Development and validation of a cryogenic far-infrared diffraction grating spectrometer used to post-disperse the output from a Fourier transform spectrometer.

Recent advances in far-infrared detector technology have led to increases in raw sensitivity of more than an order of magnitude over previous state-of-the-art detectors. With such sensitivity, photon noise becomes the dominant noise component, even when using cryogenically cooled optics, unless a method of restricting the spectral bandpass is employed. The leading instrument concept features reflecting diffraction gratings, which post-disperse the light that has been modulated by a polarizing Fourier transform spectrometer (FTS) onto a detector array, thereby reducing the photon noise on each detector. This paper discusses the development of a cryogenic (4 K) diffraction grating spectrometer that operates over the wavelength range of 285 to 500 µm and was used to post-disperse the output from a room-temperature polarizing FTS. Measurements of the grating spectral response and diffraction efficiency are presented as a function of both wavelength and polarization to characterize the instrumental performance.

Decision Factors for Glaucoma Suspects and Ocular Hypertensive Treatment at an Academic Center.

Aims and background: Practice guidelines assert that high-risk glaucoma suspects should be treated. Yet, there is ambiguity regarding what constitutes a high enough risk for treatment. The purpose of this study was to determine which factors contribute to the decision to treat glaucoma suspects and ocular hypertensive patients in an academic ophthalmology practice. Materials and methods: Retrospective cohort study of glaucoma suspects or ocular hypertensives at an academic ophthalmology practice from 2014 to 2020. Demographics, comorbidities, intraocular pressure (IOP), optical coherence tomography (OCT) findings, and visual field measurements were compared between treated and untreated patients. A multivariable logistic regression model assessed predictors of glaucoma suspected treatment. Results: Of the 388 patients included, 311 (80%) were untreated, and 77 (20%) were treated. There was no statistical difference in age, race/ethnicity, family history of glaucoma, central corneal thickness (CCT), or any visual field parameters between the two groups. Treated glaucoma suspects had higher IOP, thinner retinal nerve fiber layers (RNFL), more RNFL asymmetry, thinner ganglion cell-inner plexiform layers (GCIPL), and a higher prevalence of optic disc drusen, disc hemorrhage, ocular trauma, and proliferative diabetic retinopathy (PDR) (p < 0.05 for all). In the multivariable model, elevated IOP {odds ratio [OR] 1.16 [95% confidence interval (CI) 1.04-1.30], p = 0.008}, yellow temporal [5.76 (1.80-18.40), p = 0.003] and superior [3.18 (1.01-10.0), p = 0.05] RNFL quadrants, and a history of optic disc drusen [8.77 (1.96-39.34), p = 0.005] were significant predictors of glaucoma suspect treatment. Conclusion: Higher IOP, RNFL thinning, and optic disc drusen were the strongest factors in the decision to treat a glaucoma suspect or ocular hypertensive patient. RNFL asymmetry, GCIPL thinning, and ocular comorbidities may also factor into treatment decisions. Clinical significance: Understanding the clinical characteristics that prompt glaucoma suspect treatment helps further define glaucoma suspect disease status and inform when treatment should be initiated. How to cite this article: Ciociola EC, Anderson A, Jiang H, et al. Decision Factors for Glaucoma Suspects and Ocular Hypertensive Treatment at an Academic Center. J Curr Glaucoma Pract 2023;17(3):157-165.

Longitudinal assessment of SARS-CoV-2 IgG seroconversionamong front-line healthcare workers during the first wave of the Covid-19 pandemic at a tertiary-care hospital in Chile.

BACKGROUND: Healthcare workers (HCWs) are at high risk of exposure to SARS-CoV-2. Cross-sectional studies have provided variable rates of seroprevalence in HCWs. Longitudinal assessments of the serological response to Covid-19 among HCWs are crucial to understanding the risk of infection and changes in antibody titers over time. We aimed to investigate seroprevalence and risk factors associated with seroconversion in a prospective cohort of HCWs during the peak of the first wave of the Covid-19 pandemic. METHODS: We conducted a longitudinal study among 446 front-line HCWsin a tertiary-care hospital in Chile from April to July 2020. IgG was determined monthly using two different ELISAs in serum samples of HCWs, during the three-month period. In each visit, demographic data, symptoms, risk factors, and exposure risks were also assessed. RESULTS: The overall seroprevalence at the end of the study period was 24% (95% CI20.2-28.3), with 43% of seropositive HCWs reporting no prior symptoms. Seroconversion rates significantly differed over the study period, from 2.1% to as high as 8.8% at the peak of the epidemic. There were no statistically significant differences observed between HCWs in direct clinical care of patients with Covid-19 and those working in low risk areas. Antibody titers appeared to wane over time. CONCLUSIONS: HCWs were severely affected with a high rate of seroconversion that appeared to mirror the local epidemiological situation. A significant amount of participants underwent an asymptomatic infection, highlighting the need for improved surveillance policies. Antibody titers appear to wane over time; further studies to understand this finding's impact on the risk of reinfection are warranted.

