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
Expect a bright day today with plenty of winter sunshine and clear blue skies across the country.
Clear skies allowed a satellite image to be taken, showing snow in the Pennines, north Midlands, Northern Ireland and Scotland yesterday.
Molly Smith, 5, won £500 after her accidental selfie with a snowman caught the attention of competition judges.