Sharps injuries among healthcare workers in Liberia and Ghana: a cross-sectional survey.

There is little data on sharps injuries among healthcare workers in West Africa despite the region's high rate of Hepatitis B and HIV. The purpose of this study is to investigate healthcare workers' history of sharps injury in Liberia and Ghana. An electronic cross-sectional survey was administered to healthcare workers in Liberia and Ghana from February to June 2022. A link to the survey was texted to participants through professional association membership lists, including nursing, midwifery, and physician assistant organizations in both Liberia and Ghana and a physician organization in Ghana only. 509 participants reported an average of 1.8 injuries per year in Liberia and 1.1 in Ghana (p=<0.01). 15.1% of healthcare workers reported three or more injuries in the past year. Liberia had a higher proportion of frequently injured workers (p = 0.01). Frequently injured workers were evenly distributed across worker types. Workers in this region are vulnerable to sharps injuries. A frequently injured subset of workers likely has distinctive risk factors and would benefit from further investigation and intervention.

Intestinal parasitic infections and predisposing factors among prison inmates in Southern Ghana: A cross-sectional study.

Background and Aims: The environment within prisons, such as overcrowding, lack of access to portable water, poor sanitation, and hygiene predisposes inmates to infections, including intestinal parasitic infections (IPIs). This study therefore determined the prevalence and associated factors of IPIs among prison inmates in Southern Ghana. Methods: A cross-sectional study using the stratified sampling technique was employed. The study recruited 461 prison inmates across three notable prisons, with 50 inmates from Ho Central, 357 inmates from Nsawam Medium Security, and 54 inmates from Sekondi Central Prisons all in Southern Ghana. A structured closed-ended questionnaire was administered to collect data on sociodemographics, lifestyle/behavioral characteristics, and signs and symptoms of IPIs. In addition, stool samples were collected and analyzed for the presence of various stages of intestinal parasites (trophozoites, cysts, ova, and larva) using formol-ether concentration, and the modified Ziehl-Neelsen techniques. Results: The prevalence of IPIs among inmates of the three selected prisons was 38.2% (95% confidence interval [CI]: 33.72%-42.79%). The prevalence of IPIs among inmates of the three prisons, the Ho Central, Nsawam Medium Security, and Sekondi Central were 46% (95% CI: 31.82%-60.68%), 37.5% (95% CI: 32.49%-42.79%), and 35.2% (95% CI: 22.68%-49.38%), respectively. After adjusting for confounders, the following factors; handwashing after defecation (adjusted odds ratio [AOR]: 0.05 [0.00-0.67]; p = 0.024), trimmed fingernails (AOR: 0.32 [0.13-0.76]; p = 0.011), itchy skin (AOR [95% CI]: 5.99 [3.43-10.43]; p < 0.001), anal itching (AOR [95% CI]: 0.35 [0.19-0.62]; p < 0.001), nausea (AOR [95% CI]: 5.57 [3.22-9.65]; p < 0.001), and worm expulsion (AOR [95% CI]: 3.80 [1.42-10.18]; p = 0.008) were found to be associated with intestinal parasitic infections. Conclusion: The study revealed that the prevalence of intestinal parasitic infections among prisons in Southern Ghana is high and is therefore an important public health concern. The Public Health Department of Ghana Health Service should therefore embark on health promotion and deworming exercise in all prisons in Ghana.

Genomic analysis of multidrug-resistant Escherichia coli from Urban Environmental water sources in Accra, Ghana, Provides Insights into public health implications.

