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El-Sabbagh NM, Khalil RH, Khallaf MM, Shakweer MS, Ghetas HA, Atallah MM. Pharmacological and ameliorative effects of Withania somnifera against cadmium chloride-induced oxidative stress and immune suppression in Nile tilapia, Oreochromis niloticus. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:6777-6792. [PMID: 34458972 DOI: 10.1007/s11356-021-15630-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
This study was carried out to evaluate the effects of dietary supplementation of aqueous extract of Withania somnifera (W. somnifera) against cadmium chloride-induced toxicity in the Nile tilapia, Oreochromis niloticus. Five experimental groups were designed: group (I) was free from cadmium chloride and W. somnifera and served as a control, group (II) was exposed to 1.775 mg L-1 of cadmium chloride only (which is equivalent to 1/4 96-h LC50), while groups (III), (IV), and (V) were exposed to 1.775 mg cadmium chloride L-1 with co-supplementation of dietary W. somnifera in doses of 1.0, 2.0, and 3.0 mL kg-1 body weight (bwt), respectively. The experiment lasted for 4 weeks. In the second and fourth weeks of the experiment, the following indicators were evaluated: hematological (hemogram and blood protein profile), biochemical (activities of serum liver enzymes, namely alanine transaminase (ALT) and aspartate transaminase (AST)), immunological (immunoglobulin M (IgM), serum lysozyme), and tissue antioxidant changes (malondialdehyde (MDA) levels and activities of catalase (CAT) and superoxide dismutase (SOD)). Additionally, gene expressions of glutathione-S-transferase (GST) in the liver were assessed. At the end of the experiment, all fish in all groups were experimentally challenged with Aeromonas hydrophila and the relative protection survival (RPS) was demonstrated. The results revealed that groups exposed to cadmium chloride toxicity and co-supplemented with dietary aqueous extract of W. somnifera at high doses showed significant ameliorative effects in hemogram parameters, total protein, globulin, IgM, and lysozyme against cadmium chloride-induced toxicity compared to the control group and the group exposed to a sublethal dose of cadmium chloride without co-suplemntation of W. somnifera. The results showed also that groups supplemented orally with W. somnifera at high doses have higher antioxidant activities of CAT and SOD and reduction of MDA formation. Levels of gene expressions of GST in the liver were higher in W. somnifera extract-supplemented groups more than those in the group exposed to cadmium chloride-induced toxicity without W. somnifera supplementation. In addition, the results revealed improved RPS with the dietary supply of W. somnifera extract in high doses. In conclusion, this study showed that the dietary supplementation of W. somnifera extract to diets of O. niloticus could be suggested as an effective way to overcome cadmium chloride-induced toxicity because it improves blood parameters and antioxidants, and it can be used as an immunostimulant against the invading bacterial pathogens.
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Affiliation(s)
- Nasser M El-Sabbagh
- Department of Veterinary Pharmacology, Faculty of Veterinary Medicine, Alexandria University, Alexandria, Egypt.
| | - Riad H Khalil
- Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Alexandria University, Alexandria, Egypt
| | - Mohammed M Khallaf
- Department of Aquatic Animal Medicine and Management Department, Faculty of Veterinary Medicine, Sadat City University, Sadat, Egypt
| | - Medhat S Shakweer
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Hanan A Ghetas
- Department of Aquatic Animal Medicine and Management Department, Faculty of Veterinary Medicine, Sadat City University, Sadat, Egypt
| | - Mohamed M Atallah
- Faculty of Aquaculture and Fish Wealth, Alexandria University, Alexandria, Egypt
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Berlin M. Mercury in dental amalgam: a risk analysis. Neurotoxicology 2020; 81:382-386. [DOI: 10.1016/j.neuro.2020.09.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Cannas D, Loi E, Serra M, Firinu D, Valera P, Zavattari P. Relevance of Essential Trace Elements in Nutrition and Drinking Water for Human Health and Autoimmune Disease Risk. Nutrients 2020; 12:E2074. [PMID: 32668647 PMCID: PMC7400883 DOI: 10.3390/nu12072074] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023] Open
Abstract
Trace elements produce double-edged effects on the lives of animals and particularly of humans. On one hand, these elements represent potentially toxic agents; on the other hand, they are essentially needed to support growth and development and confer protection against disease. Certain trace elements and metals are particularly involved in humoral and cellular immune responses, playing the roles of cofactors for essential enzymes and antioxidant molecules. The amount taken up and the accumulation in human tissues decisively control whether the exerted effects are toxic or beneficial. For these reasons, there is an urgent need to re-consider, harmonize and update current legislative regulations regarding the concentrations of trace elements in food and in drinking water. This review aims to provide information on the interrelation of certain trace elements with risk of autoimmune disease, with a particular focus on type 1 diabetes and multiple sclerosis. In addition, an overview of the current regulations and regulatory gaps is provided in order to highlight the importance of this issue for everyday nutrition and human health.
