Frequency and Geographic Distribution of Borrelia miyamotoi, Borrelia burgdorferi, and Babesia microti Infections in New England Residents.

BACKGROUND: Borrelia miyamotoi is a relapsing fever spirochete that relatively recently has been reported to infect humans. It causes an acute undifferentiated febrile illness that can include meningoencephalitis and relapsing fever. Like Borrelia burgdorferi, it is transmitted by Ixodes scapularis ticks in the northeastern United States and by Ixodes pacificus ticks in the western United States. Despite reports of clinical cases from North America, Europe, and Asia, the prevalence, geographic range, and pattern of expansion of human B. miyamotoi infection are uncertain. To better understand these characteristics of B. miyamotoi in relation to other tickborne infections, we carried out a cross-sectional seroprevalence study across New England that surveyed B. miyamotoi, B. burgdorferi, and Babesia microti infections. METHODS: We measured specific antibodies against B. miyamotoi, B. burgdorferi, and B. microti among individuals living in 5 New England states in 2018. RESULTS: Analysis of 1153 serum samples collected at 11 catchment sites showed that the average seroprevalence for B. miyamotoi was 2.8% (range, 0.6%-5.2%), which was less than that of B. burgdorferi (11.0%; range, 6.8%-15.6%) and B. microti (10.0%; range, 6.5%-13.6%). Antibody screening within county residence in New England showed varying levels of seroprevalence for these pathogens but did not reveal a vectoral geographical pattern of distribution. CONCLUSIONS: Human infections caused by B. miyamotoi, B. burgdorferi, and B. microti are widespread with varying prevalence throughout New England.

Neighborhood Social Cohesion and Inequalities in COVID-19 Diagnosis Rates by Area-Level Black/African American Racial Composition.

Geographic inequalities in COVID-19 diagnosis are now well documented. However, we do not sufficiently know whether inequalities are related to social characteristics of communities, such as collective engagement. We tested whether neighborhood social cohesion is associated with inequalities in COVID-19 diagnosis rate and the extent the association varies across neighborhood racial composition. We calculated COVID-19 diagnosis rates in Philadelphia, PA, per 10,000 general population across 46 ZIP codes, as of April 2020. Social cohesion measures were from the Southeastern Pennsylvania Household Health Survey, 2018. We estimated Poisson regressions to quantify associations between social cohesion and COVID-19 diagnosis rate, testing a multiplicative interaction with Black racial composition in the neighborhood, which we operationalize via a binary indicator of ZIP codes above vs. below the city-wide average (41%) Black population. Two social cohesion indicators were significantly associated with COVID-19 diagnosis. Associations varied across Black neighborhood racial composition (p <0.05 for the interaction test). In ZIP codes with ≥41% of Black people, higher collective engagement was associated with an 18% higher COVID-19 diagnosis rate (IRR=1.18, 95%CI=1.11, 1.26). In contrast, areas with <41% of Black people, higher engagement was associated with a 26% lower diagnosis rate (IRR=0.74, 95%CI=0.67, 0.82). Neighborhood social cohesion is associated with both higher and lower COVID-19 diagnosis rates, and the extent of associations varies across Black neighborhood racial composition. We recommend some strategies for reducing inequalities based on the segmentation model within the social cohesion and public health intervention framework.

Immune Control in Repeated Babesia microti Infection in a Patient With B-Cell Deficiency.

The immunology of human babesiosis is poorly investigated. We present a comprehensive investigation of a 75-year-old man with B-cell deficiency who experienced 3 episodes of babesiosis over a 6-year period. Slowly evolving clinical immunity was observed, as evidenced by milder clinical symptoms and lower peak parasite burden after each subsequent babesiosis episode. The patient exhibited several striking immunologic findings. First, the patient had exceptionally high Babesia microti-specific antibodies despite very few circulating B cells, which predominantly coexpressed CD27 (memory marker) and CD95 (death receptor). Second, we demonstrated the presence of long-lasting NK cells and expansion of T memory stem cells. Third, levels of the IP-10 cytokine directly correlated with parasite burden. These results raise fundamental questions on the priming, maintenance, and location of a B-cell population that produces high antibody levels in the face of severe B-cell deficiency. Our results should invoke interest among researchers to study the immunology and pathogenesis of human babesiosis.