Outbreak Of Cryptosporidiosis Research Articles

Cryptosporidium Attenuation across the Wastewater Treatment Train: Recycled Water Fit for Purpose.

Compliance with guideline removal targets for Cryptosporidium which do not provide any credit for the inactivation of oocysts through wastewater treatment processes can considerably increase the cost of providing recycled water. Here we present the application of an integrated assay to quantify both oocyst numbers and infectivity levels after various treatment stages at three Victorian and two South Australian (SA) wastewater treatment plants (WWTPs). Oocyst density in the raw sewage was commensurate with community disease burden, with early rounds of sampling capturing a widespread cryptosporidiosis outbreak in Victoria. The level of infectivity of oocysts in sewage was stable throughout the year but was significantly lower at the SA WWTPs. Removals across secondary treatment processes were seasonal, with poorer removals associated with inflow variability; however, no decrease in the oocyst infectivity was identified. For SA WWTPs, those oocysts remaining within the secondary treatment-clarified effluent were proportionally more infectious than those in raw sewage. Lagoon systems demonstrated significant inactivation or removal of oocysts, with attenuation being seasonal. Examination of a UV system emphasized its efficacy as a disinfectant barrier but conversely confirmed the importance of a multibarrier approach with the detection of infectious oocysts postdisinfection. The ability to characterize risk from infectious oocysts revealed that the risk from Cryptosporidium is significantly lower than previously thought and that its inclusion in quantitative risk assessments of reuse systems will more accurately direct the selection of treatment strategies and capital expenditure, influencing the sustainability of such schemes.IMPORTANCE Here we present the application of a recently developed integrated assay not only to quantify the removal of Cryptosporidium oocysts but also to quantify their infectivity across various treatment stages at five wastewater treatment plants (WWTPs), thereby better measuring the "true effect" of the treatment train on oocyst risk reduction. For a number of the WWTPs analyzed in this study the risk, is significantly lower than previously thought. Therefore, the inclusion of oocyst infectivity in guideline values and in quantitative microbial risk assessment (QMRA) has the potential to affect future treatment directions and capital expenditure.

Waterborne outbreak of cryptosporidiosis in the South East of Ireland: weighing up the evidence.

In late Spring 2012, 12 cases of cryptosporidiosis in a town in the South East of Ireland were notified to the regional Department of Public Health. The purpose of this paper is to describe the outbreak and the investigative process which led to the conclusion that the source was a public drinking water supply. Outbreak and incident control teams were convened to investigate and control the outbreak. Eleven cases were speciated as Cryptosporidium parvum. GP60 analysis demonstrated that 10 were C. parvum IIaA20G3R1, indicating that the cases were linked. The public water supply was the only common risk factor identified. Increased water sampling identified Cryptosporidium muris/andersoni in the treated water at one of two water treatment plants (Water Treatment Plant, WTP A) for the supply, and on the network. C. parvum was subsequently identified in raw water from WTP A. The Health Service Executive (HSE) concluded that this outbreak was "probably associated with water" produced at WTP A based on (1) descriptive epidemiological evidence suggesting water-related illness and excluding other obvious explanations; and (2) water treatment failure at WTP A. WTP A was closed to facilitate an upgrade. No boil water notice was required as a supplementary supply was available. The upgrade was completed and the incident closed in 2013.

Cryptosporidiosis outbreak at an academic animal research laboratory-Colorado, 2014.

After cryptosporidiosis was reported in three workers caring for preweaned calves at an academic research laboratory, we sought to identify cases, determine risk factors, and implement control measures. A cryptosporidiosis case was defined as diarrhea duration ≥72 hr, abdominal cramps, or vomiting in an animal research laboratory worker during July 14-July 31. A confirmed case had laboratory evidence of Cryptosporidium infection. Staff were interviewed regarding illness, potential exposures, training, and personal protective equipment (PPE) standard operating procedures (SOPs). The cryptosporidiosis attack rate (AR) was 74% (20/27); five were laboratory-confirmed. Median job training was 2 hr including respiratory-fit testing. No SOPs existed for doffing PPE. AR for workers who removed their gloves first was 84% (16/19) compared with 20% (1/5) for workers who removed gloves last (risk ratio = 4.2; P < 0.02). This outbreak highlights the importance of adequate training, enforced proper PPE procedures, and promoting a culture of safety. Am. J. Ind. Med. 60:208-214, 2017. © 2017 Wiley Periodicals, Inc.

