Officials are therefore concentrating their attention on the possibility that people picked it up when cleaning out their nostrils - a practice which is common in South Asia, BBC regional analyst Jill McGivering says.

The amoeba travels to the brain through the nasal passages.

Those infected have symptoms including fever, nausea and vomiting, as well as a stiff neck and headaches. Most die within a week.

[link to www.bbc.co.uk]