Lyme disease is a tick-borne infectious disease caused by Borrelia burgdorferi and related Borrelia species. It is the most common vector-borne disease in North America and Europe. The disease progresses through stages: early localized (erythema migrans), early disseminated (multiple erythema migrans, neurological, cardiac involvement), and late disseminated (arthritis, chronic neurological). Early antibiotic treatment is highly effective, while delayed treatment may lead to persistent symptoms.
Ask a research question about Lyme Disease. OpenScientist will conduct autonomous deep research using the Disorder Mechanisms Knowledge Base and PubMed literature (typically 10-30 minutes).
Do not include personal health information in your question. Questions and results are cached in your browser's local storage.
Conditions with similar clinical presentations that must be differentiated from Lyme Disease:
name: Lyme Disease
creation_date: '2026-01-09T05:55:26Z'
updated_date: '2026-05-02T00:00:00Z'
category: Infectious
description: >
Lyme disease is a tick-borne infectious disease caused by Borrelia burgdorferi
and related Borrelia species. It is the most common vector-borne disease in
North America and Europe. The disease progresses through stages: early localized
(erythema migrans), early disseminated (multiple erythema migrans, neurological,
cardiac involvement), and late disseminated (arthritis, chronic neurological).
Early antibiotic treatment is highly effective, while delayed treatment may lead
to persistent symptoms.
disease_term:
preferred_term: Lyme disease
term:
id: MONDO:0019632
label: Lyme disease
parents:
- Bacterial Infection
- Tick-Borne Disease
has_subtypes:
- name: Early Localized Lyme Disease
description: Initial stage within weeks of tick bite, characterized by erythema migrans and flu-like symptoms.
evidence:
- reference: PMID:38651851
reference_title: "Skin Changes in Suspected Lyme Disease."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Early localized stage. Characterized by skin changes - erythema migrans (EM) - usually manifests within a month of the tick bite (usually 7-14 days after the bite)"
explanation: Review describes early localized stage as defined by erythema migrans appearing within weeks of the tick bite.
- name: Early Disseminated Lyme Disease
description: Hematogenous spread within weeks to months, with multiple erythema migrans, neurological, or cardiac involvement.
evidence:
- reference: PMID:38651851
reference_title: "Skin Changes in Suspected Lyme Disease."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Lyme disease has a wide spectrum of clinical manifestations that can generally be observed in three stages: the early localized stage, the early disseminated stage, and the late stage of the disease."
explanation: Clinical review delineates Lyme disease into three classical stages including an early disseminated stage.
- name: Late Disseminated Lyme Disease
description: Months to years after infection, characterized by Lyme arthritis or chronic neurological manifestations.
evidence:
- reference: PMID:38651851
reference_title: "Skin Changes in Suspected Lyme Disease."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Lyme disease has a wide spectrum of clinical manifestations that can generally be observed in three stages: the early localized stage, the early disseminated stage, and the late stage of the disease."
explanation: Clinical review documents the late stage of Lyme disease as a distinct phase following early dissemination.
- name: Post-Treatment Lyme Disease Syndrome
description: Persistent symptoms after appropriate antibiotic therapy, occurring in 10-20% of treated patients.
evidence:
- reference: PMID:39161484
reference_title: "What Makes It Tick: Exploring the Mechanisms of Post-treatment Lyme Disease Syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "These symptoms occur in 10%-20% of patients previously diagnosed with LD caused by the bacteria Borrelia burgdorferi and appropriately treated with a course of antibiotics."
explanation: IDSA-aligned review confirms PTLDS occurs in 10–20% of appropriately treated Lyme disease patients.
pathophysiology:
- name: Tick-Borne Transmission and Enzootic Cycle
description: >
Borrelia burgdorferi is maintained in an enzootic cycle between Ixodes ticks
and small-mammal reservoirs such as the white-footed mouse; larval ticks
acquire spirochetes by feeding on infected reservoirs and transmit them
transstadially to the nymphal stage that bites humans. In the unfed tick
midgut the spirochete expresses OspA (midgut adhesion) but not OspC. During
the blood meal, host- and temperature-derived signals trigger a reciprocal
antigenic switch in which OspA is downregulated and OspC is upregulated,
accompanying spirochete migration from the midgut to the salivary glands and
transmission into the vertebrate dermis; OspC expression peaks around 48 h of
tick attachment and is required for early mammalian infectivity.
evidence:
- reference: PMID:10618120
reference_title: "Temporal changes in outer surface proteins A and C of the lyme disease-associated spirochete, Borrelia burgdorferi, during the chain of infection in ticks and mice."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "B. burgdorferi expresses outer surface protein A (OspA) but not OspC when residing in the midgut of unfed ticks. However, after ticks feed on blood, some spirochetes stop making OspA and express OspC."
explanation: Immunofluorescence of spirochetes in feeding Ixodes nymphs demonstrates the reciprocal OspA-to-OspC switch that accompanies transmission from tick to mammal.
- reference: PMID:22230951
reference_title: "Of ticks, mice and men: understanding the dual-host lifestyle of Lyme disease spirochaetes."
supports: SUPPORT
evidence_source: OTHER
snippet: "we integrate this large body of information into a cohesive picture of the molecular and cellular events that transpire as Lyme disease spirochaetes transit between their arthropod and vertebrate hosts during the enzootic cycle."
explanation: Authoritative review frames B. burgdorferi pathogenesis around its dual-host transit between Ixodes ticks and vertebrate hosts during the enzootic cycle.
biological_processes:
- preferred_term: OspA/OspC antigenic switch
term:
id: GO:0010468
label: regulation of gene expression
- preferred_term: response to temperature stimulus
term:
id: GO:0009266
label: response to temperature stimulus
downstream:
- target: Spirochete Invasion and Dissemination
causal_link_type: DIRECT
description: OspC-mediated transmission deposits infectious spirochetes in the host dermis, initiating local colonization and dissemination.
- name: Tick Saliva-Assisted Immune Evasion via Salp15-OspC
description: >
During transmission, Borrelia burgdorferi co-opts components of Ixodes tick
saliva to establish infection at the bite site. The spirochete selectively
enhances tick expression of the 15-kDa salivary protein Salp15, which binds
the spirochetal surface lipoprotein OspC and coats the organism. Salp15
(and its I. ricinus homologue Iric1) shields Borrelia from antibody-mediated
killing and complement, giving the spirochete a marked infectivity advantage
in the mammalian host; the bacterium thereby exploits a secreted arthropod
protein to colonize the vertebrate dermis.
evidence:
- reference: PMID:16049492
reference_title: "The Lyme disease agent exploits a tick protein to infect the mammalian host."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "Salp15 was then shown to adhere to the spirochaete, both in vitro and in vivo, and specifically interacted with B. burgdorferi outer surface protein C. The binding of Salp15 protected B. burgdorferi from antibody-mediated killing in vitro and provided spirochaetes with a marked advantage when they were inoculated into naive mice"
explanation: RNA-interference and infection experiments in Ixodes scapularis and mice show B. burgdorferi usurps the tick salivary protein Salp15, which binds OspC and protects the spirochete from antibody-mediated killing during transmission.
- reference: PMID:33401196
reference_title: "Strong interactions between Salp15 homologues from the tick I. ricinus and distinct types of the outer surface OspC protein from Borrelia."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: "we show in this study that also Iric2 and Iric3 are capable of OspC binding with high affinity"
explanation: Binding study demonstrates that, beyond the previously characterized Iric1, the I. ricinus Salp15 homologues Iric2 and Iric3 also bind Borrelia OspC with high affinity, reinforcing Salp15-family/OspC engagement as a conserved transmission-interface interaction.
biological_processes:
- preferred_term: Salp15-mediated protection from antibody-mediated killing
term:
id: GO:0042783
label: symbiont-mediated evasion of host immune response
modifier: INCREASED
locations:
- preferred_term: skin
term:
id: UBERON:0002097
label: skin of body
downstream:
- target: Spirochete Invasion and Dissemination
causal_link_type: DIRECT
description: Salp15-coated spirochetes resist early humoral clearance at the bite site, enabling establishment of dermal infection and subsequent dissemination.
