Objective:To compare the genotype frequencies of HLA class-ⅡDRB1 alleles in Giardia(G.)lamblia-infected children.Methods:A total of 490 Egyptian children aged 2-16 years were subjected to microscopic stool examinatio...Objective:To compare the genotype frequencies of HLA class-ⅡDRB1 alleles in Giardia(G.)lamblia-infected children.Methods:A total of 490 Egyptian children aged 2-16 years were subjected to microscopic stool examination to detect G.lamblia infection,and to exclude other intestinal pathogens.On the basis of their microscopic findings,a group of 80 children were chosen as giardiasis cases,another 80 children were confirmed as Giardia free control group by immunochromatographic test,and the remaining children were excluded.Both giardiasis and control groups were then subjected to blood examination to identify their genetic type of HLA-DRB1 alleles.Results:HLA class-ⅡDRB1*03:01 and DRB1*13:01 alleles were significantly associated with G.lamblia infection(P<0.001 for each variable).On the other hand,HLA class-ⅡDRB1*04:02,DRB1*10:01,DRB1*14:01 and DRB1*15:01 alleles were significantly demonstrated in Giardia free children.However,other HLA-DRB1 alleles did not show any significant association with giardiasis.Conclusions:HLA class-ⅡDRB1*03,DRB1*13,DRB1*04,DRB1*10,DRB1*14 and DRB1*15 alleles may be involved in the establishment of host immune response to G.lamblia infection.展开更多
AIM： To compare the efficacy and safety of five days apostrophe therapy of mebendazole （MBZ） versus quinacrine （QC） on human giardiasis in children.METHODS： A clinical trial was carried out in paediatric patien...AIM： To compare the efficacy and safety of five days apostrophe therapy of mebendazole （MBZ） versus quinacrine （QC） on human giardiasis in children.METHODS： A clinical trial was carried out in paediatric patients （aged 5-15 years） with confirmed symptomatic G. duodenalis mono-infection. Patients were randomly assigned to receive either MBZ [200 mg taken three times per day GRID） （n = 61）] or QC [2 mg/kg bodyweight tid （n = 61）], both for five days. Follow-up faecal samples were obtained at 3, 5 and 7 d after the end of the treatment.RESULTS： Although the frequency of cure was higher for QC （83.6%） than for MBZ （78.7%）, the difference was not statistically significant （P 〉 0.05）. Adverse events were reported more in the QC group （P 〈 0.05）, all of them transient and self-limiting.CONCLUSION： Despite final cure rates ocurring lower than expected, the overall results of this study reconfirmed the efficacy of MBZ in giardiasis and also indicate that, although comparable to QC, at least in this setting the 5 d course of MBZ did not appear to improve the cure rates in this intestinal parasitic infection.展开更多
The occurrence and risks of Giardia in China have been unclear to date,which has made it difficult to properly manage source water as well as to create reasonable drinking water standards.The levels of Giardia in rive...The occurrence and risks of Giardia in China have been unclear to date,which has made it difficult to properly manage source water as well as to create reasonable drinking water standards.The levels of Giardia in river networks of several cities in Zhejiang Province,China were found to be in the range of 0-5 oocysts/10 L in the rainy season in 2008.The mortality due to Giardia infection for people in this region was calculated to be from 0 to 1.95 × 10？8 persons using a conditional probability equation.Based on multiple unboiled water intake routes,the disability-adjusted life years（DALYs） due to Giardia infection for people who consumed conventionally treated water was 0.625（95% CI：0.137-2.05） per 105 persons,with the symptom of hospitalization making the highest contribution to total DALYs（0.56 per 105 persons;95% CI：0.122-1.84）.The DALYs decreased to 0.425（95% CI：0.137-2.05） per 105 persons per year for those consuming water treated with advanced technology.These values were lower than the acceptable risk（1.97 × 10？5 DALYs per year）.This study revealed the risk of Giardia infection to the people in river networks of Zhejiang Province for the first time,and provides a method to evaluate the risk of Giardia infection.The results are useful for the modification of drinking water quality standards based on cost-benefit analysis.展开更多
Objective: To investigate the efficacy of pomegranate(Punica granatum) peel extract as an alternative treatment on the white laboratory mice against giardiasis.Methods: Experimental animals were divided into five grou...Objective: To investigate the efficacy of pomegranate(Punica granatum) peel extract as an alternative treatment on the white laboratory mice against giardiasis.Methods: Experimental animals were divided into five groups, including Group A:control(infected untreated), Group B: infected and fed with pectin 7 days before infection, Group C: infected and fed with pectin starting from 7th day of infection,Group D: infected and fed with pomegranate peel extract 7 days before infection, and Group E: infected and fed with pomegranate peel extract starting from 7th day of infection.Results: Results from this study revealed that the prevention rate in the experimental groups reached approximately 50% by the 10 th day of using pomegranate peel extract.Moreover, stool cyst counts of groups showed a significant reduction in the shedding of cysts approximately 75.6% by day 20 post-infection. ELISA test showed a reduction in Giardia antigen in the stools of the experimental groups which received pomegranate peel extract. The cure rate of these groups was approximately 97.4% by 28 th day of infection.Conclusions: Our present findings indicated that the pomegranate peel extract proved to be valuable in prevention and treatment of Giardia lamblia infection. Further studies are required to determine the effective dose of pomegranate peel extract against Giardia lamblia infection.展开更多
