It summarized the status quo of viral pollution of digestive endoscope from HBV, HCV and HIV pollution. It analyzed the causes of these pollutions and the sterilization state of digestive endoscope.

Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution.

Experts said hereditary diseases, viral infections, environmental pollution, unhealthy lifestyles and poor nutrition were among the main known causes.