Parents are furious with a school which failed to inform them after one of its pupils was diagnosed with TB.
A Year Nine pupil at Harlington Community School in Pinkwell Lane, Hayes, was found to have contracted the potentially fatal disease, but only parents of students who may have been affected have been sent letters and given advice.
A parent, who has two children at the school but who did not wish to be named, said: "I think it's outrageous. I only found out through my daughter.
"I'm just very upset at the school's lack of communication; they should have at least told us and what symptoms to look out for.
"When children have nits at primary school every parent is told, and now there's a case of TB and we're not even supposed to know."
Another parent said: "We've heard that the pupil's class have been treated but not the rest of the school. I'm angry because I feel other parents have a right to know.
"And I want to know why it's taken two weeks since the pupil was found to have TB for the school to decide to test the pupils?"
TB is an airbourne bacterium spread by coughs or sneezes which primarily attacks the lungs but can spread to affect the central nervous system. Treatment can take the form of a long course of antibiotics and prevention is by an injection called the BCG.
Neil Sherman, headteacher of the school, said: "We can confirm a single case of Tuberculosis has been diagnosed and the individual is receiving treatment and is no longer infectious.
"Guidance from the Health Protection Agency has been taken to ensure all precautionary measures are taken.
"A screening was arranged on Monday for Year Nine, and following the results, pupils and staff will be referred to the local chest clinic should it be necessary."
Dr Margie Meltzer, a consultant at the north-west London Health Protection Unit, said: "Tuberculosis is a disease that typically requires close, prolonged and frequent contact before transmission occurs.
"The greatest risk of spread is to people who live in the same household as a person with this disease.
"The risk to other contacts, including those in a school setting, is low.
"However, the school are still taking precautionary measures and screening students."