AIM: To evaluate whether a higher prevalence of Giardia lamblia infection is associated with an increase in irritable bowel syndrome (IBS) prescriptions at the county level in Michigan. METHODS: The Michigan Disease S...AIM: To evaluate whether a higher prevalence of Giardia lamblia infection is associated with an increase in irritable bowel syndrome (IBS) prescriptions at the county level in Michigan. METHODS: The Michigan Disease Surveillance System (MDSS) was used to ascertain both the numbers of Giardia lamblia infections as well as the total number of foodborne illnesses per population by county in Michigan during 2005. This was compared with Blue Cross Blue Shield (BCBS) of Michigan numbers of drug prescriptions for IBS per one thousand members per county in 2005. These data were also analyzed for associations with per capita income by county and the number of refugees entering each county in 2005. RESULTS: There were a total of 786 confirmed cases of Giardia lamblia reported to MDSS in 2005. During the same time period, the number of prescriptions for IBS varied from 0.5 per 1000 members up to 6.0 per 1000 members per month. There was no trend towards higher numbers of IBS prescriptions in the counties with more Giardia lamblia infections. Per capita income was not associated with either IBS prescriptions or Giardiasis. There was a significant linear association between the number of refugees entering each county, and the number of Giardia lamblia cases per 100 000 population. CONCLUSION: In this ecological study, there was no association found between BCBS prescriptions for IBS and Giardia lamblia infections in Michigan counties. Our findings may have been influenced by the disparate number of refugees admitted per county.展开更多
Objective:To construct rapidly a full-length cDNA library from nanogram amounts total RIMA of Giardia lamblia(G.lamblia) trophozoites stocked in RNA stabilization reagent.Methods:Total RNA of Giardia was extracted usi...Objective:To construct rapidly a full-length cDNA library from nanogram amounts total RIMA of Giardia lamblia(G.lamblia) trophozoites stocked in RNA stabilization reagent.Methods:Total RNA of Giardia was extracted using Trizol reagent.A full-length cDNA library of G.lamblia trophozoites was constructed by a long-distance PCR(LD-PCR) method.The recombinant rate and the coverage rate of full-length clones of the library were evaluated.The inserted fragments were identified and sequenced by PCR amplification.Results:The titer of cDNA library was 3.85×10~7 pfu/mL.The length of inserted fragments ranged from 0.4 to 2.5 kb,and the recombination efficiency accounted for 100%(20/20).The coverage rate of full-length clones is high(17/20). Conclusions:The RNA stabilization reagent may be used to fix the cells and prevent the RNA in cells even though delivered under normal atmospheric temperature.The long-distance PCR can be used to construct a full-length cDNA library rapidly and it needs less RNA than the traditional method from mRNA.展开更多
Membrane bioreactors（MBR） are highly efficient at intercepting particles and microbes and have become an important technology for wastewater reclamation. However, many pathogens can accumulate in activated sludge du...Membrane bioreactors（MBR） are highly efficient at intercepting particles and microbes and have become an important technology for wastewater reclamation. However, many pathogens can accumulate in activated sludge due to the long residence time usually adopted in MBR, and thus may pose health risks when membrane integrity problems occur.This study presents data from a survey on the occurrence of water-borne Giardia pathogens in reclaimed water from a full-scale wastewater treatment plant with MBR experiencing membrane integrity failure, and assessed the associated risk for green space irrigation. Due to membrane integrity failure, the MBR effluent turbidity varied between 0.23 and 1.90 NTU over a period of eight months. Though this turbidity level still met reclaimed water quality standards（≤ 5 NTU）, Giardia were detected at concentrations of 0.3 to 95 cysts/10 L, with a close correlation between effluent turbidity and Giardia concentration. All β-giardin gene sequences of Giardia in the WWTP influents were genotyped as Assemblages A and B, both of which are known to infect humans. An exponential dose–response model was applied to assess the risk of infection by Giardia. The risk in the MBR effluent with chlorination was9.83 × 10-3, higher than the acceptable annual risk of 1.0 × 10^-4. This study suggested that membrane integrity is very important for keeping a low pathogen level, and multiple barriers are needed to ensure the biological safety of MBR effluent.展开更多
Objective To simultaneously detect viable Cryptosporidium parvum oocysts and Giardia duodenalis cysts for the purpose of reducing time and cost spent. Methods A duplex reverse transcription polymerase chain reaction ...Objective To simultaneously detect viable Cryptosporidium parvum oocysts and Giardia duodenalis cysts for the purpose of reducing time and cost spent. Methods A duplex reverse transcription polymerase chain reaction （RT-PCR） method was newly developed. Results Using duplex RT-PCR method for the hsp70 gene, viable （oo）cyst concentrations of 10^1 and l0^3 （oo）cysts/100 I.tL could be detected for C. parvum and G duodenalis, respectively. However, after heat-shock stimulation the expression of hsp70 mRNAs was detectable at 10^0 and 10^1 （oo）cysts/100 μL concentrations of C. parvum and G. duodenalis, respectively. Thus, the detection sensitivity was significantly increased when the viable （oo）cysts were exposed to heat shock. Conclusion This study describes a new duplex RT-PCR method for hsp70 gene to detect the viable （oo）cysts of the C. parvum and G duodenalis with less time consumed and at a lower cost. This newly developed duplex RT-PCR method may be used to detect these parasites not only in aquatic environments but also in clinical samples.展开更多
Objective: To investigate the prevalence and risk factors of Giardia infection among rural communities among rural communities in Yemen.Methods: In this cross-sectional study, a total of 605 stool samples were collect...Objective: To investigate the prevalence and risk factors of Giardia infection among rural communities among rural communities in Yemen.Methods: In this cross-sectional study, a total of 605 stool samples were collected and screened for the presence of Giardia duodenalis(G.duodenalis) cysts and/or trophozoites by using three different diagnostic methods: direct smear, formalin-ether sedimentation,and trichrome staining.A pre-tested questionnaire was used to collect information on the demographic, socioeconomic, behavioural and environmental characteristics of the participants.Results: Overall, 28.1%(170/605) of the participants were infected by G.duodenalis.The prevalence was significantly higher among male participants compared to female(P = 0.034); however, it was not significant among different age groups(P > 0.05).Univariate and multivariate analyses identified four variables as the significant key risk factors of Giardia infection among the sampled communities.These are, in addition to being of the male gender, using unsafe water sources for drinking water, not washing hands after defecation, presence of other family members infected with Giardia, and close contact with domestic animals.Conclusions: The study reveals that Giardia infection is still prevalent among rural communities in Yemen.The provision of clean and safe drinking water, proper sanitation,and health education regarding personal hygiene practices, particularly handwashing, as well as identifying and treating infected family members is imperative and these interventions should be considered in a strategy to control intestinal parasites among these communities in order to curtail the transmission and morbidity caused by G.duodenalis.展开更多
