Accumulation of antibiotics in the environment: Have appropriate measures been taken to protect Canadian human and ecological health?

In Canada, every day, contaminants of emerging concern (CEC) are discharged from waste treatment facilities into freshwaters. CECs such as pharmaceutical active compounds (PhACs), personal care products (PCPs), per- and polyfluoroalkyl substances (PFAS), and microplastics are legally discharged from sewage treatment plants (STPs), water reclamation plants (WRPs), hospital wastewater treatment plants (HWWTPs), or other forms of wastewater treatment facilities (WWTFs). In 2006, the Government of Canada established the Chemicals Management Plan (CMP) to classify chemicals based on a risk-priority assessment, which ranked many CECs such as PhACs as being of low urgency, therefore permitting these substances to continue being released into the environment at unmonitored rates. The problem with ranking PhACs as a low priority is that CMP's risk management assessment overlooks the long-term environmental and synergistic effects of PhAC accumulation, such as the long-term risk of antibiotic CEC accumulation in the spread of antibiotic resistance genes. The goal of this review is to specifically investigate antibiotic CEC accumulation and associated environmental risks to human and environmental health, as well as to determine whether appropriate legislative strategies are in place within Canada's governance framework. In this research, secondary data on antibiotic CEC levels in Canadian and international wastewaters, their potential to promote antibiotic-resistant residues, associated environmental short- and long-term risks, and synergistic effects were all considered. Unlike similar past reviews, this review employed an interdisciplinary approach to propose new strategies from the perspectives of science, engineering, and law.

The significance of fluorinated compound chain length, treatment technology, and influent composition on per- and polyfluoroalkyl substances removal in worldwide wastewater treatment plants.

Wastewater treatment plants (WWTPs) are deemed major conveyors and point sources of per- and polyfluoroalkyl substances (PFAS) to the environment. This statistical meta-analysis of existing literature from the past 15 years focused on the significance of treatment type for PFAS removal efficiencies and the influence of PFAS sources (domestic vs. industrial) on their removal. Different sampling events, WWTPs across the world, different treatment technologies, configurations, and processes, as well as different PFAS classes and compounds were considered. This study evaluated 13 PFAS analyzed predominantly in 161 WWTPs across the world. The statistical test results revealed that these 13 frequently detected and reported PFAS can be divided into four groups based on their behavior during wastewater treatment, namely (1) C6-10 perfluorocarboxylic acids (PFCAs), (2) C4,5,11,12 PFCAs, (3) C4,6,8 perfluoroalkane sulfonic acids (PFSAs), and (4) C10 PFSA. In this study, biological treatments such as (1) membrane bioreactors, (2) combination of two or more biological treatments, and (3) biofilm processes revealed the highest PFAS removals, although the addition of a tertiary treatment actually had a nonbeneficial effect on PFAS removal. Moreover, a strong statistical correlation was observed between industrial wastewater sources and the presence of high influent PFAS concentrations in the receiving WWTPs. This indicates that industrial sources were the main contributors of the PFAS load in the analyzed WWTPs. Integr Environ Assess Manag 2024;20:59-69. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Impact of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) on secondary sludge microorganisms: removal, potential toxicity, and their implications on existing wastewater treatment regulations in Canada.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are two of the most commonly researched per- and polyfluoroalkyl substances (PFAS). Globally, many long-chain PFAS compounds including PFOS and PFOA are highly regulated and, in some countries, PFAS use in commercial products is strictly prohibited. Despite the legal regulation of these 'forever chemicals' under the Canadian Environmental Protection Act, PFOA and PFOS compounds are still found in high concentrations in discharges from wastewater treatment plants, both from liquid and sludge streams. Yet, their potential impact on wastewater treatment effectiveness remains poorly understood. The findings of this research show that: (1) PFOS and PFOA might be hindering the overall outcome treatment performance - calling into question the efficacy of Canada's existing wastewater treatment regulatory standard (Wastewater Systems Effluent Regulations, SOR/2012-139), and (2) specific microorganisms from the Thiobacillus and Pseudomonas genera seem capable of adsorbing PFOS and PFOA onto their cell wall and even degrading the chemicals, but it is unclear as to what extent degradation occurs. The results also raise questions whether existing wastewater regulations should be expanded to include the detection and monitoring of PFAS, as well as the establishment of a regulatory wastewater treatment plant discharge standard for PFAS that is protective of human and ecological health.

