Diphtheria is a highly infectious bacterial infection that can affect the nose and throat (respiratory diphtheria), and sometimes the skin (cutaneous diphtheria). The bacterium can infect the nose and throat and release a toxin. The main symptoms are sore throat, difficulty and/or pain on swallowing, husky voice, fever, cough and headache. The toxin produced may affect other organs and it can be fatal. In countries where hygiene is poor, cutaneous diphtheria is the main source of infection causing painful, non-healing skin ulcers which often become infected with other bacteria. Severe illness is unusual. This type of diphtheria is spread by contact with discharge from contagious skin lesions.

Tetanus is a vaccine-preventable disease caused by a toxin produced by bacteria called Clostridium tetani. Tetanus spores are found in soil throughout the world but is more common in resource-poor countries. The disease is acquired when material containing these spores, such as soil, contaminates a wound. The toxin released from the bacteria may then attack the nerves of the brain and spinal cord, the main symptom is lockjaw (trismus), characterised by uncontrollable spasms and possibly death.

Poliomyelitis (polio) is a potentially paralysing, vaccine-preventable, viral infection. The virus is transmitted through food or water contaminated by infected human faeces or by direct contact with an infectious person. Polio is extremely rare in UK travellers, those at increased risk include travellers visiting friends and relatives, those in direct contact with an infected person, long-stay travellers, and those visiting areas of poor sanitation. Most individuals (about 95 percent) who acquire polio do not develop symptoms. When they do occur symptoms may range from a mild illness with fever, to symptoms of meningitis (inflammation of the lining of the brain) or paralysis. Although paralysis occurs in less than one percent of infections it is frequently long lasting.