The genes encoding type II DNA topoisomerases were investigated in Giardia lamblia genome, and a type IIA gene,GlTop 2 was identified. It is a single copy gene with a 4476 bp long ORF without intron. The deduced amino...The genes encoding type II DNA topoisomerases were investigated in Giardia lamblia genome, and a type IIA gene,GlTop 2 was identified. It is a single copy gene with a 4476 bp long ORF without intron. The deduced amino acid sequence shows strong homology to eukaryotic DNA Top 2. However, some distortions were found, such as six insertions in the ATPase domain and the central domain, a -100 aa longer central domain; a ~200 aa shorter C-terminal domain containing rich charged residues. These features revealed by comparing with Top 2 of the host, human, might be helpful in exploiting drug selectivity for antigiardial therapy. Phylogenetic analysis of eukaryotic enzymes showed that kinetoplastids, plants, fungi, and animals were monophyletic groups, and the animal and fungi lineages shared a more recent common ancestor than either did with the plant lineage; microsporidia grouped with fungi. However, unlike many previous phylogenetic analyses, the ''amitochondriate'' G. lamblia was not the earliest branch but diverged after mitochondriate kinetoplastids in our trees. Both the finding of typical eukaryotic type IIA topoisomerase and the phylogenetic analysis suggest G, lamblia is not possibly as primitive as was regarded before and might diverge after the acquisition of mitochondria. This is consistent with the recent discovery of mitochondrial remnant organelles in G. lamblia.展开更多
Diarrheal disease is a chronic public health problem in Chobe District, Botswana. Acute diarrheal outbreaks occur annually with a bimodal seasonal pattern coinciding with major hydrological phenomena. Information is l...Diarrheal disease is a chronic public health problem in Chobe District, Botswana. Acute diarrheal outbreaks occur annually with a bimodal seasonal pattern coinciding with major hydrological phenomena. Information is lacking regarding the etiology of reoccurring outbreaks. Cryptosporidium and Giardia are recognized as important waterborne causes of diarrheal disease with Cryptosporidium transmission potentially involving zoonotic reservoirs. In Chobe District, municipal water is obtained from the Chobe River after it exits the Chobe National Park where high concentrations of wildlife occur. Using the Giardia/Cryptosporidium QUIK CHEK rapid antigen cartridge test, we evaluate the occurrence of Giardia and Cryptosporidium among patients (n = 153) presenting to medical facilities in Chobe District with diarrhea (August 2011-July 2012). Cryptosporidium was only identified in children less than two years of age (10%, n = 42, 95% CI 3% - 23%), with positive cases occurring during diarrheal outbreak periods. Infections were not identified in adults despite the high level of human immunodeficiency virus infection/acquired immunodeficiency syndrome (HIV/AIDS) in the region (n = 117). Although not significant, cases were predominately identified in the wet season outbreak (p = 0.94, 25%, n = 12, 95% CI 5% - 57%, dry season outbreaks 3%, n = 30, CI 95% 0% - 17%). Giardia infections occurred across age groups and seasons (7%, n = 153, 95% CI 4% - 10%). This is the first published report of human infections with Cryptosporidium and Giardia in this area of Africa. This study suggests that Cryptosporidium may be a potentially important cause of diarrheal disease in children less than 2 years of age in this region. Further research is required to identify pathogen transmission and persistence dynamics and public health implications, particularly the role of HIV/AIDS and vulnerability to waterborne disease.展开更多
Objective:To identify the frequencies(F) of ferredoxin and nitroreductase mutations were identified on Iranian clinical isolates of Giardia lamblia in order to predict whether the nitazoxanide can be prescribed as sui...Objective:To identify the frequencies(F) of ferredoxin and nitroreductase mutations were identified on Iranian clinical isolates of Giardia lamblia in order to predict whether the nitazoxanide can be prescribed as suitable drug for symptomatic to metronidazoleresistant giardiasis.Methods:Forty Giardia lamblia isolates as of 38 symptomatic and two metronidazole-resistant patients were collected from Iran.DNAs were extracted and amplified by targeting ferredoxin and Gl NR genes.The amplicons were directly sequenced to determine gene mutations.Results:The various amino acid substitutions(F:20%,Haplotype diversity:0.891,Tajima's D:-0.44013) were identified by analyzing ferredoxin gene in four symptomatic and two resistant isolates.Only,two haplotypes(F:5%,HD:0.345; Tajima's D:0.77815) characterized in metronidazole-resistant isolates of Gl NR,however,no point mutations was found in symptomatic isolates.Conclusions:Non-synonymous mutations of ferredoxin oxidoreductase gene reduce translational regulatory protein's binding affinity which concludes reduction of ferredoxin expression and its activity.This leads to decrease in metronidazole drug delivery into the cells.Mutations in these isolates may lead to their resistance to metronidazole.No to low synonymous mutations of Gl NR demonstrates that nitazoxanide can be prescribed as promising alternative treatment for symptomatic to metronidazole-resistant giardiasis in Iranian clinical isolates.展开更多