Limiting swimming pool outbreaks of cryptosporidiosis - the roles of regulations, staff, patrons and research.

Cryptosporidium is the leading cause of swimming pool outbreaks of gastroenteritis. Transmission occurs through the ingestion of oocysts that are passed in the faeces of an infected person or animal when an accidental faecal release event occurs. Cryptosporidium parasites present specific challenges for infection control as oocysts are highly resistant to chlorine levels used for pool disinfection, infected individuals can shed large numbers of oocysts, there is a long incubation period and shedding of oocysts occurs even after symptom resolution. The purposes of this review are to identify key barriers to limiting swimming pool-associated outbreaks of cryptosporidiosis and to outline needs for research and collaboration to advance co-ordinated management practices. We reviewed swimming pool-associated cryptosporidiosis outbreaks, disinfection teachniques, current regulations and the role of staff and patrons. Key barriers to limiting swimming pool-associated outbreaks of cryptosporidiosis are a lack of uniform national and international standards, poor adherence and understanding of regulations governing staff and patron behaviour, and low levels of public knowledge and awareness.

Discovery of new variable number tandem repeat loci in multiple Cryptosporidium parvum genomes for the surveillance and investigation of outbreaks of cryptosporidiosis

Cryptosporidium parvum is a protozoan parasite causing gastro-intestinal disease (cryptosporidiosis) in humans and animals. The ability to investigate sources of contamination and routes of transmission by characterization and comparison of isolates in a cost- and time-efficient manner will help surveillance and epidemiological investigations, but as yet there is no standardised multi-locus typing scheme. To systematically identify variable number tandem repeat (VNTR) loci, which have been shown to provide differentiation in moderately conserved species, we interrogated the reference C. parvum Iowa II genome and seven other C. parvum genomes using a tandem repeat finder software. We identified 28 loci that met criteria defined previously for robust typing schemes for inter-laboratory surveillance, that had potential for generating PCR amplicons analysable on most fragment sizing platforms: repeats ≥6 bp, occurring in tandem in a single repeat region, and providing a total amplicon size of <300 bp including 50 bp for the location of the forward and reverse primers. The qualifying loci will be further investigated in vitro for consideration as preferred loci in the development of a robust VNTR scheme.

Cryptosporidium hominis Is a Newly Recognized Pathogen in the Arctic Region of Nunavik, Canada: Molecular Characterization of an Outbreak.

BackgroundCryptosporidium is a leading cause of childhood diarrhea in low-resource settings, and has been repeatedly associated with impaired physical and cognitive development. In May 2013, an outbreak of diarrhea caused by Cryptosporidium hominis was identified in the Arctic region of Nunavik, Quebec. Human cryptosporidiosis transmission was previously unknown in this region, and very few previous studies have reported it elsewhere in the Arctic. We report clinical, molecular, and epidemiologic details of a multi-village Cryptosporidium outbreak in the Canadian Arctic.Methodology/Principal FindingsWe investigated the occurrence of cryptosporidiosis using a descriptive study of cases with onset between April 2013 and April 2014. Cases were defined as Nunavik inhabitants of any age presenting with diarrhea of any duration, in whom Cryptosporidium oocysts were detected by stool microscopy in a specialised reference laboratory. Cryptosporidium was identified in stool from 51 of 283 individuals. The overall annual incidence rate (IR) was 420 / 100,000 inhabitants. The IR was highest among children aged less than 5 years (1290 /100,000 persons). Genetic subtyping for stool specimens from 14/51 cases was determined by DNA sequence analysis of the 60 kDa glycoprotein (gp60) gene. Sequences aligned with C. hominis subtype Id in all cases. No common food or water source of infection was identified.Conclusions/SignificanceIn this first observed outbreak of human cryptosporidiosis in this Arctic region, the high IR seen is cause for concern about the possible long-term effects on growth and development of children in Inuit communities, who face myriad other challenges such as overcrowding and food-insecurity. The temporal and geographic distribution of cases, as well as the identification of C. hominis subtype Id, suggest anthroponotic rather than zoonotic transmission. Barriers to timely diagnosis delayed the recognition of human cryptosporidiosis in this remote setting.

