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Cryptosporidium is the leading aetiology of waterborne disease outbreaks in the United States. This report briefly describes the temporal and geographical distribution of US cryptosporidiosis cases and presents analyses of cryptosporidiosis case data reported in the United States for 1995-2012. The Cochran-Armitage test was used to assess changes in the proportions of cases by case status (confirmed vs. non-confirmed), sex, race, and ethnicity over the study period. Negative binomial regression models were used to estimate rate ratios (RR) and 95% confidence intervals (CI) for comparing rates across three time periods (1995-2004, 2005-2008, 2009-2012). The proportion of confirmed cases significantly decreased (P < 0·0001), and a crossover from male to female predominance in case-patients occurred (P < 0·0001). Overall, compared to 1995-2004, rates were higher in 2005-2008 (RR 2·92, 95% CI 2·08-4·09) and 2009-2012 (RR 2·66, 95% CI 1·90-3·73). However, rate changes from 2005-2008 to 2009-2012 varied by age group (P interaction < 0·0001): 0-14 years (RR 0·55, 95% CI 0·42-0·71), 15-44 years (RR 0·99, 95% CI 0·82-1·19), 45-64 years (RR 1·47, 95% CI 1·21-1·79) and ⩾65 years (RR 2·18, 95% CI 1·46-3·25). The evolving epidemiology of cryptosporidiosis necessitates further identification of risk factors in population subgroups. Adding systematic molecular typing of Cryptosporidium specimens to US national cryptosporidiosis surveillance would help further identify risk factors and markedly expand understanding of cryptosporidiosis epidemiology in the United States. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

The search for an association between disease incidence and possible risk factors using surveillance data needs to account for possible spatial and temporal correlations in underlying risk. This can be especially difficult if there are missing values for some important covariates. We present a case study to show how this problem can be overcome in a Bayesian analysis framework by adding to the usual spatio-temporal model a component for modelling the missing data. [ABSTRACT FROM AUTHOR]

Faecal samples from 804 cattle and buffaloes and 165 diarrhoeal children of Ismailia province were investigated by an immunochromatographic screening test and PCR to determine prevalences and distributions of Cryptosporidium spp. Results were analysed statistically for clustering of animal and human cases. Cryptosporidium herd prevalence was 73·3% and individual animal prevalence 32·3%. C. parvum was the dominant species in animals (65·7%). Young calves watered with canal or underground water were at particular risk of infection. Detection rates were higher when calves showed diarrhoea, fever and dehydration. Human Cryptosporidium prevalence was 49·1%. C. hominis dominated in humans (60·5%), followed by C. parvum (38·3%). Living in villages, drinking underground water and having contact with animals were risk factors. Cluster analysis revealed differences in the distribution of infections between animals and humans and suggests different transmission dynamics. [ABSTRACT FROM AUTHOR]

Water supply-associated cryptosporidiosis outbreaks have decreased in England since the application of risk reduction measures to public water supplies. We hypothesized that smaller outbreaks were occurring which could be better detected by enhanced surveillance. Rolling analysis of detailed questionnaire data was applied prospectively in a population of 2·2 million in the south of England in 2009 and 2010. Detection of spatiotemporal clusters using SaTScan was later undertaken retrospectively. Together these approaches identified eight outbreaks, compared to an expectation of less than one based on national surveillance data. These outbreaks were small and associated with swimming pool use or, less commonly, direct (e.g. petting-farm) contact with animals. These findings suggest that frequent small-scale transmission in swimming pools is an important contributor to disease burden. Identification of swimming pool-level risk factors may inform preventative measures. These findings and the approaches described may be applicable to many other populations and to some other diseases. [ABSTRACT FROM PUBLISHER]

During 2012 real-time syndromic surveillance formed a key part of the daily public health surveillance for the London Olympic and Paralympic Games. It was vital that these systems were evaluated prior to the Games; in particular what types and scales of incidents could and could not be detected. Different public health scenarios were created covering a range of potential incidents that the Health Protection Agency would require syndromic surveillance to rapidly detect and monitor. For the scenarios considered it is now possible to determine what is likely to be detectable and how incidents are likely to present using the different syndromic systems. Small localized incidents involving food poisoning are most likely to be detected the next day via emergency department surveillance, while a new strain of influenza is more likely to be detected via GP or telephone helpline surveillance, several weeks after the first seed case is introduced. [ABSTRACT FROM PUBLISHER]

In September 2010, an outbreak of cryptosporidiosis affected members of a swimming club. A cohort study was undertaken to identify the number affected and risk factors for infection. Of 101 respondents, 48 met the case definition for probable cryptosporidiosis. Multivariate analysis demonstrated a strong and highly significant association between illness and attendance at a training session on 13 September 2010 (adjusted odds ratio 28, P < 0·0001). No faecal incidents were reported and pool monitoring parameters were satisfactory. The competitive nature of club swimming requires frequent training and participation in galas, potentially facilitating contamination into other pools and amplification of outbreaks among wider groups of swimmers. There was a lack of awareness of the 2-week exclusion rule among swimmers and coaches, and a high level of underreporting of illness. The study demonstrates the benefits of rapid field epidemiology in identifying the true burden of illness, the source of infection and limiting spread. [ABSTRACT FROM AUTHOR]

