Anaplasmosis (HGA) Clinical Trials and Treatments

Anaplasmosis is caused by Anaplasma phagocytophilum, an obligate intracellular bacterium that specifically targets neutrophils, a type of white blood cell critical for immune defense. By infecting and suppressing these cells, the bacterium causes leukopenia and thrombocytopenia while inducing immune dysregulation that can lead to secondary infections and reactivation of latent viruses such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV). The disease is transmitted by Ixodes scapularis (blacklegged tick) in the eastern United States and Ixodes pacificus (western blacklegged tick) on the Pacific coast.

The most common symptoms of Anaplasmosis include Sudden high fever, severe headache, and muscle pain, Nausea, vomiting, diarrhea, and loss of appetite, Low white blood cell count (leukopenia) and low platelet count (thrombocytopenia), Elevated liver enzymes indicating liver involvement, Confusion or altered mental status in severe cases, among others. Classified as rare with prevalence < 1 per 1,000,000 (Orphanet). Case counts have been rising steadily, with the CDC reporting increasing incidence in the Northeast and upper Midwest as tick habitats expand.. Symptoms can range from mild to severe and may vary between individuals.

Trial Friend lists all active clinical trials for Anaplasmosis from ClinicalTrials.gov, with eligibility criteria translated into plain English. Patients can filter by trial phase and recruitment status, search by location, and use the Match Me tool to score trials against their profile. Clinical trial activity for anaplasmosis is limited because doxycycline works well for uncomplicated cases. However, patients with anaplasmosis alongside Lyme disease or babesiosis face significantly more complex treatment decisions.

Yes. As of September 2026, Trial Friend lists 1 FDA-approved drug used to treat Anaplasmosis: Vibramycin (doxycycline), first approved in 1967.

Each has its own page with what the label covers, side effects and how it is given, and the Treatments section of this page adds any further approved drugs found in FDA labeling data.

Anaplasmosis is caused by Anaplasma phagocytophilum, an obligate intracellular bacterium transmitted by the blacklegged tick (Ixodes scapularis) in the eastern United States and the western blacklegged tick (Ixodes pacificus) on the Pacific coast. The bacterium specifically targets and infects neutrophils, a type of white blood cell critical for immune defense. By reprogramming neutrophil gene expression, Anaplasma prevents these cells from self-destructing and suppresses their antimicrobial functions, essentially hijacking host immune cells. This immune suppression causes leukopenia and thrombocytopenia while also creating vulnerability to secondary infections and reactivation of latent viruses like EBV and CMV. When anaplasmosis coexists with Lyme disease, the immune suppression may reduce the body's ability to clear Borrelia spirochetes, which are pleomorphic organisms capable of shifting between active spirochetes, dormant round bodies, and biofilm communities.

Anaplasmosis is not a genetic disease, but host immune genetics influence disease severity and recovery. MHC class II variants (HLA-DR alleles) affect antigen presentation to T cells and likely influence the efficiency of the adaptive immune response to Anaplasma phagocytophilum. HLA-DR4, already associated with treatment-resistant Lyme arthritis, may compound immune challenges in coinfected patients. TLR1 polymorphisms (1805GG variant) appear at significantly higher frequency in patients with post-infectious inflammatory complications from tick-borne disease (60 percent versus 43 percent in treatment-responsive patients). Cytokine gene variants in IL-10, TNF-alpha, and IFN-gamma influence whether patients mount a controlled or exaggerated inflammatory response to Anaplasma infection. Patients on immunosuppressive therapy face disproportionate risk because Anaplasma specifically targets and reprograms neutrophils, the immune cells these patients can least afford to lose.

Eligibility for Anaplasmosis clinical trials depends on factors like age, diagnosis, treatment history, and overall health. Each trial sets its own inclusion and exclusion criteria. Trial Friend translates these requirements from medical language into plain English so patients can review them more easily. The Match Me tool can score your profile against active trials to help identify studies that may be a fit.

Participating in a Anaplasmosis clinical trial typically involves scheduled visits, medical tests, and close monitoring by a research team. Depending on the study phase, you may receive an investigational treatment, a placebo, or the current standard of care. Trials may last from a few weeks to several years. Study participation is voluntary, and you can withdraw at any time.

Anaplasmosis is primarily treated with doxycycline, which is highly effective for uncomplicated cases. Clinical trial activity is focused on surveillance and diagnostics rather than new drugs, so medication conflicts are most relevant when anaplasmosis coexists with Lyme disease or babesiosis and patients are on multi-drug regimens. Trial Friend's medication conflict checker scans each trial's exclusion criteria against common tick-borne disease medications including doxycycline, amoxicillin, ceftriaxone (for Lyme coinfection), atovaquone and azithromycin (for Babesia coinfection), rifampin (alternative for pregnant women and children), and immunosuppressive agents. The checker flags the specific drug, exclusion language, and a confidence level so you can discuss timing with your Lyme-literate doctor or infectious disease specialist.

Key questions to ask your Lyme-literate doctor (LLMD) or infectious disease specialist about anaplasmosis include: Was my diagnosis confirmed by blood smear showing morulae in neutrophils or by PCR, not just antibody serology? Have I been tested for Lyme and Babesia coinfection since all three pathogens share the Ixodes tick vector? Has my immune recovery been monitored after treatment, including white blood cell and platelet count normalization? Could the immune suppression from anaplasmosis have allowed latent EBV or CMV to reactivate, explaining persistent fatigue? If I was coinfected with Borrelia, has persistent infection been considered given that Anaplasma suppresses the neutrophils needed to clear it? If I am pregnant or a young child, what is the evidence for rifampin as a doxycycline alternative? Are there active surveillance or diagnostic studies through the CDC Tick-Borne Disease Research Program that I could participate in?