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1.
J Toxicol Environ Health A ; 81(1-3): 1-5, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29173133

RESUMO

To increase current knowledge on the epidemiology of protozoan parasites in wastewater treatment plants (WWTP), the occurrence of Entamoeba histolytica and Toxoplasma gondii in raw and treated wastewater was investigated. Samples were collected from WWTP twice a month over a period of 8 months. Determination of protozoa was performed using polymerase chain reaction (PCR) and light microscopy. After concentration and purification of wastewater samples, DNA extraction was conducted followed by PCR amplification of small subunit ribosomal RNA (SSU rRNA) gene sequences of E. histolytica and B1 gene of T. gondii. Loop-Mediated Isothermal Amplification (LAMP) primer set was designed from E. histolytica hemolysin gene HLY6. Amplification of DNA in the LAMP mixture was monitored by naked eye as a blue color solution after addition of, hydroxynaphthol blue (HNB) to the reaction tube. Light microscopy revealed the presence of Entamoeba in all raw wastewater samples and treated water samples. PCR amplification of DNA products revealed that all, (9/9) wastewater samples were positive for Entamoeba. None was positive for Toxoplasma. These findings, which corroborate recent observations, indicate that E. histolytica may pose a public health risk.


Assuntos
Entamoeba histolytica/isolamento & purificação , Toxoplasma/isolamento & purificação , Águas Residuárias/parasitologia , Animais , Primers do DNA , DNA de Protozoário/análise , Alemanha , Técnicas de Amplificação de Ácido Nucleico , Reação em Cadeia da Polimerase , Purificação da Água/métodos
2.
J Toxicol Environ Health A ; 78(6): 381-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25734765

RESUMO

Microbial pathogens are among the major health problems associated with water and wastewater. Classical indicators of fecal contamination include total coliforms, Escherichia coli, and Clostridium perfringens. These fecal indicators were monitored in order to obtain information regarding their evolution during wastewater treatment processes. Helminth eggs survive for a long duration in the environment and have a high potential for waterborne transmission, making them reliable contaminant indicators. A large quantity of helminth eggs was detected in the wastewater samples using the Bailanger method. Eggs were found in the influent and effluent with average concentration ranging from 11 to 50 eggs/L. Both E. coli and total coliforms concentrations were significantly 1- to 3-fold higher in influent than in effluent. The average concentrations of E. coli ranged from 2.5×10(3) to 4.4×10(5) colony-forming units (CFU)/100 ml. Concentrations of total coliforms ranged from 3.6×10(3) to 7.9×10(5) CFU/100 ml. Clostridium perfringens was also detected in influent and effluent of wastewater treatment plants (WWTP) at average concentrations ranging from 5.4×10(2) to 9.1×10(2) most probable number (MPN)/100 ml. Significant Spearman rank correlations were found between helminth eggs and microbial indicators (total coliform, E. coli, and C. perfringens) in the WWTP. There is therefore need for additional microbial pathogen monitoring in the WWTP to minimize public health risk.


Assuntos
Enterobacteriaceae/fisiologia , Monitoramento Ambiental , Helmintos/fisiologia , Águas Residuárias/microbiologia , Águas Residuárias/parasitologia , Animais , Cidades , Clostridium perfringens/isolamento & purificação , Clostridium perfringens/fisiologia , Contagem de Colônia Microbiana , Enterobacteriaceae/isolamento & purificação , Escherichia coli/isolamento & purificação , Escherichia coli/fisiologia , Fezes/microbiologia , Fezes/parasitologia , Alemanha , Helmintos/crescimento & desenvolvimento , Helmintos/isolamento & purificação , Eliminação de Resíduos Líquidos
3.
Parasitol Res ; 112(9): 3335-46, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23820606

