NEW YORK (Reuters Health) - Exposure to waste water does not appear to increase the risk of Helicobacter pylori infection, which is associated with ulcers and stomach cancer, or hepatitis E infection, the inflammation of the liver, a study in Swiss sewage workers shows.

But the risks may be different in areas where people are more likely to be infected with H. pylori or more virulent forms of the hepatitis E virus, Dr. Philipp Hotz of the Med. Poliklinik USZ in Zurich and colleagues suggest.

The results of studies have had mixed results on the occupational infection risk of sewage workers, Hotz and his team note in their report, published in the Occupational Environmental Medicine journal. The researchers followed 332 sewage workers and 446 municipal workers who were not exposed to sewage for several years, checking for evidence of exposure to H. pylori and hepatitis E. Study participants underwent clinical exams and blood tests every 6 months to 1 year for about 4 years, on average.

At the study's outset the researchers also checked workers' personal protective equipment, and found 66 percent used gloves that provided adequate protection against exposure to wastewater for at least half their work time, while 27 percent used adequate masks for at least half of their time on the job.

The researchers found no difference in the rate of hepatitis E or H. pylori positivity or infection between the two groups of workers.

Hotz and his colleagues point out that in Switzerland most sewage plant workers undergo 5 years of training as well as regular courses on hand washing and personal protective equipment use.

The findings show that sewage workers in regions with good sanitation who use personal protective equipment do not have an increased risk of infection with H. pylori or hepatitis E virus on the job. However, "the results of this study may not be applicable to endemic areas or regions with poor sanitation," they add.

SOURCE: Occupational Environmental Medicine, January 2009.

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