To identify climatic trends associated with the frequency of sand enteritis.


Horses were included if they: (1) had radio-dense intestinal contents or sand impaction confirmed at exploratory laparotomy; (2) originated from East Anglia; (3) presented between 1 January 2005 and 31 December 2012. Historical weather data for East Anglia were obtained from the Met Office website. Associations between prevalence and climatic variables were examined separately for March–April and October–November.


Ninety-two horses were included. Peaks in admissions of sand enteritis cases were seen in March–April (n = 21, 23%) and October–November (n = 25, 27%). The frequency of March–April cases was positively correlated with mean temperature in those months (r2 = 0.37); negatively correlated with frost (r2 = 0.58) and rainfall (r2 = 0.54) in the 2 previous months; and negatively correlated with sunshine in the preceding 3 months (r2 = 0.44). The frequency of October–November cases was positively correlated with higher average temperatures (r2 = 0.14) and fewer frost days (r2 = 0.16) in the preceding 3 months. Twenty-nine (32%) horses presented in a temporal cluster from September 2010 to April 2011 (P<0.001), coinciding with peak rainfall (121.6 mm; August 2010); peak frost (23.2 days); lowest mean temperature (0.0°C; both December 2010); and least sunshine (39.3 h/month; January 2011) recorded over the 8-year period.


In our population, spring cases of sand enteritis are more likely following dark, dry winters, and autumn cases more likely following hot summers. A wet summer followed by a cold dark winter may have contributed to the cluster of cases in 2010/2011. These weather combinations may adversely affect grass growth.

Practical significance

Weather patterns may have a role in the epidemiology of sand enteritis. Horses at pasture are likely to graze closer to the ground and ingest sand particles when grass growth is poor.

Ethical animal research

Not required by this Congress: retrospective analysis of clinical cases. Sources of funding: Polly Compston is supported by the Margaret Giffen Trust. Competing interests: None.