Objective:To determine the prevalence and risk factors of Giardia(G.)lamblia infections among the aboriginal community during the wet and dry seasons.Methods:A total of 473 stool samples from the aborigines in Temerlo...Objective:To determine the prevalence and risk factors of Giardia(G.)lamblia infections among the aboriginal community during the wet and dry seasons.Methods:A total of 473 stool samples from the aborigines in Temerloh,Pahang,Malaysia were collected during wet(n=256)and dry seasons(n=217).Smear of all the PVA-preserved stool samples were subjected to Trichrome staining and microscopic examination under 1000伊magnification(Nikon eclipse E100)for the detection of G.lamblia.Positivity was recorded based on the presence of G.lamblia in trophozoite and/or cyst forms.Results:The prevalence of giardiasis was 12.10%and 8.29%during the wet and dry season,respectively.Age of less or equal to 15 years old and presence of other family members with G.lamblia infection were found to be the significant risk factors to acquire G.lamblia infections during both seasons.Untreated water supply was the significant risk factor of giardiasis during the dry season.This study highlighted the possibility of anthroponotic transmission of G.lamblia during both seasons and waterborne transmission during the dry season in the aboriginal community.Conclusions:This study suggests that seasonal variation plays an important role in the prevalence and risk factor of G.lamblia infection in the aboriginal community.Therefore,close contact with Giardia-infected family members and water-related activities or usage of untreated water must be avoided to reduce the burden of G.lamblia infection in this community.展开更多
Swimming pools adopt chlorination to ensure microbial safety. Giardia has attracted attention in swimming pool water because of its occurrence, pathogenicity, and chlorine resistance. To control Giardia concentrations...Swimming pools adopt chlorination to ensure microbial safety. Giardia has attracted attention in swimming pool water because of its occurrence, pathogenicity, and chlorine resistance. To control Giardia concentrations in pool water and reduce the microbial risk, higher chlorine doses are required during disinfection. Unfortunately, this process produces carcinogenic disinfection byproducts that increase the risk of chemical exposure. Therefore, quantitatively evaluating the comparative microbial vs. chemical exposure risks that stem from chlorination inactivation of Giardia in swimming pool water is an issue that demands attention. We simulated an indoor swimming pool disinfection scenario that followed common real-world disinfection practices. A quantitative microbial risk assessment coupled with a chemical exposure risk assessment was employed to compare the Giardia microbial exposure risk(MER) and the trihalomethane chemical exposure risk(CER) to humans. The results demonstrated a 22% decrease in MER-and CER-induced health exposure risk, from 8.45E-5 at 8:00 to 6.60E-5 at 19:00. Both the MER and CER decreased gradually, dropping to 3.26E-5 and 3.35E-5 at 19:00, respectively. However, the CER exceeded the MER after 18:30 and became the dominant factor affecting the total exposure risk. Past the 18 hr mark, the contribution of trihalomethane CER far exceeded the risk aversion from microbial inactivation, leading to a net increase in total exposure risk despite the declining MER. Swimmers may consider swimming after 19:00, when the total exposure risk is the lowest. Lowering water temperature and/or p H were identified as the most sensitive factors to minimize the overall health exposure risk.展开更多
The nuclear matrix of diplomonad Giardia lamblia was detected for the first time with DGD embedmentsectioning- embedment free electron microscopy after a series of specific extractions. The result showed that archaezo...The nuclear matrix of diplomonad Giardia lamblia was detected for the first time with DGD embedmentsectioning- embedment free electron microscopy after a series of specific extractions. The result showed that archaezoa Giardia lamblia already possessed nuclear matrix within its two nuclei. The finest fibrils of the nuclear matrix of Giardia lamblia were measured to be about 11 to 13 nm in thickness. However, the nuclear lamina and nucleolus have never been observed. These results seem to suggest that nuclear matrix is an indispensable intranuclear structural component even in the primitive nucleus.展开更多
Objective: To investigate the efficacy of (Commiphora molmol(Myrrh)) extract as alternative treatment in hamsters against giardiasis. This study was conducted to evaluate the effect of the new compound (Commiphora mol...Objective: To investigate the efficacy of (Commiphora molmol(Myrrh)) extract as alternative treatment in hamsters against giardiasis. This study was conducted to evaluate the effect of the new compound (Commiphora molmol(Myrrh)), as agent a natural product extracted from the roots of Zingiber officinal, on Giardia lamblia infection as anti-protozoal and to study the parasitological and Histopathological impact of this treatment on the duodenal mucosa of infected hamsters. Fifty hamsters were divided into five groups: Group (A): normal control. Group (B): Giardia lamblia infected and untreated hamsters served as control. Group (C): infected with Giardia lamblia and treated with metronidazole in dose (120 μg/kg body weight twice daily for 7 successive days). Group (D) Giardia lamblia infected and orally treated with Myrrh (500 mg/Kg for 1 week). Group (E): Giardia lamblia infected and orally treated with combination 1/3 dose of (120 μg/kg body weight) metronidazole and Myrrh (250 mg/Kg) for 1 week). After 2 weeks of the treatment, hamsters were sacrificed. The highest percentages of reduction in the number of Giardia lamblia cysts and trophozoites were in the group receiving combined metronidazole and myrrh. Histopathological examination revealed complete healing of intestinal mucosa after the combined treatment, while partial healing of the lining epithelium of the intestine was noticed after metronidazole and either myrrh plant treatment.展开更多
