Marked increase in cryptosporidiosis cases, Spain, 2023.

BackgroundBy mid-September 2023, several event notifications related to cryptosporidiosis had been identified from different regions in Spain. Therefore, a request for urgent notification of cryptosporidiosis cases to the National Surveillance Network was launched.AimWe aimed at assessing the extent of the increase in cases, the epidemiological characteristics and the transmission modes and compared to previous years.MethodsWe analysed data on case notifications, outbreak reports and genotypes focusing on June-October 2023 and compared the results to 2016-2022.ResultsIn 2023, 4,061 cryptosporidiosis cases were notified in Spain, which is an increase compared to 2016-2022. The cumulative incidence was 8.3 cases per 100,000 inhabitants in 2023, sixfold higher than the median of 1.4 cases per 100,000 inhabitants 2016-2022. Almost 80% of the cases were notified between June and October. The largest outbreaks were related to contaminated drinking water or swimming pools. Cryptosporidium hominis was the most common species in the characterised samples (115/122), and the C. hominis IfA12G1R5 subtype, previously unusual in Spain, was detected from 76 (62.3%) of the 122 characterised samples.ConclusionsA substantial increase in cryptosporidiosis cases was observed in 2023. Strengthening surveillance of Cryptosporidium is essential for prevention of cases, to better understand trends and subtypes circulating and the impact of adverse meteorological events.

Assessment of pathogenic protozoa in a drinking water treatment plant with UV treatment.

Controlling drinking water treatment processes is essential to address water contamination and the adaptability of certain pathogenic protozoa. Sometimes, standard treatment methods and chlorine disinfection may prove insufficient in eliminating pathogenic protozoa. However, ultraviolet (UV) radiation has proved to be more effective than chlorine. This study aims to characterize the eukaryotic community of a drinking water treatment plant that applies a final UV disinfection treatment, focusing on pathogenic protozoa. Fifty water samples (raw water, before and after UV treatment) were evaluated to comply with regulation parameters and identify relevant protozoa. Despite physicochemical and microbiological parameters meeting the regulation, some potentially pathogenic protozoa, such as Blastocystis or Cryptosporidium, were still detected in very low relative abundances in treated water. It was found for the first time in Spain the pathogenic amoebae Naegleria fowleri in one river water, which was not found after the treatment. Moreover, Blastocystis subtypes ST1-ST6 were detected in this study in raw, before and after UV water samples. Blastocystis was only found in 2 two samples after UV treatment, with a very low abundance (≤0.02%). Obtained results demonstrate the effectiveness of water treatment in reducing the prevalence of pathogenic protozoa.

Commercial reverse osmosis point-of-use systems in Egypt failed to purify tap water.

This study addresses the heightened global reliance on point-of-use (PoU) systems driven by water quality concerns, ageing infrastructure, and urbanization. While widely used in Egypt, there is a lack of comprehensive evaluation of these systems. We assessed 10 reverse osmosis point-of-use systems, examining physicochemical, bacteriological, and protozoological aspects of tap water (inlets) and filtered water (outlets), adhering to standard methods for the examination of water and wastewater. Results showed significant reductions in total dissolved solids across most systems, with a decrease from 210 ± 23.6 mg/L in tap water to 21 ± 2.8 mg/L in filtered water for PoU-10. Ammonia nitrogen levels in tap water decreased from 0.05 ± 0.04 to 2.28 ± 1.47 mg/L to 0.02 ± 0.04 to 0.69 ± 0.64 mg/L in filtered water. Despite this, bacterial indicators showed no significant changes, with some systems even increasing coliform levels. Protozoological analysis identified prevalent Acanthamoeba (42.5%), less frequent Naegleria (2.5%), Vermamoeba vermiformis (5%), and potentially pathogenic Acanthamoeba genotypes. Elevated bacterial indicators in filtered water of point-of-use systems, combined with essential mineral removal, indicate non-compliance with water quality standards, posing a public health concern. Further research on the long-term health implications of these filtration systems is essential.

Ozone and peroxone disinfection of Toxocara canis eggs in water.

