Earthworms may spread soil-borne diseases through their activity in the soil, as in the case of anthrax, or act as intermediate hosts for virus diseases of pigs and poultry, thus complicating the control of the disease and its eradication.
Any soil-borne diseases may be spread by the activity of worms. Since worms can live as long as 10 years, they may harbour and spread viral animal diseases over a long period.