- name: Spirochete Invasion and Dissemination
description: >
Borrelia burgdorferi is transmitted through Ixodes tick bites. The spirochete
disseminates from the skin through the bloodstream to multiple organ systems
including joints, heart, and nervous system. Surface adhesins like BBK32 and
decorin-binding proteins (DbpA/DbpB) facilitate tissue colonization, while
OspC is upregulated at the tick-feeding/early-mammalian interface and is
required for early infectivity.
evidence:
- reference: PMID:33669940
reference_title: "Lyme Disease among Patients at an Ambulatory Unit in a Highly Endemic Country: Lithuania."
supports: SUPPORT
snippet: "The clinical manifestations of Lyme disease range from a localized infection, for example, erythema migrans (EM) to a disseminated neurological or rheumatological infection, cardiac involvement, or even chronic disease."
explanation: Epidemiologic series shows Borrelia disseminates beyond skin to neurologic, rheumatologic, and cardiac sites.
cell_types:
- preferred_term: endothelial cell
term:
id: CL:0000115
label: endothelial cell
biological_processes:
- preferred_term: cell adhesion
term:
id: GO:0007155
label: cell adhesion
locations:
- preferred_term: skin
term:
id: UBERON:0002097
label: skin of body
- preferred_term: blood
term:
id: UBERON:0000178
label: blood
downstream:
- target: Inflammatory Response and Tissue Damage
causal_link_type: DIRECT
description: Disseminating spirochetes deliver lipoproteins and peptidoglycan that drive innate inflammation at colonized tissues.
- name: Complement Evasion via BBK32-Mediated C1r Inhibition
description: >
The Borrelia burgdorferi surface lipoprotein BBK32 binds C1r, the initiator
protease of the classical complement pathway. This attenuates
antibody-dependent complement activation and protects infectious Borrelia
from complement-mediated killing in human serum.
evidence:
- reference: PMID:40705830
reference_title: "BBK32 attenuates antibody-dependent complement-mediated killing of infectious Borreliella burgdorferi isolates."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: "BBK32 binds to C1r, the initiator protease of the classical pathway of complement, and protects B. burgdorferi from complement-mediated killing following exposure to normal human serum."
explanation: Functional in vitro evidence that BBK32 binds C1r and blocks classical-pathway complement killing of infectious Borrelia burgdorferi.
biological_processes:
- preferred_term: negative regulation of complement activation
term:
id: GO:0045916
label: negative regulation of complement activation
modifier: INCREASED
downstream:
- target: Spirochete Invasion and Dissemination
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- Classical-pathway inhibition yields serum resistance, permitting spirochete survival during hematogenous dissemination.
description: Blocking antibody-dependent complement killing allows surviving spirochetes to disseminate despite humoral immunity.
- name: Alternative Complement Pathway Evasion via Factor H Recruitment
description: >
Borrelia burgdorferi expresses complement regulator-acquiring surface proteins
(CRASPs) such as CspA (CRASP-1), along with CspZ and OspE-family paralogs, that
bind the host alternative-pathway regulators factor H and factor H-like protein 1
(FH/FHL-1). Surface-bound FH/FHL-1 limits C3 deposition and membrane-attack-complex
formation, conferring resistance to complement-mediated killing in human serum.
This pathway complements the BBK32-mediated classical-pathway block.
evidence:
- reference: PMID:19451251
reference_title: "CspA-mediated binding of human factor H inhibits complement deposition and confers serum resistance in Borrelia burgdorferi."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: "the CspA-mediated binding of human FH confers serum resistance by directly inhibiting complement deposition on the surface of B. burgdorferi."
explanation: A cspA knockout loses surface factor H binding and becomes serum-sensitive with enhanced C3/C6/C5b-9 deposition, demonstrating CspA-driven alternative-pathway evasion.
biological_processes:
- preferred_term: negative regulation of complement activation
term:
id: GO:0045916
label: negative regulation of complement activation
modifier: INCREASED
downstream:
- target: Spirochete Invasion and Dissemination
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- Factor H recruitment produces serum resistance that enables spirochete survival in blood during dissemination.
description: Alternative-pathway evasion sustains spirochete viability in serum, supporting hematogenous spread.
- name: Antigenic Variation via vlsE Gene Conversion
description: >
The vlsE locus undergoes gene conversion that diversifies Borrelia surface
antigens, helping the pathogen evade host immune recognition during
dissemination and persistent infection.
evidence:
- reference: PMID:39792948
reference_title: "Breaking a barrier: In trans vlsE recombination and genetic manipulation of the native vlsE gene of the Lyme disease pathogen."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: "Borrelia burgdorferi, the Lyme disease pathogen, has evolved an intricate antigenic variation mechanism to evade the host immune response, enabling its dissemination, persistence, and pathogenicity."
explanation: Mechanistic study of the vlsE locus confirms antigenic variation as the immune-evasion mechanism enabling B. burgdorferi persistence.
biological_processes:
- preferred_term: DNA recombination
term:
id: GO:0006310
label: DNA recombination
modifier: INCREASED
downstream:
- target: Spirochete Invasion and Dissemination
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- Continuous surface-antigen diversification produces immune escape and persistent infection that sustain ongoing dissemination.
description: Antigenic variation maintains an immune-evasive, persistent infection that supports continued tissue colonization.
- name: Inflammatory Response and Tissue Damage
description: >
The host immune response to Borrelia antigens contributes to tissue damage.
Spirochetal lipoproteins and peptidoglycan trigger robust innate immune
activation with production of IL-6, IL-8, TNF, and chemokines (CCL3/CCL4).
Persistent inflammation in joints may continue even after spirochete clearance.
evidence:
- reference: PMID:37407232
reference_title: "Trauma-related Lyme arthritis."
supports: SUPPORT
snippet: "Aspiration of the left knee joint revealed a white cell count of 21.0×109/L (83% neutrophils) with negative Gram stain and culture. However, Lyme PCR was positive and accompanied by serologies consistent with Lyme arthritis."
explanation: Lyme arthritis joint fluid shows marked neutrophilic inflammation despite negative cultures, consistent with immune-driven damage.
cell_types:
- preferred_term: neutrophil
term:
id: CL:0000775
label: neutrophil
- preferred_term: macrophage
term:
id: CL:0000235
label: macrophage
- preferred_term: T cell
term:
id: CL:0000084
label: T cell
biological_processes:
- preferred_term: inflammatory response
term:
id: GO:0006954
label: inflammatory response
locations:
- preferred_term: synovial membrane
term:
id: UBERON:0002018
label: synovial membrane of synovial joint
downstream:
- target: Autoimmune Activation after Persistent Infection
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: Sustained antigen-driven inflammation is proposed to break self-tolerance in genetically predisposed hosts.
- target: Post-Infectious Immune Dysregulation
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: Tissue damage and inflammation from viable or nonviable spirochetes are a proposed driver of persistent post-treatment symptoms.
- name: Autoimmune Activation after Persistent Infection
description: >
Prolonged exposure of the host immune system to Borrelia antigens can drive
post-infectious autoimmunity, with reported triggers of systemic autoimmune
disease after Lyme borreliosis.
evidence:
- reference: PMID:34786243
reference_title: "Lyme Borreliosis as a Trigger for Autoimmune Disease."
supports: SUPPORT
snippet: "long-term exposure of the host's immune system to spirochetes can contribute to the development of chronic autoimmune disease de novo."
explanation: Case review links persistent Borrelia exposure to downstream autoimmune disease.
cell_types:
- preferred_term: T cell
term:
id: CL:0000084
label: T cell
biological_processes:
- preferred_term: adaptive immune response
term:
id: GO:0002250
label: adaptive immune response
downstream:
- target: Post-Infectious Immune Dysregulation
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: Post-infectious autoimmune responses are one of the leading proposed mechanisms underlying persistent post-treatment symptoms.
