Human interactions with bats and bat coronaviruses in rural Côte d'Ivoire.

Bats are presumed reservoirs of diverse α- and ß- coronaviruses (CoVs) and understanding the diversity of bat-CoVs and the role bats play in CoV transmission is highly relevant in the context of the current COVID pandemic. We sampled bats in Côte d'Ivoire (2016-2018) living at ecotones between anthropogenic and wild habitats in the Marahoué National Park, a recently encroached protected area, to detect and characterize the CoVs circulating in bats and humans. A total of 314 bats were captured, mostly during the rainy season (78%), and CoV RNA was detected in three of the bats (0.96%). A CoV RNA sequence similar to Chaerephon bat coronavirus/Kenya/KY22/2006 (BtKY22) was found in a Chaerephon cf. pumilus and a Mops sp. fecal swab, while a CoV RNA sequence similar to the two almost identical Kenya bat coronaviruses BtKY55 and BtKY56 (BtKY55/56) was detected in an Epomops buettikoferi oral swab. Phylogenetic analyses indicated differences in the degree of evolutionary host-virus co-speciation for BtKY22 and BtKY55/56. To assess potential for human exposure to these viruses, we conducted human syndromic and community-based surveillance in clinics and high-risk communities. We collected data on participant characteristics, livelihoods, animal contact, and high-risk behaviors that may be associated with exposure to zoonotic diseases. We then collected biological samples for viral testing from 401 people. PCR testing of these biological samples revealed no evidence of CoV infection among the enrolled individuals. We identified higher levels of exposure to bats in people working in crop production and in hunting, trapping and fishing. Finally, we used the 'Spillover' risk-ranking tool to assess the potential for viral spillover and concluded that, while there is no evidence to suggest imminent risk of spillover for these CoVs, their host range and other traits suggest caution and vigilance are warranted in people with high exposure risk.

Relationship of Time-Activity-Adjusted Particle Number Concentration with Blood Pressure.

Emerging evidence suggests long-term exposure to ultrafine particulate matter (UFP, aerodynamic diameter < 0.1 µm) is associated with adverse cardiovascular outcomes. We investigated whether annual average UFP exposure was associated with measured systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and hypertension prevalence among 409 adults participating in the cross-sectional Community Assessment of Freeway Exposure and Health (CAFEH) study. We used measurements of particle number concentration (PNC, a proxy for UFP) obtained from mobile monitoring campaigns in three near-highway and three urban background areas in and near Boston, Massachusetts to develop PNC regression models (20-m spatial and hourly temporal resolution). Individual modeled estimates were adjusted for time spent in different micro-environments (time-activity-adjusted PNC, TAA-PNC). Mean TAA-PNC was 22,000 particles/cm³ (sd = 6500). In linear models (logistic for hypertension) adjusted for the minimally sufficient set of covariates indicated by a directed acyclic graph (DAG), we found positive, non-significant associations between natural log-transformed TAA-PNC and SBP (ß = 5.23, 95%CI: -0.68, 11.14 mmHg), PP (ß = 4.27, 95%CI: -0.79, 9.32 mmHg), and hypertension (OR = 1.81, 95%CI: 0.94, 3.48), but not DBP (ß = 0.96, 95%CI: -2.08, 4.00 mmHg). Associations were stronger among non-Hispanic white participants and among diabetics in analyses stratified by race/ethnicity and, separately, by health status.

Concentration-time extrapolation of short-term inhalation exposure levels: dimethyl sulfide, a case study using a chemical-specific toxic load exponent.

OBJECTIVE: Dimethyl sulfide (DMS, CAS 75-18-3) is an industrial chemical. It is both an irritant and neurotoxicant that may be life-threatening because of accidental release. The effects of DMS on public health and associated public health response depend on the exposure concentration and duration. However, currently, public health advisory information exists for only a 1 h exposure duration, developed by the American Industrial Hygiene Association (AIHA). In the present work, the AIHA-reviewed data were computationally extrapolated to other common short-term durations. METHODS: The extrapolation was carried out using the toxic load equation, Cn × t = TL, where C and t are exposure concentration and duration, TL is toxic load, and n is a chemical-specific toxic load exponent derived in the present work using probit meta-analysis. The developed threshold levels were vetted against the AIHA database of clinical and animal health effects induced by DMS. RESULTS: Tier-1 levels were derived based on human exposures that resulted in an easily detectable odor, because DMS is known to have a disagreeable odor that may cause nausea. Tier-2 levels were derived from the lower 95% confidence bounds on a benchmark concentration that caused 10% incidence (BMCL10) of coma in rats during a 15 min inhalation exposure to DMS. Tier-3 levels were based on a BMCL05 for mortality in rats. CONCLUSION: Emergency responders and health assessors may consider these computationally derived threshold levels as a supplement to traditional chemical risk assessment procedures in instances where AIHA developed public health advisory levels do not exist.