Water pollution in developing countries continues to be a major health problem due to various anthropological activities that contribute to the spread of many parasitic diseases, including those caused by helminths. The aim of this study is to explore the ability of ozone and peroxone to disinfect drinking water contaminated samples with Toxocara canis eggs. The oxidants used were ozone and ozone-hydrogen peroxide combination. The treatment of Toxocara canis eggs was carried out in a 50 ml reactor with an operating volume of 10 ml. The pH conditions (5, 7 and 10) were varied for each treatment. The treatment effect was calculated by counting eggs and examining the condition of the larvae larval condition (whole, broken and hatched larvae) using an optical microscope. The experiment was carried out by exposing the eggs for 60 and 120 minutes to ozone and peroxone. The best results were obtained for helminths treated with the ozone/hydrogen peroxide combination at pH 10, with an inactivation of 79.2%. The synergistic effect of ozone combined with hydrogen peroxide allows higher helminth egg inactivation rates, demonstrating that advanced oxidation processes are a real alternative to apply in the inactivation of Toxocara canis eggs. The results obtained in this study show that the ozone and peroxone treatment could be a useful disinfection process to destroy or inactivate Toxocara canis eggs in processes commonly applied in water treatment.

Year-round monitoring of three water sources in Québec, Canada, reveals site-specific differences in conditions for Cryptosporidium and Giardia contamination.

Cryptosporidium and Giardia are protozoan parasites responsible for gastrointestinal illnesses in humans and in animal species. The main way these parasites are transmitted is by ingestion of their (oo)cysts in drinking water. Monitoring (oo)cysts in water sources is beneficial to evaluate the quality of raw water supplying treatment plants. Currently, the only standardized protocol to enumerate these parasites from water samples is United States Environmental Protection Agency (USEPA) Method 1623.1. With this method, we monitored three major water sources in Quebec over a year to assess temporal and geographical variations of these parasite (oo)cysts. These three water sources have independent watersheds despite being in the same region. We found a general pattern for Giardia, with high concentrations of cysts during cold and transition periods, and significantly lower concentrations during the warm period. Cryptosporidium's concentration was more variable throughout the year. Statistical correlations (Pearson's correlation coefficients) were established between the concentration of each parasite and various environmental parameters. The three study sites each showed unique factors correlating with the presence of both protozoa, supporting the idea that each water source must be seen as a unique entity with its own particular characteristics and therefore, must be monitored independently. Although some environmental parameters could be interesting proxies to the parasitic load, no parameter was strongly correlated throughout the whole sampling year and none of the parameters could be used as a single proxy for all three studies sources.

An Investigation of Parasitic Protozoa in Drinking Water in Samarra, Iraq.

Protozoan parasites are very important in drinking water production systems because their cystic forms are stable in the environment and resistant to conventional disinfection methods. The present study aimed to investigate protozoan parasites in the drinking water of different places in Samarra, Iraq. To this end, 100 samples of tap drinking water were collected from 10 places in Samarra, Iraq (i.e., Al-Sekek, Al-Kadesia, Alzeraa, Al-Shuhdaa, Al-Muthana, Al-Shorta, Al-Mamal, Al-Khedraa, Al-Efraz, and Al-Jubereaa), from the beginning of December to the end of February. After sample collection, water samples were examined to detect oocysts or cysts of protozoan parasites by using Direct wet smear, Lugol's iodine, and Modified Ziehle Nelseen stain methods. The results indicate that 80% of the samples under investigation were infected with protozoan parasites, and the ratio of diagnostic parasites in the samples under investigation was determined at 36% with Entamoeba histolytica, 23% with Giardia lamblia, and 21% with Cryptosporidium parvum. The findings reveal the presence of protozoan parasites in the drinking water of the area under study and specify the need for a rapid improvement of the monitoring systems for the treatment of drinking water to control diseases caused by these pathogens, as well as to identify the sources of contamination.

Human health risk assessment for (re)emerging protozoan parasites in surface water used for public supply and recreational activities.

