When most people think about tick-borne disease, Lyme disease immediately comes to mind. But there are two other serious bacterial infections transmitted by ticks that are frequently missed, misdiagnosed, and dangerously underestimated: Ehrlichiosis (caused by Ehrlichia bacteria) and Anaplasmosis (caused by Anaplasma phagocytophilum).

Every year, thousands of patients across the United States seek medical care for persistent fatigue, fever, and unexplained symptoms—only to receive a generic diagnosis while the real cause remains undetected. Ehrlichia and Anaplasma are the culprits hiding behind those symptoms.

Understanding these infections, how they present, and—most importantly—how they are accurately detected can mean the difference between a full recovery and months of chronic suffering.

What Are Ehrlichia and Anaplasma?

Ehrlichia are intracellular bacteria that infect white blood cells—specifically monocytes and granulocytes. The most common species causing human disease in the United States is Ehrlichia chaffeensis.

Anaplasma phagocytophilum, the organism responsible for Human Granulocytic Anaplasmosis (HGA), similarly targets white blood cells—specifically neutrophils—and disrupts the immune system from within.

Patients being evaluated for Lyme disease may simultaneously carry Anaplasma, dramatically complicating their clinical picture and treatment response. This overlap is critical and frequently overlooked by clinicians.

Symptoms: Why These Infections Are So Easy to Miss

One of the most challenging aspects of Ehrlichia and Anaplasma infections is how non-specific their symptoms are. Early presentation often looks like the flu, a viral illness, or — very commonly — Lyme disease itself.

Unlike Lyme disease, the classic “bull’s-eye” rash (erythema migrans) is rarely present with Ehrlichia or Anaplasma infections. This absence often leads physicians to dismiss the possibility of a tick-borne infection entirely — a dangerous and costly mistake.

Who Is Most at Risk?

The Diagnostic Challenge: Why Standard Tests Miss These Infections

Traditional serological (antibody-based) testing requires the immune system to mount a detectable response — a process that can take 2 to 4 weeks. In acute infection, antibodies may not yet be present, resulting in a false negative.

Thrombocytopenia (low platelets), leukopenia (low white blood cells), and elevated liver enzymes are classic findings — but these are non-specific and often attributed to viral infections.

Ehrlichia and Anaplasma form characteristic clusters inside white blood cells called “morulae.” As seen in the microscopy images above, this finding is present in only a fraction of positive cases and requires an experienced eye to identify.

When a patient tests positive for Lyme disease but continues to deteriorate despite antibiotic treatment, a missed co-infection with Ehrlichia or Anaplasma may be responsible. This is where advanced molecular diagnostics become essential.

Advanced Molecular Testing: The TLabDX Approach

At TLabDX, our CAP-accredited, CLIA-certified laboratory uses state-of-the-art molecular testing methods to detect Ehrlichia and Anaplasma infections with precision — even in the earliest stages of disease when antibody tests would return a false negative.

Early detection—PCR can identify infection within days of exposure, before antibodies develop. Active infection confirmation—unlike antibody tests showing past exposure, PCR confirms a current, active infection. High specificity—molecular primers target specific Ehrlichia and Anaplasma species, reducing false positives.

Because Ehrlichia and Anaplasma frequently co-occur with Lyme disease, Bartonella, and Babesia, TLabDX offers comprehensive tick-borne co-infection panels that evaluate multiple pathogens simultaneously—especially important for patients with persistent symptoms despite Lyme treatment.

Why Timely Diagnosis Is Critical

⚠ Untreated, These Infections Can Become Life-Threatening

Ehrlichiosis and Anaplasmosis can progress rapidly from a flu-like illness to respiratory failure, renal failure, neurological complications (meningitis, encephalitis), septic shock, and death—particularly in elderly and immunocompromised individuals.

The CDC estimates that severe outcomes and fatalities from Ehrlichiosis are significantly under reported because many cases are never properly diagnosed.

The good news: when caught early, both infections respond well to doxycycline, a first-line antibiotic. Early treatment leads to rapid improvement. Delayed treatment dramatically increases the risk of hospitalisation and serious complications.

Ehrlichia and Anaplasma vs. Lyme Disease: Key Differences

What Patients Should Ask Their Doctor

If you have been exposed to ticks—or experience symptoms like sudden fever, severe fatigue, and headache, especially during tick season—consider asking your healthcare provider:

💡 Key Questions to Ask

The TLabDX Difference

TLabDX is a College of American Pathologists (CAP)-accredited and CLIA-certified diagnostic laboratory located in Gaithersburg, Maryland. We specialise in advanced testing for tick-borne diseases:

Our laboratory combines rigorous scientific standards with a patient-first mission. We partner with physicians and healthcare providers nationwide to deliver accurate, actionable results—so patients can finally get the answers they deserve.

Contact TLabDX

Don’t let Ehrlichia or Anaplasmosis go undetected. Advanced molecular diagnostics are available now — accurate, early, and actionable.

TLabDX | Advanced Tick-Borne Disease Diagnostics | CAP-Accredited | CLIA-Certified

Tags: Ehrlichia testing | Anaplasmosis diagnosis | Tick-borne co-infections | PCR testing | Molecular diagnostics