- name: Post-Infectious Immune Dysregulation
description: >
In an estimated 10-20% of appropriately treated patients, symptoms such as
fatigue, pain, and cognitive complaints persist for more than six months
(post-treatment Lyme disease syndrome, PTLDS). The mechanism is not fully
established; proposed drivers include an autoimmune response to spirochete-induced
tissue damage and inflammation, broader immune dysfunction, and persistent
viable or nonviable antigen. This node is a terminal post-infectious state
rather than ongoing high-burden active infection in most cases.
evidence:
- reference: PMID:39161484
reference_title: "What Makes It Tick: Exploring the Mechanisms of Post-treatment Lyme Disease Syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "We propose that ongoing PTLDS symptoms seem to be related to an autoimmune response to the tissue damage and inflammation caused by the viable or nonviable spirochete pathogen."
explanation: IDSA-aligned clinical review proposes post-infectious autoimmune/immune-dysregulation mechanisms for persistent PTLDS symptoms.
- reference: PMID:27358211
reference_title: "CCL19 as a Chemokine Risk Factor for Posttreatment Lyme Disease Syndrome: a Prospective Clinical Cohort Study."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Receiver operating characteristic analysis identified a CCL19 cutoff of >111.67 pg/ml at 1 month following treatment completion to be 82% sensitive and 83% specific for later PTLDS."
explanation: Prospective cohort identifies persistently elevated posttreatment levels of the T-cell chemokine CCL19 as an immunologic risk marker for PTLDS, supporting ongoing immune-driven dysregulation rather than resolved infection.
cell_types:
- preferred_term: T cell
term:
id: CL:0000084
label: T cell
- preferred_term: B cell
term:
id: CL:0000236
label: B cell
biological_processes:
- preferred_term: inflammatory response
term:
id: GO:0006954
label: inflammatory response
agent_life_cycle:
description: >-
Borrelia burgdorferi is maintained in an enzootic cycle between Ixodes ticks
and small-mammal reservoirs, notably the white-footed mouse. Larval ticks
acquire spirochetes by feeding on infected reservoir hosts, carry them
transstadially through the molt to the nymphal stage, and infected nymphs
transmit spirochetes to new vertebrate hosts during a subsequent blood meal.
Humans are incidental, dead-end hosts who do not contribute to maintenance of
the cycle. The OspA-to-OspC antigenic switch coordinates these host
transitions: OspA mediates midgut colonization in the unfed tick, whereas
OspC is required for transmission to and early infection of the mammal.
hosts:
- preferred_term: White-footed mouse (small-mammal reservoir)
role: reservoir host
term:
id: NCBITaxon:10041
label: Peromyscus leucopus
- preferred_term: Human (incidental dead-end host)
role: incidental (dead-end) host
term:
id: NCBITaxon:9606
label: Homo sapiens
- preferred_term: Blacklegged tick (vector and maintenance host)
role: vector host for transstadial maintenance and transmission
term:
id: NCBITaxon:6945
label: Ixodes scapularis
- preferred_term: Western blacklegged tick (vector host, western North America)
role: vector host
term:
id: NCBITaxon:29930
label: Ixodes pacificus
- preferred_term: Castor bean tick (vector host, Europe)
role: vector host
term:
id: NCBITaxon:34613
label: Ixodes ricinus
vectors:
- Ixodes scapularis (blacklegged/deer tick, eastern North America)
- Ixodes pacificus (western blacklegged tick, western North America)
- Ixodes ricinus (castor bean tick, Europe)
notes: >-
This structured life-cycle view intentionally complements the
"Tick-Borne Transmission and Enzootic Cycle" pathophysiology node: that node
narrates the molecular OspA-to-OspC switch and its causal edges, whereas this
block captures the host, vector, and stage facts in queryable form. The two
deliberately share references (PMID:10618120, PMID:22230951).
evidence:
- reference: PMID:22230951
reference_title: "Of ticks, mice and men: understanding the dual-host lifestyle of Lyme disease spirochaetes."
supports: SUPPORT
evidence_source: OTHER
snippet: "we integrate this large body of information into a cohesive picture of the molecular and cellular events that transpire as Lyme disease spirochaetes transit between their arthropod and vertebrate hosts during the enzootic cycle."
explanation: Authoritative review frames B. burgdorferi biology around an obligate dual-host enzootic cycle alternating between Ixodes ticks and vertebrate hosts.
life_cycle_stages:
- name: Larval acquisition from reservoir host
description: >-
Uninfected larval (and nymphal) ticks acquire B. burgdorferi by taking a
blood meal on an infected small-mammal reservoir such as the white-footed
mouse; newly acquired spirochetes express OspA but not OspC.
evidence:
- reference: PMID:10618120
reference_title: "Temporal changes in outer surface proteins A and C of the lyme disease-associated spirochete, Borrelia burgdorferi, during the chain of infection in ticks and mice."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "uninfected I. scapularis larvae and nymphs as they first acquired spirochetes from infected mice"
explanation: Immunofluorescence of tick midguts shows uninfected larvae and nymphs acquiring spirochetes while feeding on infected mice, the acquisition step of the enzootic cycle.
- name: Transstadial maintenance in the unfed tick midgut
description: >-
Spirochetes acquired at the larval stage persist through the molt into the
nymph (transstadial passage) and colonize the unfed-tick midgut, where they
express OspA but not OspC until the next blood meal.
evidence:
- reference: PMID:10618120
reference_title: "Temporal changes in outer surface proteins A and C of the lyme disease-associated spirochete, Borrelia burgdorferi, during the chain of infection in ticks and mice."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "prior to feeding spirochetes in nymphs expressed OspA but not OspC"
explanation: Infected nymphs (carrying spirochetes acquired as larvae) express OspA but not OspC before feeding, characterizing the transstadial midgut-maintenance stage.
- name: Nymphal transmission to the mammalian host
description: >-
During the nymphal blood meal, the OspA-to-OspC switch accompanies
spirochete migration to the salivary glands and transmission into the
vertebrate dermis; OspC is required for transmission from tick to mammal.
evidence:
- reference: PMID:10618120
reference_title: "Temporal changes in outer surface proteins A and C of the lyme disease-associated spirochete, Borrelia burgdorferi, during the chain of infection in ticks and mice."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "this surface protein is involved in transmission from tick to mammal but not from mammal to tick"
explanation: Stage-specific OspC expression only in feeding infected ticks indicates OspC mediates the tick-to-mammal transmission stage of the cycle.
phenotypes:
- name: Erythema Migrans
category: Dermatologic
frequency: VERY_FREQUENT
description: Characteristic expanding circular rash at the site of tick bite, often with central clearing (bull's-eye appearance). Present in 70-80% of cases.
phenotype_term:
preferred_term: Erythema migrans
term:
id: HP:0031180
label: Erythema migrans
evidence:
- reference: PMID:33669940
reference_title: "Lyme Disease among Patients at an Ambulatory Unit in a Highly Endemic Country: Lithuania."
supports: SUPPORT
snippet: "Results: In total, 1005 patients were enrolled with the following prevalence of clinical syndromes: erythema migrans (EM), 945 (94.02%); Lyme arthritis, 32 (3.18%); neuroborreliosis, 23 (2.28%); Lyme carditis, 4 (0.39%); and acrodermatitis, 1 (0.09%)."
explanation: Large Lithuanian cohort confirms erythema migrans as the dominant presentation.
- name: Fatigue
category: Constitutional
frequency: VERY_FREQUENT
description: Profound fatigue is common in all stages of Lyme disease and may persist in post-treatment Lyme disease syndrome.
phenotype_term:
preferred_term: Fatigue
term:
id: HP:0012378
label: Fatigue
evidence:
- reference: PMID:33669940
reference_title: "Lyme Disease among Patients at an Ambulatory Unit in a Highly Endemic Country: Lithuania."
supports: SUPPORT
snippet: "Clinical symptoms were as follows: arthralgia (33.2%), general weakness (19%), head pain (13.1%), myalgia (11.2%), fever (6.2%), joint swelling (5.9%), head dizziness (5.1%), nervus facialis neuropathy (2.4%), and radiculitis (2.0%)."
explanation: Population data list general weakness among frequent symptoms of Lyme disease.
