One in seven schoolchildren could carry the meningitis bacteria - many more than previously thought, a new study suggests.
The research, published in the Journal of Clinical Microbiology, found that more than 14% of 10 to 18-year-olds could host the meningococcal bacteria in the back of their nose or throat.
While the bacteria here are normally harmless, they can be passed from person to person.
Scientists took swabs from just under 1,000 10 to 18-year-old pupils in the Gambia, west Africa, as part of the MenAfriCar project.
They then grew the bacteria in a liquid broth - rather than the traditional agar plate - which more than doubled the detection of the germs.
The new technique has led scientists to conclude that many more people carry meningitis than previously thought.
There are an average of 3,200 cases of meningitis and septicaemia each year in the UK, the Meningitis Research Foundation (MRF) - which funded the research - estimates.
Linda Glennie, head of research at MRF, said: "This is a big step forward in terms of detecting meningococcal bacteria and it should help accelerate future research into the prevention of meningitis and septicaemia.
"These illnesses can be deadly and survivors are often left with life-changing disabilities. We are committed to funding research that works towards a world free from meningitis and septicaemia."