Superwomen and Sleep: an Assessment of Black College Women Across the African Diaspora.

BACKGROUND: Women and racial/ethnic minority groups in the U.S. report poor sleep health. While stress and alcohol use may contribute to sleep problems, few studies have examined the roles of stress and alcohol use on sleep among Black college women. Gender-racial ideology of Black womanhood may also play a role in sleep. This exploratory study sought to examine the relationships between stress, alcohol, ethnic-gender identity, and sleep. METHOD: Guided by the biopsychosocial model and intersectionality theory, a cross-sectional study design recruited undergraduate women (18-24 years) attending a Historically Black College and University (HBCU) who self-identified as Black (N = 110). Participants completed the Insomnia Severity Index, Pittsburgh Sleep Quality Index, Perceived Stress Scale, Alcohol Use Disorders Test, and Giscombe Superwoman Schema Questionnaire. Univariate and multiple linear regressions were conducted to examine independent and multiple effects of stress, alcohol, and ethnic-gender identity on insomnia and sleep quality. RESULTS: Participants (mean age 19.4 years) represented diverse ethnic groups, 53% American, 25% African, and 20% Caribbean. Nearly 23% reported moderate to severe levels of insomnia. Scores from the Perceived Stress Scale, the Alcohol Use Disorders Test, and the Giscombe Superwoman Schema Questionnaire were independently associated with insomnia and sleep quality. In multivariate analyses, only perceived stress exhibited a significant association with insomnia and sleep quality. CONCLUSION: This exploratory study demonstrated that stress, excessive alcohol use, and ethnic-gender identity have relational impact on sleep health. Yet, stress may have greater importance and further research is needed to explore factors that mediated the relationship between stress and sleep.

Life vs Loans: Does Debt Affect Career Satisfaction in Osteopathic Graduates?

BACKGROUND: The cost of undergraduate osteopathic medical education continues to grow. It is important to understand how the rising cost of matriculation negatively affects training and career satisfaction of entering students. OBJECTIVE: To better understand any association between level of educational debt and satisfaction with osteopathic medical education, career choice, and financial services. METHODS: Responses were analyzed from the American Association of Colleges of Osteopathic Medicine survey of pending medical school graduates from 2007 through 2016 regarding indebtedness and specialty selection. RESULTS: From 2007 to 2016, the mean educational debt level at graduation rose consistently among osteopathic graduates (from $155,698 to $240,331, respectively). In all years, there was no significant effect of debt quartile on satisfaction with choice of osteopathic medicine as a career. Quartile variable with debt did not show a significant effect on satisfaction with education experience in 2010, 2013, and 2016. Top quartile debt was associated with higher satisfaction with financial service departments in all years. CONCLUSION: Although debt has consistently increased for osteopathic medical graduates, it does not affect their satisfaction with either their educational experience or their choice of osteopathic medicine as a career.

Loss of Elongation-Like Factor 1 Spontaneously Induces Diverse, RNase H-Related Suppressor Mutations in Schizosaccharomyces pombe.

A healthy individual may carry a detrimental genetic trait that is masked by another genetic mutation. Such suppressive genetic interactions, in which a mutant allele either partially or completely restores the fitness defect of a particular mutant, tend to occur between genes that have a confined functional connection. Here we investigate a self-recovery phenotype in Schizosaccharomyces pombe, mediated by suppressive genetic interactions that can be amplified during cell culture. Cells without Elf1, an AAA+ family ATPase, have severe growth defects initially, but quickly recover growth rates near to those of wild-type strains by acquiring suppressor mutations. elf1Δ cells accumulate RNAs within the nucleus and display effects of genome instability such as sensitivity to DNA damage, increased incidence of lagging chromosomes, and mini-chromosome loss. Notably, the rate of phenotypic recovery was further enhanced in elf1Δ cells when RNase H activities were abolished and significantly reduced upon overexpression of RNase H1, suggesting that loss of Elf1-related genome instability can be resolved by RNase H activities, likely through eliminating the potentially mutagenic DNA-RNA hybrids caused by RNA nuclear accumulation. Using whole genome sequencing, we mapped a few consistent suppressors of elf1Δ including mutated Cue2, Rpl2702, and SPBPJ4664.02, suggesting previously unknown functional connections between Elf1 and these proteins. Our findings describe a mechanism by which cells bearing mutations that cause fitness defects and genome instability may accelerate the fitness recovery of their population through quickly acquiring suppressors. We propose that this mechanism may be universally applicable to all microorganisms in large-population cultures.