Wastewater discharge into the environment in resource-poor countries poses a threat to public health. Studies in this area within these countries are limited, and the use of high-throughput whole-genome sequencing technologies is lacking. Therefore, understanding of environmental impacts is inadequate. The present study investigated the antibiotic resistance profiles and diversity of beta-lactamases in Escherichia coli strains isolated from environmental water sources in Accra, Ghana. Microbiological analyses were conducted on wastewater samples from three hospitals, a sewage and wastewater treatment plant, and water samples from two urban surface water bodies. Confirmed isolates (N = 57) were selected for phenotypic antibiotic resistance profiles. Multi-drug-resistant isolates (n = 25) were genome sequenced using Illumina MiSeq sequencing technology and screened for sequence types, antibiotic resistance, virulence and beta-lactamase genes, and mobile genetic elements. Isolates were frequently resistant to ampicillin (63%), meropenem (47%), azithromycin (46%), and sulfamethoxazole-trimethoprim (42%). Twenty different sequence types (STs) were identified, including clinically relevant ones such as ST167 and ST21. Five isolates were assigned to novel STs: ST14531 (n = 2), ST14536, ST14537, and ST14538. The isolates belonged to phylogroups A (52%), B1 (44%), and B2 (4%) and carried ß-lactamase (TEM-1B, TEM-1C, CTX-M-15, and blaDHA-1) and carbapenemase (OXA-1, OXA-181) resistance genes. Dominant plasmid replicons included Col440I (10.2%) and IncFIB (AP001918) (6.8%). Polluted urban environments in Accra are reservoirs for antibiotic-resistant bacteria, posing a substantial public health risk. The findings underscore the need for targeted public health interventions to mitigate the spread of antibiotic-resistant bacteria and protect public health.

Assessing the combined effect of multiple metal exposures on pregnancy and birth outcomes: Methodological insights in systematic review research.

This systematic review focused on pregnant women and aimed to evaluate how exposure to multiple metals impacts their pregnancy and birth outcomes. Previous research has predominantly focused on the effects of individual metal exposures on adverse birth outcomes. However, it is crucial to recognize that real-world scenarios often involve simultaneous exposure to multiple pollutants. Recent studies have emphasized the significance of considering exposure to mixtures of metals to gain a more comprehensive understanding of their collective health impacts. This article outlines the essential steps taken during the systematic review process, which involved synthesizing existing evidence and evaluating the strength and consistency of the relationship between metal mixtures and pregnancy and birth outcomes.

Exposure to metal mixtures and adverse pregnancy and birth outcomes: A systematic review.

BACKGROUND: Prenatal exposure to metal mixtures is associated with adverse pregnancy and birth outcomes like low birth weight, preterm birth, and small for gestational age. However, prior studies have used individual metal analysis, lacking real-life exposure scenarios. OBJECTIVES: This systematic review aims to evaluate the strength and consistency of the association between metal mixtures and pregnancy and birth outcomes, identify research gaps, and inform future studies and policies in this area. METHODS: The review adhered to the updated Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) checklist, along with the guidelines for conducting systematic reviews and meta-analyses of observational studies of etiology (COSMOS-E). Our data collection involved searching the PubMed, MEDLINE, and SCOPUS databases. We utilized inclusion criteria to identify relevant studies. These chosen studies underwent thorough screening and data extraction procedures. Methodological quality evaluations were conducted using the NOS framework for cohort and case-control studies, and the AXIS tool for cross-sectional studies. RESULTS: The review included 34 epidemiological studies, half of which focused on birth weight, and the others investigated neonate size, preterm birth, small for gestational age, miscarriage, and placental characteristics. The findings revealed significant associations between metal mixtures (including mercury (Hg), nickel (Ni), arsenic (As), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), zinc (Zn), barium (Ba), cesium (Cs), copper (Cu), selenium (Se), and chromium (Cr)) and adverse pregnancy and birth outcomes, demonstrating diverse effects and potential interactions. CONCLUSION: In conclusion, this review consistently establishes connections between metal exposure during pregnancy and adverse consequences for birth weight, gestational age, and other vital birth-related metrics. This review further demonstrates the need to apply mixture methods with caution but also shows that they can be superior to traditional approaches. Further research is warranted to deeper understand the underlying mechanisms and to develop effective strategies for mitigating the potential risks associated with metal mixture exposure during pregnancy.

Sharps Injuries Among Healthcare Workers in Liberia and Ghana: A Cross-Sectional Survey.

