Cryptosporidium Contamination Research Articles

Unveiling the Dynamics of Cryptosporidium in Urban Surface Water: A Quantitative Microbial Risk Assessment and Insights into Climatic and Seasonal Influences

In response to global urbanization and economic development, urban surface water pollution has become a universal challenge and particularly affects densely populated megacities, and Dhaka is no exception. The discharge of 98% of untreated domestic sewage and massive volumes of industrial wastewater from over 7000 industries escalate surface water crises. This study investigates microbial and fecal contamination with particular emphasis on Cryptosporidium in surface water, known for causing waterborne diseases, such as cryptosporidiosis. Findings reveal high Cryptosporidium oocyst concentrations and fecal contamination in various water bodies in Dhaka City. Among the investigated water bodies, the Buriganga River exhibits the highest Cryptosporidium oocyst concentration (46%), while the Balu River, Turag River, Shitalakkhya River, Dhanmondi Lake, Gulshan Lake, Banani Lake, Ramna Lake, and Crescent Lake also present high levels of oocyst concentrations ranging from 21–40%. This study also calculated infection risks and found that the infection risk of swimming is highest during the wet season and is (3.9 ± 2.2 (95% CI: 3.0–5.0)) × 10−2 per swimming event, whereas it is approximately (2.4 ± 1.9 (95% CI: 1.6–3.3)) × 10−2 during the dry season. Annual diving risks are approximately (1.2 ± 0.6 (95% CI: 0.9–1.4)) × 10−2, indicating considerably high risks. Most of the sampling sites generally show significantly higher risks than other study areas like the Mymensingh and Kushtia Districts. In light of these results, we strongly recommend immediate measures to address water quality issues and mitigate the risks associated with Cryptosporidium contamination in Dhaka’s surface water.

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.

Risk factors for Cryptosporidium contamination in Minnesota public supply wells.

In a recent monitoring study of Minnesota's public supply wells, Cryptosporidium was commonly detected with 40% of the wells having at least one detection. Risk factors for Cryptosporidium occurrence in drinking water supply wells, beyond surface water influence, remain poorly understood. To address this gap, physical and chemical factors were assessed as potential predictors of Cryptosporidium occurrence in 135 public supply wells in Minnesota. Univariable analysis, regression techniques, and classification trees were used to analyze the data. Many variables were identified as significant risk factors in univariable analysis and several remained significant throughout the succeeding analysis techniques. These factors fell into general categories of well use and construction, aquifer characteristics, and connectedness to the land surface, well capture zones, and land use therein, existence of potential contaminant sources within 200-feet of the well, and variability in the chemical and isotopic parameters measured during the study. These risk categories, and the specific variables and threshold values we have identified, can help guide future research on factors influencing Cryptosporidium contamination of wells and can be used by environmental health programs to develop risk-based sampling plans and design interventions that reduce associated health risks.

Statewide Quantitative Microbial Risk Assessment for Waterborne Viruses, Bacteria, and Protozoa in Public Water Supply Wells in Minnesota

Infection risk from waterborne pathogens can be estimated via quantitative microbial risk assessment (QMRA) and forms an important consideration in the management of public groundwater systems. However, few groundwater QMRAs use site-specific hazard identification and exposure assessment, so prevailing risks in these systems remain poorly defined. We estimated the infection risk for 9 waterborne pathogens based on a 2-year pathogen occurrence study in which 964 water samples were collected from 145 public wells throughout Minnesota, USA. Annual risk across all nine pathogens combined was 3.3 × 10–1 (95% CI: 2.3 × 10–1 to 4.2 × 10–1), 3.9 × 10–2 (2.3 × 10–2 to 5.4 × 10–2), and 1.2 × 10–1 (2.6 × 10–2 to 2.7 × 10–1) infections person–1 year–1 for noncommunity, nondisinfecting community, and disinfecting community wells, respectively. Risk estimates exceeded the U.S. benchmark of 10–4 infections person–1 year–1 in 59% of well-years, indicating that the risk was widespread. While the annual risk for all pathogens combined was relatively high, the average daily doses for individual pathogens were low, indicating that significant risk results from sporadic pathogen exposure. Cryptosporidium dominated annual risk, so improved identification of wells susceptible to Cryptosporidium contamination may be important for risk mitigation.