This study was to investigate the effect of ozone （ O3 ） inactivation on Giardia in water by the fluorescence staining method. In order to elucidate the dominant mechanisms of inactivation, cell surface or inner cel...This study was to investigate the effect of ozone （ O3 ） inactivation on Giardia in water by the fluorescence staining method. In order to elucidate the dominant mechanisms of inactivation, cell surface or inner cell components damage were comparatively examined by scanning dectron microscopy （SEM）. Results suggested that O3 had a stronger effect on inactivating capability. Firstly, when the concentration of O3 was above 2.0 mg/L and the contact time was up to 5 min, it showed a significant inactivating effect. Secondly, the effect of turbidity on inactivation was also found to be significant in synthetic water; when turbidity increased, the inactivating effect decreased. Thirdly, the inactivating rates were improved with a temperature increase from 5 to 25℃, but decreased when the temperature were out of this range. The inactivating capability of O3 was stronger under acidic conditions than alkalic conditions. Lastly, when the concentration of organic matter in the reactive system was increased, probably due to the competition between G/ard/a and organics on O3, the inactivating rate was decreased; in addition, the cellular morphology of Giardia varied with different contact times. At contact time of 30 s, cells were rotundity and sphericity; at 60 s they became folded, underwent emboly, and burst; and at 240 s, the cell membrane of Giardia shrinked and collapsed completely.展开更多
文摘Objective:To compare the genotype frequencies of HLA class-ⅡDRB1 alleles in Giardia(G.)lamblia-infected children.Methods:A total of 490 Egyptian children aged 2-16 years were subjected to microscopic stool examination to detect G.lamblia infection,and to exclude other intestinal pathogens.On the basis of their microscopic findings,a group of 80 children were chosen as giardiasis cases,another 80 children were confirmed as Giardia free control group by immunochromatographic test,and the remaining children were excluded.Both giardiasis and control groups were then subjected to blood examination to identify their genetic type of HLA-DRB1 alleles.Results:HLA class-ⅡDRB1*03:01 and DRB1*13:01 alleles were significantly associated with G.lamblia infection(P<0.001 for each variable).On the other hand,HLA class-ⅡDRB1*04:02,DRB1*10:01,DRB1*14:01 and DRB1*15:01 alleles were significantly demonstrated in Giardia free children.However,other HLA-DRB1 alleles did not show any significant association with giardiasis.Conclusions:HLA class-ⅡDRB1*03,DRB1*13,DRB1*04,DRB1*10,DRB1*14 and DRB1*15 alleles may be involved in the establishment of host immune response to G.lamblia infection.
文摘AIM： To compare the efficacy and safety of five days apostrophe therapy of mebendazole （MBZ） versus quinacrine （QC） on human giardiasis in children.METHODS： A clinical trial was carried out in paediatric patients （aged 5-15 years） with confirmed symptomatic G. duodenalis mono-infection. Patients were randomly assigned to receive either MBZ [200 mg taken three times per day GRID） （n = 61）] or QC [2 mg/kg bodyweight tid （n = 61）], both for five days. Follow-up faecal samples were obtained at 3, 5 and 7 d after the end of the treatment.RESULTS： Although the frequency of cure was higher for QC （83.6%） than for MBZ （78.7%）, the difference was not statistically significant （P 〉 0.05）. Adverse events were reported more in the QC group （P 〈 0.05）, all of them transient and self-limiting.CONCLUSION： Despite final cure rates ocurring lower than expected, the overall results of this study reconfirmed the efficacy of MBZ in giardiasis and also indicate that, although comparable to QC, at least in this setting the 5 d course of MBZ did not appear to improve the cure rates in this intestinal parasitic infection.
基金supported by the Foundation of Major Science and Technology Program for Water Pollution Control and Treatment (No. 2009ZX07419-002)the National Natural Science Foundation of China (No. 50778171,50809066, 20807013)
文摘The occurrence and risks of Giardia in China have been unclear to date,which has made it difficult to properly manage source water as well as to create reasonable drinking water standards.The levels of Giardia in river networks of several cities in Zhejiang Province,China were found to be in the range of 0-5 oocysts/10 L in the rainy season in 2008.The mortality due to Giardia infection for people in this region was calculated to be from 0 to 1.95 × 10？8 persons using a conditional probability equation.Based on multiple unboiled water intake routes,the disability-adjusted life years（DALYs） due to Giardia infection for people who consumed conventionally treated water was 0.625（95% CI：0.137-2.05） per 105 persons,with the symptom of hospitalization making the highest contribution to total DALYs（0.56 per 105 persons;95% CI：0.122-1.84）.The DALYs decreased to 0.425（95% CI：0.137-2.05） per 105 persons per year for those consuming water treated with advanced technology.These values were lower than the acceptable risk（1.97 × 10？5 DALYs per year）.This study revealed the risk of Giardia infection to the people in river networks of Zhejiang Province for the first time,and provides a method to evaluate the risk of Giardia infection.The results are useful for the modification of drinking water quality standards based on cost-benefit analysis.
文摘Objective: To investigate the efficacy of pomegranate(Punica granatum) peel extract as an alternative treatment on the white laboratory mice against giardiasis.Methods: Experimental animals were divided into five groups, including Group A:control(infected untreated), Group B: infected and fed with pectin 7 days before infection, Group C: infected and fed with pectin starting from 7th day of infection,Group D: infected and fed with pomegranate peel extract 7 days before infection, and Group E: infected and fed with pomegranate peel extract starting from 7th day of infection.Results: Results from this study revealed that the prevention rate in the experimental groups reached approximately 50% by the 10 th day of using pomegranate peel extract.Moreover, stool cyst counts of groups showed a significant reduction in the shedding of cysts approximately 75.6% by day 20 post-infection. ELISA test showed a reduction in Giardia antigen in the stools of the experimental groups which received pomegranate peel extract. The cure rate of these groups was approximately 97.4% by 28 th day of infection.Conclusions: Our present findings indicated that the pomegranate peel extract proved to be valuable in prevention and treatment of Giardia lamblia infection. Further studies are required to determine the effective dose of pomegranate peel extract against Giardia lamblia infection.
