Tularemia is a rare nationally notifiable zoonosis, caused by the tier-1 select agent Francisella tularensis, that has been reported from all U.S. states except Hawaii. Clinical manifestations typically include fever and localized symptoms that vary by route of infection. The case fatality rate of tularemia is typically <2% but can be higher depending on clinical manifestation and infecting strain. Tularemia is treatable with antibiotics. During 2011-2022, a total of 47 states reported 2,462 tularemia cases, but four central states (Arkansas, Kansas, Missouri, and Oklahoma) accounted for 50% of all reported cases. Incidence was highest among children aged 5-9 years (0.083 per 100,000 population) and adult males aged 65-84 years (range = 0.133-0.161). Incidence among American Indian or Alaska Native persons (0.260) was approximately five times that among White persons (0.057). The average annual incidence of tularemia in the United States during 2011-2022 (0.064) was 56% higher than that reported during 2001-2010 (0.041), largely resulting from increased reporting of probable cases. These findings might reflect an actual increase in human infection or improved case detection amid changes in commercially available laboratory tests during this period. Reducing tularemia incidence will require tailored prevention education; mitigating morbidity and mortality will require health care provider education, particularly among providers serving tribal populations, regarding early and accurate diagnosis and treatment.

Bartonella quintana infection can cause severe disease that includes clinical manifestations such as endocarditis, chronic bacteremia, and vasoproliferative lesions of the skin and viscera. B. quintana bacteria is transmitted by the human body louse (Pediculus humanus corporis) and is associated with homelessness and limited access to hygienic services. We report B. quintana infection in 2 kidney transplant recipients in the United States from an organ donor who was experiencing homelessness. One infection manifested atypically, and the other was minimally symptomatic; with rapid detection, both recipients received timely treatment and recovered. B. quintana was identified retrospectively in an archived donor hematoma specimen, confirming the transmission link. Information about the organ donor's housing status was critical to this investigation. Evaluation for B. quintana infection should be considered for solid organ transplant recipients who receive organs from donors with a history of homelessness or of body lice infestation.

OBJECTIVE: Pet ownership among people experiencing homelessness (PEH) is common, but access to shelter, veterinary care, and flea-preventative products for PEH who own pets in the US is not well described. We sought to evaluate current knowledge of fleas and flea-borne diseases and characterize practices around pets and service animals among staff at homeless shelters and outreach organizations. METHODS: In-person surveys were administered to staff at homeless shelters and on outreach teams in 7 states from August 2022 to April 2023 to evaluate knowledge, attitudes, and practices and to assess homeless shelter/organizational characteristics. RESULTS: Surveys were administered to 333 staff members at 60 homeless shelters and among 29 outreach teams. Seventy-eight percent of homeless shelters allowed pets or service animals. Only 2% of homeless shelters and 7% of outreach teams provided veterinary care; 15% of homeless shelters and 7% of outreach teams provided flea preventatives. Nearly three-quarters of surveyed homeless shelter staff responded that no steps were taken to treat fleas at their shelters. CONCLUSIONS: Veterinary care and availability of flea-preventative products are limited in homeless shelter and outreach organizations serving people experiencing homelessness. CLINICAL RELEVANCE: Pets of PEH might be at an increased risk of flea infestation and flea-borne diseases because of limited access to veterinary care and preventatives. Improving knowledge and access to flea prevention, screening, and treatment are critical to ensure PEH and their pets can consistently access homeless shelters or outreach services, and to prevent flea-borne disease transmission.

Bartonella quintana infection can lead to bacillary angiomatosis, peliosis hepatis, chronic bacteremia, and culture-negative endocarditis. Transmitted by the human body louse (Pediculus humanus humanus), B. quintana infection has become an emerging disease in recent decades among persons experiencing homelessness. By using retrospective laboratory surveillance, we identified 5 cases of left-sided, culture-negative B. quintana endocarditis among persons in New York, New York, USA, during January 1, 2020-November 23, 2023. Identifications were made by using molecular assays. All patients experienced unsheltered homelessness in the year before hospitalization. Of those patients, 4 experienced heart failure, 3 renal failure, and 2 embolic strokes; 2 died. Aortic valve replacement occurred in 4 cases. A history of possible body louse infestation was found in 4 cases. Clinicians should consider housing status and history of lice exposure in patients with suspected bartonellosis and have a low threshold for diagnostic testing and empiric treatment in patients experiencing homelessness.

