No Worms are beneficial and not disease carriers.
Here is a quote from Charles Darwin
"It may be doubted whether there are any other animals which have played so important a part in the history of the world, as have these lowly creatures"
It is probably not much of an exaggeration in his statement that the humble earthworm is one of the most vital living creatures on the planet, for its actions are essential for the creation and vitality of soil, upon which almost all land plants and animals dependent.
Biological: The earthworm is essential to composting; the process of converting dead organic matter into rich humis, vital to the growth of healthy plants, and ensuring the the cycle of fertility. This is achieved by the worm's actions of pulling down below any organic matter deposited on the soil surface (eg, leaf fall, manure, etc) either for food or when it needs to plug its burrows. Once in the burrow, the worm will shred the leaf and partially digest it, then mingle it with the earth by saturating it with intestinal secretions. Worm casts can contain 40% more humus than the top 6" of soil in which the worm is living.
Chemical: As well as dead organic matter, the earthworm also ingests any other soil particles that are small enough (including stones up to one-twentieth of an inch across) into its 'crop' where minute fragments of grit grind everything into a fine paste which is then digested in the stomach. When the worm excretes this in the form of casts which are deposited on the surface or deeper in the soil, a perfectly balanced selection of minerals and plant nutrients is made available. Investigations in the United States show that fresh earthworm casts are Five times richer in available nitrogen. Seven times richer in available phosphates and eleven times richer in potash than the surrounding upper six inches of soil. In conditions where there is plenty of available humus, the weight of casts produced may be greater than 4.5 kg (10lb) per worm per year, in itself an indicator of why it pays the gardener or farmer to keep worm populations high.
Everything can get diseases
There aren't many insects that eat garden worms. However, ants will eat garden worms that they find around the garden dead.
They are useful because worms chew your food and turn it into garden fertilizer.
Everything can spread diseases. What, 'which' are you concerned about?
Most diseases are spread by germs.
Many diseases can be caused by parasitic worms. Trichinosis and intestinal diseases can be caused by the roundworm. Hookworm and whip worm disease are caused by the Hookworm.
worms
The spread of epidemic diseases- smallpox,bubonic plagueYOU'REWELCOME!
spread diseases that leave painful sores but are not fatal spread by bite, physical contact, or feces
elephantiasis
can earth worms be put directly in garden
They can be spread to anyone?
Usually you will see them.