文摘AIM: To evaluate whether a higher prevalence of Giardia lamblia infection is associated with an increase in irritable bowel syndrome (IBS) prescriptions at the county level in Michigan. METHODS: The Michigan Disease Surveillance System (MDSS) was used to ascertain both the numbers of Giardia lamblia infections as well as the total number of foodborne illnesses per population by county in Michigan during 2005. This was compared with Blue Cross Blue Shield (BCBS) of Michigan numbers of drug prescriptions for IBS per one thousand members per county in 2005. These data were also analyzed for associations with per capita income by county and the number of refugees entering each county in 2005. RESULTS: There were a total of 786 confirmed cases of Giardia lamblia reported to MDSS in 2005. During the same time period, the number of prescriptions for IBS varied from 0.5 per 1000 members up to 6.0 per 1000 members per month. There was no trend towards higher numbers of IBS prescriptions in the counties with more Giardia lamblia infections. Per capita income was not associated with either IBS prescriptions or Giardiasis. There was a significant linear association between the number of refugees entering each county, and the number of Giardia lamblia cases per 100 000 population. CONCLUSION: In this ecological study, there was no association found between BCBS prescriptions for IBS and Giardia lamblia infections in Michigan counties. Our findings may have been influenced by the disparate number of refugees admitted per county.
基金supported by grants from the Education Department of Jilin Province(2010D532)the open grant from the State Key Laboratory of Genetic Resources and Evolution,Kunming Institute of Zoology(GREKF08-07)+2 种基金Natural Grant of Jilin City(201032243)Natural Foundation of Hainan Province of China(310043 and 811197)Key Project of Hainan Provincial Bureau of Health(No2010-41)
文摘Objective:To construct rapidly a full-length cDNA library from nanogram amounts total RIMA of Giardia lamblia(G.lamblia) trophozoites stocked in RNA stabilization reagent.Methods:Total RNA of Giardia was extracted using Trizol reagent.A full-length cDNA library of G.lamblia trophozoites was constructed by a long-distance PCR(LD-PCR) method.The recombinant rate and the coverage rate of full-length clones of the library were evaluated.The inserted fragments were identified and sequenced by PCR amplification.Results:The titer of cDNA library was 3.85×10~7 pfu/mL.The length of inserted fragments ranged from 0.4 to 2.5 kb,and the recombination efficiency accounted for 100%(20/20).The coverage rate of full-length clones is high(17/20). Conclusions:The RNA stabilization reagent may be used to fix the cells and prevent the RNA in cells even though delivered under normal atmospheric temperature.The long-distance PCR can be used to construct a full-length cDNA library rapidly and it needs less RNA than the traditional method from mRNA.
基金supported by the Creative Research Groups of China (No. 51221892, 21277169)
文摘Membrane bioreactors（MBR） are highly efficient at intercepting particles and microbes and have become an important technology for wastewater reclamation. However, many pathogens can accumulate in activated sludge due to the long residence time usually adopted in MBR, and thus may pose health risks when membrane integrity problems occur.This study presents data from a survey on the occurrence of water-borne Giardia pathogens in reclaimed water from a full-scale wastewater treatment plant with MBR experiencing membrane integrity failure, and assessed the associated risk for green space irrigation. Due to membrane integrity failure, the MBR effluent turbidity varied between 0.23 and 1.90 NTU over a period of eight months. Though this turbidity level still met reclaimed water quality standards（≤ 5 NTU）, Giardia were detected at concentrations of 0.3 to 95 cysts/10 L, with a close correlation between effluent turbidity and Giardia concentration. All β-giardin gene sequences of Giardia in the WWTP influents were genotyped as Assemblages A and B, both of which are known to infect humans. An exponential dose–response model was applied to assess the risk of infection by Giardia. The risk in the MBR effluent with chlorination was9.83 × 10-3, higher than the acceptable annual risk of 1.0 × 10^-4. This study suggested that membrane integrity is very important for keeping a low pathogen level, and multiple barriers are needed to ensure the biological safety of MBR effluent.
文摘Objective To simultaneously detect viable Cryptosporidium parvum oocysts and Giardia duodenalis cysts for the purpose of reducing time and cost spent. Methods A duplex reverse transcription polymerase chain reaction （RT-PCR） method was newly developed. Results Using duplex RT-PCR method for the hsp70 gene, viable （oo）cyst concentrations of 10^1 and l0^3 （oo）cysts/100 I.tL could be detected for C. parvum and G duodenalis, respectively. However, after heat-shock stimulation the expression of hsp70 mRNAs was detectable at 10^0 and 10^1 （oo）cysts/100 μL concentrations of C. parvum and G. duodenalis, respectively. Thus, the detection sensitivity was significantly increased when the viable （oo）cysts were exposed to heat shock. Conclusion This study describes a new duplex RT-PCR method for hsp70 gene to detect the viable （oo）cysts of the C. parvum and G duodenalis with less time consumed and at a lower cost. This newly developed duplex RT-PCR method may be used to detect these parasites not only in aquatic environments but also in clinical samples.
基金funded by the University of Malaya High Impact Research Grant UM-MOHE(UM.C/625/1/HIR/MOHE/MED/18)from the Ministry of Higher Education Malaysiathe University of Malaya Research Grants(RG331-15AFR)
文摘Objective: To investigate the prevalence and risk factors of Giardia infection among rural communities among rural communities in Yemen.Methods: In this cross-sectional study, a total of 605 stool samples were collected and screened for the presence of Giardia duodenalis(G.duodenalis) cysts and/or trophozoites by using three different diagnostic methods: direct smear, formalin-ether sedimentation,and trichrome staining.A pre-tested questionnaire was used to collect information on the demographic, socioeconomic, behavioural and environmental characteristics of the participants.Results: Overall, 28.1%(170/605) of the participants were infected by G.duodenalis.The prevalence was significantly higher among male participants compared to female(P = 0.034); however, it was not significant among different age groups(P > 0.05).Univariate and multivariate analyses identified four variables as the significant key risk factors of Giardia infection among the sampled communities.These are, in addition to being of the male gender, using unsafe water sources for drinking water, not washing hands after defecation, presence of other family members infected with Giardia, and close contact with domestic animals.Conclusions: The study reveals that Giardia infection is still prevalent among rural communities in Yemen.The provision of clean and safe drinking water, proper sanitation,and health education regarding personal hygiene practices, particularly handwashing, as well as identifying and treating infected family members is imperative and these interventions should be considered in a strategy to control intestinal parasites among these communities in order to curtail the transmission and morbidity caused by G.duodenalis.
