Which tests should be performed after a tick bite in a person?

Immediate Actions After a Tick Bite

Proper Tick Removal

Proper removal of a tick minimizes the chance of pathogen transmission and ensures that subsequent diagnostic evaluation is based on accurate exposure information. The removed specimen should be intact, as fragmented mouthparts can complicate risk assessment and may necessitate additional laboratory analysis.

Use fine‑point tweezers or a specialized tick‑removal tool.
Grasp the tick as close to the skin surface as possible, avoiding the body.
Apply steady, downward pressure to pull the tick straight out without twisting or jerking.
Inspect the mouthparts; if any remain embedded, repeat the removal process with fresh instruments.
Disinfect the bite area with an antiseptic solution.
Place the tick in a sealed container with a moist cotton ball; label with date, location, and host details for possible laboratory identification.
Preserve the specimen at 4 °C if testing is planned within 24 hours; otherwise freeze at –20 °C for longer storage.

After removal, monitor the site for erythema, swelling, or necrosis. If any of these signs appear, or if systemic symptoms such as fever, headache, or fatigue develop, initiate appropriate laboratory investigations, including serology for Borrelia, PCR for Anaplasma, and blood smears for Babesia, based on the tick species and regional disease prevalence. Immediate medical consultation is warranted when symptoms emerge or when the tick could not be removed whole.

Wound Care and Monitoring

After a tick attachment, immediate wound management reduces the risk of infection and facilitates early detection of tick‑borne diseases. Clean the bite site with mild soap and water, then apply an antiseptic such as chlorhexidine or povidone‑iodine. Cover the area with a sterile, non‑adhesive dressing to protect against secondary bacterial entry.

Monitoring the bite includes daily inspection for changes in size, color, or the appearance of a target‑shaped rash. Record the date of removal, the tick’s developmental stage, and any symptoms such as fever, headache, or joint pain. Promptly report the following findings to a healthcare professional:

Expanding erythema or a central clearing lesion (suggestive of early Lyme disease).
Persistent fever or flu‑like symptoms within weeks of the bite.
New neurological signs, such as facial weakness or meningitis‑type headache.
Unusual swelling or redness extending beyond the immediate bite area.

Laboratory evaluation should be guided by the clinical picture. Baseline serologic testing for Borrelia burgdorferi, Anaplasma phagocytophilum, and Ehrlichia species is recommended when systemic symptoms develop or when the bite occurred in a high‑risk region. Repeat serology after 2–4 weeks confirms seroconversion if the initial test is negative but suspicion remains. In cases of suspected Rocky Mountain spotted fever, obtain a complete blood count and liver function panel, and initiate empiric doxycycline pending confirmatory PCR.

Document all observations in a personal health record and maintain communication with a medical provider throughout the incubation period, typically up to 30 days. Early intervention based on vigilant wound care and systematic monitoring maximizes the chance of successful outcomes.

When to Seek Medical Attention

Symptoms Warranting a Doctor’s Visit

A tick bite can introduce pathogens that cause serious illness. Prompt medical evaluation is required when specific clinical signs appear, because they indicate a higher probability of infection and guide the choice of laboratory investigations.

Expanding rash with central clearing (often described as a “bull’s‑eye” lesion)
Fever exceeding 38 °C (100.4 °F)
Severe headache, especially with neck stiffness
Muscle or joint pain that is persistent or worsening
Unexplained fatigue, chills, or night sweats
Swollen lymph nodes near the bite site
Neurological symptoms such as facial palsy, tingling, or numbness
Cardiac complaints including palpitations, chest pain, or shortness of breath

When any of these manifestations develop, the patient should be examined by a clinician. The physician will order appropriate diagnostics, which may include serologic testing for Borrelia antibodies, polymerase chain reaction assays, complete blood count, inflammatory markers, and, if indicated, cardiac or neurological imaging. Early detection through these tests improves treatment outcomes and reduces the risk of long‑term complications.

