In Britain, the most important nematode of dogs is the ascarid, ''[[Toxocara canis]]''. Almost all puppies harbour this worm, which in large numbers can cause serious disease during the first weeks of life. ''T. canis'' larvae can also invade human tissues - impairment of vision is a possible outcome. | In Britain, the most important nematode of dogs is the ascarid, ''[[Toxocara canis]]''. Almost all puppies harbour this worm, which in large numbers can cause serious disease during the first weeks of life. ''T. canis'' larvae can also invade human tissues - impairment of vision is a possible outcome. |