Gastrointestinal diseases caused by protozoan parasites remain a major challenge in developing countries and ingestion of contaminated surface water represents one of the main sources by which these diseases are contracted. This study assessed the risk of infection and diseases caused by Cryptosporidium spp. and Giardia sp. due to ingestion of surface water used for public supply and recreational activities, focusing on the southeastern Brazilian Pardo River and applying the USEPA 1623 method to quantify (oo)cyst concentrations. Infection and disease probabilities due to ingestion of drinking water or during recreational activities were estimated using the Quantitative Microbial Risk Assessment (QMRA) approach. Mean concentrations of Cryptosporidium spp. and Giardia sp. in surface water ranged from 0.2 to 0.4 oocysts L-1 and 0.2 to 4.4 cysts L-1, respectively. Considering public water supply, annual infection probabilities were higher for adults than children and exceeded the USEPA limit; also, disease probabilities were higher for adults than children. For recreational activities, annual infection and disease probabilities were higher for children, followed by men and women. The occurrence of both parasites likely reflects raw sewage discharge, effluent from sewage treatment plants, and diffuse sources of pollution, such as runoff from pasture lands and deforested riparian forest corridors. Our results highlight substantial infection risks by both parasite types after conventional treatment of water used for public supply and also call for careful monitoring of water bodies used for recreational purposes.

Cryptosporidiosis outbreak in Amazonia, French Guiana, 2018.

BACKGROUND: Cryptosporidiosis outbreaks in South America are poorly documented. In March 2018, 51 cases of cryptosporidiosis were reported in Maripasoula, a village located in a remote forest area along the border between Surinam and French Guiana. METHOD: To identify the origin of the epidemic, we performed epidemiological, microbiological, and environmental investigations. Only the cases involving diarrhoea and Cryptosporidium-positive stool were considered as bona fide, while cases involving diarrhoea and close contact with a confirmed case were classified as "possible". RESULTS: We identified 16 confirmed cases and 35 possible ones. Confirmed cases comprised nine children (median age of 18 months, range: 6-21), one immunocompromised adult and six soldiers. One child required a hospitalisation for rehydration. All 16 Cryptosporidium stools were PCR positive, and sequencing of the gp60 gene confirmed only one Cryptosporidium hominis subtype IbA10G2. Tap water consumption was the only common risk factor identified. Contamination of the water network with Cryptosporidium parvum subtype IIdA19G2 was found. CONCLUSION: Water quality is a major public health issue in Amazonian French Guiana, especially for population at risk (children, people with comorbidity, travelers). For them, alternative water supply or treatment should be implemented.

Amebiasis and Amebic Liver Abscess in Children.

Although rare in the developed world, amebiasis continues to be a leading cause of diarrhea and illness in developing nations with crowding, poor sanitation, and lack of clean water supply. Recent immigrants or travelers returning from endemic regions after a prolonged stay are at high risk of developing amebiasis. A high index of suspicion for amebiasis should be maintained for other high-risk groups like men having sex with men, people with AIDS/HIV, immunocompromised hosts, residents of mental health facility or group homes. Clinical presentation of intestinal amebiasis varies from diarrhea to colitis and dysentery. Amebic liver abscess (ALA) is the most common form of extraintestinal amebiasis. Various diagnostic tools are available and when amebiasis is suspected, a combination of stool tests and serology should be sent to maximize the yield of testing. Treatment with an amebicidal drug such as metronidazole/tinidazole and a luminal cysticidal agent such as paromomycin for clinical disease is indicated. However, for asymptomatic disease treatment with a luminal cysticidal agent to decrease chances of invasive disease and transmission is recommended.

Zoonotic enteric parasites in Mongolian people, animals, and the environment: Using One Health to address shared pathogens.

BACKGROUND: Cryptosporidium spp. and Giardia duodenalis are important zoonotic enteric pathogens of One Health concern for humans, animals, and the environment. For this study, we investigated parasite prevalence and risk factors among rural, peri-urban, and urban households and environments of Mongolia. METHODS: This cross-sectional study implemented a household risk factor survey at 250 home sites along with sample collection from humans, animals, flies, and drinking water. Multiplex real-time PCR analysis was conducted to look for Cryptosporidium spp. and/or Giardia duodenalis within household samples. RESULTS: Lab analysis found one or both zoonotic parasites at 20% of the participating households (51/250). Human samples had a parasite prevalence of 6.4% (27/419), domestic animals at 3.3% (19/570), pooled filth flies at 14.8% (17/115), and drinking water samples at 2% (5/250). Parasite presence at the household was significantly associated with a household's use of an improved drinking water source (OR 0.27; CI 0.12-0.61; p = < 0.01), having an indoor handwashing site (OR 0.41; CI 0.19-0.92; p = 0.03), domestic animal ownership (OR 2.40; CI 1.02-5.65; p = 0.05), and rural location (OR 0.50; CI 0.25-0.98; p = 0.04). Household use of an improved drinking water source remained significant in the multivariate model (OR 0.16; CI 0.04-0.68; p = 0.01). CONCLUSION: In Mongolia, public and veterinary health are intertwined, particularly for rural herding households. Increased access to safe water, sanitation and hygiene infrastructure could help prevent further transmission of zoonotic enteric parasites. Public health interventions, policy and messaging should utilize a One Health framework employing joint leadership from local human and animal health sectors.