Objective: There is little data on sharps injuries among healthcare workers in West Africa, despite the region's high rate of Hepatitis B and HIV. The purpose of this study is to investigate healthcare workers' history of sharps injury in Liberia and Ghana. Design: An electronic cross-sectional survey disseminated by local nursing, midwifery, physician assistant, and physician associations. Setting: Healthcare workers in Liberia and Ghana from February to June 2022. Participants: Participant were registered nurses, physician assistants, physicians, or midwives, and had been working in a patient care role for at least nine of the previous twelve months. Methods: A link to the survey was texted to participants through their professional association membership lists, including nursing, midwifery, and physician assistant organizations in both Liberia and Ghana and a physician organization in Ghana only. Results: 509 participants reported an average of 1.8 injuries per year in Liberia and 1.1 in Ghana (p=<0.01). 15.1% of healthcare workers reported three or more injuries in the past year. Liberia had a higher proportion of frequently injured workers (p=<0.01). Frequently injured workers were evenly distributed across worker types. Conclusions: Workers in this region are vulnerable to sharps injuries. A frequently injured subset of workers likely has distinctive risk factors and would benefit from further investigation and intervention.

Computer-aided design of proline-rich antimicrobial peptides based on the chemophysical properties of a peptide isolated from Olivancillaria hiatula.

The chemophysical properties of a peptide isolated from Olivancillaria hiatula were combined with computational tools to design new antimicrobial peptides (AMPs). The in silico peptide design utilized arbitrary sequence shuffling, AMP sequence prediction and alignments such that putative sequences mimicked those of proline-rich AMPs (PrAMPs) and were potentially active against bacteria. Molecular modelling and docking experiments were used to monitor peptide binding to some intracellular targets like bacteria ribosome, DnaK and LasR. Peptide candidates were tested in vitro for antibacterial and antivirulence activities. Chemophysical studies of peptide extract suggested hydrophobic, acidic and proline-rich peptide properties. The amino acid signature of the extract matched that of AMPs that inhibit intracellular targets. Two of the designed PrAMP peptides (OhPrP-3 and OhPrP-5) had high affinity for the ribosome and DnaK. OhPrP-1, 2 and 4 also had favorable interactions with the biomolecular targets investigated. Peptides had bactericidal activity at the minimum inhibitory concentration against Pseudomonas aeruginosa. The designed peptides docked strongly to LasR suggesting possible interference with quorum sensing, and this was corroborated by in vitro data where sub-inhibitory doses of all peptides reduced pyocyanin and pyoverdine expression. The designed peptides can be further studied for the development of new anti-infective agents.

Electronic waste exposure and DNA damage: a systematic review and meta-analysis.

OBJECTIVES: Inappropriate processing and disposal of electronic waste (e-waste) expose workers and surrounding populations to hazardous chemicals, including clastogens and aneugens. Recently, considerable literature has grown around e-waste recycling, associated chemical exposures and intermediate health outcomes, including DNA damage. Micronuclei (MN) frequency has been widely used as a biomarker to investigate DNA damage in human populations exposed to genotoxic agents. We conducted a systematic review of published studies to assess DNA damage in e-waste-exposed populations and performed a meta-analysis to evaluate the association between e-waste exposure and DNA damage. METHODS: This systematic review with meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement checklist. Articles published in English from January 2000 through December 2020 investigating the associations between e-waste exposure and DNA damage were retrieved from the following three major databases: MEDLINE, ProQuest, and Scopus. Studies that reported the use of MN assay as a biomarker of DNA damage were included for meta-analysis. Studies that also reported other DNA damage biomarkers such as chromosomal aberrations, comet assay biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG), telomere length, apoptosis rate were reported using narrative synthesis. RESULTS: A total of 20 publications were included in this review, of which seven studies were within the occupational setting, and the remaining 13 studies were ecological studies. The review found six biomarkers of DNA damage (micronuclei, comets assay parameters (tail length, % tail DNA, tail moment, and olive tail moment), 8-OHdG, telomere length, apoptosis rate and chromosomal aberrations) which were assessed using seven different biological matrices (buccal cells, blood, umbilical cord blood, placenta, urine and semen). Most studies showed elevated levels of DNA damage biomarkers among e-waste exposed populations than in control populations. The most commonly used biomarkers were micronuclei frequency (n=9) in peripheral blood lymphocytes or buccal cells and 8-OHdG (n=7) in urine. The results of the meta-analysis showed that electronic waste recycling has contributed to an increased risk of DNA damage measured using MN frequency with a pooled estimate of the standardized mean difference (SMD) of 2.30 (95% CI: 1.36, 3.24, p<0.001) based on 865 participants. CONCLUSIONS: Taken together, evidence from this systematic review with meta-analysis suggest that occupational and non-occupational exposure to e-waste processing is associated with increased risk of DNA damage measured through MN assay and other types of DNA damage biomarkers. However, more studies from other developing countries in Africa, Latin America, and South Asia are needed to confirm and increase these results' generalizability.

