Body Lice among People Experiencing Homelessness and Access to Hygiene Services during the COVID-19 Pandemic—Preventing Trench Fever in Denver, Colorado, 2020

INTRODUCTION

Bartonella quintana is a bacterium that causes trench fever, a febrile illness most known for plaguing troops during World War I.^1–3 Serology testing can show historical prevalence of B. quintana in a population; a study in France detected antibody titers in 30% of a population experiencing homelessness.^1,4 Symptoms of B. quintana include headache, dizziness, leg pain, lymphadenopathy, and a relapsing fever lasting 4–8 days; severe medical complications such as endocarditis, chronic bacteremia, and bacillary angiomatosis can occur among those infected.^4–8 Although death from B. quintana infection is extremely rare, a study conducted by Raoult et al. identified 12 deaths out of 101 Bartonella endocarditis cases (12% mortality).⁹

Bartonella quintana, a vector-borne infection transmitted by the human body louse (Pediculus humanus humanus), reemerged in Europe and North America during the 1990s. It was most common among people living in crowded conditions with a lack of access to hygiene services, particularly among people experiencing homelessness (PEH) in urban areas where conditions might facilitate disease transmission.^{1,5–7,10–12} Homeless populations have an estimated 2–30% prevalence of B. quintana and 19–68% prevalence of body lice.^13,14 In 2014, Bonilla et al., found that PEH who sleep outdoors also have a statistically significant association with having body lice.¹⁵ Risk factors facilitating body louse infestation include poor hygiene, lack of sanitation, inadequate laundry services, sharing of clothing and bedding, crowded conditions, and high-risk behaviors (e.g., intravenous drug use).⁸ The human body louse typically lives in clothing where it can easily feed and potentially transmit B. quintana to its human hosts.^3,4,11 These studies have examined body lice prevalence and risk among PEH, but have not compared these factors in sheltered versus unsheltered PEH. Although not a reportable condition in Colorado, B. quintana was detected among PEH in Denver during January–September 2020.

Denver’s PEH population typically sleeps overnight in outdoor encampments or indoor homeless shelters, where preventive measures for body lice transmission can be difficult to perform. The COVID-19 pandemic produced additional difficulties for PEH; cities that imposed lockdown measures to prevent spread of SARS-CoV-2 typically did not have emergency preparedness plans in place to provide additional shelter and hygiene services to PEH.¹² Colorado issued statewide stay-at-home orders on March 26 to reduce transmission of SARS-CoV-2 during the COVID-19 pandemic, closing businesses and restricting access to essential services for PEH, including shelters, showers, laundry services, and medical providers. The Metro Denver Homelessness Initiative (MDHI) released the first State of Homelessness 2020 report showing at least 31,207 people in the Denver Metropolitan Area accessed services or housing supports for PEH during July 2019–June 2020.¹⁶ In the United States, 580,466 total people were experiencing homelessness during January 2020.¹⁷ Within this population, 9,846 people were experiencing homelessness in Colorado in January 2020. Although effects of COVID-19 on the homeless population have not yet been quantified, an economic model from Columbia University projected a 40–45% increase in homelessness in the United States by the end of 2020 despite eviction moratoriums and federal unemployment benefits.^16,18

Because of the detection of B. quintana among PEH in Denver, the Colorado Department of Public Health and Environment (CDPHE) initiated an investigation. Colorado Department of Public Health and Environment sought to determine magnitude of body lice infestation among PEH in Denver, identify and compare risk factors for body lice transmission in outdoor encampments and overnight shelters, and determine how COVID-19 might have affected access to hygiene resources necessary to prevent body lice transmission. Collaborations with homeless coalitions and local public health jurisdictions sought to provide community education and outreach for body lice prevention and B. quintana treatment.

MATERIALS AND METHODS

RESULTS

Eight B. quintana cases among Denver’s PEH population were reported to CDPHE during January–September 2020; four cases were laboratory-confirmed by PCR and four cases met the probable case definition. All eight patients were hospitalized, five experienced endocarditis, and three experienced septicemia. One patient with B. quintana isolation died during hospitalization; the hospital diagnosis included valvular cardiomyopathy and infective endocarditis. Three of eight B. quintana patients were identified during January–February, before Colorado’s stay-at-home orders. Five of the eight patients tested positive for B. quintana during the months of May through September, after statewide stay-at-home orders were issued (Table 1).

Effects of COVID-19.

During this investigation, CDPHE staff learned that several overnight shelters in Denver were reallocated to exclusive use for PEH with COVID-19 and closed to the public for several months. Other overnight shelters traditionally used by PEH were moved entirely, often to locations less accessible by public transportation in the metropolitan area. Mobile shower and laundry facilities previously available to PEH staying in encampments were discontinued during the COVID-19 shutdown, while certain other essential services (e.g., day centers and laundromats) were temporarily closed. Government services and identification document offices were also closed during Colorado’s stay-at-home orders, which presented challenges for people to acquire or replace forms of identification. Difficulties acquiring such documents restricted PEH from applying for housing, jobs, and entering overnight shelters that required identification on arrival.

Among 153 study participants, 115 (75%) indicated COVID-19 had affected their access to essential services and PEH resources in some way. Sleeping sheltered was not associated with participant opinions on whether COVID-19 has changed their access to resources (78% of sheltered participants and 78% of unsheltered participants, not shown). A keyword frequency analysis (Figure 1) showed the most frequent open response category among all participants who indicated COVID-19 had changed their access to resources was that things are “harder” (32%).

