Public Health England has said the risk of cat owners contracting tuberculosis is "very low" after two people developed the disease after coming into contact with a cat.
Professor Dilys Morgan told ITV News, "Something strange has happened in this instance".
"We don't know exactly what's happened but I don't think that we can read too much into it, that it is an increasing trend," she added.
More top news
Downing Street is likely to confirm that the UK will fund extra security guards at the Eurotunnel perimeter.
Very warm in the southeast tomorrow
An astronaut on the International Space Station has shared his experiences from outer space in the first Twitter chat from the craft.