Iron- and protein rich diets may boost hemoglobin levels among informal electronic waste recyclers exposed to metals at Agbogbloshie, Ghana.

While human exposure to metals may play a role in the pathogenesis of anemia, consumption of balanced diets may boost blood hemoglobin (Hb) levels in humans. Although informal electronic waste (e-waste) recycling processes have recently drawn attention as an important source of pollution, there is almost no empirical evidence on the relationship between diet, metals exposure and anemia among e-waste recyclers. Therefore, we evaluated possible ameliorating effects of diet on metal exposure related anemia, as measured by Hb levels of e-waste recyclers and a reference population in Ghana. This repeated measure study used data collected from e-waste recyclers (n=142) and a reference population (n=65) between March 2017 and October 2018. Stored whole blood samples were analyzed for the following metals; Cd, Pb, Rb, Tb, Tl, and Eu. Next, Hb levels were analysed using the URIT-810® semiautomatic biochemistry analyzer. Furthermore, a 48-hour dietary recall questionnaire was administered to assess dietary intake parameters such as protein, folate, carbohydrates, Fe, Ca, Mg, Se, Zn, and Cu. Ordinary regression models were used to estimate joint effects of metals and nutrients on Hb levels. At baseline, the mean Hb was lower among recyclers (12.99 ± 3.17 g/dL) than the reference group (13.02 ±2.37 g/dL). Blood Pb, Cd, Rb, Eu and Tb were associated with significant decreases in Hb levels of e-waste recyclers. Dietary intake of proteins and Fe was associated with concomitant increase in Hb levels of both groups as well as when analysis was restricted to recyclers. Despite the high exposure of e-waste recyclers to a myriad of metals, consumption of Fe-rich diets appears to ameliorate anemia and improved Hb levels (ß=0.229; 95% CI: 0.013, 0.445; p=0.04). Therefore, the consumption of Fe and protein-rich foods may boost blood Hb levels in e-waste recyclers, even though exposure to high levels of metals is a predictor of anemia among this worker-group.

Health Risks Associated with Informal Electronic Waste Recycling in Africa: A Systematic Review.

Informal electronic waste (e-waste) recycling in Africa has become a major public health concern. This review examined studies that report on the association between e-waste exposure and adverse human health outcomes in Africa. The review was conducted following the updated version of the Preferred Items for Systematic Review and Meta-analysis (PRISMA 2020) statement checklist. We included papers that were original peer-reviewed epidemiological studies and conference papers, written in English, and reported on e-waste exposure among human populations and any health-related outcome in the context of Africa. Our results from the evaluation of 17 studies found an association between informal e-waste recycling methods and musculoskeletal disease (MSD) symptoms and physical injuries such as back pains, lacerations, eye problems, skin burns, and noise-induced hearing loss (NIHL). In addition, the generation and release of particulate matter (PM) of various sizes, and toxic and essential metals such as cadmium (Cd), lead (Pb), zinc (Zn), etc., during the recycling process are associated with adverse systemic intermediate health outcomes including cardiopulmonary function and DNA damage. This systematic review concludes that the methods used by e-waste recyclers in Africa expose them to increased risk of adverse health outcomes. However, there is a need for more rigorous research that moves past single pollutant analysis.

Preponderance of vaccine-preventable diseases hotspots in northern Ghana: a spatial and space-time clustering analysis from 2010 to 2014.