- name: Arthralgia
category: Musculoskeletal
frequency: FREQUENT
description: Joint pain, particularly affecting large joints such as the knee, commonly precedes frank arthritis.
phenotype_term:
preferred_term: Arthralgia
term:
id: HP:0002829
label: Arthralgia
evidence:
- reference: PMID:33669940
reference_title: "Lyme Disease among Patients at an Ambulatory Unit in a Highly Endemic Country: Lithuania."
supports: SUPPORT
snippet: "Clinical symptoms were as follows: arthralgia (33.2%), general weakness (19%), head pain (13.1%), myalgia (11.2%), fever (6.2%), joint swelling (5.9%), head dizziness (5.1%), nervus facialis neuropathy (2.4%), and radiculitis (2.0%)."
explanation: Arthralgia was reported in one-third of patients in a large endemic cohort.
- name: Facial Palsy
category: Neurological
frequency: OCCASIONAL
description: Unilateral or bilateral facial nerve palsy (Bell's palsy) in early disseminated disease, occurring in approximately 5% of untreated patients.
phenotype_term:
preferred_term: Facial palsy
term:
id: HP:0010628
label: Facial palsy
evidence:
- reference: PMID:33669940
reference_title: "Lyme Disease among Patients at an Ambulatory Unit in a Highly Endemic Country: Lithuania."
supports: SUPPORT
snippet: "The main symptoms were the following: nervus facialis neuropathy (47.8%), myalgia (39%), head pain (26%), and radiculitis (21%)."
explanation: Neuroborreliosis cases frequently manifested facial nerve palsy.
- name: Arthritis
category: Musculoskeletal
frequency: FREQUENT
description: Inflammatory arthritis, typically monoarticular or oligoarticular, affecting large joints especially the knee. Occurs in approximately 60% of untreated patients.
phenotype_term:
preferred_term: Arthritis
term:
id: HP:0001369
label: Arthritis
evidence:
- reference: PMID:33669940
reference_title: "Lyme Disease among Patients at an Ambulatory Unit in a Highly Endemic Country: Lithuania."
supports: SUPPORT
snippet: "Lyme arthritis mainly manifested among middle-aged women as an oligoarthritis, mostly affecting the knee joint."
explanation: Cohort study documents oligoarticular knee-predominant Lyme arthritis.
- name: Atrioventricular Block
category: Cardiac
frequency: OCCASIONAL
description: Cardiac involvement including AV block (first, second, or third degree) and myocarditis. Lyme carditis occurs in 1-5% of untreated patients.
phenotype_term:
preferred_term: Atrioventricular block
term:
id: HP:0001678
label: Atrioventricular block
evidence:
- reference: PMID:37234726
reference_title: "Lyme disease presenting as complete heart block in a young man: Case report and review of pathogenesis."
supports: SUPPORT
snippet: "the most common clinical manifestation is AV block, which can be acute in onset and can rapidly progress to complete heart block."
explanation: Case report and review emphasize AV block as the hallmark of Lyme carditis.
- name: Dementia (Reversible Neuroborreliosis)
category: Neurological
frequency: VERY_RARE
description: Subcortical or reversible dementia presentations of neuroborreliosis that improve with antibiotic therapy.
phenotype_term:
preferred_term: Dementia
term:
id: HP:0000726
label: Dementia
evidence:
- reference: PMID:30046879
reference_title: "Secondary dementia due to Lyme neuroborreliosis."
supports: SUPPORT
snippet: "Dementia-like syndromes are rare manifestations of Lyme neuroborreliosis... The response to 2-4 weeks of antibiotic treatment with ceftriaxone was excellent."
explanation: Review of definite neuroborreliosis cases shows dementia syndromes resolving after ceftriaxone.
- reference: PMID:36740841
reference_title: "A Case of Reversible Dementia? Dementia vs Delirium in Lyme Disease."
supports: SUPPORT
snippet: "Lyme disease is an uncommon cause of reversible dementia... the brilliant clinical improvement after the appropriate antimicrobial therapy is strongly suggestive for a diagnosis of neuroborreliosis."
explanation: Geriatric case of reversible dementia with marked improvement after antimicrobial therapy.
- name: Myelitis
category: Neurological
frequency: VERY_RARE
description: Inflammatory spinal cord involvement as a rare manifestation of acute neuroborreliosis, sometimes with mild clinical symptoms despite marked MRI edema.
phenotype_term:
preferred_term: Myelitis
term:
id: HP:0012486
label: Myelitis
evidence:
- reference: PMID:33082765
reference_title: "Isolated Cervical Myelitis in Lyme Disease: A Rare Manifestation of Acute Neuroborreliosis."
supports: SUPPORT
snippet: "We report a case of acute neuroborreliosis that manifested as extended isolated cervical myelitis."
explanation: Case report confirms Lyme-associated cervical myelitis with CSF pleocytosis and intrathecal Borrelia antibodies.
- name: Bullous Skin Lesions
category: Dermatologic
frequency: VERY_RARE
description: Autoimmune blistering lesions (epidermolysis bullosa acquisita-like) following Lyme infection; reported after atypical erythema migrans.
phenotype_term:
preferred_term: Subepidermal blistering
term:
id: HP:0033804
label: Subepidermal blistering
evidence:
- reference: PMID:41133080
reference_title: "Lyme Disease Causing Complex Bullous Lesions: A Case Report."
supports: SUPPORT
snippet: "developed acquired epidermolysis bullosa (EBA) following an LD diagnosis. Initially, the patient presented with atypical erythema migrans, which later evolved into multiple bullous lesions"
explanation: Case report documents bullous lesions evolving after Lyme disease.
biochemical:
- name: Anti-Borrelia Antibodies (IgM/IgG)
presence: Detected
context: Two-tier testing with ELISA screening and Western blot confirmation; antibodies may take 2-4 weeks to develop
evidence:
- reference: PMID:38651851
reference_title: "Skin Changes in Suspected Lyme Disease."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "IgM and IgG specific for Borrelia burgdorferi was also performed: IgG was borderline, whereas IgM was positive at 218 U/mL."
explanation: Case demonstrates serological IgM/IgG detection against Borrelia burgdorferi as part of Lyme disease diagnosis.
- name: Elevated ESR/CRP
presence: Elevated
context: Markers of systemic inflammation, especially in disseminated disease
- name: CSF Pleocytosis
presence: Elevated
context: In neuroborreliosis, lymphocytic pleocytosis with elevated protein and intrathecal antibody production
evidence:
- reference: PMID:42001681
reference_title: "Metabolomic insights into Lyme neuroborreliosis: Exploring cerebrospinal fluid for diagnostic clues."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "accurate diagnosis of LNB requires cerebrospinal fluid (CSF) analysis, demonstrating pleocytosis and intrathecal synthesis of Bbsl-specific antibodies."
explanation: Lyme neuroborreliosis diagnosis is anchored on demonstrated CSF pleocytosis and intrathecal Bbsl-specific antibody synthesis.
genetic:
- name: HLA-DRB1 Susceptibility Alleles
association: Susceptibility
notes: European antibiotic-refractory Lyme arthritis cohorts show disease-specific T helper responses linked predominantly to HLA-DRB1*11 or *13 alleles, distinct from alleles reported in North American cohorts.
evidence:
- reference: PMID:39225104
reference_title: "Wider recognition and greater understanding of postinfectious, antibiotic-refractory Lyme arthritis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "the TCR-β motif was linked predominantly to HLA-DRB1*11 or 13 alleles, which differed from alleles in patients from North America."
explanation: Editorial highlights HLA-DRB1 allele linkage to T cell receptor motifs that distinguish antibiotic-refractory Lyme arthritis from other rheumatic diseases.
environmental:
- name: Tick Exposure
notes: Ixodes scapularis (deer tick) in eastern North America, I. pacificus in western North America, I. ricinus in Europe
- name: Geographic Location
notes: Endemic areas include northeastern and upper midwestern United States, and parts of Europe and Asia
- name: Seasonal Exposure
notes: Peak transmission during late spring and summer months (May-August) when nymphal ticks are active
evidence:
- reference: PMID:37075475
reference_title: "Seasonal activity patterns of host-seeking Ixodes scapularis (Acari: Ixodidae) in Minnesota, 2015-2017."
supports: SUPPORT
evidence_source: OTHER
snippet: "Nymphs were most active from May through August, with continuing low-level activity in October, and peak activity most commonly observed in June. The observed nymphal peak corresponded with the typical peak in reported human Lyme disease and anaplasmosis cases."
explanation: Field surveillance of Ixodes scapularis confirms that peak nymphal host-seeking from May–August aligns with the seasonal peak of human Lyme disease cases.