A Whooping Cough Education Module for WIC Clients in Utah.

BACKGROUND: Clients in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) are required to complete education modules quarterly to maintain eligibility. The purposes of this project were to: (1) create a whooping cough vaccination education module for WIC clients; (2) evaluate baseline perceptions of WIC clients on the whooping cough vaccine and disease; and (3) evaluate whooping cough knowledge following completion of the module. PROBLEM: A decline in vaccination rates among infants and children using WIC services was reported by a local WIC program director who requested whooping cough vaccination education materials. This quality improvement project included development of a whooping cough education module and evaluation of learning. METHODS: Learning was evaluated using a pre- and posttest design. Client feedback was solicited via open-ended questions. Quantitative analysis was performed on visual analog-type questions with paired t-tests and a Cohen's d. Content analysis was conducted on open-ended items. INTERVENTIONS: The module was designed by a team of vaccination experts and included general definitions, signs and symptoms during the three stages of disease, recommendations to prevent whooping cough, and vaccination recommendations. Learning of users of the module was then evaluated. RESULTS: After using the module, clients indicated they were significantly more likely to vaccinate themselves and their child against whooping cough, and to recommend the vaccination to their family members. The greatest concern of participants about whooping cough was how it affected infants. Participants reported they learned new information on disease seriousness, recognition of symptoms, and treatment options but still requested additional information on the whooping cough disease and vaccine. CONCLUSIONS: A whooping cough education module is an effective strategy to improve whooping cough knowledge and promote the whooping cough vaccine.

Prime Time Sister Circles(®)II: Evaluating a Culturally Relevant Intervention to Decrease Psychological and Physical Risk Factors for Chronic Disease in Mid-Life African American Women.

PURPOSE: This article presents the results of two evaluation studies of the Prime Time Sister Circles(®) (PTSC). The PTSC is a gender, cultural, and age specific, curriculum-based, low-cost, short-term, replicable support group approach aimed at reducing key modifiable health risk factors for chronic illnesses in midlife African American women. METHODS: Study 1 includes an evaluation of 31 PTSCs (N=656 women) documenting changes in psychological and attitudinal outcomes (health satisfaction, health locus of control), behavioral outcomes (healthy eating patterns, physical activity, stress management), and clinical outcomes (weight, BMI, blood pressure, non-fasting blood sugar). Study 2 includes evaluation of a subset of the PTSC sites (N=211 women) with comparison (N=55 women) data from those same locations. RESULTS: Study 1 showed significant changes (p<.0001) in the PTSC women's reports of (lower) stress, (higher) health locus of control, (increased) health satisfaction, (increased) physical activity, and (healthier) eating patterns. The PTSC women demonstrated a significant weight reduction at posttest (p <.0001) and had slightly better clinical outcomes in BMI, hypertension, and non-fasting blood sugar. Results document the sustainability of selected changes over a six-month period. Findings from the Study 2 strengthen the effectiveness claims of the PTSC intervention with significant changes for the PTSC women on selected outcomes and little changes for the comparison women. CONCLUSIONS: Results reaffirm findings regarding the effectiveness of the PTSC, as originally reported in Gaston, Porter, and Thomas (2007) and extends the credibility of findings by examining participants' clinical outcomes in addition to self-reports.

Coxiella burnetii Infection in a Community Operating a Large-Scale Cow and Goat Dairy, Missouri, 2013.

