Waterborne disease resulting from contaminated drinking and recreational waters is preventable. Since 2000 there has been a significant reduction in cryptosporidiosis in the first half of the year in England and Wales, but not in the second. This probably resulted from implementation of new drinking water regulations and substantial investment in water treatment. We estimate an annual reduction in disease of 905 reported cases and approximately 6700 cases in the population as a result of improvements in water treatment, most of which was caused by C. parvum. In order to investigate whether drinking water is still a risk factor for cryptosporidiosis a geographical information system (GIS)-based casecontrol study was conducted, investigating the role of drinking water, as well as wider environmental and socioeconomic factors, upon cryptosporidiosis. Detailed locations of 3368 cases post-2000 were compared to the location of an equal number of controls. Environmental datasets included socioeconomic status, the percentage of the population under 4 years old, water distribution, water treatment, rainfall, animal distribution, urban/ rural distribution, sewage outflows and estimated Cryptosporidium application to land. All cases were genotyped into species, enabling C. hominis and C. parvum to be examined separately. Illness was strongly associated with locations that on average had higher socioeconomic-status individuals, more children aged under 4 years, more livestock and areas with poorer water treatment. Strongly significant risk factors for C. hominis were areas with many higher socioeconomic-status individuals, areas with many children aged less than 4 years and urban areas. Strongly significant risk factors for C. parvum were rural location and a combination of Cryptosporidium in the water catchment and groundwater supply. These results highlight the fact that, in spite of the overall fall in cryptosporidiosis, drinking water is still a risk factor for cryptosporidiosis in England and Wales.
|Title of host publication||Giardia and Cryptosporidium|
|Subtitle of host publication||From Molecules to Diseases|
|Number of pages||11|
|Publication status||Published - 25 Feb 2009|