dyspnea without exertion)

Hemolytic anemia

Dark urine from hemoglobin breakdown

Severe fatigue and malaise

Splenomegaly (enlarged spleen)

Jaundice in severe cases

Distinguishing Features

Parasitizes red blood cells (intra-erythrocytic)

Air hunger is a hallmark symptom unique to Babesiosis

Can be fatal in immunocompromised or asplenic patients

Does not respond to standard Lyme antibiotics

Diagnostic Tests

Giemsa-stained thin blood smear

Microscopy

Sensitivity: ~50% (low parasitemia may be missed)

Look for "Maltese cross" tetrad formation inside red blood cells; distinguishes from Plasmodium

Babesia PCR (polymerase chain reaction)

Molecular

Sensitivity: 95-100%

Most sensitive test; can detect low-level parasitemia; recommended for acute infection

Babesia IFA (Indirect Fluorescent Antibody)

Serology

Sensitivity: 88-96%

IgM rises first (1-2 weeks); IgG peaks at 2-4 weeks; titers >= 1:256 considered positive

Babesia FISH (Fluorescent In Situ Hybridization)

Molecular

Sensitivity: ~93%

Rapid test (under 2 hours); offered by IGeneX; detects ribosomal RNA in blood

Treatment Protocols

Atovaquone + Azithromycin

7-10 days (mild); 6+ weeks (chronic/relapsing)

First-line for mild-to-moderate disease; better tolerated than quinine regimen

Clindamycin + Quinine

7-10 days

Reserved for severe disease or treatment failures; significant GI side effects

Exchange transfusion

As needed

For life-threatening cases with parasitemia > 10%, severe hemolysis, or organ failure

Critical Notes

Can be life-threatening in asplenic, elderly, or immunocompromised patients

Relapses are common, especially in immunosuppressed individuals

Standard Lyme treatment (doxycycline alone) does NOT treat Babesiosis

Blood supply screening for Babesia became mandatory in the US in 2024

Explore Related Modules

Treatment Guide

Evidence-based treatment info

Lab Test Guide

Diagnostic test interpreter

Symptom Screener

Clinical pre-screening tool

Tick Prevention

Bite prevention & response guide

Data Sources (6)

Centers for Disease Control and Prevention (CDC). Tick-Borne Disease Surveillance and Epidemiology Data. 2024-2026.
International Lyme and Associated Diseases Society (ILADS). Evidence-Based Guidelines for Management of Lyme Disease. 2014-2024.
Infectious Diseases Society of America (IDSA). Clinical Practice Guidelines for Tick-Borne Diseases. 2020-2025.
Galaxy Diagnostics / Dr. Ed Breitschwerdt Research. Bartonella Diagnosis and Treatment Protocols. 2018-2026.
National Institutes of Health (NIH). Human Babesiosis: Clinical Implications of Emerging Parasite. 2021-2025.
Centers for Disease Control and Prevention (CDC). Rocky Mountain Spotted Fever: Diagnosis and Treatment. 2023-2026.