RESUMO

The macrophage migration inhibitory factors (MIFs) from the filarial parasite Onchocerca volvulus (OvMIF) were compared to the MIFs from the free-living nematode Caenorhabditis elegans (CeMIF) with respect to molecular, biochemical and immunological properties. Except for CeMIF-4, all other MIFs demonstrated tautomerase activity. Surprisingly, OvMIF-1 displayed oxidoreductase activity. The strongest immunostaining for OvMIF-1 was observed in the outer cellular covering of the adult worm body, the syncytial hypodermis; moderate immunostaining was observed in the uterine wall. The generation of a strong humoral immune response towards OvMIF-1 and reduced reactivity to OvMIF-2 was indicated by high IgG levels in patients infected with O. volvulus and cows infected with the closely related Onchocerca ochengi, both MIFs revealing identical amino acid sequences. Using Litomosoides sigmodontis-infected mice, a laboratory model for filarial infection, MIFs derived from the tissue-dwelling O. volvulus, the rodent gut-dwelling Strongyloides ratti and from free-living C. elegans were recognized, suggesting that L. sigmodontis MIF-specific IgM and IgG1 were produced during L. sigmodontis infection of mice and cross-reacted with all MIF proteins tested. Thus, MIF apparently functions as a target of B cell response during nematode infection, but in the natural Onchocerca-specific human and bovine infection, the induced antibodies can discriminate between MIFs derived from parasitic or free-living nematodes.


Assuntos
Caenorhabditis elegans/metabolismo , Fatores Inibidores da Migração de Macrófagos/metabolismo , Onchocerca volvulus/metabolismo , Sequência de Aminoácidos , Animais , Anticorpos Anti-Helmínticos/biossíntese , Caenorhabditis elegans/genética , Caenorhabditis elegans/imunologia , Bovinos , Reações Cruzadas , Feminino , Filariose/imunologia , Filariose/parasitologia , Filarioidea/imunologia , Filarioidea/fisiologia , Humanos , Imunidade Humoral , Fatores Inibidores da Migração de Macrófagos/genética , Fatores Inibidores da Migração de Macrófagos/imunologia , Fatores Inibidores da Migração de Macrófagos/isolamento & purificação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Onchocerca volvulus/genética , Onchocerca volvulus/imunologia , Oncocercose/imunologia , Oncocercose/parasitologia , Proteínas Recombinantes , Alinhamento de Sequência , Análise de Sequência de DNA , Sigmodontinae , Especificidade por Substrato
4.
J Toxicol Environ Health A ; 76(8): 509-14, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23721585

RESUMO

Giardia is one of the most common human enteric parasites that continue to be a major cause of diarrheal disease globally. Wastewater is an important source of Giardia transmission, and control of the pathogen by appropriate treatment of wastewater would limit its transmission. In this study the occurrence of Giardia cysts at various stages of the wastewater treatment plants was monitored for a period of 18 mo. Using immunomagnetic separation and immunofluorescence with monoclonal antibodies, cysts were detected in all samples throughout the sampling period at a concentration ranging from 50 to 7548 cysts/L. The overall removal efficiency of the cysts in the treatment plants was 78%. Seasonal analyses of results revealed that the pathogens (cysts) were most prevalent in influents and effluents during autumn and winter.


Assuntos
Giardia/isolamento & purificação , Esporos de Protozoários/isolamento & purificação , Águas Residuárias/parasitologia , Microbiologia da Água , Purificação da Água , Animais , Monitoramento Ambiental , Imunofluorescência , Alemanha , Giardia/fisiologia , Esporos de Protozoários/imunologia
5.
PLoS One ; 8(4): e60731, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23593298

RESUMO

Glutathione (GSH) and GSH-dependent enzymes play a key role in cellular detoxification processes that enable organism to cope with various internal and environmental stressors. However, it is often not clear, which components of the complex GSH-metabolism are required for tolerance towards a certain stressor. To address this question, a small scale RNAi-screen was carried out in Caenorhabditis elegans where GSH-related genes were systematically knocked down and worms were subsequently analysed for their survival rate under sub-lethal concentrations of arsenite and the redox cycler juglone. While the knockdown of γ-glutamylcysteine synthetase led to a diminished survival rate under arsenite stress conditions, GSR-1 (glutathione reductase) was shown to be essential for survival under juglone stress conditions. gsr-1 is the sole GSR encoding gene found in C. elegans. Knockdown of GSR-1 hardly affected total glutathione levels nor reduced glutathione/glutathione disulphide (GSH/GSSG) ratio under normal laboratory conditions. Nevertheless, when GSSG recycling was impaired by gsr-1(RNAi), GSH synthesis was induced, but not vice versa. Moreover, the impact of GSSG recycling was potentiated under oxidative stress conditions, explaining the enormous effect gsr-1(RNAi) knockdown had on juglone tolerance. Accordingly, overexpression of GSR-1 was capable of increasing stress tolerance. Furthermore, expression levels of SKN-1-regulated GSR-1 also affected life span of C. elegans, emphasising the crucial role the GSH redox state plays in both processes.