- name: Outdoor Activities
notes: Risk factors include hiking, camping, gardening, and activities in wooded or grassy areas
evidence:
- reference: PMID:37075475
reference_title: "Seasonal activity patterns of host-seeking Ixodes scapularis (Acari: Ixodidae) in Minnesota, 2015-2017."
supports: SUPPORT
evidence_source: OTHER
snippet: "These findings are consistent with previous studies from the Upper Midwest and highlight a risk of human exposure to I. scapularis at least from April through November."
explanation: Seasonal tick surveillance highlights prolonged human exposure risk in woodland habitats during months when outdoor activity can lead to Ixodes contact.
- name: Non-Ixodes Tick Exposure
notes: Rare reports of dog tick (Rhipicephalus) transmission in India; underscores need to consider atypical vectors in endemic settings
evidence:
- reference: PMID:36352974
reference_title: "Dog tick (Rhipecephalus) causing Lyme disease in an adult human."
supports: SUPPORT
snippet: "we present the case of Lyme's disease in an adult male with dog tick, Rhipecephalus as a vector."
explanation: Case report documents Lyme transmission by Rhipicephalus dog tick, highlighting atypical vector risk.
treatments:
- name: Oral Doxycycline
description: >
First-line treatment for early localized and early disseminated Lyme disease
in adults. Typical dose is 100mg twice daily for 10-21 days. Also provides
prophylaxis for tick bites in endemic areas.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: doxycycline
term:
id: CHEBI:50845
label: doxycycline
evidence:
- reference: PMID:17029130
reference_title: "The clinical assessment, treatment, and prevention of lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America."
supports: SUPPORT
snippet: "Tables list the doses and durations of antimicrobial therapy recommended for treatment and prevention of Lyme disease"
explanation: IDSA guidelines provide evidence-based antibiotic treatment recommendations for Lyme disease.
- name: Oral Amoxicillin
description: >
Alternative first-line agent for early Lyme disease, preferred in children
under 8 years and pregnant women. Typical dose is 500mg three times daily.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: amoxicillin
term:
id: CHEBI:2676
label: amoxicillin
evidence:
- reference: PMID:17176487
reference_title: "Lyme disease in pregnancy: case report and review of the literature."
supports: SUPPORT
snippet: "We describe a favorable outcome in a 42-year-old woman who developed Lyme disease in the third trimester and was treated with a full course of oral amoxicillin."
explanation: Case report in pregnancy shows successful treatment with amoxicillin.
- name: Intravenous Ceftriaxone
description: >
Recommended for neurological Lyme disease (neuroborreliosis), Lyme carditis
with high-degree AV block, and some cases of Lyme arthritis. Duration
typically 14-28 days.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: ceftriaxone
term:
id: CHEBI:29007
label: ceftriaxone
evidence:
- reference: PMID:37692616
reference_title: "Lyme Disease Presenting With Interesting Neurological Features of Weakness and Hyporeflexia: A Case Report."
supports: SUPPORT
snippet: "The patient's symptoms resolved quickly with a four-day inpatient course of IV ceftriaxone followed by 10 days of oral doxycycline."
explanation: Neuroborreliosis case improved with intravenous ceftriaxone then doxycycline.
differential_diagnoses:
- name: Southern Tick-Associated Rash Illness (STARI)
disease_term:
preferred_term: Southern Tick-Associated Rash Illness
term:
id: MONDO:0025294
label: tick-borne infectious disease
description: Lone star tick-associated erythema migrans–like rash without Borrelia burgdorferi infection.
distinguishing_features:
- Occurs after Amblyomma americanum bite in southeastern/south-central US; Borrelia testing negative.
- Typically lacks systemic neurologic or cardiac involvement seen in disseminated Lyme.
evidence:
- reference: PMID:40788480
reference_title: "Could alpha-gal syndrome be the cause of southern tick-associated rash illness (STARI)? : A simple study could answer that question."
supports: SUPPORT
snippet: "Southern tick-associated rash illness (STARI)"
explanation: Highlights STARI as a distinct erythema migrans–like illness linked to lone star tick bites.
- name: Cellulitis
disease_term:
preferred_term: cellulitis
term:
id: MONDO:0005230
label: cellulitis
description: Bacterial skin infection that can mimic early erythema migrans.
distinguishing_features:
- Painful, warm, expanding erythema often with fever.
- No central clearing.
- Responds rapidly to anti-staphylococcal/streptococcal therapy.
evidence:
- reference: PMID:26437159
reference_title: "Vesicular erythema migrans: an atypical and easily misdiagnosed form of Lyme disease."
supports: SUPPORT
snippet: "atypical vesicular features... resulted in multiple misdiagnoses and delayed treatment"
explanation: Atypical erythema migrans presentations can be misdiagnosed as bacterial cellulitis.
- name: Septic Arthritis
disease_term:
preferred_term: infective arthritis
term:
id: MONDO:0042485
label: infective arthritis
description: Acute bacterial arthritis of large joints.
distinguishing_features:
- Very high synovial WBC with positive Gram stain/culture.
- Lacks migratory arthralgias and Borrelia serology.
- Requires urgent drainage.
evidence:
- reference: PMID:24028811
reference_title: "[Lyme arthritis in children: a diagnostic trap]."
supports: SUPPORT
snippet: "clinical and biological picture often resembles that of septic arthritis"
explanation: Pediatric Lyme arthritis cases can initially be confused with septic arthritis.
- name: Rheumatoid Arthritis
disease_term:
preferred_term: rheumatoid arthritis
term:
id: MONDO:0008383
label: rheumatoid arthritis
description: Chronic symmetric inflammatory polyarthritis.
distinguishing_features:
- Small-joint symmetric involvement with RF/anti-CCP positivity.
- No tick exposure history or erythema migrans.
- Nodules and erosions on imaging.
evidence:
- reference: PMID:24028811
reference_title: "[Lyme arthritis in children: a diagnostic trap]."
supports: SUPPORT
snippet: "clinical and biological picture often resembles that of septic arthritis and juvenile rheumatoid arthritis"
explanation: Lyme arthritis may mimic rheumatoid patterns, prompting serologic differentiation.
- name: Viral Encephalitis
disease_term:
preferred_term: viral encephalitis
term:
id: MONDO:0006009
label: viral encephalitis
description: CNS infection causing encephalopathy that can overlap with neuroborreliosis symptoms.
distinguishing_features:
- CSF PCR panels for HSV/VZV/arboviruses.
- Absent Borrelia intrathecal antibodies.
- Often acute febrile onset.
evidence:
- reference: PMID:29848409
reference_title: "Serologic Evidence of Tick-Borne Encephalitis Virus Infection in a Patient with Suspected Lyme Disease in Japan."
supports: SUPPORT
snippet: "Two serum samples from one patient showed neutralizing antibodies against TBE virus."
explanation: Tick-borne encephalitis virus infection was found in a patient initially suspected of Lyme, illustrating viral encephalitis as a key differential.
- name: Multiple Sclerosis and Other Demyelinating Myelopathies
disease_term:
preferred_term: multiple sclerosis
term:
id: MONDO:0005301
label: multiple sclerosis
description: Demyelinating CNS disease that can mimic neuroborreliosis with cord lesions.
distinguishing_features:
- Oligoclonal bands without intrathecal Borrelia antibodies.
- Typical MS lesion distribution.
- Relapsing course without tick exposure.
evidence:
- reference: PMID:34861197
reference_title: "Mistaken Identity: Many Diagnoses are Frequently Misattributed to Lyme Disease."
supports: SUPPORT
snippet: "examples... newly diagnosed included multiple sclerosis"
explanation: Cohort of presumed Lyme referrals identified multiple sclerosis as a frequent alternate diagnosis.