BACKGROUND: Vaccine-preventable diseases (VPDs) persist globally with a disproportionately high burden in Low and Middle-Income Countries (LMICs). Although this might be partly due to the failure to sustain vaccination coverage above 90% in some WHO regions, a more nuanced understanding of VPD transmission beyond vaccination coverage may unveil other important factors in VPD transmission and control. This study identified VPDs hotspots and explored their relationships with ecology, urbanicity and land-use variations (Artisanal and Small-scale Gold Mining (ASGM) activities) in Ghana. METHODS: District-level disease count data from 2010 to 2014 from the Ghana Health Service (GHS) and population data from the Ghana Population and Housing Census (PHC) were used to determine clustering patterns of six VPDs (Measles, Meningitis, Mumps, Otitis media, Pneumonia and Tetanus). Spatial and space-time cluster analyses were implemented in SaTScan using the discrete Poisson model. P-values were estimated using a combination of sequential Monte Carlo, standard Monte Carlo, and Gumbel approximations. RESULTS: The study found a preponderance for VPD hotspots in the northern parts of Ghana and northernmost ecological zones (Sudan Savannah and Guinea Savannah). Incidence of meningitis was higher in the Sudan Savannah ecological zone relative to: Tropical Rain Forest (p = 0.001); Semi Deciduous Forest (p < 0.0001); Transitional Zone (p < 0.0001); Coastal Savannah (p < 0.0001) and Guinea Savannah (p = 0.033). Except for mumps, which recorded a higher incidence in urban districts (p = 0.045), incidence of the other five VPDs did not differ across the urban-rural divide. Whereas spatial analysis suggested that some VPD hotspots (tetanus and otitis media) occur more frequently in mining districts in the southern part of the country, a Mann-Whitney U test revealed a higher incidence of meningitis in non-mining districts (p = 0.019). Pneumonia and meningitis recorded the highest (722.8 per 100,000) and least (0.8 per 100,000) incidence rates respectively during the study period. CONCLUSION: This study shows a preponderance of VPD hotspots in the northern parts of Ghana and in semi-arid ecoclimates. The relationship between ASGM activities and VPD transmission in Ghana remains blurred and requires further studies with better spatial resolution to clarify.

Relationship between Metal Exposures, Dietary Macronutrient Intake, and Blood Glucose Levels of Informal Electronic Waste Recyclers in Ghana.

While metal exposures are generally high among informal electronic waste (e-waste) recyclers, the joint effect of metals and dietary macronutrients on their metabolic health is unknown. Therefore, we investigated the relationship between metal exposures, dietary macronutrients intake, and blood glucose levels of e-waste recyclers at Agbogbloshie using dietary information (48-h recall survey), blood metals (Pb & Cd), and HbA1C levels of 151 participants (100 e-waste recyclers and 51 controls from the Accra, Ghana) in March 2017. A linear regression model was used to estimate the joint relationship between metal exposures, dietary macronutrient intake, and blood glucose levels. Except for dietary proteins, both groups had macronutrient deficiencies. Diabetes prevalence was significantly higher among controls. Saturated fat, OMEGA-3, and cholesterol intake were associated with significant increases in blood glucose levels of recyclers. In a joint model, while 1 mg of cholesterol consumed was associated with a 0.7% increase in blood glucose, 1 g/L of Pb was found to significantly increase blood glucose levels by 0.9% among recyclers. Although the dietary consumption of cholesterol and fat was not high, it is still possible that exposure to Pb and Cd may still increase the risk of diabetes among both e-waste recyclers and the general population.

Derivation of sex and age-specific reference intervals for clinical chemistry analytes in healthy Ghanaian adults.

OBJECTVIES: This study is aimed at establishing reference intervals (RIs) of 40 chemistry and immunochemistry analytes for Ghanaian adults based on internationally harmonized protocol by IFCC Committee on Reference Intervals and Decision Limits (C-RIDL). METHODS: A total of 501 healthy volunteers aged ≥18 years were recruited from the northern and southern regions of Ghana. Blood samples were analyzed with Beckman-Coulter AU480 and Centaur-XP/Siemen auto-analyzers. Sources of variations of reference values (RVs) were evaluated by multiple regression analysis (MRA). The need for partitioning RVs by sex and age was guided by the SD ratio (SDR). The RI for each analyte was derived using parametric method with application of the latent abnormal values exclusion (LAVE) method. RESULTS: Using SDR≥0.4 as threshold, RVs were partitioned by sex for most enzymes, creatinine, uric acid (UA), bilirubin, immunoglobulin-M. MRA revealed age and body mass index (BMI) as major source of variations of many analytes. LAVE lowered the upper limits of RIs for alanine/aspartate aminotransferase, γ-glutamyl transaminase and lipids. Exclusion of individuals with BMI≥30 further lowered the RIs for lipids and CRP. After standardization based on value-assigned serum panel provided by C-RIDL, Ghanaian RIs were found higher for creatine kinase, amylase, and lower for albumin and urea compared to other collaborating countries. CONCLUSIONS: The LAVE effect on many clinical chemistry RIs supports the need for the secondary exclusion for reliable derivation of RIs. The differences in Ghanaian RIs compared to other countries underscore the importance of country specific-RIs for improved clinical decision making.