Energy and reliability analysis of wastewater treatment plants in small communities in Ontario.

This paper presents energy and reliability analyses of eight wastewater treatment plants (WWTPs) operating in small communities in Ontario, Canada, with rated capacities ranging from 60 to 4,400 m3/d. Five different treatment technologies were investigated, namely, rotating biological contactor (RBC), sequencing batch reactor (SBR), membrane bioreactor (MBR), lagoon, and extended aeration activated sludge process (EAAS). Energy benchmarking based on key performance indicators (KPIs) was used to quantify the specific consumption of energy in WWTPs per unit of the pollutant removed. The overall annual electrical energy consumption was correlated to the volume of treated wastewater, the population equivalent, and the amounts of TSS and BOD removed. The RBC plants showed a distinctive advantage for all energy KPIs assessed, while SBR plants yielded the highest values of energy KPIs. Analyses of the expected percentage of compliance with discharge standards and the coefficient of reliability (COR) based on the WWTPs' performance records showed that few WWTPs were able to achieve reliability levels over 95%, considering the mandated discharge standards under the current operating and maintenance conditions. Within each technology, the treatment train, operating conditions, maintenance level, and age of infrastructure were important elements that contributed to the large variability observed.

Enhancement of denitrification efficiency using municipal and industrial waste fermentation liquids as external carbon sources.

The addition of external carbon source for nitrogen removal from wastewater is an essential step in wastewater treatment. In this study, various external carbon sources from the fermentation of primary sludge (PS), thickened waste activated sludge (TWAS), food waste (FW), bakery processing & kitchen waste (BP + KW), fat, oil, & grease (FOG), and whey powder (WP) were successfully employed for wastewater denitrification. Methanol and acetate were also used as controls due to their common use as external carbon sources for wastewater denitrification. The denitrification performance and kinetics such as the specific denitrification rate (SDNR), denitrification potential (PDN), and the biomass yield were studied at a constant TVFA as COD/N ratio of 5 for all substrates. Complete denitrification was achieved with a NO3--N removal efficiency of 98-99%, and no NO2- accumulation was observed at the end of the experiments for all substrates. The results revealed that the liquid fermentation filtrates exhibited higher SDNRs than methanol and acetate. This indicates the high organic matter utilization efficiency and better denitrification ability of fermentation filtrates over conventional carbon sources. WP exhibited the highest SDNR of 17.6 mg NOx - N/g VSS/h, which is approximately four times that of methanol (4.6 mg NOx - N/g VSS/h). The other carbon sources had SDNRs two to three times higher than that of methanol. However, the fermentation filtrates exhibited higher biomass yields of 0.26-0.37 mg VSS/mg COD compared to methanol of 0.21 mg VSS/mg COD, which could lead to higher sludge handling costs. Moreover, methanol exhibited higher PDN of 0.25 g N/g COD compared to all the fermentation filtrates.

Development of an ensemble of machine learning algorithms to model aerobic granular sludge reactors.

Machine learning models provide an adaptive tool to predict the performance of treatment reactors under varying operational and influent conditions. Aerobic granular sludge (AGS) is still an emerging technology and does not have a long history of full-scale application. There is, therefore, a scarcity of long-term data in this field, which impacted the development of data-driven models. In this study, a machine learning model was developed for simulating the AGS process using 475 days of data collected from three lab-based reactors. Inputs were selected based on RReliefF ranking after multicollinearity reduction. A five-stage model structure was adopted in which each parameter was predicted using separate models for the preceding parameters as inputs. An ensemble of artificial neural networks, support vector regression and adaptive neuro-fuzzy inference systems was used to improve the models' performance. The developed model was able to predict the MLSS, MLVSS, SVI5, SVI30, granule size, and effluent COD, NH4-N, and PO43- with average R2, nRMSE and sMAPE of 95.7%, 0.032 and 3.7% respectively.

Aerobic granular sludge membrane bioreactor (AGMBR): Extracellular polymeric substances (EPS) analysis.

