Bacterial Infections

A large group of diseases is caused by bacteria entering the body and multiplying too fast to be destroyed by the immune system. Some types of bacteria also release powerful poisons, known as toxins, that rapidly damage tissues. In the past, bacterial diseases were a major cause of death; today, most serious infections can be treated effectively with antibiotics.

Each of the bacterial infections covered in this section affects many areas of the body simultaneously. The most serious of these infections is septicaemia, described in the first article, which can be due to almost any bacterium. The diseases in the following articles are caused only by particular bacteria. They include both relatively recently identified infections, such as toxic shock syndrome, and those that have long been recognized, such as diphtheria and plague. The final articles describe illnesses caused by the rickettsiae bacteria, some of which may be transmitted to humans through insect bites.

Many other bacterial infections, such as pneumonia, tuberculosis, and meningitis, cause damage to certain organs, and for this reason they are covered in the sections on specific body systems.

Bacterial skin infections, such as boils, are discussed in skin infections and infestations.

Key structures

For information on the structure and function of bacteria.


Toxic Shock Syndrome

Scarlet Fever




Typhoid and Paratyphoid




Hansen’s Disease


Lyme Disease


Rocky Mountain Spotted Fever

Q Fever


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.

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