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Affiliation(s)
- Daniela Cannas
- Department of Biomedical Sciences, Unit of Biology and Genetics, University of Cagliari, 09042 Cagliari, Italy; (D.C.); (E.L.)
| | - Eleonora Loi
- Department of Biomedical Sciences, Unit of Biology and Genetics, University of Cagliari, 09042 Cagliari, Italy; (D.C.); (E.L.)
| | - Matteo Serra
- Department of Civil, Environmental Engineering and Architecture, University of Cagliari, 09123 Cagliari, Italy;
| | - Davide Firinu
- Department of Medical Sciences and Public Health, Monserrato Campus, University of Cagliari, 09042 Cagliari, Italy;
| | - Paolo Valera
- Department of Civil, Environmental Engineering and Architecture, University of Cagliari, 09123 Cagliari, Italy;
| | - Patrizia Zavattari
- Department of Biomedical Sciences, Unit of Biology and Genetics, University of Cagliari, 09042 Cagliari, Italy; (D.C.); (E.L.)
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Batista-Duharte A, Téllez-Martínez D, Aparecida Jellmayer J, Leandro Portuondo Fuentes D, Campos Polesi M, Martins Baviera A, Zeppone Carlos I. Repeated Exposition to Mercury (II) Chloride Enhances Susceptibility to S. schenckii sensu stricto Infection in Mice. J Fungi (Basel) 2018; 4:jof4020064. [PMID: 29799450 PMCID: PMC6023541 DOI: 10.3390/jof4020064] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 01/18/2023] Open
Abstract
Sporotrichosis is a subcutaneous mycosis that has re-emerged in several tropical and subtropical regions over the last decades. Growing findings suggest that the interplay of host, pathogen, and environment has a determinant effect on the diversity, local distribution, and virulence of Sporothrix schenckii sensu lato, the etiologic agent. Among the environmental factors, we have studied the potential role of repeated exposures to mercury (Hg), a known immunotoxic xenobiotic that is widely used in gold mining regions where sporotrichosis outbreaks are frequently reported. In this study, male Swiss mice received subcutaneous injections of either 300 or 1200 µg/kg of mercury (II) chloride (HgCl2) for 14 days, three times a week. A control group was injected with the vehicle Phosphate Buffered Saline (PBS). Treatment with HgCl2 impaired several immunologic parameters that are involved in host response to Sporothrix infection, such as the production of TNFα, IL-1, and nitric oxide by macrophages, and Th1/Th2/Th17 populations and their respective cytokines. The consequences of these effects on the host resistance to S. schenckii infection were subsequently evaluated. Hg-exposed mice exhibited a higher fungal load in the fungal inoculation site associated to systemic dissemination to spleen and liver on 14 days post-infection and a higher production of specific IgG1 and mild reduction of IgG2a. These findings suggest that repeated exposition to Hg enhances susceptibility to S. schenckii infection in mice and can be a factor associated to sporotrichosis outbreaks in endemic and highly Hg-polluted areas.
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Affiliation(s)
- Alexander Batista-Duharte
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú km 1, Araraquara 14800-903, Brazil.
| | - Damiana Téllez-Martínez
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú km 1, Araraquara 14800-903, Brazil.
| | - Juliana Aparecida Jellmayer
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú km 1, Araraquara 14800-903, Brazil.
| | - Deivys Leandro Portuondo Fuentes
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú km 1, Araraquara 14800-903, Brazil.
| | - Marisa Campos Polesi
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú km 1, Araraquara 14800-903, Brazil.
| | - Amanda Martins Baviera
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú km 1, Araraquara 14800-903, Brazil.
| | - Iracilda Zeppone Carlos
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú km 1, Araraquara 14800-903, Brazil.