Occurrence of Cryptosporidium and Giardia in surface water supply from 2016 to 2020 in South Brazil.

The objectives of this research are to evaluate Giardia and Cryptosporidium contamination in surface water supply in Rio Grande do Sul (RS) State in South Brazil in the years 2016 to 2020, assess seasonality, and to infer the population that may have been exposed to these protozoa through drinking water based on drinking water treatment efficiency. Data were obtained through the drinking water surveillance national information system. From 204 DWT plants in the state, 66 have been analyzed for protozoa. A total of 2304 analyses of protozoa in raw water were evaluated, of which 223 had both Giardia spp. cysts and/or Cryptosporidium spp. oocysts in concentrations that varied from 0.1 to 21.5/L. A total of 2,712,125 people from 48 cities were at risk of having the presence of pathogenic protozoa in their drinking water. The probability of finding these protozoa was higher in winter. Giardia cysts were more likely to be found in a period without rain, suggesting that sewage was the main source of contamination. It is concluded that the springs of Rio Grande do Sul are impacted and the circulation of pathogenic protozoa through the territory is endemic with a probable source of contamination to sewage and livestock activity.

Molecular surveillance of Cryptosporidium spp. for microbial source tracking of fecal contamination in Laguna Lake, Philippines.

Water quality deterioration in source waters poses increased health, environmental, and economic risks. Here, we genotyped Cryptosporidium spp. obtained from water samples of Laguna Lake, Philippines, and its tributaries for the purpose of source-tracking fecal contamination. A total of 104 surface water samples were collected over a 1-year period (March 2018 to April 2019). Detection of Cryptosporidium was carried out using genus-specific primers targeting a fragment of the small subunit (SSU) rRNA gene. The study revealed 8 (14%) tributary samples and 1 (2.77%) lake sample positive for contamination. The species were determined to be C. parvum (n = 4), C. muris (n = 2), C. hominis (n = 1), C. galli (n = 1), C. baileyi (n = 1), C. suis (n = 1), as well as rat genotype IV (n = 1). Two species were detected in duck (C. baileyi) and cattle (C. parvum) fecal samples. The data presented suggest that Cryptosporidium contamination is likely to come from sewage or human feces as well as various agricultural sources (i.e. cattle, swine, and poultry). This information reveals the importance of mitigating fecal pollution in the lake system and minimizing health risks due to exposure to zoonotic Cryptosporidium species.

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

BackgroundFood 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 findingsWe 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.ConclusionsThe 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.

Detection of Cryptosporidium oocysts and Giardia cysts in vegetables from street markets from the Qinghai Tibetan Plateau Area in China.

Cryptosporidium and Giardia are well-known parasitic protozoans responsible for waterborne and foodborne diarrhoeal diseases. However, data are not available on market vegetables contaminated with Cryptosporidium and Giardia in China. In the present study, 642 different vegetable samples were collected from Xining City street vendors in the Qinghai Province to study the Cryptosporidium and Giardia contamination rates via PCR and sequence analyses. Cryptosporidium spp. and Giardia duodenalis were detected in 16 (2.5%) and 73 (11.4%) samples, respectively. Two species of Cryptosporidium, C. parvum (n = 11) and C. andersoni (n = 5), were identified. G. duodenalis assemblage B was identified in almost all positive samples (n = 72), except one sample that contained G. duodenalis assemblage E. We report on the rate of Cryptosporidium and Giardia contamination in vegetables for the first time from the Qinghai Tibetan Plateau Area (QTPA) in China.

Microbiological Contamination of Strawberries from U-Pick Farms in Guangzhou, China.

