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
Cloud for many on Monday and the risk of freezing fog patches to the east which could take a while to clear.
Scarlett Moffatt has been crowned Queen of the Jungle in this year's I'm a Celebrity... Get Me Out Of Here!
Emily Middlemas has been kicked out in the X Factor semi-finals - leaving 5 After Midnight, Saara Aalto and Matt Terry through to the finals