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Ebers Smith JH, Cristol DA, Swaddle JP. Experimental Infection and Clearance of Coccidian Parasites in Mercury-Exposed Zebra Finches. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2018; 100:89-94. [PMID: 29236156 DOI: 10.1007/s00128-017-2246-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/07/2017] [Indexed: 06/07/2023]
Abstract
Mercury is a globally distributed, persistent environmental contaminant that affects the health of many taxa. It can suppress the immune system, which often plays a role in defense against parasites. However, there have been few investigations of whether mercury affects the abilities of animals to resist parasitic infection. Here, we exposed zebra finches to a lifetime dietary exposure of methylmercury (1.2 μg/g wet weight) and experimentally infected them with coccidian parasites to examine the effect of methylmercury exposure on parasitic infection. The mercury-exposed birds did not have an altered immune response (heterophil:lymphocyte ratio) nor a reduced ability to clear the infection. However, mercury-exposed birds tended to have higher parasite loads at the time when we expected the greatest immune response (2-3 weeks post-infection). Although mercury did not greatly influence the infection-course of this parasite in captivity, responses may be more accentuated in the wild where birds face additional immune challenges.
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Affiliation(s)
- Jessica H Ebers Smith
- Department of Biology, College of William and Mary, Institute for Integrative Bird Behavior Studies, Williamsburg, VA, 23187, USA
| | - Daniel A Cristol
- Department of Biology, College of William and Mary, Institute for Integrative Bird Behavior Studies, Williamsburg, VA, 23187, USA.
| | - John P Swaddle
- Department of Biology, College of William and Mary, Institute for Integrative Bird Behavior Studies, Williamsburg, VA, 23187, USA
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Oxidative stress biomarkers are associated with visible clinical signs of a disease in frigatebird nestlings. Sci Rep 2017; 7:1599. [PMID: 28487518 PMCID: PMC5431617 DOI: 10.1038/s41598-017-01417-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 03/29/2017] [Indexed: 02/07/2023] Open
Abstract
Infectious diseases are one of the most common threats for both domestic and wild animals, but little is known about the effects on the physiological condition and survival of wild animals. Here, we have tested for the first time in a wild vertebrate facing a viral disease possibly due to herpesvirus (i) whether nestlings with either low levels of oxidative damage or high levels of antioxidant protection are less susceptible to develop visible clinical signs, (ii) whether the disease is associated with the nestlings’ oxidative status, (iii) whether the association between the disease and oxidative status is similar between males and females (iv), and whether cloacal and tracheal swabs might be used to detect herpesvirus. To address our questions, we took advantage of a population of Magnificent frigatebirds (Fregata magnificens) whose nestlings have experienced high mortality rates in recent times. Our work shows that (i) blood lipid oxidative damage is associated with observable clinical signs and survival probabilities of nestling frigatebirds, and (ii) that high glutathione levels in red blood cells are associated with the emergence of visible clinical signs of the disease. Our work provides evidence that differences in the oxidative status of nestlings might underlie individual health and survival.
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Wyatt LH, Luz AL, Cao X, Maurer LL, Blawas AM, Aballay A, Pan WKY, Meyer JN. Effects of methyl and inorganic mercury exposure on genome homeostasis and mitochondrial function in Caenorhabditis elegans. DNA Repair (Amst) 2017; 52:31-48. [PMID: 28242054 PMCID: PMC5394729 DOI: 10.1016/j.dnarep.2017.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 12/05/2016] [Accepted: 02/06/2017] [Indexed: 12/21/2022]
Abstract
Mercury toxicity mechanisms have the potential to induce DNA damage and disrupt cellular processes, like mitochondrial function. Proper mitochondrial function is important for cellular bioenergetics and immune signaling and function. Reported impacts of mercury on the nuclear genome (nDNA) are conflicting and inconclusive, and mitochondrial DNA (mtDNA) impacts are relatively unknown. In this study, we assessed genotoxic (mtDNA and nDNA), metabolic, and innate immune impacts of inorganic and organic mercury exposure in Caenorhabditis elegans. Genotoxic outcomes measured included DNA damage, DNA damage repair (nucleotide excision repair, NER; base excision repair, BER), and genomic copy number following MeHg and HgCl2 exposure alone and in combination with known DNA damage-inducing agents ultraviolet C radiation (UVC) and hydrogen peroxide (H2O2), which cause bulky DNA lesions and oxidative DNA damage, respectively. Following exposure to both MeHg and HgCl2, low-level DNA damage (∼0.25 lesions/10kb mtDNA and nDNA) was observed. Unexpectedly, a higher MeHg concentration reduced damage in both genomes compared to controls. However, this observation was likely the result of developmental delay. In co-exposure treatments, both mercury compounds increased initial DNA damage (mtDNA and nDNA) in combination with H2O2 exposure, but had no impact in combination with UVC exposure. Mercury exposure both increased and decreased DNA damage removal via BER. DNA repair after H2O2 exposure in mercury-exposed nematodes resulted in damage levels lower than measured in controls. Impacts to NER were not detected. mtDNA copy number was significantly decreased in the MeHg-UVC and MeHg-H2O2 co-exposure treatments. Mercury exposure had metabolic impacts (steady-state ATP levels) that differed between the compounds; HgCl2 exposure decreased these levels, while MeHg slightly increased levels or had no impact. Both mercury species reduced mRNA levels for immune signaling-related genes, but had mild or no effects on survival on pathogenic bacteria. Overall, mercury exposure disrupted mitochondrial endpoints in a mercury-compound dependent fashion.