This study quantified the association of rodent fruit damage and the microbiological quality of irrigation water on the risk of microbiological contamination of strawberries collected from 18 U-pick farms across five different districts in the Guangzhou metropolitan region of southern China. Fifty-four composite strawberries samples, with or without evidence of rodent or avian foraging damage (i.e., bitten), along with 16 irrigation water samples, were collected during the spring of 2014 and winter of 2015 from our cohort of 18 farms. Composite strawberry samples and irrigation water were analyzed for total coliforms, E. coli, Salmonella, E. coli O157, Giardia, and Cryptosporidium. Total coliforms and E. coli were detected in 100% and ~90% of irrigation water samples, respectively. In contrast, Cryptosporidium was detected in only two water samples, while Salmonella, E. coli O157, and Giardia were not detected in any water samples. Strawberries with signs of being bitten by wildlife had significantly higher concentrations of total coliforms and E. coli, compared to strawberries with no physical evidence of rodent damage (p < 0.001). Similarly, Cryptosporidium was detected in 7/18 (39%) of bitten, 4/18 (22%) of edge, and 5/18 (28%) of central strawberry samples, respectively. Concentration of E. coli on strawberries (p < 0.001), air temperature (p = 0.025), and presence of Cryptosporidium in irrigation water (p < 0.001) were all associated with the risk of Cryptosporidium contamination on strawberries. Salmonella and Giardia were detected in <4% strawberry samples and E. coli O157 was not detected in any samples. These results indicate the potential food safety and public health risks of consuming unwashed strawberries from U-pick farms, and the need for improved rodent biosecurity of U-pick strawberry fields and enhanced microbiological quality of irrigation water used at these facilities.

Cryptosporidium Prevalence in Calves and Geese Co-Grazing on Four Livestock Farms Surrounding Two Reservoirs Supplying Public Water to Mainland Orkney, Scotland.

The parasite Cryptosporidium parvum represents a threat to livestock health and production, water quality and public health. Cattle are known to be significant reservoirs of C. parvum, but transmission routes are complex and recent studies have implicated the potential role of wildlife in parasite transmission to cattle and water sources. On the Orkney Isles, high densities of Greylag geese (Anser anser) cause widespread faecal contamination of cattle pastures, where cryptosporidiosis is known to be the main cause of neonatal calf diarrhoea and Cryptosporidium contamination frequently occurs in two reservoirs supplying Mainland Orkney’s public water. This study aimed to determine the Cryptosporidium species and subtypes present in geese and calves co-grazing on four farms surrounding two reservoirs on Mainland Orkney. Results indicated a high level of C. parvum prevalence in calves, geese and water samples. gp60 analysis illustrated that higher genotypic diversity was present in the goose population compared with calves, but did not yield sequence results for any of the water samples. It can be concluded that the high levels of C. parvum evident in calves, geese and water samples tested represents a significant risk to water quality and public health.

Cryptosporidiosis outbreaks — United States, 2009–2017

Cryptosporidium is a parasite that causes cryptosporidiosis, a profuse, watery diarrhea that can last up to 3 weeks in immunocompetent patients and can lead to life-threatening malnutrition and wasting in immunocompromised patients.* Fecal-oral transmission can occur by ingestion of contaminated recreational water, drinking water, or food, or through contact with infected persons or animals. For the period 2009-2017, public health officials from 40 states and Puerto Rico voluntarily reported 444 cryptosporidiosis outbreaks resulting in 7,465 cases. Exposure to treated recreational water (e.g., in pools and water playgrounds) was associated with 156 (35.1%) outbreaks resulting in 4,232 (56.7%) cases. Other predominant outbreak exposures included contact with cattle (65 outbreaks; 14.6%) and contact with infected persons in child care settings (57; 12.8%). The annual number of reported cryptosporidiosis outbreaks overall increased an average of approximately 13% per year over time. Reversing this trend will require dissemination of prevention messages to discourage swimming or attending child care while ill with diarrhea and encourage hand washing after contact with animals. Prevention and control measures can be optimized by improving understanding of Cryptosporidium transmission through regular analysis of systematically collected epidemiologic and molecular characterization data.

Molecular Epidemiology of Cryptosporidiosis in China.