Assuntos
Caenorhabditis elegans/enzimologia , Caenorhabditis elegans/fisiologia , Glutationa Redutase/metabolismo , Longevidade , Estresse Oxidativo , Animais , Arsenitos/toxicidade , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Glutationa/metabolismo , Glutationa Redutase/deficiência , Glutationa Redutase/genética , Longevidade/efeitos dos fármacos , Naftoquinonas/toxicidade , Oxidantes/toxicidade , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fenótipo , Interferência de RNA , Estresse Fisiológico/efeitos dos fármacos
6.
J Toxicol Environ Health A ; 75(22-23): 1351-8, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23095153

RESUMO

Cryptosporidium parvum is one of the most common human parasitic protozoa and is responsible for many waterborne outbreaks in several industrialized countries. The oocyst, which is the infective form, is known to be highly resistant to wastewater treatment procedures and represents a potential hazard to human populations through contaminated raw or treated wastewater. In this investigation, the occurrence of Cryptosporidium in wastewater samples was monitored and removal efficiency was assessed. Treated (effluent) and untreated (influent) wastewater samples were collected seasonally over a period of 2 years. Oocysts were repeatedly detected in influent and effluent samples collected from the treatment plant during all sampling seasons, with a mean concentration of 782 oocysts/L. The seasonal distribution showed that oocysts are predominant during autumn and winter. Molecular analyses via the small (18S) subunit of rRNA amplification and subsequent sequencing with an objective of characterizing the oocysts revealed that Cryptosporidium parvum was the dominant Cryptosporidium parasite present in wastewater.


Assuntos
Cryptosporidium/isolamento & purificação , Eliminação de Resíduos Líquidos , Águas Residuárias/parasitologia , Anticorpos Monoclonais/metabolismo , Anticorpos Antiprotozoários/metabolismo , Cryptosporidium/classificação , Cryptosporidium/crescimento & desenvolvimento , Cryptosporidium/metabolismo , Monitoramento Ambiental , Alemanha , Separação Imunomagnética , Resíduos Industriais , Tipagem Molecular , Oocistos/crescimento & desenvolvimento , Parasitologia/métodos , RNA de Protozoário/metabolismo , RNA Ribossômico 18S/metabolismo , Estações do Ano , Esgotos/parasitologia , Poluição da Água/prevenção & controle , Purificação da Água
7.
Trop Med Int Health ; 8(7): 643-9, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12828548

RESUMO

There is a lack of data on the Anopheles fauna, its biology and the roles played by different vector species in the transmission of malaria in the mount Cameroon region. The biting habits, feeding behaviour and entomological inoculation rates of different Anopheles species during the dry and rainy season were investigated. A total of 2165 Anopheles was collected, 805 in the rainy season and 1360 in the dry season. Five Anopheles species were identified: Anopheles gambiae s.l., An. funestus, An. hancocki, An. moucheti and An. nili. An. gambiae, An. funestus and An. hancocki, recorded during both seasons, were the main vectors of malaria in the region. An. gambiae s.s. was the only member of the An. gambiae (Giles) complex. These three species had their peak activity between 1 and 2 am. A human blood index (HBI) of 98.29% was recorded for fed Anopheles. The sporozoite rate, for all vectors together, was significantly higher in the rainy season (9.4%) than in the dry season (4.2%) with all the species infected by Plasmodium falciparum. The average inoculation rate was 0.44 infective bites per man per night, which adds up to 161 infective bites per year in this study area. Analyses of relative abundance and infection rate of malaria vectors at different sites situated along a transect of 20 km during the dry season showed high heterogeneity in biting and sporozoite rates. No malaria vector was caught at 1200 m a.s.l. The mount Cameroon region should be considered an area of high malaria transmission intensity.


Assuntos
Anopheles/fisiologia , Comportamento Alimentar , Mordeduras e Picadas de Insetos/epidemiologia , Insetos Vetores/fisiologia , Malária Falciparum/transmissão , Altitude , Animais , Anopheles/classificação , Anopheles/parasitologia , Comportamento Animal , Camarões/epidemiologia , Humanos , Insetos Vetores/classificação , Insetos Vetores/parasitologia , Plasmodium falciparum/isolamento & purificação , Estações do Ano , Esporozoítos/isolamento & purificação
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