A report says Aids, tuberculosis (TB), measles, malaria, diarrhoeal diseases such as dysentery and cholera, and acute respiratory infections such as pneumonia were responsible for 90% of all deaths due to infectious diseases in 1998.

And the WHO warned that the world has dangerously overestimated its ability to control dangerous bacteria and viruses such as these.

Cholera sufferers can be saved by hospital treatment

With bacteria gaining extra resistance to treatments such as antibiotics, and world travel on the increase, greater investment is needed to halt their spread.

Dr David Heymann, the WHO's executive director, said: "We are moving towards a future full of new opportunities for diseases to quickly spread from one continent to another.

"Simultaneously, drug resistance is sending us back in history to a time when we lacked medicines to cure some diseases."

Societies crippled by disease

Economic development, particularly in poorer countries, was being hamstrung by the loss of children and young workers to these diseases, said the WHO.

Dr Gro Harlem Brundtland, WHO director-general said: "The World Health Organisation is issuing a wake-up to the world's governments, decision-makers and the private sector to take action against infectious diseases before it is too late.

"Infectious diseases are causing half of all deaths among families and young labourers, farmers, supervisors and shop owners around the world.

"How can anyone reach their economic potential with this burden?"

Although these diseases are major killers in developing countries, evidence of the resurgance of bacteria and viruses is emerging even in the UK.

New vigillance for TB

The Public Health Laboratory Service (PHLS), recently set up an enhanced surveillance system to find out more about cases of TB.

The disease, rampant in the UK at the end of the Second World War, has fallen to between 5,000 and 6,000 cases a year, but experts are even concerned by this low level.

MMR vaccination has saved lives in the UK

Epidemics of measles killed or disabled thousands of British children a year until recent years, when innovations such as the MMR (measles, mumps and rubella) vaccine, virtually eradicated the disease.

And while food poisoning cases have soared over the last decade, even the most powerful bacteria, such as E. coli 0157, are generally only fatal in the elderly or among those with pre-existing illnesses.

However, the UK government is acting to try and prevent bacteria gaining extra resistance to antibiotics.

A PHLS spokesman said: "We need to use antibiotics carefully in order to conserve their power for the future.

"Infections like MRSA (Methycillin Resistant Staphyloccus Aureus), are hospital bugs rather than community bugs, but are still a problem."