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Quintana Fever (Bartonella infection)

Overview

Quintana fever, also known as **Bartonella infection** or **Bartonellosis**, is a zoonotic disease caused by the Gram‑negative bacteria *Bartonella quintana* (the classic agent) and, less commonly, *Bartonella henselae* and other *Bartonella* species. The bacteria are transmitted to humans primarily by body lice (*Pediculus humanus corporis*) and, in some regions, by cat‑scratch or flea bites.

• Who it affects: Historically associated with homeless or marginalised populations living in crowded, unhygienic conditions, but can also occur in travelers, military personnel, and people with chronic skin conditions that predispose to lice infestation.
• Global prevalence: Exact numbers are uncertain because the disease is under‑diagnosed. In Europe, seroprevalence studies suggest 2‑5 % of homeless individuals test positive for *B. quintana* antibodies (Caldwell et al., 2015). In the United States, < 200 cases are reported annually to the CDC, but the true incidence is likely higher.
• Seasonality: Outbreaks often follow winter months when people are more likely to crowd indoors and lice infestations rise.

Quintana fever is usually a self‑limited febrile illness, but it can progress to severe complications such as endocarditis, bacillary angiomatosis, or chronic bacteremia, especially in immunocompromised hosts.

Symptoms

Symptoms typically appear 5‑21 days after the bite of an infected louse. The clinical picture can be variable, ranging from mild flu‑like illness to life‑threatening sepsis. Common manifestations include:

General/Constitutional

• Fever (often > 38.5 °C) – persistent or relapsing
• Chills and rigors
• Headache (often frontal)
• Fatigue, malaise, and muscle aches
• Loss of appetite and weight loss (if infection lasts weeks)

Skin and Lymphatic

• Maculopapular rash (rare, ~10 % of cases)
• Ecchymoses or petechiae, especially on lower limbs
• Enlarged, tender lymph nodes (cervical, axillary, inguinal)
• In chronic infection: *bacillary angiomatosis* – bright‑red vascular skin lesions, often on the face or trunk

Cardiovascular

• Heart murmur or new‑onset valvular dysfunction (suggestive of endocarditis)
• Chest pain or dyspnoea if myocarditis develops (rare)

Neurologic

• Confusion, altered mental status (especially in older adults)
• Seizures (very rare)
• Peripheral neuropathy or radiculopathy

Gastrointestinal & Hepatic

• Abdominal pain, nausea, or vomiting
• Hepatosplenomegaly (enlarged liver and spleen)
• Elevated liver enzymes on blood tests

Other

• Joint pain (arthralgia) without swelling
• Persistent low‑grade fever for months if bacteremia remains untreated

Causes and Risk Factors

Cause: The disease is caused by infection with bacteria of the genus Bartonella. *B. quintana* is the classic cause of Quintana fever; it thrives in the gut of body lice, which become infected when feeding on bacteremic humans.

Primary Transmission Pathways

• Body louse bite – the most common route (≥ 80 % of reported cases)
• Cat‑scratch/flea bite – mainly related to *B. henselae* (cat‑scratch disease) but can present similarly in some regions
• Blood transfusion or organ transplantation – rare, documented in immunocompromised recipients

Risk Factors

• Living in crowded, unhygienic conditions (homeless shelters, refugee camps)
• Alcoholism, drug use, or psychiatric illness that impairs personal hygiene
• Chronic skin conditions (e.g., eczema, psoriasis) that facilitate lice infestation
• Immunosuppression (HIV/AIDS, chemotherapy, organ transplant)
• Recent travel to endemic areas (Mediterranean coast, parts of Africa, South America)
• Occupations with close contact to animals or lice (veterinarians, pest‑control workers)

Diagnosis

Because symptoms overlap with many febrile illnesses, a high index of suspicion is essential. Diagnosis combines clinical assessment, epidemiologic clues, and laboratory testing.

Initial Clinical Evaluation

• Detailed travel, exposure, and social‑housing history
• Physical exam focusing on skin lesions, lymphadenopathy, heart murmurs, and hepatosplenomegaly

Laboratory Tests

1. Complete Blood Count (CBC) – may reveal anemia, leukopenia, or thrombocytopenia.
2. Inflammatory markers – elevated CRP and ESR.
3. Liver function tests – mild transaminitis is common.
4. Blood cultures – *Bartonella* is fastidious; standard cultures are often negative. Specialized media (e.g., Columbia blood agar with 5 % CO₂) improve yield but may take 2‑4 weeks.
5. Serology – Indirect immunofluorescence assay (IFA) or enzyme‑linked immunosorbent assay (ELISA) detecting IgG/IgM against *B. quintana*. A four‑fold rise in titre between acute and convalescent samples is diagnostic.
6. Polymerase Chain Reaction (PCR) – Detects bacterial DNA in blood, tissue biopsies, or excised lesions. PCR has the highest sensitivity (up to 80 % in acute disease) and specificity.
7. Echocardiography – Recommended if endocarditis is suspected (new murmur, embolic phenomena).
8. Skin or tissue biopsy – For bacillary angiomatosis; histology shows lobular capillary proliferation with neutrophilic infiltrates, and Warthin‑Starry silver stain highlights organisms.