In a US survey of infectious disease specialists, 61 respondents reported seeing >1 Bartonella quintana infection during 2014-2024. Diagnostic challenges included limited healthcare provider awareness, inadequate testing, and inconsistent healthcare access among affected populations. Early recognition of B. quintana infections is needed to improve outcomes among affected populations.

BACKGROUND AND AIMS: Louse-borne Bartonella quintana infection and flea-borne murine typhus are two potentially serious vector-borne diseases that have led to periodic outbreaks among people experiencing homelessness in the United States. Little is known about louse- and flea-borne disease awareness and prevention among staff who provide services to the population. We surveyed staff in seven US states to identify gaps in knowledge and prevention practices for these diseases. METHODS AND RESULTS: Surveys were administered to 333 staff at 89 homeless shelters and outreach teams in California, Colorado, Georgia, Maryland, Minnesota, New York and Washington from August 2022 to April 2023. Most participants (>68%) agreed that body lice and fleas are a problem for people experiencing homelessness. About half were aware that diseases could be transmitted by these vectors; however, most could not accurately identify which diseases. Less than a quarter of staff could describe an appropriate protocol for managing body lice or fleas. Misconceptions included that clients must isolate or be denied services until they are medically cleared. CONCLUSIONS: Our findings reveal significant knowledge gaps among staff who provide services to people experiencing homelessness in the prevention and control of louse- and flea-borne diseases. This demonstrates an urgent need for staff training to both reduce disease and prevent unnecessary restrictions on services and housing.

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.

Molecular HIV surveillance is a promising public health strategy for curbing the HIV epidemic. Clustering technologies used by health departments to date are limited in their ability to infer/forecast cluster growth trajectories. Resolution of the spatiotemporal dynamics of clusters, through phylodynamic and phylogeographic modelling, is one potential strategy to develop a forecasting tool; however, the projected utility of this approach needs assessment. Prior to incorporating novel phylodynamic-based molecular surveillance tools, we sought to identify possible issues related to their feasibility, acceptability, interpretation, and utility. Qualitative data were collected via focus groups among field experts (n = 17, 52.9% female) using semi-structured, open-ended questions. Data were coded using an iterative process, first through the development of provisional themes and subthemes, followed by independent line-by-line coding by two coders. Most participants routinely used molecular methods for HIV surveillance. All agreed that linking molecular sequences to epidemiological data is important for improving HIV surveillance. We found that, in addition to methodological challenges, a variety of implementation barriers are expected in relation to the uptake of phylodynamic methods for HIV surveillance. The participants identified several opportunities to enhance current methods, as well as increase the usability and utility of promising works-in-progress.

BACKGROUND: Persons living with HIV (PWH) with resistance to antiretroviral therapy (ART) are vulnerable to adverse HIV-related health outcomes and can contribute to transmission of HIV drug resistance (HIVDR) when non-virally suppressed. The degree to which HIVDR contributes to disease burden in Florida -the US state with the highest HIV incidence- is unknown. METHODS: We explored sociodemographic, ecological, and spatial-temporal associations of HIVDR. HIV-1 sequences (n=34,447) collected during 2012-2017 were obtained from the Florida Department of Health. HIVDR was categorized by ART class: nucleoside reverse transcriptase inhibitors (NRTI), non-NRTI (NNRTI), protease inhibitors (PI), and integrase inhibitors (INSTI). Multi-drug resistance (MDR) and transmitted-drug resistance (TDR) were also evaluated. Multivariable fixed-effects logistic regression models were fitted to associate individual and county-level sociodemographic and ecological health indicators with HIVDR. RESULTS: HIVDR prevalence was 19.2% (NRTI), 29.7% (NNRTI), 6.6% (PI), 23.5% (TDR), 13.2% (MDR), and 8.2% (INSTI) with significant variation by Florida county. Individuals who were older, Black, or acquired HIV through mother-to-child transmission had significantly higher odds of HIVDR. HIVDR was linked to counties with lower socioeconomic status, higher unemployment, and poor mental health. CONCLUSIONS: Our findings indicate HIVDR prevalence is higher in Florida than aggregate North American estimates with significant geographic and socioecological heterogeneity.