Molecular epidemiology of cryptosporidiosis is an active research area in China. The use of genotyping and subtyping tools in prevalence studies has led to the identification of unique characteristics of Cryptosporidium infections in humans and animals. Human cryptosporidiosis in China is exemplified by the high diversity of Cryptosporidium spp. at species and subtype levels, with dominant C. hominis and C. parvum subtypes being rarely detected in other countries. Similarly, preweaned dairy calves, lambs, and goat kids are mostly infected with non-pathogenic Cryptosporidium species (C. bovis in calves and C. xiaoi in lambs and goat kids), with C. parvum starting to appear in dairy calves as a consequence of concentrated animal feeding operations. The latter Cryptosporidium species is dominated by IId subtypes, with IIa subtypes largely absent from the country. Unlike elsewhere, rodents in China appear to be commonly infected with C. parvum IId subtypes, with identical subtypes being found in these animals, calves, other livestock, and humans. In addition to cattle, pigs and chickens appear to be significant contributors to Cryptosporidium contamination in drinking water sources, as reflected by the frequent detection of C. suis, C. baileyi, and C. meleagridis in water samples. Chinese scientists have also made significant contributions to the development of new molecular epidemiological tools for Cryptosporidium spp. and improvements in our understanding of the mechanism involved in the emergence of hyper-transmissible and virulent C. hominis and C. parvum subtypes. Despite this progress, coordinated research efforts should be made to address changes in Cryptosporidium transmission because of rapid economic development in China and to prevent the introduction and spread of virulent and zoonotic Cryptosporidium species and subtypes in farm animals.

Cryptosporidium species from common edible bivalves in Manila Bay, Philippines

Manila Bay is one of the major propagation sites of edible bivalves in the Philippines. Studies have shown that bivalves might be contaminated with human pathogens like the protozoan parasite Cryptosporidium, one of the major causes of gastroenteritis in the world. In this study, Cryptosporidium from four species of edible bivalves were isolated using a combination of sucrose flotation and immunomagnetic separation. Using direct fluorescent antibody test, Cryptosporidium oocysts were found in 67 out of 144 samples collected. DNA sequence analysis of the 18S rRNA gene of the isolates detected C. parvum and C. hominis (major causes of human cryptosporidiosis) and C. meleagridis (causes infection in avian species). Analysis of the 60kDa glycoprotein gene further confirmed the genotypes of the Cryptosporidium isolates. This study is the first to provide baseline information on Cryptosporidium contamination of Manila Bay where bivalves are commonly cultured.

LAMP DETECTION of Cryptosporidium SPECIES in SURFACE WATER SAMPLES COLLECTED from RIVER YESILIRMAK and STREAM TERSAKAN (Samsun-Amasya)

The water samples collected from six stations of Stream Tersakan which include Havza; Suluova-Celtek, Kanlıdere, Bogazkoy, Karasu, Tersakan-Last and eight stations of River Yesilirmak which include Amasya Bridge, Yassıcal, Durucasu, Tasova, Kumkoy, Carsamba entrance, Carsamba Bridge, Hacıomer in Amasya and Samsun Provinces were investigated for detection of Cryptosporidium oocysts by Loop Mediated Isothermal Amplification (LAMP). The water samples were regularly collected in every month from the 14 stations in investigated area between 2010 December to 2011 November for LAMP tests.Ten of 14 investigated stations were found contaminated with Cryptosporidium oocyst by LAMP. The pollution with Cryptosporidium oocysts were determined in stations which are Tersakan–Havza; Tersakan-Suluova, Celtek; Tersakan-Kanlıdere; Tersakan-Bogazkoy; Tersakan-Karasu Tersakan-Last, Yesilirmak-Amasya Bridge, Yesilirmak-Yassıcal, Yesilirmak-Durucasu, Yesilirmak-Tasova. The high contamination rate of Cryptosporidium oocysts were found in Tersakan–Suluova, Celtek and Tersakan-Bogazkoy stations in the all investigated stations. However, River Yesilirmak which is last in Samsun more clean than Stream Tersakan which is last in Amasya in terms of the Cryptosporidium oocysts contamination. The reason in excess of the rate of Cryptosporidium contamination in Stream Tersakan are more animal husbandry in Havza and Suluova Boroughs and no processing domestic and agricultural waste water mixing to surface water.

Modeling Cryptosporidium and Giardia in Ground and Surface Water Sources in Rural India: Associations with Latrines, Livestock, Damaged Wells, and Rainfall Patterns.