- name: Viral Myocarditis/Other Causes of AV Block
disease_term:
preferred_term: myocarditis
term:
id: MONDO:0004496
label: myocarditis
description: Cardiac conduction disease from viral myocarditis or idiopathic fibrosis.
distinguishing_features:
- Elevated cardiac biomarkers and viral serologies.
- Absence of erythema migrans or Lyme serology.
- Persistent AV block without rapid reversal on antibiotics.
evidence:
- reference: PMID:40385752
reference_title: "Dengue Fever-Induced Complete Heart Block (Cardiac Dengue) Requiring Permanent Pacemaker Implantation in a 53-Year-Old Man: A Case Report."
supports: SUPPORT
snippet: "Comprehensive investigations excluded other bradyarrhythmia causes, such as Lyme disease, sarcoidosis, and myocarditis"
explanation: Case of dengue-related complete heart block underscores non-Lyme infectious causes of advanced AV block.
clinical_trials:
- name: NCT03769194
phase: PHASE_II
status: COMPLETED
description: Randomized, controlled, observer-blind Phase 2 study evaluating immunogenicity and safety of VLA15, a multivalent recombinant OspA-based Lyme borreliosis vaccine candidate in healthy adults aged 18-65 years. Participants received 3 immunizations at monthly intervals.
target_phenotypes:
- preferred_term: Erythema migrans
term:
id: HP:0031180
label: Erythema migrans
evidence:
- reference: clinicaltrials:NCT03769194
reference_title: "VLA15 Phase 2 Lyme borreliosis vaccine immunogenicity and safety study (NCT03769194)"
supports: SUPPORT
snippet: "The study was investigated 3 doses of a multivalent OspA (Outer Surface Protein A) based Lyme vaccine (VLA15) in healthy adults aged 18 to 65 years of age. Study participants received 3 immunizations of the vaccine at a monthly interval."
explanation: This Phase 2 trial evaluates VLA15, a preventive vaccine targeting OspA surface protein, offering evidence for active immunization against Lyme borreliosis.
- name: NCT06785402
phase: PHASE_II
status: RECRUITING
description: Randomized, double-blind, placebo-controlled Phase 1/2 trial evaluating pulse-dosed intravenous ceftriaxone for Post-Treatment Lyme Disease Syndrome (PTLDS). Investigates whether periodic high-dose antibiotic therapy can eliminate persistent Borrelia burgdorferi in patients with persistent symptoms.
target_phenotypes:
- preferred_term: Fatigue
term:
id: HP:0012378
label: Fatigue
- preferred_term: Arthralgia
term:
id: HP:0002829
label: Arthralgia
evidence:
- reference: clinicaltrials:NCT06785402
reference_title: "Pulse-Dosed IV Ceftriaxone for Post-Treatment Lyme Disease Syndrome (NCT06785402)"
supports: SUPPORT
snippet: "Lyme disease is a public health crisis in the US. It is estimated that over 400,000 cases occur every year with 10-20% of those infected going on to develop Post-Treatment Lyme disease Syndrome (PTLDS). The goal of this study is to investigate if giving Ceftriaxone every 5 days for about 6 weeks kills the organism that produces persistent Lyme infection."
explanation: This Phase 1/2 trial directly addresses post-treatment Lyme disease syndrome with a novel pulse-dosing regimen, providing clinical evidence for managing antibiotic-refractory cases.
- name: NCT03584919
phase: NOT_APPLICABLE
status: COMPLETED
description: European prospective clinical trial comparing doxycycline and cefuroxime axetil for treatment of erythema migrans in adult patients. Participants were evaluated at baseline, 14 days, and 2, 6, and 12 months post-enrollment to assess treatment efficacy and long-term outcomes.
target_phenotypes:
- preferred_term: Erythema migrans
term:
id: HP:0031180
label: Erythema migrans
evidence:
- reference: clinicaltrials:NCT03584919
reference_title: "Doxycycline versus Cefuroxime Axetil for Adult Erythema Migrans (NCT03584919)"
supports: SUPPORT
snippet: "A European, prospective clinical trial in which doxycycline and cefuroxime axetil were compared in the treatment of adult patients with erythema migrans included a control group to address this question. Evaluations of patients were conducted at baseline, 14 days and 2, 6, and 12 months after enrollment."
explanation: This comparative trial evaluates two oral antibiotics for early Lyme disease, providing evidence for treatment options and long-term symptom outcomes in erythema migrans patients.
datasets:
Disease Pathophysiology Research Report
Target Disease - Disease Name: Lyme disease (Borreliella/Borrelia burgdorferi infection) - MONDO ID: [not provided] - Category: Infectious
Pathophysiology description (current understanding) Lyme disease pathophysiology reflects a sequence of vector-mediated inoculation, early dermal colonization, hematogenous dissemination with vascular-interstitial transitions, and tissue-specific persistence, enabled by a large repertoire of outer-surface lipoproteins that coordinate adhesion, immune evasion (especially complement inhibition), and antigenic variation. The host response spans robust innate and adaptive activation with characteristic cytokine/chemokine patterns and, in subsets, post-infectious immune dysregulation (including autoimmunity) that underlies antibiotic-refractory manifestations such as post-infectious Lyme arthritis and post-treatment Lyme disease syndrome (PTLDS). Mechanistic highlights from recent literature (2023–2024 priority; later data included when highly pertinent) are summarized below with genes/proteins and processes mapped to ontology terms.
1) Core pathophysiology - Immune evasion via complement inhibition and antigenic variation • Classical pathway inhibition: The multifunctional surface lipoprotein BBK32 binds C1r (initiator protease of the classical pathway) and reduces C4 deposition, attenuating antibody-dependent complement-mediated killing while simultaneously retaining fibronectin adhesion functionality (mechanistic evidence and imaging/flow cytometry) (https://doi.org/10.1371/journal.ppat.1013361; PLOS Pathogens, 2025) (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). • Alternative pathway inhibition: B. burgdorferi expresses a suite of complement regulator–acquiring surface proteins (CRASPs; e.g., CspA, CspZ, OspE family) that bind factor H or FHL-1 to block alternative pathway activation and membrane attack complex formation; variant-specific factor H binding contributes to host tropism and transmission biology (review synthesis) (farooq2025osteoimmunologicalcharacterizationof pages 42-44, powellpierce2025bbk32attenuatesantibodydependent pages 19-20). • Antigenic variation: The vlsE locus undergoes continuous segmental recombination with ~15 silent cassettes during mammalian infection, driving immune escape of surface antigenicity (farooq2025osteoimmunologicalcharacterizationof pages 42-44).
Dissemination and tissue adhesion • BBK32–fibronectin binding supports vascular interactions and, together with glycosaminoglycan (GAG) binding, facilitates endothelial adhesion and extravasation; BBK32’s dual complement- and fibronectin-binding functionalities allow parallel immune evasion and tissue dissemination (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). • Decorin-binding proteins (DbpA/DbpB) promote ECM engagement and tissue tropism; computational/biophysical evidence further implicates integrin interactions and plasminogen activation in trans-endothelial migration (nasrallah2023screeninginsilico pages 8-14). • OspC is upregulated at tick feeding/early mammalian infection and is required for infectivity; OspC–Salp15 interactions contribute to immune evasion at the vector–host interface (farooq2025osteoimmunologicalcharacterizationof pages 42-44).
Inflammatory drivers and persistence factors • Spirochetal peptidoglycan (localized to the periplasmic space with periplasmic flagella) is a potent innate stimulus; in comparative contexts B. burgdorferi evokes higher IL-6, IL-8, IL-10, CCL3/4, and TNF responses than some Eurasian species (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). Motility up to ~4.25 μm/s and chemotaxis toward host carbohydrates (e.g., N-acetylglucosamine) facilitate tissue spread and immune engagement (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). • Neuroinflammatory cytokines (e.g., IL-6) are implicated in disease models; host IL-6 modulation has been linked to altered neuroinflammatory readouts in preclinical systems (farooq2025osteoimmunologicalcharacterizationof pages 42-44).
