MedWire News: People who work in the sewage industry are no more likely to become infected with the hepatitis E virus or the stomach ulcer-causing bug Helicobacter pylori than other manual workers, say researchers.

As sewage workers are exposed to higher levels of harmful bacteria than other people, it has been proposed that they may face an increased risk of infection with Helicobacter pylori and the hepatitis E virus, explain Dr Philipp Hotz, from the University of Zurich in Switzerland, and team.

But they add that few studies have investigated the possible association.

To address this, the researchers studied 332 Swiss municipal workers who were regularly exposed to sewage and 446 other municipal manual workers who did not have such exposure.

All the participants underwent blood tests and other examinations to test for antibodies to Helicobacter pylori and hepatitis E.

They also completed questionnaires about travelling to areas with high levels of Helicobacter pylori and hepatitis E infection, the use of personal protective equipment, their age, socioeconomic status, number of siblings and the country in which their childhood was spent.

The researchers found that just one sewage worker and none of the other manual workers had developed a peptic ulcer, while three sewage workers and 12 of the other manual workers had undergone eradication therapy for Helicobacter pylori infection.

There were also no significant differences between the two groups regarding levels of antibodies to Helicobacter pylori and hepatitis E.

Writing in the journal Occupational and Environmental Medicine, Dr Hotz and team conclude: “These results do not support the hypothesis of sewage as a source of occupational infection for Helicobacter pylori or hepatitis E virus in sewage workers trained for this job with available personal protective equipment and working in a region with good sanitation.”