Surface and groundwater contamination with fecal pathogens is a public health concern especially in low-income settings where these sources are used untreated. We modeled observed Cryptosporidium and Giardia contamination in community ponds (n = 94; 79% contaminated), deep tubewells (DTWs) (n = 107; 17%), and shallow tubewells (STWs) (n = 96; 19%) during the 2012 and 2013 monsoon seasons (June–August) in 60 villages in Puri District, India to understand sources and processes of contamination. Detection of Cryptosporidium and/or Giardia in a tubewell was positively associated with damage to the well pad for DTWs, the amount of human loading into pour-flush latrine pits nearby (≤15 m) for STWs, and the village literacy rate (for Giardia in STWs). Pond concentration levels were positively associated with the number of people practicing open defecation within 50 m and the sheep population for Cryptosporidium, and with the village illiteracy rate for Giardia. Recent rainfall increased the risk of Cryptosporidium in STWs (an extreme event) and ponds (any), while increasing seasonal rainfall decreased the risk of Giardia in STWs and ponds. Full latrine coverage in this setting is expected to marginally reduce pond Cryptosporidium contamination (16%) while increasing local groundwater protozoal contamination (87–306%), with the largest increases predicted for Cryptosporidium in STWs.

Detection and quantification of Cryptosporidium oocysts in environmental surfaces of an Equine Perinatology Unit

The presence of Cryptosporidium in institutions such as veterinary teaching hospitals, where students and staff are in frequent contact with animals, could represent a serious public health risk. In this study the detection and quantification of the Cryptosporidium oocysts present on the environmental surfaces of an Equine Perinatology Unit (EPU) were investigated. During 3 foaling seasons 175 samples obtained by swabbing an area of the floor and walls of boxes and utility rooms of EPU with sterile gauze, in 3 different moments. Samples were collected at the end of foaling season (July), after washing procedures (September) and after washing and disinfecting procedures, at the beginning of a new foaling season (December). All the samples were subjected to nested-PCR, followed by genotyping and sub-typing methods and to qPCR, allowing the oocyst quantification. Cryptosporidium spp. was detected in 14 samples, of which 11 were from walls and three were from floors. The highest number of oocysts was found in a sample collected from the floor of one utility room used for setting up therapies and treatments. In most cases, oocyst numbers, estimated by qPCR, were reduced or eliminated after washing and disinfecting procedures. The genotyping and sub-typing methods allowed identification of 2 subtypes of C. parvum (IIaA15G2R1 and IIdA23G1) and 1 of Cryptosporidium horse genotype (VIaA15G4) that were described in foals hospitalized at the EPU in the same years. The results of the present study show that qPCR can be used to evaluate Cryptosporidium contamination of environmental surfaces of a veterinary teaching hospital and the efficacy of the disinfection procedures.

Using Host-Specificity of &amp;lt;i&amp;gt;Cryptosporidium&amp;lt;/i&amp;gt; to Understand Contaminant Sources, Seasonality, and Human Health Risk in Three Watersheds of Differing Land-Use

Three tributaries of the Grand River watershed (Ontario, Canada), each representing different watershed types (urban, agricultural/rural, and mixed land-use) were examined to understand the spatial, temporal, and host-source distribution of the waterborne pathogen, Cryptosporidium. Cryptosporidium was frequently found throughout the study (73%, 65/89) with occurrence and concentrations observed to be similar among the varying watershed types. However, applying advanced genotyping techniques, marked differences in dominant host sources could be observed in each watershed. The agricultural/rural and mixed land-use watersheds were dominated by genotypes typically associated with cattle (i.e., C. andersoni), while the urban watershed had the highest diversity of Cryptosporidium genotypes with a variety of wildlife as the common source of contamination (e.g., muskrat and cervine genotypes). A similar seasonal trend observed in the urban, agricultural, and mixed land-use watershed suggests that factors beyond specific land use activities (e.g. autumn manure spreading) may influence the timing and concentration of Cryptosporidium in these streams. Corresponding genotyping results provided additional insight into source inputs during these seasonal peaks, indicating that wildlife may be important seasonal contributors to Cryptosporidium contamination in these streams. Despite the abundance of Cryptosporidium in these watersheds, most of the genotypes observed were of limited human health importance. This study provides evidence regarding the significance of including genotyping results into studies examining waterborne Cryptosporidium. Using this technique can provide a greater understanding of the risk to the population using water sources, as well as provide insight into the probable sources and timing of contamination. This ancillary information can contribute to implementation of targeted management strategies to further protect sources of drinking water and recreation areas.