Cryptosporidium parvum: From foal to veterinary students

This paper describes the transmission of a zoonotic subtype of Cryptosporidium parvum between two foals hospitalized in an Equine Perinatology Unit (EPU) linked to an outbreak of cryptosporidiosis in veterinary students. Fecal specimens of 36 mares (105 samples) and 28 foals (122 samples) were subjected to Ziehl–Neelsen staining, nested PCR of 18S rDNA. Two foals tested positive for Cryptosporidium; PCR restriction fragment length polymorphism (PCR-RFLP) analysis and subtyping by nested PCR of the 60kDa glycoprotein (gp60) gene revealed C. parvum subtype IIdA23G1. The introduction of Cryptosporidium into the EPU is suspected to be in a foal showing no initial clinical signs that tested positive for C. parvum during an asymptomatic phase. A second foal, hospitalized afterwards for perinatal asphyxia syndrome complicated with failure of passive transfer and sepsis, showed severe watery diarrhea after 4 days of hospitalization and was positive for the same subtype. During this period, six students attending the EPU complained of abdominal pain and diarrhea and were positive for the same subtype of C. parvum. To the authors’ knowledge, this is the first description of this subtype in foals and the first report of evidence of zoonotic transmission of cryptosporidiosis from foals to human.

A multiplex PCR test to identify four common cattle-adapted Cryptosporidium species

SUMMARYCryptosporidiumis a well-known cause of neonatal enteritis in cattle worldwide. Cattle are commonly infected with four different species ofCryptosporidiumbut only one of these,Cryptosporidium parvum, is associated with clinical disease. Identification of species in cases of calf scour can give an indication ifCryptosporidiumis the causative agent or not. In addition,C. parvumis a zoonotic species and so has implications for human health, for this reason it is important to identify the species ofCryptosporidiuminfecting cattle particularly where a farm is implicated in an outbreak of cryptosporidiosis in humans. Here a multiplex PCR test, which can identify the four common cattle-adaptedCryptosporidiumspecies, includingC. parvum, has been developed. This test allows quick and accurate detection ofCryptosporidiumspecies in cattle fecal samples including mixed infections, which could be missed by the more common method of sequencing the same gene.

Field Calibration and Verification of a Pathogen Transport Model

Outbreaks of cryptosporidiosis throughout the world, especially the massive outbreak in Milwakee in 1993 drew public attention to the quality of drinking water supplies and to the efficiency of water treatment methods. Cryptosporidiosis is a severe gastrointestinal disease caused by the transmissive form of Cryptosporidium parvum protozoan – its oocysts. Digestion of as few as 30 oocysts may be fatal to infants, elderly and immunocompromized persons. C. parvum oocysts are ubiquitous in untreated water and extremely resistant to harsh environmental conditions including standard water treatment procedures. We have developed an integrated modeling strategy to quantify the risk of surface drinking water contamination by water borne pathogens, in particular the oocysts of C. parvum, from agricultural non-point pollution sources. This project is comprised of both a modeling and an experimental effort. The main experimental effort focused on the measurement of C. parvum oocysts partitioning in the soil/water systems with the objective of parameterizing the transport model. This title belongs to WERF Research Report Series ISBN: 9781780404271 (eBook) ISBN: 9781843397113 (Print)

Cryptosporidiosis outbreak in visitors of a UK industry-compliant petting farm caused by a rare Cryptosporidium parvum subtype: a case-control study.