基金supported by Grants (30070362, 30170135,30021004) the National Natural Science Foundationof China and Grants (KSCX2-SW-101C, STZ-00-23)the Chinese Academy of Sciences.
文摘The genes encoding type II DNA topoisomerases were investigated in Giardia lamblia genome, and a type IIA gene,GlTop 2 was identified. It is a single copy gene with a 4476 bp long ORF without intron. The deduced amino acid sequence shows strong homology to eukaryotic DNA Top 2. However, some distortions were found, such as six insertions in the ATPase domain and the central domain, a -100 aa longer central domain; a ~200 aa shorter C-terminal domain containing rich charged residues. These features revealed by comparing with Top 2 of the host, human, might be helpful in exploiting drug selectivity for antigiardial therapy. Phylogenetic analysis of eukaryotic enzymes showed that kinetoplastids, plants, fungi, and animals were monophyletic groups, and the animal and fungi lineages shared a more recent common ancestor than either did with the plant lineage; microsporidia grouped with fungi. However, unlike many previous phylogenetic analyses, the ''amitochondriate'' G. lamblia was not the earliest branch but diverged after mitochondriate kinetoplastids in our trees. Both the finding of typical eukaryotic type IIA topoisomerase and the phylogenetic analysis suggest G, lamblia is not possibly as primitive as was regarded before and might diverge after the acquisition of mitochondria. This is consistent with the recent discovery of mitochondrial remnant organelles in G. lamblia.
文摘Diarrheal disease is a chronic public health problem in Chobe District, Botswana. Acute diarrheal outbreaks occur annually with a bimodal seasonal pattern coinciding with major hydrological phenomena. Information is lacking regarding the etiology of reoccurring outbreaks. Cryptosporidium and Giardia are recognized as important waterborne causes of diarrheal disease with Cryptosporidium transmission potentially involving zoonotic reservoirs. In Chobe District, municipal water is obtained from the Chobe River after it exits the Chobe National Park where high concentrations of wildlife occur. Using the Giardia/Cryptosporidium QUIK CHEK rapid antigen cartridge test, we evaluate the occurrence of Giardia and Cryptosporidium among patients (n = 153) presenting to medical facilities in Chobe District with diarrhea (August 2011-July 2012). Cryptosporidium was only identified in children less than two years of age (10%, n = 42, 95% CI 3% - 23%), with positive cases occurring during diarrheal outbreak periods. Infections were not identified in adults despite the high level of human immunodeficiency virus infection/acquired immunodeficiency syndrome (HIV/AIDS) in the region (n = 117). Although not significant, cases were predominately identified in the wet season outbreak (p = 0.94, 25%, n = 12, 95% CI 5% - 57%, dry season outbreaks 3%, n = 30, CI 95% 0% - 17%). Giardia infections occurred across age groups and seasons (7%, n = 153, 95% CI 4% - 10%). This is the first published report of human infections with Cryptosporidium and Giardia in this area of Africa. This study suggests that Cryptosporidium may be a potentially important cause of diarrheal disease in children less than 2 years of age in this region. Further research is required to identify pathogen transmission and persistence dynamics and public health implications, particularly the role of HIV/AIDS and vulnerability to waterborne disease.
基金financially supported by Immunology Research Center,Tabriz University of Medical Sciences,Tabriz,Iranthe master’s thesis of the first author(Thesis No.93/2-4/12)
文摘Objective:To identify the frequencies(F) of ferredoxin and nitroreductase mutations were identified on Iranian clinical isolates of Giardia lamblia in order to predict whether the nitazoxanide can be prescribed as suitable drug for symptomatic to metronidazoleresistant giardiasis.Methods:Forty Giardia lamblia isolates as of 38 symptomatic and two metronidazole-resistant patients were collected from Iran.DNAs were extracted and amplified by targeting ferredoxin and Gl NR genes.The amplicons were directly sequenced to determine gene mutations.Results:The various amino acid substitutions(F:20%,Haplotype diversity:0.891,Tajima's D:-0.44013) were identified by analyzing ferredoxin gene in four symptomatic and two resistant isolates.Only,two haplotypes(F:5%,HD:0.345; Tajima's D:0.77815) characterized in metronidazole-resistant isolates of Gl NR,however,no point mutations was found in symptomatic isolates.Conclusions:Non-synonymous mutations of ferredoxin oxidoreductase gene reduce translational regulatory protein's binding affinity which concludes reduction of ferredoxin expression and its activity.This leads to decrease in metronidazole drug delivery into the cells.Mutations in these isolates may lead to their resistance to metronidazole.No to low synonymous mutations of Gl NR demonstrates that nitazoxanide can be prescribed as promising alternative treatment for symptomatic to metronidazole-resistant giardiasis in Iranian clinical isolates.