Risk Factors for Tick-Borne Diseases

Geographic Location of Bite

The area where a tick attachment occurs determines the spectrum of pathogens that must be considered, and therefore guides laboratory evaluation. In the United States, bites in the Northeast, Mid-Atlantic, and upper Midwest raise suspicion for Borrelia burgdorferi (Lyme disease), Anaplasma phagocytophilum (anaplasmosis), and Babesia microti (babesiosis). The appropriate investigations include:

Two‑tier serology for Lyme disease (ELISA followed by Western blot if positive) performed 2–4 weeks after exposure or at symptom onset.
PCR or serology for Anaplasma and Babesia when fever, leukopenia, or hemolytic anemia are present.
Complete blood count and liver function tests to detect cytopenias or hepatic involvement.

In the Pacific Northwest, Ixodes pacificus transmits Borrelia miyamotoi and Borrelia burgdorferi but rarely Babesia. Testing focuses on:

PCR for B. miyamotoi if flu‑like illness appears within two weeks.
Lyme serology as above for later manifestations.

In the Southeast and Gulf Coast, Amblyomma americanum (the lone star tick) is prevalent, carrying Ehrlichia chaffeensis, Ehrlichia ewingii, and Francisella tularensis. Recommended labs are:

PCR or immunofluorescence assay for Ehrlichia species.
Serology for tularemia when ulceroglandular lesions develop.

In Europe, bites in central and eastern regions warrant testing for Borrelia afzelii and Borrelia garinii (Lyme disease) and Rickettsia spp. (spotted fever). The work‑up includes:

ELISA and immunoblot for Lyme disease.
PCR or serology for rickettsial infection if rash or fever is present.

In areas where Dermacentor ticks dominate, such as parts of Africa and Asia, Rickettsia conorii and Coxiella burnetii are concerns. Diagnostic steps consist of:

Serology for spotted fever group rickettsiae.
PCR for Coxiella when febrile illness is accompanied by pneumonia or hepatitis.

Regardless of location, a baseline complete blood count, liver panel, and renal function test should be obtained to identify systemic effects of tick‑borne diseases and to establish reference values before targeted assays.

Duration of Tick Attachment

The length of time a tick remains attached determines the likelihood of pathogen transmission and therefore guides the selection of diagnostic investigations. Attachment shorter than 24 hours carries minimal risk for most bacterial agents; however, prolonged feeding—generally exceeding 36–48 hours—increases the probability of infection with Borrelia burgdorferi, Anaplasma phagocytophilum, Babesia microti, and Rickettsia species. Consequently, clinicians should tailor testing according to the estimated attachment duration.

Attachment ≤ 24 hours – Observe the patient; laboratory testing is not routinely required unless symptoms develop.
Attachment 24–48 hours – Perform a baseline Lyme serology (ELISA with reflex Western blot) and a complete blood count to detect early hematologic changes.
Attachment > 48 hours – Add the following to the baseline panel:
- Lyme disease serology (ELISA and confirmatory Western blot).
- PCR for Babesia microti in whole blood if fever or hemolysis is present.
- Serology for Anaplasma phagocytophilum (IgM/IgG) or PCR if leukopenia or thrombocytopenia occurs.
- Rickettsial serology or PCR when rash or unexplained fever is noted.
- Liver function tests to assess hepatic involvement, especially in severe cases.

The decision matrix hinges on the documented or estimated feeding period; accurate recall of attachment time enhances diagnostic yield and prevents unnecessary investigations.

Type of Tick

The species of tick that attached to a patient determines which infectious agents are most likely to have been transmitted and therefore which laboratory investigations are warranted. Accurate identification—by visual examination of mouthparts, scutum pattern, or professional taxonomic analysis—provides the basis for targeted testing.

Ixodes scapularis (black‑legged tick) – primary vector of Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti. Recommended investigations:
– Enzyme‑linked immunosorbent assay (ELISA) for Lyme disease antibodies, followed by Western blot confirmation if positive.
– PCR or serology for Anaplasma.
– PCR and thick‑blood‑smear examination for Babesia.
Dermacentor variabilis (American dog tick) – transmitter of Rickettsia rickettsii (Rocky Mountain spotted fever) and Cytauxzoon felis. Recommended investigations:
– Indirect immunofluorescence assay (IFA) or PCR for Rickettsia antibodies.
– PCR for Cytauxzoon species when feline exposure is suspected.
Amblyomma americanum (lone star tick) – carrier of Ehrlichia chaffeensis, Ehrlichia ewingii, and the α‑gal carbohydrate linked to red meat allergy. Recommended investigations:
– PCR for Ehrlichia species.
– Complete blood count with differential to detect eosinophilia or leukopenia.
– Specific IgE assay for α‑gal when allergic symptoms appear.
Rhipicephalus sanguineus (brown dog tick) – vector of Rickettsia conorii and Babesia canis. Recommended investigations:
– IFA or PCR for Mediterranean spotted fever (Rickettsia conorii).
– PCR and blood smear for Babesia canis in canine patients.