Aerobic granular sludge membrane bioreactor (AGMBR) has emerged with strong potential to overcome membrane fouling. There have been no extensive studies on extracellular polymeric substances (EPS) in AGMBR. The present work aimed at conducting an in-depth study of EPS and monitoring fouling development in AGMBR using a 22 factorial design having hydraulic retention time (HRT) and total organic carbon (TOC) as independent variables. HRT was tested at three levels of 6, 8 and 10 h while the TOC levels were 104 ±â€¯13, 189 ±â€¯17, and 266 ±â€¯27 mg/L. AGMBR exhibited high proteins (PN) in the tightly-bound EPS (TB-EPS) resulting in high proteins/polysaccharides (PN/PS) ratios of 2-16. The PN in the LB-EPS was low, ranging from 0.01 to 1.92 mg/g MLVSS, but the range of PN/PS ratio was also of 2-16. Despite the high PN/PS ratio, TMP rise was low. Water jet easily sloughed off the developed membrane cake layer. The elimination of chemicals for membrane cleaning has significant cost savings. TOC had a significant main effect on both the PN and PS components of TB-EPS at α < 0.05. TB-EPS PN increased with increase in TOC. TB-EPS PN decreased as HRT increased from 6 h to 10 h at 104 ±â€¯13 mg/L TOC but the change of HRT from 10 h to 6 h at 266 ±â€¯27 mg/L TOC did not affect TB-EPS PN. The TMP increased with increasing HRT at 104 ±â€¯13 and 266 ±â€¯27 mg/L TOC. An increase in sEPS PN correlated well with increase in membrane fouling (r = 0.581). Three runs performed best: 266 ±â€¯27 mg/L TOC and 10 h HRT; 104 ±â€¯13 mg/L TOC and 6 h HRT; and 266 ±â€¯27 mg/L TOC and 6 h HRT as TMP was below the 50 kPa threshold. AGMBR achieved 98 ±â€¯1%, 99 ±â€¯1%, 52 ±â€¯33% organics degradation, NH3-N removal, total nitrogen removal, respectively.

Optimization of organics to nutrients (COD:N:P) ratio for aerobic granular sludge treating high-strength organic wastewater.

The present study attempted to optimize the nutrients required for biological growth and biomass synthesis in the treatment of high-strength organics wastewater using aerobic granular sludge (AGS). Three identical sequencing batch reactors (SBRs) were used to cultivate aerobic granules at COD concentration of ~5000 mg/L at COD:N:P ratios of 100:2.8:0.4, 100:4.4:0.5, and 100:5:0.7. Results indicated that the amount of nutrients needed for biomass growth does not follow the conventional organics to nutrients ratio (COD:N:P) of 100:5:1 when dealing with high-strength organics wastewater. The highest removal efficiency was achieved at COD:N:P ratio of 100:2.8:0.4, where COD, TN, and P removal was 98.8 ±â€¯0.3%, 100.0 ±â€¯0.0%, and 99.3 ±â€¯1.0%, respectively. Moreover, the presence of high amounts of organics led to the dominance of the fast-growing heterotrophs in all SBRs, with the genus Thauera identified as the most abundant genera (23-40%), while autotrophic nitrifiers disappeared. The observed biomass yield at COD:N ratio of 100:2.8 suggested that heterotrophic nitrification may have occurred, while at COD:N ratios of 100:4.4 and 100:5, all the nitrogen was used for biomass synthesis. Moreover, at COD:N ratio of 100:5, almost 1/5 of the organics were utilized by the biomass cells to produce EPS as defensive action against the effects of free ammonia. Batch optimization experiments showed that the fastest rate of removal occurred at COD:N:P ratio of 100:1.1:0.4. After 4 h, the COD, TN, and P removal efficiencies were 95%, 99%, and 96%, achieving overall removal efficiencies of 98%, 100%, and 97% respectively, at HRT of 8 h. The bacterial behavior in consuming the organics was altered under nutrient-deficient conditions, where faster degradation rates were observed as the amounts of nutrients decreased, with higher relative abundance of heterotrophs and diazotrophic bacterial populations.

Impact of food-to-microorganisms ratio on the stability of aerobic granular sludge treating high-strength organic wastewater.

