Fate of Cryptosporidium parvum oocysts within soil, water, and plant environment.

Vegetative Filter Strips (VFS) have long been used to control the movement of agricultural nutrients and prevent them from reaching receiving waters. Earlier studies have shown that VFS also dramatically reduce both the kinetics and extent of Cryptosporidium parvum (C. parvum) oocysts overland transport. In this study, we investigated possible mechanisms responsible for the ability of VFS to reduce oocyst overland transport. Measurement of the kinetics of C. parvum adhesion to individual sand, silt, and clay soil particles revealed that oocysts associate over time, albeit relatively slow, with clay but not silt or sand particles. Measurement of oocyst overland transport kinetics, soil infiltration depth, distance of travel, and adhesion to vegetation on bare and vegetated soil surfaces indicate that oocysts move more slowly, and penetrate the soil profile to a greater extent on a vegetated surface than on a bare soil surface. Furthermore, we demonstrate a small fraction of the oocysts become attached to vegetation at the soil-vegetation interface on VFS. These results suggest VFS function to reduce oocyst overland transport by primarily decreasing oocyst surface flow enough to allow penetration within the soil profile followed by subsequent adhesion to or entrapment within clay particle aggregates, and to a lesser extent, adhesion to the surface vegetation.

Initial impact of Australia's National Bowel Cancer Screening Program.

OBJECTIVE: To examine the initial impact of the National Bowel Cancer Screening Program (NBCSP), which was launched in May 2006 and offers faecal occult blood testing to Australians aged 55 or 65 years. DESIGN AND SETTING: Review of data on colorectal cancer (CRC) cases diagnosed between May 2006 and June 2008 from a prospective database used at 19 Australian hospitals, linked and analysed by BioGrid Australia. MAIN OUTCOME MEASURES: Number of CRC cases detected through the NBCSP or symptomatic presentation, and differences by sex, stage at diagnosis, tumour location and level of socioeconomic disadvantage. RESULTS: 1628 cases of CRC were identified; 1268 had information on the patients' test status as part of the NBCSP, and 40 of these (3.2%) were recorded as being detected by the NBCSP. Of 75 CRC cases in patients aged 55 or 65 at diagnosis, 22 were NBCSP-detected. Overall, there was no difference in NBCSP-detected cases by sex. The distribution of tumour locations was similar between NBCSP-detected cases and symptomatic cases, but NBCSP-detected cancers were diagnosed at an earlier stage than symptomatic cancers (stage I, 40% v 14%; stage IV, 3% v 15%, respectively). Of patients diagnosed through the NBCSP, 63% were from areas of least socioeconomic disadvantage (deciles 8-10) and 18% were from the most disadvantaged areas (deciles 1-4) (P=0.0375). CONCLUSION: Initiation of the Australian NBCSP has had a measurable impact on CRC stage at diagnosis, and an improvement in survival would be anticipated. The lower uptake among people from disadvantaged areas is of concern.