A case-control study was conducted to investigate an outbreak of 46 cases of cryptosporidiosis in visitors to a petting farm in England. Details of exposures on the farm were collected for 38 cases and 39 controls, recruited through snowball sampling. Multivariable logistic regression identified that cases were 5·5 times more likely than controls to have eaten without washing their hands [95% confidence interval (CI) 1·51-19·9, P = 0·01] and 10 times less likely to report being informed of risk of infection on arrival (odds ratio 0·10, 95% CI 0·01-0·71, P = 0·02). An uncommon Cryptosporidium parvum gp60 subtype (IIaA19G1R1) was identified in a lamb faecal sample and all subtyped cases (n = 22). We conclude that lack of verbal advice and non-compliance with hand washing are significantly associated with a risk of cryptosporidiosis on open farms. These findings highlight the public health importance of effectively communicating risk to petting farm visitors in order to prevent future outbreaks of zoonotic infections.

A Laboratory-Associated Outbreak of Cryptosporidiosis

An outbreak of cryptosporidiosis involving 10 primary cases, as well as several additional presumptive primary cases, occurred among third-year veterinary medical students in October 2011. The inve...

Communitywide cryptosporidiosis outbreak associated with a surface water-supplied municipal water system--Baker City, Oregon, 2013.

Cryptosporidium, a parasite known to cause large drinking and recreational water outbreaks, is tolerant of chlorine concentrations used for drinking water treatment. Human laboratory-based surveillance for enteric pathogens detected a cryptosporidiosis outbreak in Baker City, Oregon during July 2013 associated with municipal drinking water. Objectives of the investigation were to confirm the outbreak source and assess outbreak extent. The watershed was inspected and city water was tested for contamination. To determine the community attack rate, a standardized questionnaire was administered to randomly sampled households. Weighted attack rates and confidence intervals (CIs) were calculated. Water samples tested positive for Cryptosporidium species; a Cryptosporidium parvum subtype common in cattle was detected in human stool specimens. Cattle were observed grazing along watershed borders; cattle faeces were observed within watershed barriers. The city water treatment facility chlorinated, but did not filter, water. The community attack rate was 28·3% (95% CI 22·1-33·6), sickening an estimated 2780 persons. Watershed contamination by cattle probably caused this outbreak; water treatments effective against Cryptosporidium were not in place. This outbreak highlights vulnerability of drinking water systems to pathogen contamination and underscores the need for communities to invest in system improvements to maintain multiple barriers to drinking water contamination.

Notes from the Field: Outbreak of Cryptosporidiosis Among Veterinary Medicine Students--Philadelphia, Pennsylvania, February 2015.

On February 20, 2015, a northeastern university's student health center was notified of five veterinary medicine students with gastrointestinal symptoms. An investigation was conducted to establish the existence of an outbreak, determine the etiology, evaluate risk factors, and recommend control measures.

An Outbreak of Cryptosporidium parvum across England & Scotland Associated with Consumption of Fresh Pre-Cut Salad Leaves, May 2012.

BackgroundWe report a widespread foodborne outbreak of Cryptosporidium parvum in England and Scotland in May 2012. Cases were more common in female adults, and had no history of foreign travel. Over 300 excess cases were identified during the period of the outbreak. Speciation and microbiological typing revealed the outbreak strain to be C. parvum gp60 subtype IIaA15G2R1.MethodsHypothesis generation questionnaires were administered and an unmatched case control study was undertaken to test the hypotheses raised. Cases and controls were interviewed by telephone. Controls were selected using sequential digit dialling. Information was gathered on demographics, foods consumed and retailers where foods were purchased.ResultsSeventy-four laboratory confirmed cases and 74 controls were included in analyses. Infection was found to be strongly associated with the consumption of pre-cut mixed salad leaves sold by a single retailer. This is the largest documented outbreak of cryptosporidiosis attributed to a food vehicle.