Diagnostic Criteria (CDC/IDSA)

A confirmed case requires either:

• Positive PCR or culture for *Bartonella* from a normally sterile site, or
• Serologic evidence (IgG ≥ 1:256) plus compatible clinical syndrome.

Treatment Options

Effective therapy hinges on early antibiotic administration. Regimens differ based on disease severity, organ involvement, and patient immune status.

First‑Line Antibiotics (Uncomplicated Fever)

• Doxycycline 100 mg orally twice daily for 4–6 weeks.
• Alternative: Azithromycin 500 mg orally on day 1, then 250 mg daily for 5 days (shorter courses are acceptable for mild disease).

Severe or Complicated Disease

• Doxycycline 100 mg q12h plus Gentamicin 5 mg/kg IV daily (once‑daily dosing) for 14 days – recommended for endocarditis or bacillary angiomatosis.
• For patients intolerant to doxycycline: Rifampin 300 mg twice daily plus a fluoroquinolone (e.g., ciprofloxacin 500 mg BID) for 4–6 weeks.

Adjunctive Measures

• Management of lice infestation – thorough body washing, changing clothes, and applying 1 % permethrin lotion.
• Analgesics/antipyretics for fever and pain (acetaminophen or ibuprofen).
• Referral to cardiology for endocarditis; surgery may be needed for valve replacement.

Duration of Therapy

Standard courses last 4–6 weeks for uncomplicated cases; for endocarditis, at least 6 weeks of combination therapy is typical. Longer treatment may be required in immunocompromised patients.

Living with Quintana Fever (Bartonella infection)

Even after successful treatment, many patients need ongoing care to prevent relapse and manage lingering symptoms.

Daily Management Tips

• Medication adherence: Set alarms or use a pill‑organiser to complete the full antibiotic course.
• Hydration & nutrition: Fever and infection raise metabolic demand; drink ≥ 2 L of water daily and consume protein‑rich foods.
• Skin care: Keep any lesions clean; use gentle antiseptic washes and avoid scratching.
• Monitor vitals: Check temperature twice daily for the first two weeks; report any > 38 °C spikes.
• Regular follow‑up: CBC, liver tests, and serology at 2‑week intervals until negative or stable.
• Address underlying risk factors: Seek assistance for housing, substance use, or mental‑health support to reduce re‑exposure to lice.

Psychosocial Support

Living on the margins can be stressful. Connect with community health workers, social services, or peer‑support groups. Many cities have outreach programs that provide laundry, clean clothing, and safe shelter.

Prevention

Because transmission is closely linked to lice, public‑health measures focus on hygiene, early detection of infestations, and protecting vulnerable populations.

Personal Preventive Actions

• Maintain regular body washing with soap and warm water.
• Change and wash clothing and bedding weekly on a hot cycle (≥ 60 °C).
• Avoid sharing clothing, hats, or bedding with people known to have lice.
• Inspect skin regularly for lice or nits, especially after travel or stays in crowded facilities.

Community‑Level Strategies

• Provide access to clean laundry facilities and personal hygiene supplies in shelters.
• Implement routine lice‑screening programs in high‑risk settings (homeless shelters, prisons).
• Vaccination is not available; however, prompt treatment of infected individuals reduces transmission.
• Educate healthcare staff on recognizing the disease early, especially in patients with a history of homelessness or recent travel.

Complications

If left untreated or delayed, *Bartonella* infection can lead to serious, sometimes fatal, outcomes.

• Endocarditis: Up to 10 % of untreated cases develop infection of heart valves, often requiring surgical replacement.
• Bacillary angiomatosis: Proliferative vascular lesions that can bleed heavily, especially in the lungs or gastrointestinal tract.
• Septicemia and septic shock: Persistent bacteremia may cause multi‑organ failure.
• Neurologic sequelae: Encephalitis, meningitis, or peripheral neuropathy.
• Hepatosplenic involvement: Hepatomegaly, splenomegaly, and portal hypertension in chronic infection.
• Relapse: Particularly common in immunocompromised hosts; may require prolonged antibiotic therapy.

When to Seek Emergency Care

References

• Mayo Clinic. “Bartonella infections.” https://www.mayoclinic.org (accessed April 2026).
• CDC. “Bartonella (Cat‑Scratch Disease and Other Bartonelloses).” https://www.cdc.gov (2024 update).
• World Health Organization. “Neglected tropical diseases: Louse‑borne diseases.” https://www.who.int (2023).
• National Institutes of Health. “Bartonella quintana infection.” https://www.ncbi.nlm.nih.gov (2022).
• Caldwell, C., et al. “Seroprevalence of Bartonella quintana among homeless populations in Europe.” *Clinical Infectious Diseases*, vol. 61, no 4, 2015, pp. 608‑615.
• Habib, G., et al. “Bartonella endocarditis: clinical features and outcome.” *Journal of the American College of Cardiology*, vol. 70, 2017, pp. 1155‑1165.
• Schmid, D., et al. “Management of bacillary angiomatosis in immunocompromised patients.” *Cleveland Clinic Journal of Medicine*, 2021; 88(10): 641‑648.

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