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Affiliation(s)
- Lauren H Wyatt
- Nicholas School of the Environment, Duke University, Durham, NC, United States.
| | - Anthony L Luz
- Nicholas School of the Environment, Duke University, Durham, NC, United States
| | - Xiou Cao
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Laura L Maurer
- Nicholas School of the Environment, Duke University, Durham, NC, United States
| | - Ashley M Blawas
- Nicholas School of the Environment, Duke University, Durham, NC, United States
| | - Alejandro Aballay
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - William K Y Pan
- Nicholas School of the Environment, Duke University, Durham, NC, United States; Duke Global Health Institute, Duke University, Durham, NC, United States
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, NC, United States.
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Ekerfelt C, Andersson M, Olausson A, Bergström S, Hultman P. Mercury exposure as a model for deviation of cytokine responses in experimental Lyme arthritis: HgCl2 treatment decreases T helper cell type 1-like responses and arthritis severity but delays eradication of Borrelia burgdorferi in C3H/HeN mice. Clin Exp Immunol 2007; 150:189-97. [PMID: 17672870 PMCID: PMC2219278 DOI: 10.1111/j.1365-2249.2007.03474.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Lyme borreliosis is a complex infection, where some individuals develop so-called 'chronic borreliosis'. The pathogenetic mechanisms are unknown, but the type of immune response is probably important for healing. A strong T helper cell type 1 (Th1)-like response has been suggested as crucial for eradication of Borrelia and for avoiding development of chronic disease. Many studies aimed at altering the Th1/Th2 balance in Lyme arthritis employed mice deficient in cytokine genes, but the outcome has not been clear-cut, due possibly to the high redundancy of cytokines. This study aimed at studying the importance of the Th1/Th2 balance in murine Borrelia arthritis by using the Th2-deviating effect of subtoxic doses of inorganic mercury. Ninety-eight C3H/HeN mice were divided into four groups: Borrelia-infected (Bb), Borrelia-infected exposed to HgCl(2) (BbHg), controls exposed to HgCl(2) alone and normal controls. Mice were killed on days 3, 16, 44 and 65 post-Borrelia inoculation. Arthritis severity was evaluated by histology, spirochaetal load determined by Borrelia culture, IgG2a- and IgE-levels analysed by enzyme-linked immunosorbemt assay (ELISA) and cytokine-secreting cells detected by enzyme-linked immunospot (ELISPOT). BbHg mice showed less severe histological arthritis, but delayed eradication of spirochaetes compared to Bb mice, associated with increased levels of IgE (Th2-induced) and decreased levels of IgG2a (Th1-induced), consistent with a Th2-deviation. Both the numbers of Th1 and Th2 cytokine-secreting cells were reduced in BbHg mice, possibly explained by the fact that numbers of cytokine-secreting cells do not correlate with cytokine concentration. In conclusion, this study supports the hypothesis that a Th1-like response is required for optimal eradication of Borrelia.
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Affiliation(s)
- C Ekerfelt
- Division of Clinical Immunology, and Unit of Autoimmunity and Immune Regulation, Department of Molecular and Clinical Medicine, Faculty of Health Sciences, University Hospital, Linköping, Sweden.