Solar Water Disinfection to Produce Safe Drinking Water: A Review of Parameters, Enhancements, and Modelling Approaches to Make SODIS Faster and Safer.

Solar water disinfection (SODIS) is one the cheapest and most suitable treatments to produce safe drinking water at the household level in resource-poor settings. This review introduces the main parameters that influence the SODIS process and how new enhancements and modelling approaches can overcome some of the current drawbacks that limit its widespread adoption. Increasing the container volume can decrease the recontamination risk caused by handling several 2 L bottles. Using container materials other than polyethylene terephthalate (PET) significantly increases the efficiency of inactivation of viruses and protozoa. In addition, an overestimation of the solar exposure time is usually recommended since the process success is often influenced by many factors beyond the control of the SODIS-user. The development of accurate kinetic models is crucial for ensuring the production of safe drinking water. This work attempts to review the relevant knowledge about the impact of the SODIS variables and the techniques used to develop kinetic models described in the literature. In addition to the type and concentration of pathogens in the untreated water, an ideal kinetic model should consider all critical factors affecting the efficiency of the process, such as intensity, spectral distribution of the solar radiation, container-wall transmission spectra, ageing of the SODIS reactor material, and chemical composition of the water, since the substances in the water can play a critical role as radiation attenuators and/or sensitisers triggering the inactivation process.

Impact of Hydrometeorological Events for the Selection of Parametric Models for Protozoan Pathogens in Drinking-Water Sources.

Temporal variations in concentrations of pathogenic microorganisms in surface waters are well known to be influenced by hydrometeorological events. Reasonable methods for accounting for microbial peaks in the quantification of drinking water treatment requirements need to be addressed. Here, we applied a novel method for data collection and model validation to explicitly account for weather events (rainfall, snowmelt) when concentrations of pathogens are estimated in source water. Online in situ ß-d-glucuronidase activity measurements were used to trigger sequential grab sampling of source water to quantify Cryptosporidium and Giardia concentrations during rainfall and snowmelt events at an urban and an agricultural drinking water treatment plant in Quebec, Canada. We then evaluate if mixed Poisson distributions fitted to monthly sampling data ( n = 30 samples) could accurately predict daily mean concentrations during these events. We found that using the gamma distribution underestimated high Cryptosporidium and Giardia concentrations measured with routine or event-based monitoring. However, the log-normal distribution accurately predicted these high concentrations. The selection of a log-normal distribution in preference to a gamma distribution increased the annual mean concentration by less than 0.1-log but increased the upper bound of the 95% credibility interval on the annual mean by about 0.5-log. Therefore, considering parametric uncertainty in an exposure assessment is essential to account for microbial peaks in risk assessment.

Importance of Distributional Forms for the Assessment of Protozoan Pathogens Concentrations in Drinking-Water Sources.

The identification of appropriately conservative statistical distributions is needed to predict microbial peak events in drinking water sources explicitly. In this study, Poisson and mixed Poisson distributions with different upper tail behaviors were used for modeling source water Cryptosporidium and Giardia data from 30 drinking water treatment plants. Small differences (<0.5-log) were found between the "best" estimates of the mean Cryptosporidium and Giardia concentrations with the Poisson-gamma and Poisson-log-normal models. However, the upper bound of the 95% credibility interval on the mean Cryptosporidium concentrations of the Poisson-log-normal model was considerably higher (>0.5-log) than that of the Poisson-gamma model at four sites. The improper choice of a model may, therefore, mislead the assessment of treatment requirements and health risks associated with the water supply. Discrimination between models using the marginal deviance information criterion (mDIC) was unachievable because differences in upper tail behaviors were not well characterized with available data sets ( n<30 ). Therefore, the gamma and the log-normal distributions fit the data equally well but may predict different risk estimates when they are used as an input distribution in an exposure assessment. The collection of event-based monitoring data and the modeling of larger routine monitoring data sets are recommended to identify appropriately conservative distributions to predict microbial peak events.