When the tick cannot be identified, a broader panel that includes serology for Lyme disease, PCR for Anaplasma and Ehrlichia, and a complete blood count is advisable. Early testing, ideally within two weeks of the bite, improves diagnostic sensitivity for most tick‑borne pathogens.

Recommended Tests for Tick-Borne Diseases

Understanding the Incubation Period

After a tick bite, the time between exposure and the appearance of symptoms—the incubation period—guides the selection and timing of laboratory investigations. Each tick‑borne pathogen has a characteristic window during which diagnostic tests become reliable.

The incubation period for Borrelia burgdorferi, the agent of Lyme disease, ranges from 3 days to 1 month for early localized infection and extends to several weeks for disseminated disease. An enzyme‑linked immunosorbent assay (ELISA) followed by a Western blot is recommended after at least 2 weeks of symptom onset; testing earlier yields a high false‑negative rate. Polymerase chain reaction (PCR) on skin biopsy or synovial fluid may detect the organism in the early stage when serology is still negative.

Anaplasma phagocytophilum and Ehrlichia chaffeensis typically produce symptoms within 5–14 days. Real‑time PCR on whole blood is most sensitive during the first week of illness; serology (IgM/IgG) becomes informative after 2 weeks. A single acute‑phase serum sample should be paired with a convalescent sample taken 2–4 weeks later to confirm seroconversion.

Babesia microti shows an incubation of 1–4 weeks. Microscopic examination of thick blood smears is reliable once parasitemia is detectable, usually after 1 week of fever. PCR on whole blood increases sensitivity in low‑parasitemia cases and should be performed as soon as possible after symptom onset.

Rickettsia rickettsii, the cause of Rocky Mountain spotted fever, manifests within 2–14 days. Immunofluorescence assay (IFA) for IgM and IgG is most accurate after 7 days; early PCR on skin biopsy or blood can support a prompt diagnosis. Empirical treatment should not await laboratory confirmation when clinical suspicion is high.

A concise schedule for post‑exposure testing:

Days 0‑7: PCR for Anaplasma/Ehrlichia, Babesia, and Rickettsia if fever or rash appears; consider PCR for Borrelia on skin lesion.
Days 7‑14: Repeat PCR if initial test negative and symptoms persist; begin serology for Borrelia, Anaplasma/Ehrlichia, and Rickettsia.
Days 14‑30: ELISA and Western blot for Lyme disease; paired serology for Anaplasma/Ehrlichia; IFA for Rocky Mountain spotted fever; blood smear and PCR for Babesia.
Beyond 30 days: Follow‑up serology to document seroconversion; PCR may be useful for persistent or atypical presentations.

Understanding these temporal patterns prevents premature testing, reduces false‑negative results, and ensures that appropriate antimicrobial therapy is initiated based on reliable laboratory evidence.

Early-Stage Testing

Polymerase Chain Reaction «PCR» Test

Polymerase chain reaction (PCR) is a molecular diagnostic tool used to detect the DNA of tick‑borne pathogens directly from patient specimens. After a bite, PCR can confirm infection with agents such as Borrelia burgdorferi (Lyme disease), Anaplasma phagocytophilum, Ehrlichia chaffeensis, Babesia microti and viral agents like Powassan virus.

The test requires a properly collected sample—usually whole blood, skin biopsy from the bite site, or cerebrospinal fluid when neurological involvement is suspected. Sensitivity is highest when the specimen is obtained during the acute phase, typically within 1–3 weeks of exposure for bacterial pathogens and within 7–14 days for viral agents. A negative result after this window does not exclude later serologic conversion; repeat testing may be warranted if symptoms persist.

Key considerations for ordering PCR after a tick bite:

Indicated when clinical presentation suggests early infection (e.g., erythema migrans, febrile illness, neurologic signs) and serology may still be negative.
Preferred specimen type varies by pathogen: whole blood for Anaplasma and Ehrlichia, skin biopsy for Borrelia, blood smear plus PCR for Babesia.
Turn‑around time ranges from several hours to a few days, depending on laboratory capacity.
Positive result confirms active infection; negative result must be interpreted alongside clinical assessment and other laboratory findings.

