There are vast differences in size between the various infectious organisms. However, an organism’s size does not determine the severity of the disease it causes. A microscopic virus can lead to a life-threatening illness, and a tapeworm 6 m (20 ft) long may cause only mild symptoms.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.