It is safe to assume that septic tank effluents and sludge are highly pathogenic (see Figure 7.2). Viruses, parasitic worm eggs, bacteria, and protozoa can be emitted from septic tank systems in viable condition.
Source: The Humanure Handbook. Jenkins Publishing, PO Box 607, Grove City, PA 16127. To order, phone: 1-800-639-4099.