Oxidative Stress and Apoptosis in Bisphenol AF-Induced Neurotoxicity in Zebrafish Embryos.

Bisphenol AF (BPAF) is a structural counterpart of bisphenol A that is utilized in the food and beverage industry. The present study investigated the potential mechanisms in BPAF-induced neurotoxicity in zebrafish embryos. The BPAF concentrations (0.03, 0.1, 0.3, and 1.0 µM) had no obvious effect on hatching, mortality, and body length of zebrafish larvae, while curved tail and pericardial edema were observed in the 1.0 µM group at 72 and 96 h postfertilization (hpf). Locomotor activity of the larvae (at 120 hpf) significantly decreased from dark to light but increased from light to dark transitions in BPAF groups (0.1, 0.3, and 1.0 µM). Acridine orange showed that BPAF significantly increased green fluorescence protein intensity (22.6%) in the 1.0 µM group. Consistently, the induced apoptosis significantly up-regulated caspase 3 at 0.3 µM (1.95-fold) and 1.0 µM (2.26-fold) and bax at 0.3 µM (1.60-fold) and 1.0 µM (1.78-fold), whereas bcl-2 expression was significantly decreased at 0.3 µM (0.72-fold) and 1.0 µM (0.53-fold). In addition, increased reactive oxygen species concentrations at 0.3 µM (27%) and 1.0 µM (61.4%) resulted in suppressed superoxide dismutase and catalase activities. Moreover, quantitative polymerase chain reaction results showed that BPAF (0.3 and 1.0 µM) significantly altered normal dopaminergic signaling where dat was up-regulated, while drd2a and th1 were down-regulated, in a concentration-dependent manner. Aberrations in dopamine-related genes were congruous with the dysregulations in neurodevelopment genes (sox11b, pax6a, syn2a, and rob2). Our findings suggest that BPAF-evoked oxidative stress and apoptosis could translate into phenotypical behavioral and neurodevelopmental abnormalities. These highlights could provide theoretical reference for risk assessment and act as an early indicator to BPAF exposure. Environ Toxicol Chem 2022;41:2273-2284. © 2022 SETAC.

Relationship between temperature and Anopheles gambiae sensu lato mosquitoes' susceptibility to pyrethroids and expression of metabolic enzymes.

BACKGROUND: Malaria remains one of the most devastating diseases globally, and the control of mosquitoes as the vector is mainly dependent on chemical insecticides. Elevated temperatures associated with future warmer climates could affect mosquitoes' metabolic enzyme expression and increase insecticide resistance, making vector control difficult. Understanding how mosquito rearing temperatures influence their susceptibility to insecticide and expression of metabolic enzymes could aid in the development of novel tools and strategies to control mosquitoes in a future warmer climate. This study evaluated the effects of temperature on the susceptibility of Anopheles gambiae sensu lato (s.l.) mosquitoes to pyrethroids and their expression of metabolic enzymes. METHODS: Anopheles gambiae s.l. eggs obtained from laboratory-established colonies were reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38, and 40 °C). Upon adult emergence, 3- to 5-day-old female non-blood-fed mosquitoes were used for susceptibility tests following the World Health Organization (WHO) bioassay protocol. Batches of 20-25 mosquitoes from each temperature regime (25-34 °C) were exposed to two pyrethroid insecticides (0.75% permethrin and 0.05% deltamethrin). In addition, the levels of four metabolic enzymes (α-esterase, ß-esterase, glutathione S-transferase [GST], and mixed-function oxidase [MFO]) were examined in mosquitoes that were not exposed and those that were exposed to pyrethroids. RESULTS: Mortality in An. gambiae s.l. mosquitoes exposed to deltamethrin and permethrin decreased at temperatures above 28 °C. In addition, mosquitoes reared at higher temperatures were more resistant and had more elevated enzyme levels than those raised at low temperatures. Overall, mosquitoes that survived after being exposed to pyrethroids had higher levels of metabolic enzymes than those that were not exposed to pyrethroids. CONCLUSIONS: This study provides evidence that elevated temperatures decreased An. gambiae s.l. mosquitoes' susceptibility to pyrethroids and increased the expression of metabolic enzymes. This evidence suggests that elevated temperatures projected in a future warmer climate could increase mosquitoes' resistance to insecticides and complicate malaria vector control measures. This study therefore provides vital information, and suggests useful areas of future research, on the effects of temperature variability on mosquitoes that could guide vector control measures in a future warmer climate.