Benefits of High Resolution Melting Analysis for Rapid Detection and Genotyping of Selected Protozoal and Fungal Parasites

Microsporidiosis, cryptosporidiosis, blastocystosis, etc., of humans and animals are an intestinal diseases caused predominantly by infection with zoonotic species and genotypes of these pathogens. These diseasesare transmitted mainly via the faecal-oral route.Generally, these deseasesare occurs worldwide, but in places with poor sanitation and crowded living conditions is endemic and is associated with source of water and food supply, age, and socioeconomic status [1]. The diagnosis and genetic characterization of the main species and population variants of Microsporidia, Cryptosporidium and Blastocystis infecting humans andanimalsare central to the prevention, surveillance and control of these diseases, particularly as there is presently no cost effective chemotherapeutic regimen or vaccine available. In this Minireview we want to draw attention to the possibility of using HRM analysis for species and genotypic differentiation of these pathogens in clinical samples of humans and animals. This approach is well suited for the rapid screening of large numbers of Cryptosporidium oocyst, Blastocystis cyst and Microsporidia spores DNA samples and, although qualitative, is significantly less time-consuming to carry out than electrophoretic analysis. This method provides a useful tool for investigating the epidemiology and outbreaks of cryptosporidiosis, microsporidiosis and blastocystosis and could be applicable to identification of species of these pathogens.

Preventing community-wide transmission of Cryptosporidium: a proactive public health response to a swimming pool-associated outbreak--Auglaize County, Ohio, USA.

The incidence of recreational water-associated outbreaks in the United States has significantly increased, driven, at least in part, by outbreaks both caused by Cryptosporidium and associated with treated recreational water venues. Because of the parasite's extreme chlorine tolerance, transmission can occur even in well-maintained treated recreational water venues (e.g. pools) and a focal cryptosporidiosis outbreak can evolve into a community-wide outbreak associated with multiple recreational water venues and settings (e.g. childcare facilities). In August 2004 in Auglaize County, Ohio, multiple cryptosporidiosis cases were identified and anecdotally linked to pool A. Within 5 days of the first case being reported, pool A was hyperchlorinated to achieve 99·9% Cryptosporidium inactivition. A case-control study was launched to epidemiologically ascertain the outbreak source 11 days later. A total of 150 confirmed and probable cases were identified; the temporal distribution of illness onset was peaked, indicating a point-source exposure. Cryptosporidiosis was significantly associated with swimming in pool A (matched odds ratio 121·7, 95% confidence interval 27·4-∞) but not with another venue or setting. The findings of this investigation suggest that proactive implementation of control measures, when increased Cryptosporidium transmission is detected but before an outbreak source is epidemiologically ascertained, might prevent a focal cryptosporidiosis outbreak from evolving into a community-wide outbreak.

Cryptosporidiosis outbreak in a child day-care center caused by an unusual Cryptosporidium hominis subtype

IntroductionThis work describes the genetic characterization of Cryptosporidium and Giardia involved in an outbreak in a nursery school in Granada, Spain, that affected seven children under the age of 4. MethodsNucleic acids were extracted from the seven stool samples positive to Cryptosporidium or Giardia by microscopy and/or immunochromatography. The species and subtypes of Cryptosporidium were identified by PCR-RFLP and PCR of the SSUrRNA and gp60 genes, respectively. The assemblages of Giardia duodenalis isolates were characterized by PCR of the tpi gene. PCR products were sequenced and analyzed. ResultsAll of the isolates were positive for Cryptosporidium hominis. Five of them belonged to subtype IaA11R2, one to subtype IbA10G2R2, and the other could not be identified. Three of these samples were positive for G. duodenalis by PCR, two belonging to the assemblage A, and the other one to assemblage B. DiscussionThis is the first report of Cryptosporidium hominis subtype IaA11R2 as a cause of an outbreak in Europe where subtype IbA10G2R2 is the most frequently identified. In the case of Giardia, an outbreak could not be confirmed because of the low number of positive samples and the low genetic variability of the amplified fragments for assemblage A of tpi gene. ConclusionsA new subtype, of Cryptosporidium hominis named IaA11R2, has been described as a cause of an outbreak in a nursery school in Granada, Spain. However an outbreak of giardiasis could not be confirmed.

