Wildfire particulate exposure and risks of preterm birth and low birth weight in the Southwestern United States.

OBJECTIVES: Wildfire air pollution is a growing concern on human health. The study aims to assess the associations between wildfire air pollution and pregnancy outcomes in the Southwestern United States. STUDY DESIGN: This was a retrospective cohort study. METHODS: Birth records of 627,404 singleton deliveries in 2018 were obtained in eight states of the Southwestern United States and were linked to wildfire-sourced fine particulate matter (PM2.5) and their constituents (black carbon [BC] and organic carbon [OC]) during the entire gestational period. A double-robust logistic regression model was used to assess the associations of wildfire-sourced PM2.5 exposures and preterm birth and term low birth weight, adjusting for non-fire-sourced PM2.5 exposure and individual- and area-level confounder variables. RESULTS: Wildfire-sourced PM2.5 contributed on average 15% of the ambient total PM2.5 concentrations. For preterm birth, the strongest association was observed in the second trimester (odds ratio [OR]: 1.06, 95% confidence interval [CI]: 1.05-1.07 for PM2.5; 1.06, 95% CI: 1.05-1.07 for BC; 1.04, 95% CI: 1.03-1.05 for OC, per interquartile range increment of exposure), with higher risks identified among non-smokers or those with low socio-economic status. For term low birth weight, the associations with wildfire-sourced PM2.5 exposures were consistently elevated for all trimesters except for the exposure averaged over the entire gestational period. Overall, the associations between wildfire-sourced PM2.5 and pregnancy outcomes were stronger than those with total PM2.5. CONCLUSIONS: Wildfire-sourced PM2.5 and its constituents are linked to higher risks of preterm birth and term low birth weight among a significant US population than the effects of ambient total PM2.5.

Multifactor-dimensionality reduction reveals interaction of important gene variants involved in allergy.

Elevated IgE levels in the atopic triad of asthma, allergic rhinitis and atopic dermatitis is a multifactorial condition whose genetic component involves interaction of several gene loci. One hundred and two matched pairs of allergic and nonallergic individuals were phenotyped for total serum IgE level using enzyme-linked immunosorbent assay (ELISA). Atopic status was defined by serum IgE concentration ≥100 IU mL(-1) . SNPs genotyped include the IL4 -590C>T (rs2243250), FCER1B E237G (rs569108), CD14 -159C>T (rs2569190), IL4RA Q551R (rs1801275) and ADRB2 R16G (rs1042713). Gene-gene interaction was analysed using multifactor-dimensionality reduction (MDR). Significant association between atopic allergy and the IL4 -590C>T polymorphism was confirmed in three genetic models. Interaction among the 5 gene variants was validated by MDR. The five-locus model was chosen as the best to describe the interaction of the SNPs within the context of atopy. The strongest interaction was between IL4 -590C>T and IL4RA Q551R and between FCER1B E237G and ADRB2 R16G. The IL4 variant also interacts synergistically with the FCER1B and ADRB2 coding variants. CD14 -159C>T, in general, interacts antagonistically with the rest of the SNPs. In conclusion, a five-locus interaction exists among IL4 -590C>T, FCER1B E237G, CD14 -159C>T, IL4RA Q551R and ADRB2 R16G in Filipino cases of atopic allergy.

An epidemiologic and entomologic investigation of a cluster of Rocky Mountain spotted fever cases in Delaware.

BACKGROUND: Rocky Mountain spotted fever (RMSF) continues to be the most common fatal tick-borne illness in the United States. In August of 1996, four children attending a summer camp in Delaware were diagnosed with RMSF. This report summarizes the results of the epidemiologic and entomologic investigation conducted by the Delaware Division of Public Health and the Centers for Disease Control and Prevention regarding this cluster of RMSF cases. Epidemiologic and clinical aspects of RMSF, as well as previously reported clusters of the disease, are also reviewed. METHODS: A questionnaire regarding symptoms and activities was administered via telephone to 163 (73 percent) of the 223 attendees. A suspected case was defined as an illness in a person attending the camp between August 11 and 17 that occurred during the two-week period following the session, characterized by either 1) fever with one or more symptoms (i.e., headache, rash, myalgia, or fatigue) or 2) no fever with two or more symptoms. Cases of RMSF were confirmed by serologic evaluation. RESULTS: Seven of 13 patients with suspected RMSF submitted sera for testing. Four patients had confirmed RMSF; three were males, and the median age was 12.5 years compared with 12 years for all attendees. All confirmed patients reported fever, headache, fatigue, and rash. An increased risk of becoming ill was associated with overnight camping at site A (Odds Ratio (OR) undefined, p = 0.02), visiting or overnight camping at site B (OR undefined, p = 0.003 and 0.002), and leaving the trails when hiking (OR undefined, p = 0.02). CONCLUSIONS: These data suggest that development of RMSF was associated with visiting or camping at specific sites and behavior likely to increase contact with ticks. Camp supervisors were advised to educate campers regarding tick bite prevention measures, reduce underbrush around campsites, and encourage campers to remain on the trails. Health care providers should remain aware of the increased risk for RMSF during the spring, summer, and fall months.