Cryptosporidium contamination in surface seawaters in different coastal areas of Thailand: is there any effect from tsunami attack?

*Corresponding author: Sora Yasri, KMT Primary Care Center, Bangkok, Thailand. E-mail: sorayasri@outlook.co.th Dear editor, The Cryptosporidium spp. are important protozoa that can be pathogenic for human beings[1,2]. These protozoa can cause diarrhea and contaminate several foods as well as water. These protozoa can be seen worldwide. In tropical world, they are one of presently problematic pathogenic protozoa. In Thailand, these protozoan still cause diseases and has to be controlled[3]. The contamination of the surface seawater with protozoa is interesting. A recent report showed the high contamination rate in sea mussel which is the common seafood of the Thais[4]. Here, the authors tried to assess the reported prevalence of contamination of Cryptosporidium spp. in sea waters from different coastal areas of Thailand. Of interest, there are 2 previous relating reports on this topic[5,6]. The reported rates of contamination range from 6.0% and 12.7% (Figure 1).

Prevalence, species identification and genotyping Cryptosporidium from livestock and deer in a catchment in the Cairngorms with a history of a contaminated public water supply.

BackgroundThe apicomplexan parasite Cryptosporidium represents a threat to water quality and public health. An important zoonotic species involved in human cryptosporidiosis from contaminated water is Cryptosporidium parvum (C. parvum), the main reservoirs of which are known to be farm livestock particularly neonatal calves, although adult cattle, sheep, lambs and wildlife are also known to contribute to catchment loading of C. parvum. This study aimed to establish Cryptosporidium prevalence, species and genotype in livestock, deer and water in a catchment with a history of Cryptosporidium contamination in the public water supply.MethodsA novel method of processing adult ruminant faecal sample was used to concentrate oocysts, followed by a nested species specific multiplex (nssm) PCR, targeting the 18S rRNA gene, to speciate Cryptosporidium. A multilocus fragment typing (MLFT) tool was used, in addition to GP60 sequencing, to genotype C. parvum positive samples.ResultsA very high prevalence of Cryptosporidium was detected, with speciation identifying a predominance of C. parvum in livestock, deer and water samples. Four GP60 subtypes were detected within C. parvum with the majority IIaA15G2R1 which was detected in all host species and on all farms. Multilocus fragment typing further differentiated these into 6 highly related multilocus genotypes.ConclusionThe high prevalence of Cryptosporidium detected was possibly due to a combination of the newly developed sample processing technique used and a reflection of the high rates of the parasite present in this catchment. The predominance of C. parvum in livestock and deer sampled in this study suggested that they represented a significant risk to water quality and public health. Genotyping results suggested that the parasite is being transmitted locally within the study area, possibly via free-roaming sheep and deer. Further studies are needed to verify particular host associations with subtypes/MLGs. Land and livestock management solutions to reduce Cryptosporidium on farm and in the catchment are planned with the aim to improve animal health and production as well as water quality and public health.

Large Utilities' Use of the Microbial Toolbox for LT2ESWTR Compliance

Public water systems were surveyed to determine how they chose to achieve compliance with the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). This rule, promulgated in 2006, was intended to increase protection from the risks of Cryptosporidium contamination by encouraging utilities to adopt a multibarrier approach to drinking water treatment. The rule allowed the use of a number of treatment options, or tools, for compliance. Large treatment facilities were required to demonstrate compliance with the rule by 2012. This survey determined which tools large utilities used for compliance and why they chose these particular options. This article discusses the tools chosen, outlines the requirements for obtaining credits for Cryptosporidium inactivation or removal, and reviews the scientific basis for the US Environmental Protection Agency's decision to grant these credits.