The information gained from the leprosy and listeria-causing microbes could lead to new and better treatments for these diseases.

Over two million people worldwide suffer from leprosy, according to the World Health Organisation. Most of these cases arise in South East Asia, but developed countries are also affected. More than 90 people in Europe contracted the disease last year.

The Pasteur Institute in France and the UK's Sanger Centre worked together for four years to decode the genome of Mycobacterium leprae.

Comparative study

They have already started the task of comparing the M. leprae genome with that of the bacterium that causes tuberculosis, Mycobacterium tuberculosis, which the same team successfully decoded in 1998.

The genomes of the two bacteria are very similar and scientists hope the comparative study will answer a lot of questions about how the microbes cause disease.

One of the first tasks will be to find the genes that are missing in M. leprae, rendering it impossible to grow in the lab. Once found, these genes can be cut out of M. tuberculosis and pasted into M leprae. Being able to grow cultures of M leprae will be an important step in finding a vaccine for leprosy.

Nerve damage

Leprosy is completely curable though a punishing regime of antibiotics. However, the nerve damage the disease causes often leaves people permanently disabled.

Douglas Soutar of the British Leprosy Relief Association, which helped fund the research, told BBC News Online: "This is wonderful news. The research carries very positive implications for finding more specific treatments and telling us how nerve damaged is caused. That's something we know very little about."

The other big breakthrough, the decoding of Listeria monocytogenes, was the result of a pan-European research effort co-ordinated by the Paris based Pasteur Institute

Listeria, which is fatal in 20-30% of cases, is contracted from contaminated food such as unpasteurised dairy products and cold meats.

Weakened immune systems

Listeria monocytogenes is a major public health issue, especially in France, where a recent epidemic affected more than 30 people, nine of whom died.

For people with weakened immune systems, such as newborns or the elderly, the disease can lead to meningitis and blood poisoning. It can also cause stillbirths.

The research, funded by the European Union and co-ordinated by the institute, should allow for "an earlier diagnosis of the disease and a faster identification of food contamination," said the institute's Pascale Cossart.

The Pasteur team is also studying a less virulent cousin of the bacteria in the hope of finding the genetic characteristics that make it dangerous.