PCR complements serologic assays, providing rapid identification of the causative organism and guiding targeted antimicrobial therapy.

Serological Tests «Antibody Detection»

Serological antibody detection is a core component of the diagnostic work‑up after a tick exposure. The primary aim is to identify immune responses to vector‑borne pathogens that may not be evident clinically in the early phase.

The most frequently ordered assay targets Borrelia burgdorferi, the agent of Lyme disease. A two‑step protocol is standard: an initial enzyme‑linked immunosorbent assay (ELISA) for IgM and IgG antibodies, followed by a confirmatory immunoblot (Western blot) when ELISA results are positive or equivocal. Interpretation relies on the timing of the bite; IgM antibodies typically appear within 2–4 weeks, whereas IgG seroconversion may require 4–6 weeks. Paired serum samples collected 2–4 weeks apart improve diagnostic certainty.

Additional serological tests address other tick‑transmitted infections:

Anaplasma phagocytophilum – indirect immunofluorescence assay (IFA) for IgG; a four‑fold rise in titre between acute and convalescent sera confirms infection.
Ehrlichia chaffeensis – IFA or ELISA for IgM/IgG; similar reliance on paired samples.
Babesia microti – indirect immunofluorescence or ELISA detecting IgM and IgG; serology complements microscopic examination of blood smears.
Rickettsia spp. – microimmunofluorescence assay (MIF) for IgG; a four‑fold increase between acute and convalescent phases indicates recent exposure.

When ordering serology, consider the following practical points:

Collect an acute‑phase specimen as soon as possible after the bite, preferably within 7 days.
Obtain a convalescent specimen 2–4 weeks later to assess seroconversion or titre escalation.
Document the exact date of exposure, symptoms, and any prior antibiotic treatment, as these factors influence antibody kinetics.
Use assays with validated sensitivity and specificity for the geographic region, since strain variation can affect performance.

Serological antibody detection, combined with clinical assessment and, when indicated, molecular or microscopic methods, provides a comprehensive strategy for evaluating patients after tick contact.

IgM Antibodies

IgM antibodies are the first class of immunoglobulins produced in response to a recent infection. After a tick bite, detection of IgM can help identify early-stage tick‑borne diseases such as Lyme disease, anaplasmosis, and ehrlichiosis. The presence of IgM typically indicates exposure within the past two to four weeks, before IgG antibodies reach detectable levels.

Testing for IgM is performed using enzyme‑linked immunosorbent assay (ELISA) or immunoblot techniques. Positive IgM results should be interpreted with caution because cross‑reactivity with other pathogens and nonspecific binding can generate false‑positive outcomes. Confirmation with a second‑tier test, usually an IgG‑based immunoblot, reduces the risk of misdiagnosis.

Key considerations for IgM testing after a tick bite:

Timing: collect serum at least 2 weeks post‑exposure for optimal sensitivity.
Disease specificity: use assays validated for the suspected pathogen (e.g., Borrelia burgdorferi, Anaplasma phagocytophilum).
Follow‑up: repeat testing after 4 weeks if initial IgM is negative but clinical suspicion remains.
Interpretation: combine IgM results with clinical findings, exposure history, and, when available, PCR or culture data.

In practice, IgM serology forms part of a broader diagnostic panel that may also include PCR for pathogen DNA, complete blood count, liver function tests, and inflammatory markers. Together, these investigations provide a comprehensive assessment of infection status after a tick bite.

IgG Antibodies

After a tick bite, serologic analysis of IgG antibodies provides evidence of past or ongoing infection with tick‑borne pathogens. IgG detection is most reliable when performed at least two weeks after exposure, because the antibody class rises later than IgM and persists for months.

For Lyme disease, the standard approach includes a quantitative IgG enzyme‑linked immunosorbent assay (ELISA) followed by a confirmatory IgG Western blot. A positive ELISA with a reactive IgG pattern on blot indicates established infection and guides antibiotic therapy.

