BACKGROUND: Certain occupations have greater risk for per- and polyfluoroalkyl substances (PFAS) exposure because of PFAS use in occupation-associated materials. OBJECTIVE: We sought to assess whether PFAS concentrations differed by occupation among certain Arizona workers and whether concentrations differed over time by occupation. METHODS: Serum concentrations for 14 PFAS were measured among 1960 Arizona Healthcare, Emergency Responder, and Other Essential Worker Study participants. Samples were collected at enrollment and periodically during July 2020-April 2023. Occupational categories included firefighters, other first responders, healthcare workers, and other essential workers. We fit multilevel regression models for each PFAS to estimate differences in geometric mean concentrations or odds of PFAS detection at enrollment by occupational category. For participants with ≥1 serum sample, we evaluated for yearly longitudinal differences in PFAS concentrations by occupational category. We used other essential workers for comparison, and adjusted for age, sex, race and ethnicity, year, and residential county. RESULTS: Adjusting for covariates, firefighters had higher perfluorohexanesulfonic acid (PFHxS), branched and linear perfluorooctanesulfonic acid (PFOS), and perfluoroheptanesulfonic acid (PFHpS) concentrations than other essential workers (geometric mean ratios 95% CIs: 1.26 [1.11-1.43]; 1.18 [1.06-1.32]; 1.19 [1.08-1.31]; and 1.19 [1.01-1.39], respectively). Healthcare workers had higher odds of detection of branched perfluorooctanoic acid (Sb-PFOA) and perfluorododecanoic acid (PFDoA) than other essential workers, adjusting for covariates (odds ratios 95% CIs: 1.35 [1.01-1.80]; 2.50 [1.17-5.34], respectively). During the 3-year study, we detected declines in PFAS concentrations among other essential workers; few longitudinal differences in concentrations by occupation were detected. IMPACT STATEMENT: Using data from a large prospective cohort of frontline workers in Arizona, we compared serum concentrations of 14 per-and polyfluoroalkyl substances (PFAS) among firefighters, other first responders, healthcare workers, and other frontline essential workers. We found that firefighters have higher concentrations of certain PFAS chemicals and the odds of detecting other PFAS chemicals are higher among healthcare workers compared with people in other occupations. Our findings highlight the importance of further action to reduce PFAS exposure within highly exposed occupational groups, such as firefighters, and the need to expand evaluation of exposure among other occupations, including healthcare workers.

INTRODUCTION: Envenomation after a North American rattlesnake (Crotalus spp. and Sistrusus spp.) bite is associated with substantial morbidity. Arizona reports the highest number of rattlesnake envenomations annually in the United States. We evaluated the performance of poison and drug information centers for snakebite surveillance, compared with the hospital and emergency department discharge database. We used both datasets to improve the characterization of epidemiology, healthcare costs, and clinical effects of snakebite envenomations in Arizona. METHODS: We identified patients with a snakebite during 2017-2021 using Arizona hospital and emergency department discharge data and snakebite consults with two regional Arizona poison centers. Patients were matched using name and birthdate. The performance of poison center data for snakebite surveillance was evaluated using the percentage of snakebite patients in hospital and emergency department discharge data that consulted with poison centers. Patient demographics, healthcare characteristics, clinical effects, and context of snakebite events were described using both datasets. RESULTS: In total, 1,288 patients with a snakebite were identified using the Arizona hospital and emergency department discharge data, which resulted in 953 (74%) consultations with poison centers. The median age of patients was 48 years (IQR 28-62 years), and they were predominantly male (66%), White (90%), and non-Hispanic (84%). The median billed charges were US$ 84,880 (IQR US$ 13,286-US$ 168,043); the median duration of a healthcare stay was 34 h (IQR 13-48 h), and 29% of patients were transferred between healthcare facilities. Among 953 consulted poison center calls for a snakebite, a median of 14 vials of antivenom was administered per patient; 375 (60%) bites occurred near the home, and 345 (43%) patients were bitten on a lower extremity. One death was identified. DISCUSSION: Snakebites in Arizona can cause severe morbidity and require extensive healthcare resources for treatment. Poison centers are valuable for monitoring venomous snakebites in Arizona. CONCLUSIONS: Using hospital and emergency department discharge data with poison center records can improve public health surveillance data regarding snakebite epidemiology and human-snake interaction information and be used to tailor interventions to increase awareness of snake encounters and prevent snakebites.