Post-infectious immune dysregulation • PTLDS occurs in an estimated 10–20% of appropriately treated patients and has been hypothesized to involve immune dysfunction, autoimmunity, neuroinflammation, and/or persistent antigen; transcriptomic studies report hundreds of genes differentially expressed months after therapy. Clinical evidence also links higher CCL19 at 1 month (e.g., >~112 pg/mL) with a markedly increased odds of PTLDS at 6–12 months (review synthesis) (Cureus, 2024; https://doi.org/10.7759/cureus.64987) (wester2024whatmakesit pages 4-5).
2) Key molecular players - Genes/Proteins (HGNC symbols where relevant) • BBK32 (borrelial lipoprotein; complement C1r inhibitor and fibronectin adhesin) – classical complement pathway evasion; fibronectin binding (GO:0006956; GO:0005515) (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). • CspA (CRASP family; factor H–binding) – alternative pathway inhibition (GO:0030449 complement regulation) (farooq2025osteoimmunologicalcharacterizationof pages 42-44). • CspZ (CRASP family; factor H–binding) – host-specific FH binding contributing to tropism (farooq2025osteoimmunologicalcharacterizationof pages 42-44). • OspE paralogs (CRASP family; FH/FHL-1 binding) – alternative pathway evasion (farooq2025osteoimmunologicalcharacterizationof pages 42-44). • VlsE – antigenic variation via gene conversion; immune evasion (GO:0019048 modulation by host) (farooq2025osteoimmunologicalcharacterizationof pages 42-44). • DbpA/DbpB – decorin binding; ECM adhesion and tissue localization (GO:0007155 cell adhesion) (nasrallah2023screeninginsilico pages 8-14). • OspC – early infection factor; vector-host immune-modulatory interactions (farooq2025osteoimmunologicalcharacterizationof pages 42-44).
Chemical entities (CHEBI) • Complement components targeted functionally (C1r, C4 deposition reduced by BBK32 activity) (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). • Host GAGs and ECM ligands (fibronectin, decorin) engaged by BBK32/DbpA/DbpB (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14).
Cell types (CL) • Neutrophils and macrophages responding to spirochetal peptidoglycan and lipoproteins (elevated inflammatory cytokines/chemokines) (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). • Endothelial cells at vascular interface for adhesion/extravasation (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14). • T and B lymphocytes in post-infectious dysregulation/autoimmunity hypotheses (wester2024whatmakesit pages 4-5).
Anatomical locations (UBERON) • Skin at bite site; blood vasculature and endothelium during dissemination; joints (synovium) and nervous system in disseminated disease (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14, farooq2025osteoimmunologicalcharacterizationofa pages 35-38, wester2024whatmakesit pages 4-5).
3) Biological processes (candidate GO annotations) - Complement evasion and regulation: negative regulation of complement activation (GO:0045916); classical pathway inhibition via C1r interaction (BBK32) (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). - Adhesion and dissemination: cell adhesion (GO:0007155), extracellular matrix binding (GO:0050840), plasminogen activation-dependent migration (GO:0031639) (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14). - Antigenic variation: DNA recombination and gene conversion (GO:0006310) at vlsE (farooq2025osteoimmunologicalcharacterizationof pages 42-44). - Chemotaxis and motility: chemotaxis (GO:0006935) and locomotion (GO:0040011) of spirochetes (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). - Cytokine-mediated signaling: inflammatory response (GO:0006954) with IL-6, IL-8, TNF, CCL3/4 upregulation (farooq2025osteoimmunologicalcharacterizationofa pages 35-38).
4) Cellular components (GO CC) - Outer membrane and surface-exposed lipoprotein layer where BBK32, OspC, DbpA/B, and CRASPs reside (GO:0009279 cell outer membrane) (farooq2025osteoimmunologicalcharacterizationof pages 42-44, powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14). - Extracellular matrix (host) for fibronectin/decorin binding (GO:0031012 extracellular matrix) (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14). - Periplasmic space with peptidoglycan and periplasmic flagella (GO:0030288 outer membrane-bounded periplasmic space) (farooq2025osteoimmunologicalcharacterizationofa pages 35-38).
5) Disease progression (sequence of events) - Tick feeding induces OspC upregulation and transmission from midgut to salivary glands; early dermal colonization follows (farooq2025osteoimmunologicalcharacterizationof pages 42-44). - Early localized infection: erythema migrans with high local innate activation to lipoproteins/peptidoglycan (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). - Hematogenous dissemination: BBK32–fibronectin and DbpA/B–decorin interactions promote vascular adhesion and tissue entry; classical complement inhibition (BBK32) and alternative pathway inhibition (CRASPs) permit survival in serum and tissues (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14, farooq2025osteoimmunologicalcharacterizationof pages 42-44). - Disseminated infection: involvement of joints, nervous system, heart; cytokine/chemokine programs vary by tissue, with IL-6 prominent in neuroinflammatory contexts (farooq2025osteoimmunologicalcharacterizationof pages 42-44). - Post-infectious sequelae in subsets: persistent symptoms ≥6 months (PTLDS) with associations to immune dysregulation and elevated early CCL19; autoimmunity hypothesized in joint disease (wester2024whatmakesit pages 4-5).
6) Phenotypic manifestations and mechanistic links (HP terms) - Early localized skin lesion: erythema migrans (HP:0000978) linked to dermal innate responses to lipoproteins/peptidoglycan (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). - Neuroborreliosis: radiculitis, meningitis, cranial neuropathies (HP:0001288, HP:0003401) with cytokine-driven neuroinflammation (e.g., IL-6) (farooq2025osteoimmunologicalcharacterizationof pages 42-44). - Lyme arthritis: episodic or persistent synovitis (HP:0100769) connected to strong inflammatory responses; in some patients, post-infectious immune dysregulation/autoimmunity (wester2024whatmakesit pages 4-5). - PTLDS: fatigue, pain, cognitive complaints persisting >6 months after therapy (HP:0012378, HP:0002355) with reported 10–20% incidence and evidence for immune activation signatures (wester2024whatmakesit pages 4-5).
Evidence items (primary literature; URLs and dates where available) - BBK32 and complement evasion/adhesion: Powell-Pierce AD et al. BBK32 attenuates antibody-dependent complement-mediated killing of infectious Borreliella burgdorferi isolates. PLOS Pathogens, 2025-07; doi:10.1371/journal.ppat.1013361; URL: https://doi.org/10.1371/journal.ppat.1013361 (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). - CRASPs, VlsE antigenic variation, OspC stage regulation, ECM interactions, and IL-6 in neuroinflammation: Farooq I. Osteoimmunological characterization of Borrelia burgdorferi-induced bone loss: From phenotype to molecular mechanisms. 2025 (farooq2025osteoimmunologicalcharacterizationof pages 42-44). - Peptidoglycan location, periplasmic flagella, motility/chemotaxis, and stronger proinflammatory cytokine induction by B. burgdorferi vs. some Eurasian species: Farooq I. 2025 (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). - ECM adhesion repertoire, integrin/plasminogen pathways aiding invasion; DbpA/BBK32 as adhesins: Nasrallah H. Screening in silico… 2023 (nasrallah2023screeninginsilico pages 8-14). - PTLDS burden (10–20%), transcriptomic persistence after treatment, and early CCL19 as a risk indicator for later PTLDS: Wester KE et al. Cureus, 2024-07; doi:10.7759/cureus.64987; URL: https://doi.org/10.7759/cureus.64987 (wester2024whatmakesit pages 4-5).
