When human beings began migrating from Africa some sixty thousand years ago, they brought the bacteria that causes stomach ulcers with them.
A team of scientists researching human migration patterns has found genetic evidence that Helicobacter pylori, a corkscrew-shaped bacterium which can cause stomach ulcers, has been present in human beings for the last six hundred centuries.
But as occasionally happens in scientific research, findings that give us answers to one mystery have generated questions about another.
For instance, Professor John Atherton of the University of Nottingham in England asks, “If Helicobacter has been in humans ever since we have been out of Africa, why have stomach ulcers only arrived recently?”
Further research is now needed to answer the question of why stomach ulcers only started showing up in humans in modern times. Cases of stomach ulcers were rare before the Industrial Revolution, leading many to believe that ulcers are caused by stress and lifestyle.
But in 1985, Australian microbiologist Barry Marshall swallowed a petri dish full of Helicobacter pylori to prove his theory that bacteria, rather than stress and spicy foods, were the primary cause of stomach ulcers. Two decades later his risky research method was honored with the Nobel Prize in Physiology or Medicine, which he shared with his colleague J. Robin Warren.
Marshall said the new findings fitted neatly with his work.
The recent research on Helicobacter pylori (also known as H. pylori) and human migration patterns was done led by scientists from the UK and Germany. The team compared DNA sequence patterns of bacteria and its hosts. By using computer simulations they demonstrated how the bacteria spread out of Africa and around the world.
Over half of all humans are infected by the bacteria, . The helical bacterium is the only known microorganism that can survive in the highly acidic mucus lining of the stomach and duodenum, and it is now thought to be the cause of most stomach ulcers and gastritis (an irritation or inflammation of the stomach lining). Stomach ulcers cause bouts of abdominal pain, nausea and hemorrhagic vomiting.
Stomach ulcers can usually be treated with medicines, but left untreated they can lead to serious medical complications. H pylori can also be a risk factor for stomach cancer.