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Dórea JG, de Souza JR, Rodrigues P, Ferrari I, Barbosa AC. Hair mercury (signature of fish consumption) and cardiovascular risk in Munduruku and Kayabi Indians of Amazonia. ENVIRONMENTAL RESEARCH 2005; 97:209-219. [PMID: 15533337 DOI: 10.1016/j.envres.2004.04.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 04/09/2004] [Accepted: 04/12/2004] [Indexed: 05/24/2023]
Abstract
Fish is an important natural resource in the diet of inhabitants of the Amazon rain forest and a marker of its consumption (hair Hg) was used to compare selected cardiovascular risk parameters between tribes of Eastern Amazonia. Three Munduruku (Terra Preta, Kaburua, Cururu) villages and one Kayabi village at the banks of head rivers (Tapajos, Tropas, Kabitutu, Cururu, Curuzinho, Teles Pires) of the Tapajos Basin were studied in relation to fish Hg concentrations, mercury in hair (fish consumption) and erythrocytes, body mass index (height/weight, kg/cm2), and blood pressure. The mean fish Hg concentrations were higher in predatory (578.6 ng/g) than in nonpredatory species (52.8 ng/g). Overall only 26% of fish Hg concentrations were above 500 ng/g, and only 11% were above 1000 ng/g. There was no systematic trend in fish Hg concentrations from rivers with a history of gold-mining activities. The biomarker of fish consumption (hair Hg) was significantly associated with erythrocyte-Hg (r=0.5181; P=0.0001) and was significantly higher in Kayabi (12.7 microg/g) than in the Munduruku (3.4 microg/g). Biomarker-assessed fish consumption rate was higher in the Kayabi (110 g/day) than in the Munduruku villages (30 g/day). Although no significant differences in body mass index (BMI) were observed between tribes, there was a trend of lower increase in blood pressure with age among the higher fish consumers (Kayabi). Summary clinical evaluation did not detect neurologic complaints compatible with Hg intoxication (paraparesis, numbness, tremor, balancing failure), but endemic tropical diseases such as clinical history of malaria showed a high prevalence (55.4%). Fish is an abundant natural resource, important in the Indian diet, that has been historically consumed without perceived problems and can easily be traced through hair Hg. The exposure to freshwater fish monomethyl mercury is less of an issue than endemic infectious diseases such as malaria and lack of basic medical services.
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Affiliation(s)
- José G Dórea
- Faculdade de Ciências da Saúde, Universidade de Brasília, C.P. 04322, 70919-970 Brasília, DF, Brazil.
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King MD, Lindsay DS, Holladay S, Ehrich M. Neurotoxicity and immunotoxicity assessment in CBA/J mice with chronic Toxoplasma gondii infection and multiple oral exposures to methylmercury. J Parasitol 2003; 89:856-9. [PMID: 14533705 DOI: 10.1645/ge-79r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The present study was conducted to determine the effect of multiple low doses of methylmercury (MeHg) on the course of a chronic Toxoplasma gondii infection. Four groups of 6-wk-old female CBA/J mice either were fed 25 T. gondii tissue cysts of the ME-49 strain or were vehicle control. Six weeks later, half of each group was orally gavaged with 8-mg/kg body weight doses of MeHg on days 0, 2, 4, 7, 10, and 13, totaling 4 experimental groups. Mice were killed on day 17 or 18 after MeHg exposure. Flow cytometric analysis of lymphocyte subpopulations in the thymus demonstrated a significant increase in the percentage of CD4- CD8+ T-cells in mice exposed to MeHg with a concurrent T. gondii infection. Groups of mice exposed to MeHg showed a decrease in total thymic cellularity and cellularity of all T-cell subpopulations when compared with control mice, but viability of these cells was unaffected. Splenic cell viability was decreased in mice exposed to MeHg, but alterations in T-cell subpopulations were not noted. These data indicate that multiple low doses of MeHg may not exacerbate chronic toxoplasmosis, but MeHg-induced effects on the immune system were evident.
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Affiliation(s)
- Marquea D King
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia 24061, USA
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Silbergeld EK, Nash D, Trevant C, Strickland GT, de Souza JM, da Silva RSU. Mercury exposure and malaria prevalence among gold miners in Pará, Brazil. Rev Soc Bras Med Trop 2002; 35:421-9. [PMID: 12621659 DOI: 10.1590/s0037-86822002000500001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Economic development, including resource extraction, can cause toxic exposures that interact with endemic infectious diseases. Mercury is an immunotoxic metal used in the amalgamation of gold, resulting in both occupational exposures and environmental pollution. A cross-sectional medical survey was conducted in 1997 on 135 garimpeiros in Para, Brazil, because of their risks of both mercury exposure and malaria transmission. Mean levels of blood and urine mercury were well above non-exposed background levels. Twenty-six subjects had malaria parasitemia: Health symptoms consistent with mercury exposure were reported, but neither symptoms nor signs correlated with mercury levels in blood or urine. We did not find a dose response relationship between mercury exposure and likelihood of prevalent malaria infection, but there was a possible reduction in acquisition of immunity that may be associated with conditions in gold mining, including mercury exposure.
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Affiliation(s)
- Ellen K Silbergeld
- Department of Environmental Health Sciences, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD, USA.
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