Coxiella burnetii is a zoonotic pathogen that causes Q fever in humans and is transmitted primarily from infected goats, sheep, or cows. Q fever typically presents as an acute febrile illness; however, individuals with certain predisposing conditions, including cardiac valvulopathy, are at risk for chronic Q fever, a serious manifestation that may present as endocarditis. In response to a cluster of Q fever cases detected by public health surveillance, we evaluated C. burnetii infection in a community that operates a large-scale cow and goat dairy. A case was defined as an individual linked to the community with a C. burnetii phase II IgG titer ≥ 128. Of 135 participants, 47 (35%) cases were identified. Contact with or close proximity to cows, goats, and their excreta was associated with being a case (relative risk 2.7, 95% confidence interval 1.3-5.3). Cases were also identified among individuals without cow or goat contact and could be related to windborne spread or tracking of C. burnetii on fomites within the community. A history of injection drug use was reported by 26/130 (20%) participants; follow-up for the presence of valvulopathy and monitoring for development of chronic Q fever may be especially important among this population.

Epizootiological investigation of a Q fever outbreak and implications for future control strategies.

OBJECTIVE: To describe the epizootiological investigation of an outbreak of Q fever (Coxiella burnetii infection). DESIGN: Epidemiological study. ANIMALS: 17 goat herds in Washington, Montana, and Oregon. PROCEDURES: In April 2011, an abortion storm at a commercial goat farm in Washington was determined to be caused by C burnetii. A joint epidemiological investigation by public health and veterinary professionals was subsequently performed to assess the extent of the outbreak by performing a trace-forward of goats sold from the index farm, to determine risk factors associated with infection, and to implement control measures. A herd management plan was developed to control the outbreak and reduce risk of human exposure. Quarantine and temporary holds preventing the sale or movement of goats allowed time for trace-forward investigation, education of farmers regarding disease risk, and testing to determine the scope of the outbreak. RESULTS: 17 farms were affected; 21 human Q fever cases were identified. Bacterial shedding in feces, vaginal fluid, or milk was confirmed in 156 of 629 (25%) goats tested by PCR assay. Seroprevalence of antibodies against C burnetii in goats, determined by ELISA, was 12%. The risk for C burnetii infection in goats was highest among females, those on farms associated with human Q fever, and those on Washington farms. A protective effect was observed for goats at farms where the primary form of goat carcass disposal was burial. CONCLUSIONS AND CLINICAL RELEVANCE: This outbreak illustrated the importance of a joint investigation for zoonotic pathogens and the need to expand and strengthen relationships between medical, public health, and veterinary partners. Heightened awareness and enhanced veterinary diagnostic capabilities for C burnetii are needed to identify and control outbreaks expediently.

A plan for community event-based surveillance to reduce Ebola transmission - Sierra Leone, 2014-2015.

Ebola virus disease (Ebola) was first detected in Sierra Leone in May 2014 and was likely introduced into the eastern part of the country from Guinea. The disease spread westward, eventually affecting Freetown, Sierra Leone's densely populated capital. By December 2014, Sierra Leone had more Ebola cases than Guinea and Liberia, the other two West African countries that have experienced widespread transmission. As the epidemic intensified through the summer and fall, an increasing number of infected persons were not being detected by the county's surveillance system until they had died. Instead of being found early in the disease course and quickly isolated, these persons remained in their communities throughout their illness, likely spreading the disease.

Q fever in the United States: summary of case reports from two national surveillance systems, 2000-2012.

Q fever is a worldwide zoonosis historically associated with exposure to infected livestock. This study summarizes cases of Q fever, a notifiable disease in the United States, reported to the Centers for Disease Control and Prevention through two national surveillance systems with onset during 2000-2012. The overall incidence rate during this time was 0.38 cases per million persons per year. The reported case fatality rate was 2.0%, and the reported hospitalization rate was 62%. Most cases (61%) did not report exposure to cattle, goats, or sheep, suggesting that clinicians should consider Q fever even in the absence of livestock exposure. The prevalence of drinking raw milk among reported cases of Q fever (8.4%) was more than twice the national prevalence for the practice. Passive surveillance systems for Q fever are likely impacted by underreporting and underdiagnosis because of the nonspecific presentation of Q fever.

First reported multistate human Q fever outbreak in the United States, 2011.