Investigation of Dracunculiasis Transmission among Humans, Chad, 2013-2017.

Dracunculiasis, slated for global eradication, typically is acquired by drinking stagnant water containing microscopic crustaceans (copepods) infected with Dracunculus medinensis larvae, causing clusters of case persons with worms emerging from the skin. Following a 10-year absence of reported cases, 9-26 sporadic human cases with few epidemiologic links have been reported annually in Chad since 2010; dog infections have also been reported since 2012. We conducted an investigation of human cases in Chad to identify risk factors. We conducted a case-control study using a standardized questionnaire to assess water and aquatic animal consumption, and links to dog infections. Case persons had laboratory-confirmed D. medinensis during 2013-2017. Each case person was matched to one to three controls without history of disease by age, gender, and residency in the village where the case person was likely infected. We estimated odds ratios (ORs) using simple conditional logistic regression. We enrolled 25 case persons with 63 matched controls. Dracunculiasis was associated with consumption of untreated water from hand-dug wells (OR: 13.4; 95% CI: 1.7-108.6), but neither with consumption of aquatic animals nor presence of infected dogs in villages. Unsafe water consumption remains associated with dracunculiasis. Education of populations about consuming safe water and using copepod filters to strain unsafe water should continue and expand, as should efforts to develop and maintain safe drinking water sources. Nevertheless, the peculiar epidemiology in Chad remains incompletely explained. Future studies of dogs might identify other risk factors.

Prevalence of enteric pathogens, intestinal parasites and resistance profile of bacterial isolates among HIV infected and non-infected diarrheic patients in Dessie Town, Northeast Ethiopia.

BACKGROUND: Enteric pathogens like Salmonella and Shigella species as well as intestinal parasites (IPs) are among the main causative agents of diarrhea in people with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), particularly in low income countries like Ethiopia. Antimicrobial resistance against commonly prescribed drugs has become a major global threat. This study, therefore, aimed at determining the magnitude of Salmonella, Shigella and IPs infections, their predicting factors, and antimicrobial susceptibility pattern among HIV infected and non-infected diarrheic patients in Dessie town, Northeast Ethiopia. METHODS: A cross sectional study was conducted at three health facilities in Northeast Ethiopia between January 2018 and March 2018. Data on socio-demographic and associated risk factors were collected using structured questionnaire from 354 HIV infected and non-infected diarrheic outpatients. Fresh stool specimen was processed according to standard operating procedures. Data were entered and analyzed using SPSS version 22. Descriptive statistics was used to determine frequency, Bivariate and multivariate logistic regression analyses were performed to identify predicting factors associated with the outcome variable. P-value <0.05 were used to declare statistical significance. RESULTS: Among 354 diarrheic patients, 112 were HIV infected and 242 were HIV non-infected. The overall prevalence of intestinal parasite and bacterial infection among HIV infected versus non-infected, respectively, was 26 (23.2%) and 8 (7.1%) versus 50 (20.7) and 16 (6.6%). Salmonella was the highest in both groups, 6 (5.4%) vs 11 (4.5%). Most prevalent parasite was C. parvum, 9 (8%) among HIV+ while E. histolytica/dispar 39 (16.1%) among HIV-. Having bloody plus mucoid diarrhea, not utilizing latrine and drinking river or spring water were factors significantly associated with bacterial infection. Whereas, being illiterate or having primary level education, diarrhea lasting for 6-10 days, CD4 level between 200-500 cells/µl, not washing hand with soap showed significant association with IPs. The bacterial isolates were 100% susceptible to Ceftriaxone and 95.4% to Ciprofloxacin, while 100% resistant to Ampicillin and Amoxicillin. MDR was observed among 19 (79.2%) isolates. CONCLUSION: Preventing and controlling infection by enteric pathogens as well as IPs require strengthening intervention measures. The 100% resistance of isolates to commonly prescribed antibiotics calls for expanding antimicrobial susceptibility testing so as to select appropriate antimicrobial agent and prevent emergence of drug resistant bacteria.

Cryptosporidium and Giardia in dam water on sheep farms - An important source of transmission?

