Notes from the Field: Severe Bartonella quintana Infections Among Persons Experiencing Unsheltered Homelessness — New York City, January 2020–December 2022

Shannan N. Rich, PhD1,2; Amy Beeson, MD1,2; Leah Seifu, MD1,3; Kara Mitchell, PhD4; Danielle Wroblewski, MS4; Stefan Juretschko, PhD5; Marina Keller, MD6; Rachel Gnanaprakasam, MBBS6; Mariam Agladze, MD7; Rich Kodama, DO8; Tania Kupferman, MD7; Julu Bhatnagar, PhD9; Roosecelis B. Martines, MD, PhD9; Sarah Reagan-Steiner, MD9; Sally Slavinski, DVM3; Matthew J. Kuehnert, MD10; Camille Bergeron-Parent, MD3; Gabriella Corvese, MPH11; Grace E. Marx, MD2,*; Joel Ackelsberg, MD3,* (View author affiliations)

View suggested citation
Article Metrics

Views equals page views plus PDF downloads

Related Materials

Bartonella quintana infection is a vectorborne disease transmitted by the human body louse (1). In the United States, homelessness is the principal risk factor for B. quintana infection (2), likely attributable to limited access to hygiene facilities (1). This infection is not nationally notifiable in the United States, and its incidence is unknown. Acute B. quintana infection can cause fever, headache, and bone pain; severe manifestations include chronic bacteremia, bacillary angiomatosis, and infective endocarditis (3). Because the bacterium requires special conditions to grow in culture, standard blood cultures are usually negative (4). Diagnosis by serology is most common; however, cross-reactivity with other Bartonella species (e.g., B. henselae) can hamper interpretation. Molecular assays specific for B. quintana have been developed (5), but availability is limited to a few laboratories. Once diagnosed, infection can be cured by several weeks to months of antibiotic therapy.

Investigation and Outcomes

In January and April 2023, the New York City (NYC) Department of Health and Mental Hygiene (DOHMH) was alerted to two cases of B. quintana infection that occurred during 2022 among persons who had experienced unsheltered homelessness in NYC and later died (one died because of the infection, and the other because of an unrelated cause). DOHMH conducted retrospective active surveillance within clinical laboratories of five large NYC hospital networks to identify additional cases with culture, molecular, or serologic laboratory results for B. quintana or Bartonella spp. and reviewed electronic medical records of all identified patients. One patient’s family provided clinical outcome details not found in the medical record. Housing status was determined from the medical record or the NYC Department of Homeless Services (DHS) system. This activity was reviewed by CDC, deemed not research, and was conducted consistent with applicable federal law and CDC policy.

Four additional cases were identified that occurred in NYC during January 2020–December 2022 (Table). Four of the six total cases occurred during 2022. Five patients received a positive molecular diagnostic test result specific for B. quintana§; one received a positive Bartonella polymerase chain reaction (PCR) test result not specific to B. quintana. Five patients were hospitalized for complications of B. quintana infection; the median duration of hospitalization was 34 days (range = 8–78 days). Four patients received a diagnosis of culture-negative, left-sided endocarditis and underwent surgical valve replacement; three experienced renal failure, and two died from endocarditis-related complications. One patient died from complications of traumatic injury not related to B. quintana infection. All six patients had experienced recent unsheltered homelessness either at the time of hospitalization (four) or within the preceding year (two) and had incidental contact or no contact with the NYC DHS shelter or outreach system; five had a documented mental health or substance use disorder; no cases were epidemiologically linked.

Preliminary Conclusions and Actions

B. quintana infection can result in severe outcomes, including death, and incur substantial health care costs from prolonged hospitalizations and surgical interventions. The total number of B. quintana cases is likely higher than what is reported here for several reasons: 1) persons experiencing unsheltered homelessness often do not seek health care services, 2) health care providers are less likely to consider bartonellosis in patients without severe disease, and 3) laboratory diagnosis is challenging.

To help identify patients at risk for B. quintana infection, clinicians should consider housing status. Persons experiencing homelessness who have mental health conditions or substance use disorders might be less likely to access preventive hygiene services. Clinicians and health care systems could increase diagnostic and treatment support for behavioral health conditions in this population to prevent serious medical conditions, including bartonellosis resulting from body louse infestation. In addition, it is important that patients with a history of unsheltered homelessness and either prolonged subjective fevers without a known etiology, a vasoproliferative skin rash, or a diagnosis of culture-negative endocarditis be tested for B. quintana infection with a molecular diagnostic laboratory assay and considered for empiric treatment in consultation with an infectious disease physician.