In April, 2011, the Q fever bacterium Coxiella burnetii was identified at a Washington farm where an abortion storm took place among goats. Soon after, Q fever cases were reported among visitors to the farm from Washington and Montana. A cross-sectional investigation was conducted among humans and goats associated with the index farm or with 16 other farms that purchased goats from the index farm or housed goats at the index farm for breeding purposes. Questionnaire data were analyzed, along with human and goat specimens collected for evidence of C. burnetii infection. Twenty-one persons (19%) of the 109-person cohort from Washington and Montana met the outbreak case definition of an epidemiologic link to the index farm and a C. burnetii Phase II immunoglobulin G (IgG) titer ≥1:128 by immunofluorescence assay. Seventy-one percent of cases (15 of 21) were symptomatic, compared with approximately 50% during previous Q fever outbreaks. National Q fever surveillance reports increase in frequency with age, but 29% (6 of 21) of cases during this outbreak occurred in children aged <14 years. Goat-specific Q fever risk factors included direct contact with a newborn (prevalence ratio [PR] 10.7; confidence interval [CI] 1.5, 77.4), exposure to a newborn that died (PR 5.5; CI 1.7, 18.2), exposure to a weak newborn (PR 4.4; CI 1.7, 11.6), living on a property with goats (PR 4.2; CI 1.3, 13.9), and direct contact with birth/afterbirth products (PR 2.8; CI 1.1, 6.9). Evidence of C. burnetii infection was detected in all 17 goat herds sampled (13 Washington, 3 Montana, 1 Oregon) by PCR and/or enzyme-linked immunosorbent assay. Following this investigation, Washington and Montana implemented a herd management plan to encourage best-management practices among livestock owners, reduce the potential for future outbreaks, and promote continued communication between state public health and agricultural authorities.

Diagnosis and management of Q fever--United States, 2013: recommendations from CDC and the Q Fever Working Group.

Q fever, a zoonotic disease caused by the bacterium Coxiella burnetii, can cause acute or chronic illness in humans. Transmission occurs primarily through inhalation of aerosols from contaminated soil or animal waste. No licensed vaccine is available in the United States. Because many human infections result in nonspecific or benign constitutional symptoms, establishing a diagnosis of Q fever often is challenging for clinicians. This report provides the first national recommendations issued by CDC for Q fever recognition, clinical and laboratory diagnosis, treatment, management, and reporting for health-care personnel and public health professionals. The guidelines address treatment of acute and chronic phases of Q fever illness in children, adults, and pregnant women, as well as management of occupational exposures. These recommendations will be reviewed approximately every 5 years and updated to include new published evidence.

Presence and persistence of Coxiella burnetii in the environments of goat farms associated with a Q fever outbreak.

Q fever is a zoonotic disease caused by inhalation of the bacterium Coxiella burnetii. Ruminant livestock are common reservoirs for C. burnetii, and bacteria present in aerosols derived from the waste of infected animals can infect humans. The significance of infection from material deposited in the environment versus transmission directly from infected animals is not known. In 2011, an outbreak of Q fever cases on farms in Washington and Montana was associated with infected goats. A study was undertaken to investigate the quantity and spatial distribution of C. burnetii in the environment of these goat farms. Soil, vacuum, and sponge samples collected on seven farms epidemiologically linked to the outbreak were tested for the presence of C. burnetii DNA by quantitative PCR. Overall, 70.1% of the samples were positive for C. burnetii. All farms had positive samples, but the quantity of C. burnetii varied widely between samples and between farms. High quantities of C. burnetii DNA were in goat housing/birthing areas, and only small quantities were found in samples collected more than 50 m from these areas. Follow-up sampling at one of the farms 1 year after the outbreak found small quantities of C. burnetii DNA in air samples and large quantities of C. burnetii persisting in soil and vacuum samples. The results suggest that the highest concentrations of environmental C. burnetii are found in goat birthing areas and that contamination of other areas is mostly associated with human movement.

Clinician assessment for Coxiella burnetii infection in hospitalized patients with potentially compatible illnesses during Q fever outbreaks and following a health alert, Montana, 2011.

BACKGROUND: Coxiella burnetii is an endemic bacterial pathogen in the United States and the causative agent of Q fever. Two outbreaks of Q fever occurred in Montana during 2011, which led to the issuance of a health alert urging clinicians to test patients with Q fever-compatible illnesses for C. burnetii infection. METHODS: We retrospectively evaluated the medical records of patients hospitalized for fever, pneumonia, chest pain, and viral infection of unknown etiologies during the two Q fever outbreaks and following the health alert. RESULTS: A total of 103 patients were included in the analysis. Clinicians assessed<1% of patients suffering illnesses compatible with Q fever for known risk factors or C. burnetii infection. Only 1 patient had Q fever excluded as a diagnosis. CONCLUSION: Clinicians should assess for Q fever risk factors and consider the diagnosis in patients hospitalized with Q fever-compatible illnesses when the etiology of illness is unknown. Work is warranted to evaluate the effectiveness of current healthcare alert practices for zoonotic diseases.