Cryptosporidium and Giardia infections can negatively impact livestock health and reduce productivity, and some species and genotypes infecting livestock have zoonotic potential. Infection occurs via the faecal-oral route. Waterborne infections are a recognised source of infection for humans, but the role of livestock drinking water as a source of infection in livestock has not been described. This study aimed to determine whether contaminated drinking water supplies, such as farm dams, are a likely transmission source for Cryptosporidium and Giardia infections for extensively managed sheep. Dam water samples (n = 47) were collected during autumn, winter and spring from 12 farm dams located on six different farms in south west Western Australia, and faecal samples (n = 349) were collected from sheep with access to these dams. All samples were initially screened for Cryptosporidium spp. at the 18S locus and Giardia spp. at the gdh gene using qPCR, and oocyst numbers were determined directly from the qPCR data using DNA standards calibrated by droplet digital PCR. Cryptosporidium-positive sheep faecal samples were typed and subtyped by sequence analysis of 18S and gp60 loci, respectively. Giardia-specific PCR and Sanger sequencing targeting tpi and gdh loci were performed on Giardia- positive sheep faecal samples to characterise Giardia duodenalis assemblages. To identify Cryptosporidium and Giardia spp. in dam water samples, next-generation sequencing analysis of 18S and gdh amplicons were performed, respectively. Two species of Cryptosporidium (Cryptosporidium xiaoi and Cryptospordium ubiquitum (subtype family XIIa)) were detected in 38/345 sheep faecal samples, and in water from 9/12 farm dams during the study period, with C. xiaoi the species most frequently detected in both faeces and dam water overall. Giardia duodenalis assemblages AI, AII and E were detected in 36/348 faecal samples and water from 10/12 farm dams. For dam water samples where oo/cysts were detected by qPCR, Cryptosporidium oocyst concentration ranged from 518-2429 oocysts/L (n = 14), and Giardia cyst concentration ranged from 102 to 1077 cysts/L (n = 17). Cryptosporidium and Giardia with zoonotic potential were detected in farm dam water, including C. ubiquitum, C. hominis, C. parvum, C. cuniculus, C. xiaoi, and G. duodenalis assemblages A, B and E. The findings suggest that dam water can be contaminated with Cryptosporidium species and G. duodenalis assemblages that may infect sheep and with zoonotic potential, and farm dam water may represent one source of transmission for infections.

The association between the lack of safe drinking water and sanitation facilities with intestinal Entamoeba spp infection risk: A systematic review and meta-analysis.

Intestinal protozoa infections are responsible for considerable morbidity and mortality, especially where the exposed population suffers from a lack of drinking water and sanitation facilities. In this study, the association between the lack of safe drinking water and sanitation (toilet) facilities with intestinal Entamoeba spp infection in the children (5-11 years), adult (18-55 years), and all age (5-55 years) were assessed. For this purpose, some of the international databases such as Scopus, PubMed, Web of Science, and Embase were screened to up to 7 June 2019 in order to retrieve the related citations. Also, the pooled odds ratios (ORs) following 95% confidence intervals (CIs) were calculated using a random-effects model. Twenty-nine articles with 36 studies were included while the OR extracted or calculated by using 2 × 2 contingency tables. However, the ingestion of contaminated water insignificantly can increase the odds ratio (OR) of Entamoeba spp infection (OR 1.01, (95% confidence interval [CI] 0.58 to 1.43), no access to sanitation (toilet) facilities significantly can increase odds of Entamoeba spp infection (OR 1.18, 95% CI 1.05 to 1.32). The meta-regression analysis showed that over time, odds of intestinal Entamoeba spp infection increased in both lack of safe drinking water (Coefficient: 3.24, P-value < 0.01) and sanitation (toilet) facilities (Coefficient: 2.36, P-value < 0.05) subgroups. Considering the findings, lack of safe drinking water resulted in a further increase in intestinal Entamoeba spp infection among adult (OR: 2.76), children (OR = 0.57) and all age groups (OR: 1.50), and also lack of sanitation (toilet) facilities resulted in further increase intestinal Entamoeba spp infection in children (OR: 1.06), adult (OR: 1.26) and all age (OR: 1.16). In this context, the lack of safe drinking water and sanitation facilities (toilet) was associated with a high risk of intestinal Entamoeba spp infection. Further attempts to providing public health facilities can control the prevalence of intestinal Entamoeba spp.

Biofilm Sampling for Detection of Cryptosporidium Oocysts in a Southeastern Pennsylvania Watershed.