This work investigated the long-term stability of aerobic granular sludge treating high-strength organic wastewater in a semi-pilot scale sequential batch reactor (SBR). The reactor was operated for 316 days under different operational conditions. It was found that the F/M ratio is an important parameter affecting granules formation and stability. Three selection mechanisms were investigated: (1) cultivation and maturation at moderately high influent COD concentration (2500 mg/L) followed by increase in influent COD concentration to 7500 mg/L; (2) stressed cultivation and operation at high influent COD concentration of 4500 mg/L; and (3) alternate feed loading strategy (variable influent COD concentration across the daily schedule of cycles at 50%, 75%, and 100% of the peak concentration of 5000 mg/L). It was found that adopting high OLR at the reactor start-up accelerated the formation of granules. However, the overgrowth of biomass under high organics concentration negatively affected the stability of granules and led to disintegration due to the presence of methanogens in the granule core. Cultivation at high organics concentration resulted in a rapid loss of microbial diversity and reactor failure. Under alternate feed loading, adequate selection of microbial community was maintained and resulted in stable reactor performance. Moreover, a strong correlation between F/M ratio and the granules settling ability was observed. When F/M ratio exceeded 1.5 gCOD/gSS.d, granules showed poor settleability and under very high sludge loading rates (above 2.5), sludge bulking occurred and led to washout of sludge due to the strong selection pressure of short settling time. Operating the reactor at F/M ratio of 0.5-1.4 gCOD/gSS.d appears to favor stable long-term granule stability.

Performance prediction of an aerobic granular SBR using modular multilayer artificial neural networks.

Aerobic granulation is a complex process that, while proven to be more effective than conventional treatment methods, has been a challenge to control and maintain stable operation. This work presents a static data-driven model to predict the key performance indicators of the aerobic granulation process. The first sub-model receives influent characteristics and granular sludge properties. These predicted parameters then become the input for the second sub-model, predicting the effluent characteristics. The model was developed with a dataset of 2600 observations and evaluated with an unseen dataset of 286 observations. The prediction R2 and RMSE were >99% and <5% respectively for all predicted parameters. The results of this paper show the effectiveness of data-driven models for simulating the complex aerobic granulation process, providing a great tool to help in predicting the behaviour, and anticipating failures in aerobic granular reactors.

Assessment of spiramycin-loaded chitosan nanoparticles treatment on acute and chronic toxoplasmosis in mice.

Toxoplasmosis is a zoonotic parasitic disease with worldwide distribution. Chitosan is a natural polymer which is commonly used in the production of nanomedicines. It is known to enable higher drug permeation, being biocompatible and has very low toxicity, besides its antimicrobial effects. Our study aimed to assess the effect of spiramycin-loaded chitosan nanoparticles (SLCNs) in treatment of acute and chronic toxoplasmosis in mice. 200 male Swiss albino mice were included in our study, divided to two main groups; Toxoplasma gondii RH strain infected group and ME49 strain infected group, each main group was subdivided into four subgroups; subgroup I: infected control, subgroup II: infected and received chitosan nanoparticles (CS NPs); 20 µg of CS NPs in 100 µl of PBS/mouse/dose, subgroup III: infected and treated with spiramycin (Rovamycin); 100 mg/kg/day, subgroup IV: infected and treated with 100 mg/kg/day spiramycin-loaded chitosan nanoparticles. Effect of treatment was assessed parasitologically and histopathologically. It was noticed that SLCNs significantly decreased the mortality rate of infected mice with both strains compared to high mortality rate of mice in the infected control subgroups. Moreover, there was a significant decrease in the number of organisms of SLCNs treated subgroup as compared to the other subgroups. Histopathological studies showed a marked improvement of the pathological pictures of brain, liver, spleen and eye in the subgroup received SLCNs as opposed to other groups. In conclusion, the present study revealed that loading of spiramycin on chitosan nanoparticles increased its antiparasitic effect on acute and chronic T. gondii infection.

Protein Z and Endothelin-1 genetic polymorphisms in pediatric Egyptian sickle cell disease patients.