Cryptosporidium is a zoonotic protozoan parasite with public health importance worldwide. The objectives of this study were to (1) conduct a meta-analysis of published literature for oocyst shedding and diarrhoea outcomes, and (2) develop recommendations for standardization of experimental dose–response studies. Results showed that for the outcome of oocyst shedding in faeces, the covariates ‘experimental species’, ‘immunosuppression’, ‘oocyst dose’ and ‘oocyst dose’ × ‘age’ were all significant (P ⩽ 0·05). This study suggests that exposing mice, piglets, or ruminants, and using immunosuppressed experimental hosts, is more likely to result in oocyst shedding. For the outcome of diarrhoea in experimentally infected animal species, the key covariates ‘experimental species’, ‘age’ and ‘immunosuppression’ were significant (P ⩽ 0·2). Therefore, based on the results of this meta-analysis, these variables should be carefully reported and considered when designing experimental dose–response studies. Additionally, detection of possible publication bias highlights the need to publish additional studies that convey statistically non-significant as well as significant results in the future. [ABSTRACT FROM AUTHOR]

A cohort study was performed to investigate cryptosporidial prevalence and species distribution in 13 organic and 13 conventional dairy herds. Faecal samples were collected from 221 calves and 259 cows. Management routines were recorded at farm inspection and through a questionnaire. Samples were concentrated using sodium chloride flotation and cryptosporidial oocysts were detected by epifluorescence microscopy. Molecular analysis was used to determine species and subtypes. A multivariable model for factors associated with calves being Cryptosporidium spp. positive was built. Cryptosporidium spp.-positive animals were identified in all herds. Prevalences were similar in organic and conventional calves (44·7% vs. 52·3%), as well as in cows (3·1% vs. 3·8%), P > 0·05. Cryptosporidium bovis, C. ryanae and C. parvum were identified. C. ryanae was identified in a calf younger than the described prepatent period. The multivariable model included four significant variables; calf age, cleanliness of bedding, cleaning routines for group pens and farmers' attitudes towards biosecurity. [ABSTRACT FROM AUTHOR]

The occurrence of a gastrointestinal illness among a class of 96 undergraduate veterinary students in New Zealand prompted laboratory and questionnaire-based investigations. Cryptosporidium parvum was the only enteropathogen identified in 4/7 faecal specimens analysed. The C. parvum isolates carried a rare IIa GP60 allele, indicating a point-source outbreak. The infection source could not be microbiologically traced, but the investigation suggested contact with calves during a practical class as the most likely exposure. A total of 25/80 respondents to a questionnaire were defined as cases using a clinical case definition (31% attack rate). The inferred median incubation period was 5 days (range 0–11 days), and the median illness duration was 5–6 days (range 2–23 days), corroborating previous observations in experimental cryptosporidiosis. Disease was self-limiting, characterized by abdominal discomfort, diarrhoea, and in some cases, vomiting. Originating from a rural area and having had previously handled ruminants were associated with a significant risk reduction in males. All the three students who reported chronic use of steroid inhalers for treatment of asthma were cases. This case highlighted, once again, the potential hazard for explosive outbreaks of cryptosporidiosis. [ABSTRACT FROM AUTHOR]

We carried out a study to investigate the presence of some protozoan parasites (Cryptosporidium sp., Giardia sp., Toxoplasma gondii) on three species of Antarctic penguins: Adélie (Pygoscelis adeliae), gentoo (Pygoscelis papua) and chinstrap (Pygoscelis antarctica) from different locations along the Antarctic Peninsula and the South Shetland Islands. Swabs and faeces samples were analysed by PCR assay for Cryptosporidium sp. and Giardia sp. while Toxoplasma was studied using serological methods from blood samples. We did not detect the presence of these organisms in the species studied. However, based on the upper values of the confidence intervals of the observed prevalence, their presence cannot be completely excluded. [ABSTRACT FROM AUTHOR]

The public health significance of giardiasis and cryptosporidiosis in sheep is currently unclear. Some research suggests that they are probably not an important zoonotic reservoir, whilst other research indicates this potential exists, and some outbreaks have also been associated with infections in sheep. Actions to limit water supply contamination by sheep have sometimes been severe, occasionally creating problems between farming and public health communities. Here our knowledge on these parasites in both sheep and goats is reviewed; although direct evidence of transmission to humans via water supply contamination is limited, the data accrued indicate that this is a real possibility. As cryptosporidiosis in sheep is generally more prevalent than giardiasis, and species/genotypes of Cryptosporidium infections in sheep are likely to be infectious to humans, this parasite may be considered the greater threat. Nevertheless, geographical variation in prevalence and genotypic distribution is extensive and as measures to limit sheep grazing can have a highly negative impact, it is important that cases are judged individually. If water contamination from a particular population of sheep/goats is suspected, then suitable investigations should be instigated, investigating both prevalence and species/genotype, before precautionary measures are imposed. [ABSTRACT FROM AUTHOR]

This article discusses a study which provided new data of the presence of Cryptosporidium oocyts in gentoo penguins from Antarctica detected using acid-fast stain in faeces of the penguins. The presence of this parasite is considered to be one of the indicators of environmental contamination and water quality. In this study, sixty-four stool samples were obtained directly from the penguins in January-February 2005. Microscopic obersvation under oil immersion objective of the total surface of the smear allowed the identification of the parasite.