Man's best friend may turn out to be a microbe

SCIENCE WEEK:THE MICROBES that have caused human illness over centuries may in fact be "old friends" that could actually help protect us against modern diseases. It may be that we are just too clean for our own good.

These ideas are part of a new “hygiene” hypothesis to be discussed at a public forum this evening at University College Cork, entitled “Microbes and Mankind – How Bacteria and Viruses Have Shaped Humanity”.

Four of UCC’s leading researchers will discuss the constant battle waged between humanity and microbes.

Certainly it is a microbial world given the success of bacteria, explained Prof Colin Hill, a professor of microbiology. There are about 350 tonnes of bacteria for every human currently on the planet, he said in advance of the forum.

“We are vastly overwhelmed by these organisms,” and they have helped shape human development. The Justinian Plague around AD 500 was a bubonic plague that wiped out 60 per cent of the entire world population at the time. “It really put civilisation under threat,” Prof Hill said.

Similarly, South American native populations were decimated when European diseases reduced their numbers from 100 million to 10 million.

The threat to humanity continues to this day, he said. “The threat is much larger, in a way, with six billion people on the planet, but today we have science.”

Consultant gastroenterologist Prof Fergus Shanahan will describe the hygiene hypothesis, which argues that antibiotics and our modern lifestyles have changed the bacterial populations around us, in the process leaving us more susceptible to asthma, diabetes, eczema, irritable bowel disease and other immune system diseases. “The immune system is like a sensory organ,” he said. It has sensors that respond to bacteria and has a memory and interacts with the local environment. “As with all sensory organs you need education and maturation, achieved by exposure to the environment.”

Our immune systems evolved surrounded by a collection of microbes, “old friends” that probably remained unchanged for generations. A newborn’s immune system reacted to these microbes, but we have modified the microbial mix, one that may not bring about a properly matured immune response.

There is ample experimental evidence, he said. No increase in auto-immune diseases was seen in adults moving from India to North America, but their children did show an increase. “If they migrated in childhood, the younger the age, the higher the risk,” Prof Shanahan said.

In the future, we may see these “old friend” bacteria used to create vaccines protective against auto-immune diseases, he believes.

The free forum takes place at 7.30pm tonight in the UCC Brookfield Health Sciences Centre.

Science Week: what’s on

TODAY

Cooking Up a Comet!, a workshop for primary pupils, at 10.30am at the George Bernard Shaw Room, Carlow Central Library, Tullow Street, Carlow. Free but pre-book: contact Carmel Flahavan on (059) 917 0094. Also at 1.30pm at the Muinebheag Library, Main Street, Muinebheag, Co Carlow.

DCU Astronomy photo competition and astrophotography talk, for the general public. 7pm, Dublin City University, Collins Avenue, Dublin 9. Free: contact Dr Laura Norci on (01) 700 7375.

TOMORROW

Chemistry of Fire show (weather permitting), for the general public at 8pm, outside Callan Building, National University of Ireland. Maynooth. Free: contact Ken Maddock on (01) 708 3658.

Mad Science science fair, for primary pupils, from 10am-2pm at Lanesboro Community College, Lanesboro, Co Longford. Free, but pre-book: contact Michael Lyons on (043) 333 0631.