Additional IgG assays useful after a tick bite are:

Anaplasma phagocytophilum IgG immunofluorescence assay (IFA) – confirms anaplasmosis when paired with a rising titer.
Ehrlichia chaffeensis IgG IFA – identifies ehrlichiosis, especially in endemic regions.
Babesia microti IgG indirect fluorescent antibody test – supports diagnosis of babesiosis when microscopy is equivocal.
Rickettsia spp. IgG ELISA or IFA – detects spotted fever group rickettsioses.

Interpretation of IgG results requires comparison with acute‑phase specimens or documented seroconversion. A single low‑titer IgG result may reflect past exposure without current disease; a four‑fold rise between acute and convalescent samples confirms recent infection. Negative IgG does not exclude early infection; repeat testing after the appropriate interval is advised.

Late-Stage and Confirmatory Testing

Western Blot Test

After a tick bite, clinicians often assess the possibility of Lyme disease. The Western blot serves as a confirmatory assay following an initial screening test such as an ELISA. It detects antibodies that bind to specific Borrelia burgdorferi proteins, providing evidence of an immune response to the pathogen.

The assay separates bacterial proteins by electrophoresis, transfers them to a membrane, and incubates the membrane with the patient’s serum. If antibodies are present, they bind to distinct protein bands. The resulting pattern of IgM and IgG bands is visualized with a labeled secondary antibody. Each band corresponds to a known antigen; the presence, number, and intensity of bands form the basis for interpretation.

Interpretation follows established criteria. For IgM, at least two of the three designated bands (23 kDa, 39 kDa, 41 kDa) must be present. For IgG, five of the ten specified bands (including 18 kDa, 28 kDa, 30 kDa, 39 kDa, 41 kDa, 45 kDa, 58 kDa, 66 kDa, 93 kDa, 100 kDa) are required. Results are reported as positive, negative, or equivocal. Testing is most reliable when performed ≥ 4 weeks after the bite, allowing sufficient time for antibody development.

The test requires a venous blood sample and is processed in specialized laboratories. It is not useful for early infection before seroconversion, and cross‑reactivity with other spirochetes can produce false‑positive bands. When a Western blot is positive, treatment decisions are guided by clinical presentation and disease stage.

Specific Disease Panels «e.g., Lyme, Anaplasmosis, Ehrlichiosis»

After a tick exposure, clinicians often order targeted serologic panels to identify the most common bacterial infections transmitted by Ixodes and related species. A disease‑specific panel typically includes the following assays:

Lyme disease: Enzyme‑linked immunosorbent assay (ELISA) for IgM and IgG antibodies to Borrelia burgdorferi, followed by a Western blot for confirmation when ELISA is positive. Some laboratories also provide a C6 peptide ELISA as an alternative confirmatory test.
Anaplasmosis: Indirect immunofluorescence assay (IFA) detecting IgG antibodies to Anaplasma phagocytophilum, with a paired‑sample collection 2–4 weeks apart to demonstrate seroconversion. Polymerase chain reaction (PCR) on whole blood is recommended for early detection before antibodies develop.
Ehrlichiosis: IFA for IgG antibodies to Ehrlichia chaffeensis, similarly requiring acute and convalescent specimens. PCR on peripheral blood is useful during the acute phase, especially when leukopenia or thrombocytopenia is present.

When ordering a combined panel, laboratories often run all three assays simultaneously, providing a single report that includes individual results and interpretive comments. Timing of specimen collection influences sensitivity: PCR yields the highest detection rates within the first week post‑bite, while serology becomes reliable after the second week, reaching peak sensitivity at 4–6 weeks. A negative result on an early PCR does not exclude infection; repeat testing or a convalescent‑phase serology is advisable if clinical suspicion persists.

Interpretation requires correlation with exposure history, clinical presentation, and laboratory trends. Elevated IgM without IgG may indicate recent infection, whereas isolated IgG suggests past exposure or late‑stage disease. PCR positivity combined with compatible symptoms confirms active infection and guides immediate antimicrobial therapy.

Post-Test Management and Follow-Up

Interpretation of Test Results

After a tick attachment, laboratory investigations aim to confirm or exclude infection. Interpreting the results requires awareness of test characteristics, disease stage, and timing of specimen collection.