Association between toxic and essential metals in blood and global DNA methylation among electronic waste workers in Agbogbloshie, Ghana.

Aberrant global DNA methylation status is a known biomarker for increased disease risk, especially cancer. There is little published data on the association between toxic and essential metal mixtures and global DNA methylation in electronic waste (e-waste) workers. We aimed to establish the association between toxic and essential metals in blood and the effect of their interactions on global DNA methylation among e-waste recyclers and a reference group in Ghana. We used ICP-MS to measure the level of five metals (Se, Zn, Mn, Cd, and Pb) in the blood of 100 e-waste workers and 51 controls. We quantified blood DNA methylation levels of LINE-1 as an indicator of global DNA methylation. Cd, Mn, and Se levels were significantly higher in the reference group than in e-waste workers. Only Pb was significantly higher in the e-waste workers compared to the controls. Our linear regression analysis results showed a significant inverse association between Zn and LINE-1 DNA methylation (ßZn = - 0.912; 95% CI, - 1.512, - 0.306; p = 0.003) which corresponds to a 0.009 decrease in %LINE-1 methylation (95% CI, - 0.015, - 0.003; p = 0.003) for a 1% increase in Zn concentration. Potential interactions between Cd and Zn on global DNA methylation were observed. In summary, co-exposure to toxic and essential metals is associated with global (LINE-1) DNA methylation.

Effects of Elevated Temperatures on the Growth and Development of Adult Anopheles gambiae (s.l.) (Diptera: Culicidae) Mosquitoes.

Higher temperatures expected in a future warmer climate could adversely affect the growth and development of mosquitoes. This study investigated the effects of elevated temperatures on longevity, gonotrophic cycle length, biting rate, fecundity, and body size of Anopheles gambiae (s.l.) (Diptera: Culicidae) mosquitoes. Anopheles gambiae (s.l.) eggs obtained from laboratory established colonies were reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38, and 40°C), and 80 ± 10% RH. All adults were allowed to feed on a 10% sugar solution soaked in cotton wool; however, some mosquitoes were provided blood meal using guinea pig. Longevity was estimated for both blood-fed and non-blood-fed mosquitoes and analyzed using the Kaplan-Meier survival analysis. One-way ANOVA was used to test the effect of temperature on gonotrophic cycle length, biting rate, and fecundity. Adult measurement data were log-transformed and analyzed using ordinary least square regression with robust standard errors. Increasing temperature significantly decreased the longevity of both blood-fed (Log-rank test; X2(4) = 904.15, P < 0.001) and non-blood-fed (Log-rank test; X2(4) = 1163.60, P < 0.001) mosquitoes. In addition, the fecundity of mosquitoes decreased significantly (ANOVA; F(2,57) = 3.46, P = 0.038) with an increase in temperature. Body size (ß = 0.14, 95% CI, 0.16, 0.12, P < 0.001) and proboscis length (ß = 0.13, 95% CI, 0.17, 0.09, P < 0.001) significantly decreased with increasing temperature from 25 to 34°C. Increased temperatures expected in a future warmer climate could cause some unexpected effects on mosquitoes by directly influencing population dynamics and malaria transmission.

Effects of elevated temperatures on the development of immature stages of Anopheles gambiae (s.l.) mosquitoes.