BACKGROUND: Sickle cell disease (SCD) is a monogenic disease associated with multisystem morbidity. Vasculopathy caused by delicate imbalance between coagulation and endothelial systems plays a pivotal role in disease course. As Protein Z and Endothelin-1 genetic polymorphisms may increase the thrombotic risk, the aim of the current work was to verify the possible impact of Protein Z (PROZ G79A) and Endothelin-1 (EDN1 G5665T) polymorphisms on the clinic-laboratory features of the SCD in a cohort of Egyptian pediatric patients. METHODS: Genotyping of Protein Z G79A and Endothelin-1 G5665T was carried out by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) assay for 100 SCD patients and 100 controls. RESULTS: Protein -Z G79A polymorphism was not associated with vascular complications in the studied SCD patients. Endothelin-1 G5665T polymorphism was associated with pulmonary dysfunction (pulmonary artery hypertension and acute chest syndrome) and severe vaso-occlusive crises (VOC). CONCLUSION: Endothelin-1 G5665T polymorphism could be considered as a molecular predictor for pulmonary dysfunction and severe VOC in SCD. Further researches with larger cohorts are recommended to understand the pathophysiology of SCD and to explain the inter-patients' variability of disease severity.

Paeoniflorin targets apoptosis and ameliorates fibrosis in murine schistosomiasis mansoni: A novel insight.

Schistosomiasis is a chronic helminthic disease causing hepatic fibrosis. Some studies demonstrated direct effect of targeting apoptosis on fibrosis regression. This study is a novel trial of Paeoniflorin (PAE) on S. mansoni induced hepatic fibrosis in murine model compared to Praziquantel (PZQ) evaluating their anti-parasitic and anti-fibrotic properties aiming to discover a new therapy that decrease schistosomiasis morbidity. Thirty two laboratory bred Swiss albino male CD-1 mice were used in this study. The mice were classified into four groups (8 mice each), control healthy, control infected, PZQ treated (300 mg/kg/12 h), PAE treated (50 mg/kg/d) groups. All mice groups were sacrificed 15 weeks post infection for assessment of drugs efficacy by parasitological, histopathological, immunohistochemical and serological studies. Our results showed that PAE improved the parasitological parameters including decrease worm burden, immature, mature eggs and increase dead ones yet, still PZQ had the upper hand in this aspect. However, PAE exceeded PZQ as an anti-fibrotic therapy seemed in marked decrease in hepatic mean granuloma diameter and fibrosis area, besides, marked increase in serum tumor necrosis factor-alpha; TNF-α level, caspase-3 and P53 apoptotic expressions. There was marked decrease in serum IL-13 level, nuclear factor-kappa B; NF-kB, Transforming Growth Factor-Beta1; TGF-ß1, Alpha-Smooth Muscle Actin; α-SMA fibrotic expressions. Conclusively, PAE could be an anti schistosomiasis mansoni therapy exceeding PZQ in targeting apoptosis and ameliorating fibrosis. This study provides a perspective for a novel therapeutic approach to prevent liver fibrosis following liver injury due to schistosomiasis mansoni.

Anti-angiogenic and anti-lymphangiogenic role of praziquantel and artemether in experimental mansoniasis.

Angiogenesis is one of the pillars of neoplasia. Lymphangiogenesis in context of granulomas is not yet understood. This study aimed to evaluate the role of praziquantel (PZQ) and artemether (ART) as anti-angiogenic and anti-lymphangiogenic drugs in Schistosoma mansoni induced experimental hepatic model through immunohistochemical and serological studies, this can be used as a potential novel prophylactic approach in hepatic malignancy prevention and possible management. Forty female CD-1 Swiss albino mice were used divided into 4 groups (10 mice each); control healthy, control infected untreated, PZQ-treated and ART-treated. Angiogenic and lymphangiogenic effect of the drugs assessed pathologically through counting of the newly formed capillaries and lymphatics that immunohistochemically expressed by vascular Endothelial Growth Factor (VEGF), CD34 and D2-40 in liver sections using Cell Image Analyzer and serologically by evaluation of serum level of Tumor Necrosis Factor-Alpha (TNF-α). Our results showed significant decrease in serum TNF-α in ART-treated group compared to control infected and PZQ treated groups. ART exhibited significant anti-angiogenic role on granulomas illustrated by remarkable milder intensity and significantly lower expression values of VEGF and CD34 immunostaining compared to PZQ and non-treated groups. Also, ART treated group exhibited negative D2-40 expression in the granulomas in contrast to the other groups, supporting the potent ART' anti-lymphangiogenic role that exceeded PZQ. In conclusion, ART showed not only anti-angiogenic effect but also prominent anti-lymphangiogenic effect on hepatic S. mansoni granulomas compared to PZQ. Our study supports the potential use of ART as a potential novel prophylactic approach in hepatic malignancy prevention and possible management.

