The bacteria only rarely give rise to meningococcal disease, but when they do infection spreads rapidly and is fatal in about 10% of cases. If disease is diagnosed early and treated promptly most people make a full recovery.
About 1 in 8 people who recover experience some long term effects. These can include headaches, stiffness in the joints, epileptic fits, deafness and learning difficulties.
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The girl, seven, had crossed the US-Mexico border with her father last week and was reported to be from Guatemala.
The tenants were forced into 'sleeping shifts' as night workers would swap with those who had daytime hours at the Wembley property.
The incident comes just days after four fans were suspended for abusing Manchester City's Raheem Sterling.