文摘Objective:To determine the prevalence and risk factors of Giardia(G.)lamblia infections among the aboriginal community during the wet and dry seasons.Methods:A total of 473 stool samples from the aborigines in Temerloh,Pahang,Malaysia were collected during wet(n=256)and dry seasons(n=217).Smear of all the PVA-preserved stool samples were subjected to Trichrome staining and microscopic examination under 1000伊magnification(Nikon eclipse E100)for the detection of G.lamblia.Positivity was recorded based on the presence of G.lamblia in trophozoite and/or cyst forms.Results:The prevalence of giardiasis was 12.10%and 8.29%during the wet and dry season,respectively.Age of less or equal to 15 years old and presence of other family members with G.lamblia infection were found to be the significant risk factors to acquire G.lamblia infections during both seasons.Untreated water supply was the significant risk factor of giardiasis during the dry season.This study highlighted the possibility of anthroponotic transmission of G.lamblia during both seasons and waterborne transmission during the dry season in the aboriginal community.Conclusions:This study suggests that seasonal variation plays an important role in the prevalence and risk factor of G.lamblia infection in the aboriginal community.Therefore,close contact with Giardia-infected family members and water-related activities or usage of untreated water must be avoided to reduce the burden of G.lamblia infection in this community.
基金supported by the National Natural Science Foundation of China (No. 52000184)the Guangzhou Basic and Applied Basic Research Project (No. 202102020457)the Guangdong Basic and Applied Basic Research Foundation (No. 2019B1515120052)。
文摘Swimming pools adopt chlorination to ensure microbial safety. Giardia has attracted attention in swimming pool water because of its occurrence, pathogenicity, and chlorine resistance. To control Giardia concentrations in pool water and reduce the microbial risk, higher chlorine doses are required during disinfection. Unfortunately, this process produces carcinogenic disinfection byproducts that increase the risk of chemical exposure. Therefore, quantitatively evaluating the comparative microbial vs. chemical exposure risks that stem from chlorination inactivation of Giardia in swimming pool water is an issue that demands attention. We simulated an indoor swimming pool disinfection scenario that followed common real-world disinfection practices. A quantitative microbial risk assessment coupled with a chemical exposure risk assessment was employed to compare the Giardia microbial exposure risk(MER) and the trihalomethane chemical exposure risk(CER) to humans. The results demonstrated a 22% decrease in MER-and CER-induced health exposure risk, from 8.45E-5 at 8:00 to 6.60E-5 at 19:00. Both the MER and CER decreased gradually, dropping to 3.26E-5 and 3.35E-5 at 19:00, respectively. However, the CER exceeded the MER after 18:30 and became the dominant factor affecting the total exposure risk. Past the 18 hr mark, the contribution of trihalomethane CER far exceeded the risk aversion from microbial inactivation, leading to a net increase in total exposure risk despite the declining MER. Swimmers may consider swimming after 19:00, when the total exposure risk is the lowest. Lowering water temperature and/or p H were identified as the most sensitive factors to minimize the overall health exposure risk.
文摘The nuclear matrix of diplomonad Giardia lamblia was detected for the first time with DGD embedmentsectioning- embedment free electron microscopy after a series of specific extractions. The result showed that archaezoa Giardia lamblia already possessed nuclear matrix within its two nuclei. The finest fibrils of the nuclear matrix of Giardia lamblia were measured to be about 11 to 13 nm in thickness. However, the nuclear lamina and nucleolus have never been observed. These results seem to suggest that nuclear matrix is an indispensable intranuclear structural component even in the primitive nucleus.
文摘Objective: To investigate the efficacy of (Commiphora molmol(Myrrh)) extract as alternative treatment in hamsters against giardiasis. This study was conducted to evaluate the effect of the new compound (Commiphora molmol(Myrrh)), as agent a natural product extracted from the roots of Zingiber officinal, on Giardia lamblia infection as anti-protozoal and to study the parasitological and Histopathological impact of this treatment on the duodenal mucosa of infected hamsters. Fifty hamsters were divided into five groups: Group (A): normal control. Group (B): Giardia lamblia infected and untreated hamsters served as control. Group (C): infected with Giardia lamblia and treated with metronidazole in dose (120 μg/kg body weight twice daily for 7 successive days). Group (D) Giardia lamblia infected and orally treated with Myrrh (500 mg/Kg for 1 week). Group (E): Giardia lamblia infected and orally treated with combination 1/3 dose of (120 μg/kg body weight) metronidazole and Myrrh (250 mg/Kg) for 1 week). After 2 weeks of the treatment, hamsters were sacrificed. The highest percentages of reduction in the number of Giardia lamblia cysts and trophozoites were in the group receiving combined metronidazole and myrrh. Histopathological examination revealed complete healing of intestinal mucosa after the combined treatment, while partial healing of the lining epithelium of the intestine was noticed after metronidazole and either myrrh plant treatment.
基金National High Technology Research and Development Program ("863"Program) of China(No.2006AAZ309)Science and Technology Project of Guangdong Province,China(No.2011B030800018)Natural Science Foundation of Guangdong Province,China(No.2012040007855)
文摘This study was to investigate the effect of ozone （ O3 ） inactivation on Giardia in water by the fluorescence staining method. In order to elucidate the dominant mechanisms of inactivation, cell surface or inner cell components damage were comparatively examined by scanning dectron microscopy （SEM）. Results suggested that O3 had a stronger effect on inactivating capability. Firstly, when the concentration of O3 was above 2.0 mg/L and the contact time was up to 5 min, it showed a significant inactivating effect. Secondly, the effect of turbidity on inactivation was also found to be significant in synthetic water; when turbidity increased, the inactivating effect decreased. Thirdly, the inactivating rates were improved with a temperature increase from 5 to 25℃, but decreased when the temperature were out of this range. The inactivating capability of O3 was stronger under acidic conditions than alkalic conditions. Lastly, when the concentration of organic matter in the reactive system was increased, probably due to the competition between G/ard/a and organics on O3, the inactivating rate was decreased; in addition, the cellular morphology of Giardia varied with different contact times. At contact time of 30 s, cells were rotundity and sphericity; at 60 s they became folded, underwent emboly, and burst; and at 240 s, the cell membrane of Giardia shrinked and collapsed completely.