Q Fever with unusual exposure history: a classic presentation of a commonly misdiagnosed disease.

We describe the case of a man presumptively diagnosed and treated for Rocky Mountain spotted fever following exposure to multiple ticks while riding horses. The laboratory testing of acute and convalescent serum specimens led to laboratory confirmation of acute Q fever as the etiology. This case represents a potential tickborne transmission of Coxiella burnetii and highlights the importance of considering Q fever as a possible diagnosis following tick exposures.

A case of person-to-person transmission of Q fever from an active duty serviceman to his spouse.

Coxiella burnetii has recently gained military relevance given its potential as a bioterrorism agent, and the multiple cases reported among U.S. military personnel deployed to the Middle East. Sexual transmission of Q fever is rare but has been reported in the literature. We describe the possible sexual transmission of Q fever from a returning serviceman from Iraq to his wife. In a recent editorial commentary, Dr. Raoult wrote about the reemergence of Q fever after September 11, 2001 (Raoult 2009). Indeed, C. burnetii has gained military relevance given its potential as a bioterrorism agent and the multiple cases reported among military personnel deployed in Southwest/Central Asia and North Africa (Botros et al. 1995 , Meskini et al. 1995 , Leung-Shea and Danaher 2006 ). Human serosurveys in these geographic areas have reported prevalence rates for Q fever ranging from 10% to 37% in contrast to the United States, which has an estimated Q fever seroprevalence of 3.1% (Botros et al. 1995, Meskini et al. 1995, Anderson et al. 2009). There is no data available for Q fever seroprevalence in Iraq. As a consequence, native populations in these regions may be more likely to possess immunity, and newcomers, such as U.S. military personnel, would be vulnerable to acute infection (Derrick 1973). We report on the possible sexual transmission of C. burnetii from a serviceman in the late recovery of acute Q fever to his wife.

Seroprevalence of Q fever in the United States, 2003-2004.

We performed serum testing for IgG antibodies against Coxiella burnetii (phase I and phase II) and analyzed questionnaire data from 4,437 adults > or = 20 years of age who participated in the National Health and Nutrition Examination Survey 2003-2004 survey cycle. National Q fever seroprevalence was determined by enzyme-linked immunosorbent assay and confirmed by using immunofluorescent antibody testing. Overall seroprevalence for Coxiella burnetii was 3.1% (95% confidence interval [CI] = 2.1-4.3%) among 4,437 adults > or = 20 years of age. Coxiella burnetii age-adjusted antibody prevalence was higher for men than for women (3.8%, 95% CI = 2.7-5.2% versus 2.5%, 95% CI = 1.5-3.7%, respectively, P < 0.05). Mexican Americans had a significantly higher antibody prevalence (7.4%, 95% CI = 6.6-8.3%) than either non-Hispanic whites (2.8%, 95% CI = 1.7-4.3%) or non-Hispanic blacks (1.3%, 95% CI = 0.6-2.5%) (P < 0.001). Multivariate analysis showed that the risk for Q fever antibody positivity increased with age and was higher among persons who were foreign-born, male, and living in poverty. These findings indicate that the national seroprevalence of Q fever in the United States is higher than expected on the basis of case numbers reported to the Centers for Disease Control and Prevention from state health departments. Potential differences in risk for exposure by race/ethnicity warrant further study.

Cluster of sylvatic epidemic typhus cases associated with flying squirrels, 2004-2006.

In February 2006, a diagnosis of sylvatic epidemic typhus in a counselor at a wilderness camp in Pennsylvania prompted a retrospective investigation. From January 2004 through January 2006, 3 more cases were identified. All had been counselors at the camp and had experienced febrile illness with myalgia, chills, and sweats; 2 had been hospitalized. All patients had slept in the same cabin and reported having seen and heard flying squirrels inside the wall adjacent to their bed. Serum from each patient had evidence of infection with Rickettsia prowazekii. Analysis of blood and tissue from 14 southern flying squirrels trapped in the woodlands around the cabin indicated that 71% were infected with R. prowazekii. Education and control measures to exclude flying squirrels from housing are essential to reduce the likelihood of sylvatic epidemic typhus.