OBJECTIVE: This study investigated the effects of temperature on the development of the immature stages of Anopheles gambiae (s.l.) mosquitoes. METHODS: Mosquito eggs were obtained from laboratory established colonies and reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38 and 40°C), and 80 ± 10% relative humidity. Larvae were checked daily for development to the next stage and for mortality. Pupation success, number of adults produced and sex ratio of the newly emerged adults were recorded. Larval survival was monitored every 24 h, and data were analysed using Kaplan-Meier survival analysis. Analysis of variance was used where data followed normal distribution, and a Kruskal-Wallis test where data were not normally distributed. Larval and pupal measurements were log-transformed and analysed using ordinary least square regression with robust standard errors. RESULTS: Increasing the temperature from 25 to 36°C decreased the development time by 10.57 days. Larval survival (X2 (6) = 5353.12, p < 0.001) and the number of adults produced (X2 (5) = 28.16, p < 0.001) decreased with increasing temperature. Increasing temperatures also resulted in significantly smaller larvae and pupae (p < 0.001). At higher temperatures, disproportionately more male than female mosquitoes were produced. CONCLUSIONS: Increased temperature affected different developmental stages in the life cycle of An. gambiae (s.l.) mosquitoes, from larval to adult emergence. This study contributes to the knowledge on the relationship between temperature and Anopheles mosquitoes and provides useful information for modelling vector population dynamics in the light of climate change.

Occupational exposures to particulate matter and PM2.5-associated polycyclic aromatic hydrocarbons at the Agbogbloshie waste recycling site in Ghana.

Electronic waste (e-waste) disposal and recycling activities such as burning and smelting can emit particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and other pollutants that expose workers and nearby communities. At informal e-waste recycling facilities, both emission controls and protective measures for workers are absent. This study characterizes personal exposures (breathing zone) of PM and PAHs of e-waste workers at the large Agbogbloshie e-waste site in Accra, Ghana. We collected gravimetric and optical measurements of PM2.5 and PM10 using shift samples for workers and for an age- and gender-matched reference population. PM2.5 filters were analyzed for 26 PAHs using gas chromatography/mass spectroscopy. Among e-waste workers, PM2.5 and PM10 concentrations were 99 ± 56 and 218 ± 158 µg/m3 (median ± interquartile range, optical measurements), respectively; these levels were 78 and 57% higher, respectively, than levels measured at a fixed site that was centrally located at the waste site. In the reference community, breathing zone PM2.5 and PM10 levels were lower, 49 ± 20 and 131 ± 108 µg/m3, respectively, and the fraction of coarse PM was larger. We detected all 26 target PAHs, of which naphthalene and phenanthrene were the most abundant. PAH concentrations were weakly correlated to PM levels, but PAH abundances, representing the fraction of PAH mass to the total PM2.5 mass collected, were strongly and inversely correlated to PM levels, suggesting multiple and different sources of PAHs and PM that affected exposures. Both PM and PAH levels were elevated for workers performing burning and dismantling, and both exceeded standards or risk-based guidelines, e.g., lifetime excess cancer risks for several PAHs were in the 10-4 to 10-6 range, indicating the need to reduce emissions as well as provide respiratory protection. The study emphasizes the importance of using personal and shift samples to accurately characterize worker exposure.

Association between global DNA methylation (LINE-1) and occupational particulate matter exposure among informal electronic-waste recyclers in Ghana.

This study examined the associations between PM (2.5 and 10) and global DNA methylation among 100 e-waste workers and 51 non-e-waste workers serving as controls. Long interspersed nucleotide repetitive elements-1 (LINE-1) was measured by pyrosequencing. Personal PM2.5 and PM10 were measured over a 4-hour work-shift using real-time particulate monitors incorporated into a backpack . Linear regression models were used to assess the association between PM and LINE-1 DNA methylation. The concentrations of PM2.5 and PM10 were significantly higher among the e-waste workers than the controls (77.32 vs 34.88, p < 0.001 and 210.21 vs 121.92, p < 0.001, respectively). PM2.5 exposure was associated with increased LINE-1 CpG2 DNA methylation (ß = 0.003; 95% CI; 0.001, 0.006; p = 0.022) but not with the average of all 4 CpG sites of LINE-1. In summary, high levels of PM2.5 exposure was associated with increased levels of global DNA methylation in a site-specific manner.