Malaria is a severe and potentially fatal mosquitoborne disease caused by infection with Plasmodium spp. parasites. Although malaria is no longer endemic in the United States, imported infections are reported annually; the primary risk group has been U.S. residents traveling to areas where malaria is endemic (1). In 2023, sporadic locally acquired mosquito-transmitted malaria cases were reported in several U.S. states (2,3). This report describes increases in imported malaria cases in 2023 compared with 2022 in three public health jurisdictions along the U.S. southern border.

Efforts to achieve malaria elimination need to consider both falciparum and nonfalciparum infections. The prevalence and geographic distribution of four Plasmodium species were determined by real-time PCR using dried blood spots collected during the 2017 School Malaria Parasitological Survey of eight regions of Tanzania. Among 3,456 schoolchildren, 22% had P. falciparum, 24% P. ovale spp., 4% P. malariae, and 0.3% P. vivax. Ninety-one percent of P. ovale infections had very low parasite densities, based on amplification at later cycle thresholds. Sixty-four percent of P. ovale infections were single-species, and 35% of these were detected in low malaria endemicity regions. P. malariae infections were predominantly co-infections with P. falciparum (73%). P. vivax was largely detected in northern and eastern regions. Overall, 43% of children with P. falciparum were co-infected with at least one nonfalciparum species. A large, previously under-appreciated burden of P. ovale spp. infection exists among Tanzanian schoolchildren. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.

Achieving malaria elimination requires considering both Plasmodium falciparum and non-P. falciparum infections. We determined prevalence and geographic distribution of 4 Plasmodium spp. by performing PCR on dried blood spots collected within 8 regions of Tanzania during 2017. Among 3,456 schoolchildren, 22% had P. falciparum, 24% had P. ovale spp., 4% had P. malariae, and 0.3% had P. vivax infections. Most (91%) schoolchildren with P. ovale infections had low parasite densities; 64% of P. ovale infections were single-species infections, and 35% of those were detected in low malaria endemic regions. P. malariae infections were predominantly (73%) co-infections with P. falciparum. P. vivax was detected mostly in northern and eastern regions. Co-infections with >1 non-P. falciparum species occurred in 43% of P. falciparum infections. A high prevalence of P. ovale infections exists among schoolchildren in Tanzania, underscoring the need for detection and treatment strategies that target non-P. falciparum species.

BACKGROUND: Transmission of malaria in sub-Saharan Africa has become increasingly stratified following decades of malaria control interventions. The extent to which environmental and land cover risk factors for malaria may differ across distinct strata of transmission intensity is not well known and could provide actionable targets to maximize the success of malaria control efforts. METHODS: This study used cross-sectional malaria survey data from a nationally representative cohort of school-aged children in Tanzania, and satellite-derived measures for environmental features and land cover. Hierarchical logistic regression models were applied to evaluate associations between land cover and malaria prevalence within three distinct strata of transmission intensity: low and unstable, moderate and seasonal, and high and perennial. RESULTS: In areas with low malaria transmission, each 10-percentage point increase in cropland cover was associated with an increase in malaria prevalence odds of 2.44 (95% UI: 1.27, 5.11). However, at moderate and higher levels of transmission intensity, no association between cropland cover and malaria prevalence was detected. Small associations were observed between greater grassland cover and greater malaria prevalence in high intensity settings (prevalence odds ratio (POR): 1.10, 95% UI: 1.00, 1.21), and between greater forest cover and reduced malaria prevalence in low transmission areas (POR: 0.74, 95% UI: 0.51, 1.03), however the uncertainty intervals of both estimates included the null. CONCLUSIONS: The intensity of malaria transmission appears to modify relationships between land cover and malaria prevalence among school-aged children in Tanzania. In particular, greater cropland cover was positively associated with increased malaria prevalence in areas with low transmission intensity and presents an actionable target for environmental vector control interventions to complement current malaria control activities. As areas are nearing malaria elimination, it is important to re-evaluate environmental risk factors and employ appropriate interventions to effectively address low-level malaria transmission.