Cryptosporidiosis caused by Cryptosporidium parvum subtype IIdA15G1 at a dairy farm in Northwestern China.

BackgroundCryptosporidium spp. are zoonotic parasites responsible for diarrhoeal diseases in animals and humans worldwide. Cattle are the most common mammalian species in which Cryptosporidium is detected, with pre-weaned calves considered to be reservoirs for zoonotic C. parvum. In October 2013, severe diarrhoea was observed in 396 pre-weaned calves at a farm in the Ningxia Autonomous Region of Northwestern China. 356 of the infected calves died despite antibiotic therapy.Findings252 faecal samples were collected from the investigated farm. The identity of Cryptosporidium species was determined by polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) analysis, and by DNA sequence analysis of the small subunit (SSU) rRNA gene. C. parvum was subtyped using sequence analysis of the 60 kDa glycoprotein (gp60) gene. The highest infection rate of 83.3% (40/48) was seen in 2–3-week-old calves with diarrhoea, corresponding to the age at which animals died. Three Cryptosporidium species were identified, including C. parvum (n = 51), C. bovis (n = 1), and C. ryanae (n = 1). All C. parvum isolates were further identified as subtype IIdA15G1.ConclusionsCryptosporidium parvum was likely to be most responsible for diarrhoea and death. This is the first report of a cryptosporidiosis outbreak caused by C. parvum IIdA15G1 in Chinese dairy cattle.

Cryptosporidium cuniculus--new records in human and kangaroo in Australia.

BackgroundTo date, Cryptosporidium cuniculus has been found exclusively in rabbits and humans. The present study provides the first published molecular evidence for C. cuniculus in an Australian human patient as well as a kangaroo.FindingsUsing PCR-based sequencing of regions in the actin, 60 kDa glycoprotein (gp60) and small subunit of ribosomal RNA (SSU) genes, we identified a new and unique C. cuniculus genotype (akin to VbA25) from a human, and C. cuniculus genotype VbA26 from an Eastern grey kangaroo (Macropus giganteus) in Australia.ConclusionsThe characterisation of these genotypes raises questions as to their potential to infect humans and/or other animals in Australia, given that C. cuniculus has been reported to cause cryptosporidiosis outbreaks in Europe.

Symptomatic and asymptomatic secondary transmission of Cryptosporidium parvum following two related outbreaks in schoolchildren.

Two related outbreaks (in 2009 and 2012) of cryptosporidiosis in Norwegian schoolchildren during a stay at a remote holiday farm provided us with a natural experiment to investigate possible secondary transmission of Cryptosporidium parvum IIa A19G1R1. After the children had returned home, clinical data and stool samples were obtained from their household contacts. Samples were investigated for the presence of Cryptosporidium oocysts by immunofluorescence antibody test. We found both asymptomatic and symptomatic infections, which are likely to have been secondary transmission. Laboratory-confirmed transmission rate was 17% [4/23, 95% confidence interval (CI) 7·0-37·1] in the 2009 outbreak, and 0% (95% CI 0-16·8) in the 2012 outbreak. Using a clinical definition, the probable secondary transmission rate in the 2012 outbreak was 8% (7/83, 95% CI 4·1-16·4). These findings highlight the importance of hygienic and public health measures during outbreaks or individual cases of cryptosporidiosis. We discuss our findings in light of previous studies reporting varying secondary transmission rates of Cryptosporidium spp.