Marlene DeLeon-Carnes, Infectious Diseases Pathology Branch, CDC.

Corresponding authors: Joel Ackelsberg,; Shannan N. Rich,

1Epidemic Intelligence Service, CDC; 2Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 3New York City Department of Health and Mental Hygiene, New York, New York; 4New York State Department of Health Wadsworth Center; 5Northwell Health Laboratories, Little Neck, New York; 6Westchester Medical Center, Valhalla, New York; 7Bellevue Hospital Center, New York, New York; 8Memorial Sloan Kettering Cancer Center, New York, New York; 9Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 10Office of the Director, National Center for Emerging and Zoonotic Diseases, CDC; 11New York City Department of Homeless Services, New York, New York.

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Kara Mitchell reports the following relationships with the Association of Public Health Laboratories: consultant for a public health–related doctorate program to develop molecular course content, funded travel to national meetings, and a leadership or fiduciary role with the Laboratory Systems and Standards Committee. No other potential conflicts of interest were disclosed.

* These senior authors contributed equally to this report.

45 C.F.R. part 46, 21 C.F.R. part 56; 42 U.S.C. Sect. 241(d); 5 U.S.C. Sect. 552a; 44 U.S.C. Sect. 3501 et seq.

§ Three patients received a diagnosis of B. quintana based on reverse transcriptase–PCR testing and molecular sequencing at the New York State Department of Health Wadsworth Center; two patients received a diagnosis based on B. quintana PCR testing and molecular sequencing of retrospectively identified fixed tissue samples at CDC’s Infectious Disease Pathology Branch.


  1. Karem KL, Paddock CD, Regnery RL. Bartonella henselae, B. quintana, and B. bacilliformis: historical pathogens of emerging significance. Microbes Infect 2000;2:1193–205. PMID:11008109
  2. Leibler JH, Zakhour CM, Gadhoke P, Gaeta JM. Zoonotic and vector-borne infections among urban homeless and marginalized people in the United States and Europe, 1990–2014. Vector Borne Zoonotic Dis 2016;16:435–44. PMID:27159039
  3. Angelakis E, Raoult D. Pathogenicity and treatment of Bartonella infections. Int J Antimicrob Agents 2014;44:16–25. PMID:24933445
  4. Choat J, Yockey B, Sheldon SW, Pappert R, Petersen J, Dietrich EA. Development and validation of a real-time PCR test to detect Bartonella quintana in clinical samples. Diagn Microbiol Infect Dis 2023;106:116000. PMID:37295184
  5. McCormick DW, Rassoulian-Barrett SL, Hoogestraat DR, et al. Bartonella spp. infections identified by molecular methods, United States. Emerg Infect Dis 2023;29:467–76. PMID:36823096
TABLE. Demographic information, clinical features, risk factors, and outcomes of six persons experiencing homelessness who received a diagnosis of Bartonella quintana infection — New York City, January 2020–December 2022.Return to your place in the text
Characteristic No. (%)
Age, yrs, mean (range) 52 (38–69)
Female 1 (17)
Male 5 (83)
Aortic valve endocarditis 4 (67)
Mitral valve endocarditis 1 (17)
Bacillary angiomatosis 1 (17)
Bacteremia 1 (17)
History of unsheltered homelessness 6 (100)
History of alcohol use 5 (83)
History of mental health condition 3 (50)
HIV infection 1 (17)
Hospital admission, yr
2020 1 (17)
2021 1 (17)
2022 4 (67)
Traumatic injury–related death 1 (17)
Endocarditis-related death 2 (33)
Renal failure 3 (50)

* One patient received two diagnoses.
CD4 T-cell count <50 cells/mm3 at time of diagnosis.

Suggested citation for this article: Rich SN, Beeson A, Seifu L, et al. Notes from the Field: Severe Bartonella quintana Infections Among Persons Experiencing Unsheltered Homelessness — New York City, January 2020–December 2022. MMWR Morb Mortal Wkly Rep 2023;72:1147–1148. DOI:

MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services.
Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services.
References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the U.S. Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication.

All HTML versions of MMWR articles are generated from final proofs through an automated process. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version ( and/or the original MMWR paper copy for printable versions of official text, figures, and tables.

Questions or messages regarding errors in formatting should be addressed to