Changes in Severe Acute Respiratory Syndrome Coronavirus 2 Seroprevalence Over Time in 10 Sites in the United States, March-August, 2020.

BACKGROUND: Monitoring of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody prevalence can complement case reporting to inform more accurate estimates of SARS-CoV-2 infection burden, but few studies have undertaken repeated sampling over time on a broad geographic scale. METHODS: We performed serologic testing on a convenience sample of residual serum obtained from persons of all ages, at 10 sites in the United States from 23 March through 14 August 2020, from routine clinical testing at commercial laboratories. We standardized our seroprevalence rates by age and sex, using census population projections and adjusted for laboratory assay performance. Confidence intervals were generated with a 2-stage bootstrap. We used bayesian modeling to test whether seroprevalence changes over time were statistically significant. RESULTS: Seroprevalence remained below 10% at all sites except New York and Florida, where it reached 23.2% and 13.3%, respectively. Statistically significant increases in seroprevalence followed peaks in reported cases in New York, South Florida, Utah, Missouri, and Louisiana. In the absence of such peaks, some significant decreases were observed over time in New York, Missouri, Utah, and Western Washington. The estimated cumulative number of infections with detectable antibody response continued to exceed reported cases in all sites. CONCLUSIONS: Estimated seroprevalence was low in most sites, indicating that most people in the United States had not been infected with SARS-CoV-2 as of July 2020. The majority of infections are likely not reported. Decreases in seroprevalence may be related to changes in healthcare-seeking behavior, or evidence of waning of detectable anti-SARS-CoV-2 antibody levels at the population level. Thus, seroprevalence estimates may underestimate the cumulative incidence of infection.

Comparison of Estimated Severe Acute Respiratory Syndrome Coronavirus 2 Seroprevalence Through Commercial Laboratory Residual Sera Testing and a Community Survey.

We compared severe acute respiratory syndrome coronavirus 2 seroprevalence estimated from commercial laboratory residual sera and a community household survey in metropolitan Atlanta during April and May 2020 and found these 2 estimates to be similar (4.94% vs 3.18%). Compared with more representative surveys, commercial sera can provide an approximate measure of seroprevalence.

Knowledge and practices related to louse- and flea-borne diseases among staff providing services to people experiencing homelessness in the United States.

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.

Knowledge, Attitudes, and Practices on Rocky Mountain Spotted Fever among Physicians in a Highly Endemic Region-Mexicali, Mexico.

Rocky Mountain spotted fever (RMSF) is a potentially fatal tickborne disease caused by the bacterium, Rickettsia rickettsii and transmitted primarily by the brown dog tick (Rhipicephalus sanguineus) in the southwestern United States and Mexico. RMSF can be rapidly fatal if not treated early with doxycycline, making healthcare worker awareness and education critical to reduce morbidity and mortality. During 2008-2019, Mexicali experienced a RMSF epidemic with 779 confirmed cases, and an 11-year case-fatality rate of 18% (N = 140). A cross-sectional study was conducted with 290 physicians and physicians-in-training across 12 medical facilities in Mexicali. They were asked to complete a 23-item questionnaire to assess knowledge, attitudes, and practices for clinical, epidemiologic, and preventive aspects of RMSF. Half of participants were female, the largest age group was aged 25 to 44 (47%), and median time in practice was 6 years (interquartile rate: 1-21.5). Less than half (48%) surveyed were confident where diagnostic testing could be performed, and two-thirds did not regularly order serology (67%) or molecular diagnostic (66%) tests for RMSF when a patient presented with fever. Sixty-four percent knew doxycycline as first-line treatment of children < 8 years with suspected RMSF. When comparing healthcare workers with < 6 years of experience to those with ≥ 6 years, more experience was associated with greater confidence in where to have diagnostic testing performed (prevalence odds ratio [prevalence odds ratios [pOR]] = 2.3; P = 0.004), and frequency of ordering laboratory tests (serology, pOR = 3.3; P = 0.002; polymerase chain reaction, pOR = 3.9; P = 0.001). Continued education, including information on diagnostic testing is key to reducing morbidity and mortality from RMSF.

Acute and chronic Q fever national surveillance - United States, 2008-2017.

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii and can manifest in an acute or chronic form. Many persons with acute Q fever are asymptomatic, but some develop a febrile illness, pneumonia or hepatitis. Chronic infections are rare and occur in less than 5% of persons exposed. Forms of chronic Q fever include endocarditis, infection of vascular grafts or aneurysms, osteomyelitis and osteoarthritis. Acute and chronic Q fever are nationally notifiable diseases, and presented here are the incidence, demographics and distribution of acute and chronic Q fever in the United States during 2008-2017. We summarized passive surveillance data from the Centers for Disease Control and Prevention's (CDC) National Notifiable Diseases Surveillance System (NNDSS) and supplemental case report forms (CRFs). Health departments reported 1,109 cases of acute Q fever and 272 chronic Q fever cases to NNDSS during this period. The 10-year average annual incidence for acute Q fever was 0.36 cases per million persons, and the average annual incidence for chronic Q fever was 0.09. Males accounted for nearly 75% of both acute and chronic Q fever cases. Average annual incidence was highest among persons aged 60-69 years for both acute and chronic Q fever (0.70 cases per million persons and 0.25, respectively). As reported through CRFs, many Q fever cases did not have a known exposure to C. burnetii; 60% (n = 380) of acute Q fever cases did not report exposure to animals in the 2 months before symptom onset. Almost 90% (n = 558) did not report exposure to unpasteurized milk. Only 40% (n = 247) of persons with reported Q fever were employed in high-risk occupations. Even though Q fever is a rare disease in the United States, incidence doubled from 2008 to 2017.