Gene/protein annotations with ontology terms - BBK32 (borrelial lipoprotein; adhesin and complement inhibitor) • Functions: fibronectin binding (GO:0005515), negative regulation of classical complement activation (GO:0045916) • Process: cell adhesion (GO:0007155); immune evasion (GO:0006956) • Cellular component: outer membrane (GO:0009279) • Evidence: (powellpierce2025bbk32attenuatesantibodydependent pages 19-20) - CspA/CspZ/OspE family (CRASPs) • Functions: factor H/FHL-1 binding; negative regulation of alternative pathway (GO:0045916) • Component: outer membrane (GO:0009279) • Evidence: (farooq2025osteoimmunologicalcharacterizationof pages 42-44, powellpierce2025bbk32attenuatesantibodydependent pages 19-20) - VlsE • Process: antigenic variation via gene conversion/recombination (GO:0006310) • Component: outer membrane lipoprotein layer (GO:0009279) • Evidence: (farooq2025osteoimmunologicalcharacterizationof pages 42-44) - DbpA/DbpB • Functions: decorin binding; ECM binding (GO:0050840) • Process: cell adhesion (GO:0007155) • Evidence: (nasrallah2023screeninginsilico pages 8-14) - OspC • Process: early infection/host colonization; interaction with Salp15 (vector immune modulation) • Evidence: (farooq2025osteoimmunologicalcharacterizationof pages 42-44)
Cell type involvement (CL terms) - Endothelial cell (CL:0000115): vascular adhesion/extravasation interface (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14) - Neutrophil (CL:0000096) and macrophage (CL:0000235): early innate cytokine responses to peptidoglycan/lipoproteins (farooq2025osteoimmunologicalcharacterizationofa pages 35-38) - T cell (CL:0000084) and B cell (CL:0000236): adaptive responses; dysregulation in PTLDS hypotheses (wester2024whatmakesit pages 4-5)
Anatomical locations (UBERON terms) - Skin (UBERON:0002097): inoculation site and early colonization (farooq2025osteoimmunologicalcharacterizationof pages 42-44) - Blood vessel/endothelium (UBERON:0001981/0001986): dissemination axis (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14) - Synovial membrane (UBERON:0002387): Lyme arthritis site (wester2024whatmakesit pages 4-5) - Central nervous system/meninges (UBERON:0001017/0002410): neuroinflammatory involvement (farooq2025osteoimmunologicalcharacterizationof pages 42-44)
Chemical entities (CHEBI) - Complement components (e.g., C1r, C4) (CHEBI:4887 C1r; CHEBI:33697 C4) as functional targets of BBK32-mediated inhibition (powellpierce2025bbk32attenuatesantibodydependent pages 19-20) - Fibronectin (CHEBI:8009; proteinaceous ECM) and decorin (CHEBI:16991; proteoglycan core protein) as host ligands for adhesion (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, nasrallah2023screeninginsilico pages 8-14) - Glycosaminoglycans (CHEBI:18085) in ECM binding (powellpierce2025bbk32attenuatesantibodydependent pages 19-20)
Expert opinions and analysis (authoritative perspectives) - Complement evasion is multifactorial and redundant. The BBK32 study demonstrates simultaneous binding to fibronectin and C1r, underscoring that adhesion and immune evasion are coupled rather than sequential, a principle that helps explain efficient dissemination despite antibody/complement pressure (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). - Antigenic variation at vlsE is a sustained, cassette-driven engine for immune escape in mammalian hosts, complementing complement evasion proteins and explaining serologic complexity and persistence under immune pressure (farooq2025osteoimmunologicalcharacterizationof pages 42-44). - PTLDS remains mechanistically heterogeneous; however, data synthesized in recent clinical reviews point to persistent immune activation, early chemokine risk signals (CCL19), and a subset of autoimmune phenomena, aligning with a model of post-infectious immune dysregulation rather than ongoing high-burden viable infection in most cases (wester2024whatmakesit pages 4-5).
Relevant statistics and data - PTLDS prevalence: approximately 10–20% of treated Lyme disease patients; early elevated CCL19 (~>112 pg/mL at 1 month) associated with markedly higher risk of PTLDS at 6–12 months (wester2024whatmakesit pages 4-5). - Motility: B. burgdorferi achieves speeds up to ~4.25 μm/s; chemotaxis toward N-acetylglucosamine, glucosamine, chitosan, glutamate reported, consistent with nutrient-sensing dissemination (farooq2025osteoimmunologicalcharacterizationofa pages 35-38). - Antigenic variation architecture: vlsE with ~15 silent cassettes contributing to continual sequence diversification (farooq2025osteoimmunologicalcharacterizationof pages 42-44).
Limitations and gaps (2023–2024 focus) - While 2024–2025 primary data robustly support BBK32-mediated classical pathway inhibition and dual-function adhesion, larger in vivo human correlative datasets linking specific adhesin/CRASP expression patterns to clinical phenotypes remain limited (powellpierce2025bbk32attenuatesantibodydependent pages 19-20, farooq2025osteoimmunologicalcharacterizationof pages 42-44). - High-quality prospective biomarker studies for neuroborreliosis (e.g., CSF chemokines) and PTLDS are still sparse; CCL19 is a candidate but needs external validation and standardization (wester2024whatmakesit pages 4-5).
References (with citation IDs) - Powell-Pierce AD, et al. BBK32 attenuates antibody-dependent complement-mediated killing… PLOS Pathogens. 2025-07. https://doi.org/10.1371/journal.ppat.1013361 (powellpierce2025bbk32attenuatesantibodydependent pages 19-20) - Farooq I. Osteoimmunological characterization of Borrelia burgdorferi-induced bone loss… 2025. [Mechanistic review content on CRASPs, vlsE, OspC, IL-6] (farooq2025osteoimmunologicalcharacterizationof pages 42-44) - Farooq I. Osteoimmunological characterization… (peptidoglycan, motility/chemotaxis, cytokines). 2025. (farooq2025osteoimmunologicalcharacterizationofa pages 35-38) - Nasrallah H. Screening in silico… OspA/vector proteins; DbpA, BBK32, plasminogen/integrins. 2023. (nasrallah2023screeninginsilico pages 8-14) - Wester KE, et al. What Makes It Tick: Exploring the Mechanisms of Post-treatment Lyme Disease Syndrome. Cureus. 2024-07. https://doi.org/10.7759/cureus.64987 (wester2024whatmakesit pages 4-5)
Notes on evidence strength - BBK32 mechanistic inhibition of the classical pathway and concurrent fibronectin binding has strong experimental support (binding/functional assays) (powellpierce2025bbk32attenuatesantibodydependent pages 19-20). - CRASP-mediated alternative pathway evasion and vlsE-driven antigenic variation are supported by convergent lines of evidence across models (farooq2025osteoimmunologicalcharacterizationof pages 42-44). - PTLDS immunopathophysiology remains an active research area; clinical synthesis suggests immune dysregulation and biomarkers such as CCL19 may stratify risk, but causal chains are not fully established (wester2024whatmakesit pages 4-5).
References
(powellpierce2025bbk32attenuatesantibodydependent pages 19-20): Alexandra D. Powell-Pierce, Charles E. Booth, Payton G. Smith, Brittany L. Shapiro, Shannon S. Allen, Brandon L. Garcia, and Jon T. Skare. Bbk32 attenuates antibody-dependent complement-mediated killing of infectious borreliella burgdorferi isolates. PLOS Pathogens, 21:e1013361, Jul 2025. URL: https://doi.org/10.1371/journal.ppat.1013361, doi:10.1371/journal.ppat.1013361. This article has 0 citations and is from a highest quality peer-reviewed journal.
(farooq2025osteoimmunologicalcharacterizationof pages 42-44): I Farooq. Osteoimmunological characterization of borrelia burgdorferi-induced bone loss: from phenotype to molecular mechanisms. Unknown journal, 2025.
(nasrallah2023screeninginsilico pages 8-14): H NASRALLAH. Screening in silico delle interazioni proteina-proteina tra borrelia burgdorferi e zecche: uno studio di fattibilità su ospa e proteine salivari di zecca. Unknown journal, 2023.
(farooq2025osteoimmunologicalcharacterizationofa pages 35-38): I Farooq. Osteoimmunological characterization of borrelia burgdorferi-induced bone loss: from phenotype to molecular mechanisms. Unknown journal, 2025.
(wester2024whatmakesit pages 4-5): Kate E Wester, Bianca C Nwokeabia, Rehana Hassan, Taylor Dunphy, Michael Osondu, Carson Wonders, and Misbahuddin Khaja. What makes it tick: exploring the mechanisms of post-treatment lyme disease syndrome. Cureus, Jul 2024. URL: https://doi.org/10.7759/cureus.64987, doi:10.7759/cureus.64987. This article has 5 citations and is from a poor quality or predatory journal.