Cryptosporidium surveillance and risk factors in the United States

Division of Parasitic Diseases, Centers for Disease Control and Prevention, Department of Health and Human Services, Atlanta, GA, USA.
Experimental Parasitology (Impact Factor: 1.86). 09/2009; 124(1):31-9. DOI: 10.1016/j.exppara.2009.09.020
Source: PubMed

ABSTRACT Surveillance for Cryptosporidium in the United States indicates that the reported incidence of infection has increased dramatically since 2004. The reasons for this increase are unclear but might be caused by an actual increase in incidence, improved surveillance, improved awareness about cryptosporidiosis, and/or increases in testing practices resulting from the licensing of the first-ever treatment for cryptosporidiosis. While regional differences remain, the incidence of cryptosporidiosis appears to be increasing across the United States. Onset of illness is most common during the summer, particularly among younger children. Cryptosporidiosis case reporting also influences outbreak detection and reporting; the recent rise in cases coincides with an increase in the number of reported cryptosporidiosis outbreaks, particularly in treated recreational water venues. Risk factors include ingesting contaminated recreational or drinking water, exposure to infected animals, having close contacts with cryptosporidiosis, travel to disease-endemic areas, and ingestion of contaminated food. Advances in molecular characterization of clinical specimens have improved our understanding of the changing epidemiology and risk factors. Prevention and control of cryptosporidiosis requires continued efforts to interrupt the transmission of Cryptosporidium through water, food, and contact with infected persons or animals. Of particular importance is continued improvement and monitoring of drinking water treatment and advances in the design, operation, and management of recreational water venues coupled with behavioral changes among the swimming public.

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    • "The highest prevalence rate of cryptosporidiosis was found among children aged between 0 and 10 years age (63.2%) as compared to 20.8% among children 11 to 15 years of age. This is consistent with reports of higher prevalence in younger children from other parts of the world (Iqbal et al., 1999; Abu-alrub et al., 2008; Yoder and Beach, 2010). This significant difference could be attributed to the poor living conditions of these children, lack of selfawareness , personal hygiene and cleanliness at this critical age. "
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    ABSTRACT: A retrospective study was carried out to investigate the prevalence of Cryptosporidium oocysts among diarrhoeic children (n = 650), aged between 0 and 15 years, living in Maiduguri metropolis (n = 220), Bama local government area (n = 278) and Gwoza local government area (n = 152). Stool samples were concentrated using the ethyl acetate sedimentation method. Data of stool samples with Cryptosporidium oocysts from patients within the specified age groups were collected and analysed. The overall prevalence was 42.9%. The prevalence was higher in Maiduguri metropolis 45.0%, which is an urban area as compared to Gwoza and Bama combined together 41.8% which are rural areas but not statistically significant at 95% confidence level (P > 0.05; OR = 1.14; CI = 0.82, 1.58). According to age, the prevalence in age group A (0-10 years) was higher (46.8%) as compared to age group B (11 < 15 years), which was 20.8%, and this was statistically significant at 95% confidence level (P < 0.05; OR = 3.34; CI = 1.98, 5.61). According to gender, males showed a higher prevalence (52.5%) compared with females (47.5%), but this was not statistically significant at 95% confidence level (P > 0.05; OR = 1.13; CI = 0.82, 1.53). Seasonal prevalence showed that hot dry months of March and April were higher compared with other months. Our findings indicate the presence of the pathogen in children in Borno State, Nigeria, with higher odds of the infection in younger children, and dry months may be more associated with the infection. Control and preventive measures should be taken to protect younger children from the infection.
    Zoonoses and Public Health 09/2014; 61(6):420-426. DOI:10.1111/zph.12088 · 2.07 Impact Factor
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    • "During hot weather, over 300 people have been observed to swim in the reservoir. These observations are similar to previous studies of recreational waters and catchments that had an increase in the number of visitors to the catchment during summer (Craun et al., 2005; Lake et al., 2008; McCarthy et al., 2008; Yoder and Beach, 2010). In the non-recreational sites, the prevalence ranged from 8.3% to 33.3% with the highest prevalence in site 5. Positives were detected during the winter months and only C. parvum was detected in the non-recreational sites. "
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    ABSTRACT: Cryptosporidiosis, caused by the protozoan parasite Cryptosporidium, represents the major public health concern of water utilities in developed nations due to its small size, resistance to disinfection and ability to be shed in large numbers in faeces. In Australia, recreational access is not allowed on direct supply sources, however, in Western Australia, limited recreational access to drinking water catchments has been allowed, although only in the outer catchment. Recreational activities within 2 km of the drinking water body is prohibited. The present study compared the amount, prevalence and species of Cryptosporidium in recreational versus non-recreational water catchments in the south west of Western Australia (WA). Recreational water catchments, which allowed swimming and camping had a higher prevalence of Cryptosporidium and the majority of samples were the human-associated C. hominis. Non-recreational catchments had a lower prevalence and all the samples genotyped were C. parvum. Risk analysis identified increasing population as strongly correlated with an increase in the prevalence of Cryptosporidium in recreational catchments. This suggests that recreational access to drinking water catchments is a serious public health risk and government policy limiting activities to the outer catchment should be supported.
    Experimental Parasitology 05/2012; 131(4):399-403. DOI:10.1016/j.exppara.2012.04.015 · 1.86 Impact Factor
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    • "Cryptosporidium is an important cause of gastrointestinal illnesses in many countries (WHO, 2009b). In the United States of America alone, at least 143 water-associated outbreaks of cryptosporidiosis have been reported (Yoder and Beach, 2010). For immunocompetent people, the symptom of watery diarrhea may be self-limiting and persists for up to 2 weeks (Dietz "
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    ABSTRACT: A comprehensive quantitative microbial risk assessment (QMRA) of Cryptosporidium infection, considering pathogen removal efficiency, different exposure pathways and different susceptible subpopulations, was performed based on the result of a survey of source water from 66 waterworks in 33 major cities across China. The Cryptosporidium concentrations in source water were 0-6 oocysts/10 L, with a mean value of 0.7 oocysts/10 L. The annual diarrhea morbidity caused by Cryptosporidium in drinking water was estimated to be 2701 (95% confidence interval (CI): 138-9381) cases per 100,000 immunodeficient persons and 148 (95% CI: 1-603) cases per 100,000 immunocompetent persons, giving an overall rate of 149.0 (95% CI: 1.3-606.4) cases per 100,000 population. The cryptosporidiosis burden associated with drinking water treated with the conventional process was calculated to be 8.31 × 10(-6) (95% CI: 0.34-30.93 × 10(-6)) disability-adjusted life years (DALYs) per person per year, which was higher than the reference risk level suggested by the World Health Organization (WHO), but lower than that suggested by the United States Environmental Protection Agency (USEPA). Sixty-six percent of the total health burden due to cryptosporidiosis that occurred in the immunodeficient subpopulation, and 90% of the total DALYs was attributed to adults aged 15-59 years. The sensitivity analysis highlighted the great importance of stability of the treatment process and the importance of watershed protection. The results of this study will be useful in better evaluating and reducing the burden of Cryptosporidium infection.
    Water Research 05/2012; 46(13):4272-80. DOI:10.1016/j.watres.2012.05.012 · 5.32 Impact Factor
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