Membrane fouling control in membrane bioreactors (MBRs) using granular materials.

Membrane fouling is considered the major limitation of membrane bioreactors (MBRs). This paper provides an overview on fouling mitigation in MBRs using granular materials. Adsorbents addition extends filtration period, improves critical flux as well as sludge properties (increased flocs size, reduced soluble EPS, improved dewaterability). However, determination of optimal dosages of adsorbents is needed to balance cost savings from fouling mitigation versus cost of adsorbents and sludge handling. The abrasion from granular media reduces cake layer formation, extends membrane filtration period, increases flux (∼20-30%), and reduces aeration intensity by 50%. Finding appropriate aeration intensity and optimum dose for different media is critical for full-scale application. Granular sludge substantially reduces fouling in MBRs; but, optimal operational conditions for long-term granule stability are required. Quorum quenching (QQ) mitigates biofouling (energy savings ∼27-40%). Cost savings from QQ need assessment against the production and application of QQ approaches.

Augmenting Lagoon Process Using Reactivated Freeze-dried Biogranules.

This study investigated the feasibility of using freeze-dried biogranules in lagoon basins. The effect of different operational conditions on treatment performance and detention time of granule-based lagoons was examined in a series of laboratory-scale batch studies. Optimal granule dosage was 0.1 g/L under anaerobic condition, resulting in 80-94% removal of 1000 mg/L chemical oxygen demand (COD) in 7-10 days. Under aerobic condition, granule dosage of 0.2 g/L achieved the best result for identical COD concentration. However, adequate amount of nutrients (optimal COD/N/P ratio of 100/13/0.8) should be supplied to encourage the growth of aerobic species. At optimal COD/N/P ratio, aerobic treatment interval significantly reduced to 2-3 days with corresponding COD removal efficiency of 88-92%. Inhibition of high concentrations of COD (5000 mg/L) and ammonia (480 mg/L NH4-N) was observed on microbial activity and treatment capacity of the biogranules. Mixing was a crucial measure to overcome mass transfer limitation. Onetime inoculation of lagoon with fresh granules was the best approach to achieve a satisfactory treatment efficiency. This study suggested that utilization of the biogranules is a feasible and sustainable technique for augmenting lagoon plants in terms of improved effluent quality and reduced retention time. Graphical Abstract ᅟ.

Membrane Bioreactor (MBR) Technology for Wastewater Treatment and Reclamation: Membrane Fouling.

The membrane bioreactor (MBR) has emerged as an efficient compact technology for municipal and industrial wastewater treatment. The major drawback impeding wider application of MBRs is membrane fouling, which significantly reduces membrane performance and lifespan, resulting in a significant increase in maintenance and operating costs. Finding sustainable membrane fouling mitigation strategies in MBRs has been one of the main concerns over the last two decades. This paper provides an overview of membrane fouling and studies conducted to identify mitigating strategies for fouling in MBRs. Classes of foulants, including biofoulants, organic foulants and inorganic foulants, as well as factors influencing membrane fouling are outlined. Recent research attempts on fouling control, including addition of coagulants and adsorbents, combination of aerobic granulation with MBRs, introduction of granular materials with air scouring in the MBR tank, and quorum quenching are presented. The addition of coagulants and adsorbents shows a significant membrane fouling reduction, but further research is needed to establish optimum dosages of the various coagulants/adsorbents. Similarly, the integration of aerobic granulation with MBRs, which targets biofoulants and organic foulants, shows outstanding filtration performance and a significant reduction in fouling rate, as well as excellent nutrients removal. However, further research is needed on the enhancement of long-term granule integrity. Quorum quenching also offers a strong potential for fouling control, but pilot-scale testing is required to explore the feasibility of full-scale application.

CHARACTERIZATION OF THE HEMOCYTES OF SUSCEPTIBLE AND RESISTANT BIOMPHALARIA ALEXANDRINA SNAIL.

