He presented his findings to the Ministry of Agriculture on Wednesday night, as 40 new cases were confirmed, taking the total to 435.
The government is backing a £10m advertising campaign to stem losses as high as £100m-a-week in the UK tourism industry.
The action comes as epidemiologist Professor Roy Anderson predicts that the outbreak may not peak until May and could continue until August.
Visitor numbers have fallen sharply in parts of the country worst affected by foot-and-mouth, with the Lake District in Cumbria, and parts of the south west of England particularly badly hit.
He presented his findings to the Ministry of Agriculture on Wednesday night, as 40 new cases were confirmed, taking the total to 435.
As hopes the disease could be contained within weeks fade, efforts to save the tourism industry from collapse are swinging into action.
Tourism Minister Janet Anderson has begun a whistlestop tour of the US - Britain's largest tourism market - in a bid to dispel the myth that Britain is in virtual quarantine.
Last year some four million Americans spent £2.5bn in the UK.
But some in the US now fear there are human health risks associated with foot-and-mouth, and are confusing the disease with BSE.
'Open for business'
"Britain is still open for business. Please come, we want you to come," Ms Anderson told US travel industry representatives.
The government's campaign includes advertisements in national and regional media with a list of three rules for visitors.
The adverts stress that halting foot-and-mouth is a top government priority and that visits to the countryside are not banned.
It points out that many attractions, including stately homes and museums, are open and many sporting events were continuing as normal.
The government's rules are:
Both English Heritage and the National Trust have reopened some, but not all, their attractions.
About two-thirds of English Heritage sites - 200 out of nearly 290 - remain closed.
Stonehenge, Avebury and Hadrian's Wall are amongst the major attractions still barred to tourists.
The National Trust announced on Thursday that about 160 sites will be open by Easter - just over half of its historic homes and gardens.
But the country's largest private landowner told BBC News Online that many of its unfenced land including coastal paths may remain out-of-bounds.
Government's website www.co-ordination.gov.uk or call 0845-607 1071. Separate guidelines are being issued for Scotland and Northern Ireland.