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Keyword analysis describing how COVID-19 has affected access to people experiencing homelessness resources in Denver, CO.

Citation: The American Journal of Tropical Medicine and Hygiene 107, 2; 10.4269/ajtmh.22-0118

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DISCUSSION

Bartonella quintana infections had not previously been detected in Denver, but emerged prior to and during the COVID-19 pandemic in 2020. Eight PEH with B. quintana, a louse-borne illness often spread in areas with poor hygienic conditions, were identified in Denver during January–September 2020. A majority of PEH study participants indicated COVID-19 had affected their access to essential services, including access to laundry and shower facilities. The resultant investigation examined body lice prevalence, transmission-facilitating behaviors, and access to resources between two types of PEH sleep locations, sheltered versus unsheltered, and resulted in multiple crucial findings.

This study found that self-reported exposure to body lice is prevalent in participants who sleep in indoor shelters only, in outdoor encampments only, and in both sheltered and unsheltered locations in Denver (33%, 29%, and 41% of each category, respectively), but were not reported among participants who stated they had an alternate place to sleep, such as a motel, or with a friend or family member. In contrast, previous literature reports that body louse infestation prevalence can vary from 7% to 22% among sheltered populations or be as high as 80% among unsheltered populations experiencing poor hygienic conditions.¹³

Participants who typically sleep unsheltered report having less access to PEH services that might reduce transmission of B. quintana and body lice. However, fewer unsheltered participants reported recent exposure to body lice during the previous 6 months than those who typically sleep sheltered. This might be attributable to crowded conditions in shelters, compared with encampments, or to recall bias or misidentification of body lice among participants. Despite offering onsite laundry, showers, and medical care, overnight shelters still struggle with controlling human body lice transmission. A higher proportion of unsheltered participants reported high-risk behaviors for body lice transmission than those sleeping indoors at shelters. Unsheltered participants reported sharing bedding and clothing, finding new clothing, and washing clothes in unclean and unheated water sources (e.g., buckets, ponds, or rivers) more frequently than those who are sheltered with accessible onsite laundry services. The body louse prefers temperatures ranging from 84°F to 90°F, but cannot survive when the temperature exceeds 122°F.^8,21 Hot laundering of clothing and bedding will successfully kill body lice, but unheated water sources used among PEH sleeping outdoors will not. Additionally, unsheltered participants report showering or bathing less frequently than those with onsite shower facilities at overnight shelters.

Five cases were identified during months of May–September, although body lice are typically more prevalent during colder months.³ While state-issued stay-at-home orders have been associated with a decrease in cases of COVID-19, they have also been shown to have some negative impacts on mental, physical, and financial health.^22–25 The COVID-19 pandemic and Colorado’s stay-at-home orders (issued in March 2020) decreased access to PEH resources in Denver, which might have led to increased body lice and B. quintana transmission among this population. Approximately three quarters of participants reported experiencing negative changes to essential hygienic resources during the COVID-19 lockdown in Denver, regardless of where they typically slept.

Colorado Department of Public Health and Environment collaborated with local PEH coalitions and initiatives, local public health agencies, local hospitals and clinicians, and shelter administrative staff. Shelter staff were provided educational materials to give to PEH regarding body lice, B. quintana infection, prevention methods, and locations to access medical care should they obtain body lice or experience symptoms consistent with B. quintana infection. Educational materials and handouts regarding body lice prevention, B. quintana symptom recognition, medical treatment, and complications, and PEH hygienic service locations were provided to PEH encountered during site visits and interviews. Additionally, food or beverage items and socks were also offered. Healthcare providers who routinely serve Denver’s PEH population received HAN notifications providing diagnostic and treatment information for B. quintana and body lice infestation, and instructions to report suspect B. quintana patients with recent body lice exposure. Shelter and day center staff were educated on body lice prevention in their facilities and all efforts were coordinated with local coalition groups to continue outreach beyond the interview period.

This investigation was subject to several limitations. Body lice exposure was self-reported during the interview questionnaire after providing participants with a photo and description of the human body louse; subjective identification might have resulted in inaccurate body lice exposure reporting. Second, community efforts were limited to the shelters and encampments CDPHE’s investigative team was able to visit in the specified time frame. Denver has many shelters and encampments (some mobile), and the only locations visited by the investigative team were those where a confirmed or probable B. quintana patient had previously spent time. Categorization of participant sleep location was limited by the combined group of those who sleep both sheltered and unsheltered; this group’s interviews contained robust data, but they were ultimately unable to be properly categorized in a true comparison group due to lack of information regarding the amount of time spent sheltered versus unsheltered. The combined sheltered and unsheltered participant group is unique and provides an opportunity for future PEH research. Additionally, we were unable to quantify the number of PEH who declined to be interviewed. Some PEH were congregated into groups while interviews were conducted and occasionally an individual would decline on behalf of an entire group, or interviewers would decide not to approach certain groups. The study results may contain some bias due to the willingness of the interview participants to speak with interviewers.

Community outreach efforts helped increase awareness and understanding of body lice risk and transmission among PEH in Denver. Typically, overnight shelters offer access to laundry and shower facilities for PEH who stay there and shelter administration should prioritize body lice mitigation activities to reduce transmission among their patrons. Major metropolitan areas should include essential PEH services or allocate alternative hygienic services in preparedness and response plans for future pandemics, major events, and natural disasters to prevent vector-borne transmission of B. quintana and associated outbreaks.