The internal defense system consists of soluble components of hemolymph and circulating cells known as hemocytes. The circulating hemocytes play a central role in innate immunity. This work aimed to study the hemocytes of both susceptible and resistant B. alexandrina snails exposed to S. mansoni infection using light and electron microscopes. Two tested groups were included in the study; 60 susceptible and 60 resistant B. alexandrina snails. Both tested groups were studied as regad the hemocyte count (before and after infection) and the morphological characteristics of both circulating and tissue hemocytes by light and electron microscopes. Before infection, .there was no significant difference between the two groups as regard the hemocyte count, however after infection, there is a significant decrease in the circulating hemocytes of the resistant group. Light microscopy revealed five morphological types of circulating cells of both susceptible and resistant snails. Regarding scannig electron microscopy, hemocytes of susceptible snails appeared rounded with smooth or slightly rough surface. However, that of the resistant snails appeared irregular in shaped with corrugated surface. Furthermore, Light microscopy and the transmission electron microscopy revealed signs of cell activation in the hemocytes of the resistant group. The circulating hemocytes consist of five cell types in both susceptible and resistant B. alexandarina and morphologies of these cells are quite similar, but with more signs of cell activations in the resistant group. More specific studies on the functional activities of the hemocytes and mechanisms that may affect or influence the susceptibility and/or non-susceptibility of molluscs to invade microorganisms is essential and how they can act in the immune response.

COMPARISON BETWEEN KATO-KATZ THICK SMEAR AND SEDIMENTATION TECHNIQUES IN DIAGNOSIS OF FAECAL-ORALLY TRANSMITTED HELMINTHES AND OTHER GEOHELMINTHES.

Kato-Katz technique is widely used for the diagnosis of Fecal-orally transmitted helminthic infections. It is relatively simple and inexpensive. However, a single slide prepared from a single stool specimen has low sensitivity, particularly in light infections. Therefore, there is a great need for concentration techniques. This study detected an accurate and affordable method for diagnosis of fecal-orally transmitted helminthes and other geohelminthes. The study was carried out on 217 stool samples of different sex and age groups. Stool samples were collected from different urban and rural areas in Sharkia Governorate. Stool samples were examined macroscopically and analyzed by different parasitological techniques: direct wet mount (DWM), Kato-Katz thick smear, spontaneous sedimentation in tube technique (SSTT) and formol ether sedimentation technique (FEC). The results showed that formol ether sedimentation method detected 59 positive samples followed by spontaneous sedimentation in tube technique (48/59 positive samples). FEC showed significant difference when compared to direct wet mount and Kato-Katz thick smear. SSTT also showed significant difference when compared to DWM (P <0.05).The overall prevalence of intestinal helminthes was (29.6%) among studied samples in Sharkia Governorate. The commonest helminthic infection was H. nana (12%) followed by E. vemicularis(10%) then A. lumbricoides (3.7%).

ASSESSING THE EFFICACY OF NITAZOXANIDE IN TREATMENT OF CRYPTOSPORIDIOSIS USING PCR EXAMINATION.

Cryptosporidiosis is a gastrointestinal disease of humans and other animals, caused by the genus Cryptosporidium spp. It causes persistent diarrhea and malnutrition and is associated with increased mortality. This study aimed to assess the efficacy of nitazoxanide (NTZ) on clearing the oocysts of C. parvum among infected children using both parasitological and PCR techniques.120 children (1-12y) shedding Cryptosporidium oocysts in their stools were enrolled in the study. They were classified on the basis of the immune status into immunocompetent (ICT) and immunocompromised (ICZ) groups. Each group were subdivided into two groups one of them received'NTZ, and the other received placebo. The efficacy of nitazoxanide was assessed clinically, parasitologically and by nested-PCR technique. At the end of 1st week of treatment, 80% of ICT/ NTZ group and 40% of ICT/ placebo group were free by PCR and 83.3% & 20% respectively were microscopically free. While at the end of 4th week, 93.3% of ICT/NTZ group and 43.3% of ICT/ placebo group were free by PCR and 96.7% & 26.7% respectively were microscopically free. Among the ICZ group, diarrhea was resolved in most patients receiving NTZ within 21 to 28 days of treatment initiation While, it resolved in the ICT group receiving NTZ in most patients within 3 to 5 days of treatment initiation.