This study investigated the use of biofilms to monitor Cryptosporidium in water. Benthic rock and submersible slide biofilms were sampled upstream and downstream of point sources in a suburban watershed in southeastern Pennsylvania. More oocysts were detected in biofilms scraped from rocks downstream than upstream of a wastewater treatment plant (WWTP) (19 versus 5, respectively; n = 1). Although not statistically significant, Cryptosporidium oocysts were detected more frequently, and in greater numbers, in biofilms grown on slides downstream than upstream of this same WWTP (83.3% positive samples [n = 12] versus 45.5% positive samples [n = 11], respectively; P = 0.0567). Similarly, Cryptosporidium oocysts were detected more frequently, and in greater numbers, in rock biofilms collected downstream than upstream of a stormwater outfall impacted by defective sewer laterals (50% positive samples downstream and 17% positive samples upstream; n = 6; P = 0.2207). While oocyst detection data obtained by slide biofilms versus filters did not necessarily agree on a given day, there was no seasonal difference in the frequency of oocyst detection (P > 0.05) or numbers of oocysts detected (P > 0.05) whether the water was monitored by filtration or slide biofilm sampling. Within any given season, there was no difference in the frequency of oocyst detection (P > 0.05) or the numbers of oocysts detected (P > 0.05) whether the water was monitored by filtration or slide biofilm sampling. These data show that oocyst detection in biofilms is comparable to oocyst detection in filtered water samples. Biofilm sampling offers significant cost savings compared to the filtration-based EPA Method 1623.1 and could be used to identify watershed locations at potential risk for increased oocyst loads.IMPORTANCE Monitoring Cryptosporidium occurrence in watersheds that provide drinking water is necessary to determine where limited resources should most effectively be directed to protect consumers from waterborne exposure to pathogenic oocysts. Biofilms are a useful tool to monitor complex watersheds and identify point sources of Cryptosporidium oocyst contamination that need to be managed to protect public health. Compared to EPA Method 1623.1, the cost benefit of using biofilms to monitor for Cryptosporidium contamination will enable utilities to sample water supplies more frequently, and at more locations, than is currently possible given limited operating budgets. Biofilm sampling could be used to identify high-risk regions within a large, complex watershed and the associated water treatment plants at potential risk for increased oocyst loads in the water supply; this information could then be used to select the locations within the watershed where the more expensive EPA Method 1623.1 is warranted.

A smartphone microscopic method for simultaneous detection of (oo)cysts of Cryptosporidium and Giardia.

BACKGROUND: Food and water-borne illness caused by ingestion of (oo)cysts of Cryptosporidium and Giardia is one of the major health problems globally. Several methods are available to detect Giardia cyst and Cryptosporidium oocyst in food and water. Most of the available methods require a good laboratory facility and well-trained manpower and are therefore costly. There is a need of affordable and reliable method that can be easily implemented in resource limited settings. METHODOLOGY/PRINCIPLE FINDINGS: We developed a smartphone based microscopic assay method to screen (oo)cysts of Cryptosporidium and Giardia contamination of vegetable and water samples. The method consisting of a ball lens of 1 mm diameter, white LED as illumination source and Lugols's iodine staining provided magnification and contrast capable of distinguishing (oo)cysts of Cryptosporidium and Giardia. The analytical performance of the method was tested by spike recovery experiments. The spike recovery experiments performed on cabbage, carrot, cucumber, radish, tomatoes, and water resulted in 26.8±10.3, 40.1±8.5, 44.4±7.3, 47.6±11.3, 49.2 ±10.9, and 30.2±7.9% recovery for Cryptosporidium, respectively and 10.2±4.0, 14.1±7.3, 24.2±12.1, 23.2±13.7, 17.1±13.9, and 37.6±2.4% recovery for Giardia, respectively. The spike recovery results are comparable with data obtained using commercial brightfield and fluorescence microscope methods. Finally, we tested the smartphone microscope system for detecting (oo)cysts on 7 types of vegetable (n = 196) and river water (n = 18) samples. Forty-two percent vegetable and thirty-nine percent water samples were found to be contaminated with Cryptosporidium oocyst. Similarly, thirty-one percent vegetable and thirty-three percent water samples were contaminated with Giardia cyst. CONCLUSIONS: The newly developed smartphone microscopic method showed comparable performance to commercial microscopic methods. The new method can be a low-cost and easy to implement alternative method for simultaneous detection of (oo)cysts in vegetable and water samples in resource limited settings.