Volume 11, Number 2—February 2005
Research
Sporadic Cryptosporidiosis Decline after Membrane Filtration of Public Water Supplies, England, 1996–2002
Stella Goh*, Mark Reacher†
, David P. Casemore‡, Neville Q. Verlander§, André Charlett§, Rachel M. Chalmers¶, Margaret Knowles#, Anthony Pennington*, Joy Williams*, Keith Osborn**, and Sarah Richards††
, David P. Casemore‡, Neville Q. Verlander§, André Charlett§, Rachel M. Chalmers¶, Margaret Knowles#, Anthony Pennington*, Joy Williams*, Keith Osborn**, and Sarah Richards††Table 3
Final multivariable model of risk factors for sporadic cryptosporidiosis, Allerdale and Copeland residents, March 1, 1996, to August 31, 2002
| Risk factors | Case-patients | Controls | Adjusted odds ratio* | Lower 95% CI† | Upper 95% CI | p value |
|---|---|---|---|---|---|---|
| Sex | ||||||
| Female | 85 | 265 | 1 | 0.45 | 1.184 | 0.202 |
| Male | 90 | 272 | 0.73 | |||
| Age | ||||||
| <1–5 | 96 | 300 | 1.002/y | 0.938 | 1.021 | 0.872 |
| 6–15 | 54 | 157 | ||||
| 16+ | 25 | 70 | ||||
| Water sources and water supply zones | 0.556 | |||||
| Crummock Lake | ||||||
| Crummock North | 39 | 111 | 1 | |||
| Crummock South | 23 | 62 | 1.262 | 0.547 | 2.913 | |
| Ennerdale Lake | ||||||
| Ennerdale North | 32 | 107 | 1.25 | 0.594 | 2.63 | |
| Ennerdale South | 14 | 46 | 0.556 | 0.164 | 1.881 | |
| Other sources | ||||||
| Millom | 22 | 64 | 1.502 | 0.686 | 3.288 | |
| Quarry Hill | 22 | 58 | 0.703 | 0.273 | 1.81 | |
| Hausegill | 3 | 5 | 1.356 | 0.22 | 8.34 | |
| Ayknott | 2 | 7 | 1.016 | 0.1 | 10.29 | |
| Underscar | 3 | 9 | 0.983 | 0.1 | 9.18 | |
| Fellside | 0 | 1 | 0.005 | 0 | ∞ | |
| Bridgend | 0 | 2 | 0.004 | 0 | ∞ | |
| Mixed public supplies | 12 | 55 | 0.893 | 0.32 | 2.494 | |
| Private water supplies | 3 | 10 | 0.1 | 0.007 | 1 | |
| Usual daily volume of cold unboiled tap water drunk at home | 1.543 per pint | 1.212 | 1.965 | < 0.001 | ||
| <1/4 pint | 25 | 122 | ||||
| 1/4–1 pint | 78 | 260 | ||||
| >1–2 pints | 46 | 106 | ||||
| >2 pints | 22 | 42 | ||||
| Contact with a cattle farm | ||||||
| Yes | 19 | 29 | 4.532 | 1.757 | 11.69 | 0.002 |
| No | 144 | 475 | ||||
| Contact with a noncattle farm | ||||||
| Yes | 17 | 24 | 3.809 | 1.677 | 8.651 | 0.002 |
| No | 146 | 471 | ||||
| Feed pet leftovers | ||||||
| Yes | 14 | 19 | 3.746 | 1.214 | 11.56 | 0.021 |
| No | 161 | 515 | ||||
| Interval of study | 0.585 | |||||
| March 1, 1996–February 29, 2000 | 153 | 468 | 1 | |||
| March 1, 2000–July 31, 2000 | 4 | 16 | 0.965 | 0.235 | 3.958 | |
| August 1, 2000–February 20, 2001 | 6 | 16 | 1.115 | 0.319 | 3.895 | |
| February 21, 2001–January 21, 2002 | 6 | 18 | 0.367 | 0.078 | 1.72 | |
| January 11, 2002–August 31, 2002 | 6 | 19 | 0.485 | 0.138 | 1.701 | |
*Adjusted for accidentally touching animal feces, feeding pets biscuits, feeding pets raw vegetables, contact with anyone outside the household with a history of diarrhea, type of sewage system to the house, consumption of mixed salad, and local authority of residence.
†CI, confidence interval.
