Apart from the general effects on health described above, signs of infestation are to be found in your dog's faeces (droppings). Puppies may vomit or pass round worms (looking like string) in their faeces. Segments of tapeworm (looking like grains of rice), can often be seen in the faeces or in the fur around the tail base and back legs. Roundworm eggs can only be seen by using a microscope to examine the faeces.