Serologic testing for Borrelia burgdorferi typically begins with an enzyme‑linked immunosorbent assay (ELISA). A negative ELISA effectively rules out early disseminated or late disease but may miss very recent infection because antibodies develop after 2–3 weeks. A positive ELISA must be verified by a Western blot. In the IgM blot, reactivity to at least two of the following bands (24 kDa, 39 kDa, 41 kDa) indicates recent exposure; the IgG blot requires five of ten specific bands to confirm later‑stage infection. Isolated IgM positivity beyond 30 days is unreliable and warrants repeat testing.

Polymerase chain reaction (PCR) on skin biopsy, blood, or cerebrospinal fluid detects bacterial DNA. A positive PCR establishes active infection but a negative result does not exclude disease, especially in early stages when bacterial load is low.

Complete blood count (CBC) may reveal lymphocytosis or thrombocytopenia, supporting a systemic response. Elevated liver enzymes (ALT, AST) suggest hepatic involvement, common in severe Lyme disease or co‑infection with Anaplasma phagocytophilum.

Interpretation guidelines:

Negative ELISA & negative PCR – low probability of infection; repeat serology after 2–3 weeks if symptoms persist.
Positive ELISA, confirmed by Western blot – diagnosis of Lyme disease; initiate appropriate antimicrobial therapy.
Positive IgM Western blot alone after 30 days – consider false‑positive; repeat serology.
Positive IgG Western blot – indicates past or current infection; assess clinical presentation to decide treatment.
Positive PCR with negative serology – early infection; treat promptly.
Abnormal CBC or liver enzymes – corroborate clinical suspicion; monitor during therapy.

Follow‑up testing should be performed 4–6 weeks after treatment completion to verify serologic decline and to detect possible treatment failure or reinfection.

Treatment Options

After diagnostic testing confirms exposure to a tick‑borne pathogen, therapy should be directed at the identified organism and the clinical stage of infection.

Doxycycline 100 mg twice daily for 10–21 days is first‑line for early Lyme disease, anaplasmosis, and ehrlichiosis. It also provides prophylaxis against Lyme disease when administered within 72 hours of a bite from an engorged nymphal Ixodes tick in endemic areas.
Amoxicillin 500 mg three times daily for 14–21 days is an alternative for Lyme disease in patients who cannot tolerate doxycycline, such as pregnant women and young children.
Ceftriaxone 2 g intravenously daily for 14–28 days is indicated for neurologic Lyme disease, Lyme carditis, or severe disseminated infection.
Azithromycin 500 mg on day 1 followed by 250 mg daily for 4 days can be used for mild anaplasmosis or ehrlichiosis when doxycycline is contraindicated.
Rifampin 600 mg daily for 10 days may be added in cases of co‑infection with babesiosis or when resistance to standard agents is suspected.
Supportive care, including antipyretics, hydration, and monitoring of cardiac or neurologic complications, should accompany antimicrobial therapy.

Selection of the regimen must consider patient age, pregnancy status, drug allergies, and the presence of co‑infections. Prompt initiation of the appropriate antimicrobial reduces the risk of long‑term sequelae.

Long-Term Monitoring for Complications

After a tick bite, clinicians must continue surveillance beyond the initial assessment because some infections manifest weeks or months later. Persistent fatigue, joint pain, neurological signs, or skin changes may indicate delayed disease progression and require prompt evaluation.

Follow‑up appointments are typically scheduled at 2–4 weeks, 3 months, and 6 months post‑exposure. During each visit, physicians record temperature, blood pressure, and a focused physical exam that includes skin inspection, joint palpation, and neurological testing. Any new or worsening symptoms trigger immediate re‑evaluation.

Long‑term laboratory monitoring may include:

Serologic testing for Borrelia antibodies (IgM and IgG) at 4–6 weeks and again at 3 months to detect seroconversion.
Complete blood count to identify anemia or leukocytosis suggestive of systemic infection.
Liver function panel to reveal hepatic involvement common in certain tick‑borne pathogens.
C‑reactive protein or erythrocyte sedimentation rate to quantify ongoing inflammation.

When neurological or musculoskeletal complaints persist, magnetic resonance imaging of the brain or affected joints, and cerebrospinal fluid analysis for intrathecal antibody production, become appropriate. These investigations help differentiate chronic infection from alternative etiologies.

Continued documentation of test results and symptom trends enables timely treatment adjustments, reduces the risk of long‑term sequelae, and supports evidence‑based management of tick‑related illnesses.