Travel giant Thomas Cook today said the swine flu outbreak had cost the business around £12.6 million so far.
The firm said the cost of cancelled trips - mainly in the UK and Germany - after official advice not to travel to Mexico was "more significant than we anticipated".
Thomas Cook also has more long-haul trips left to sell than at the same time last year as travellers shun the popular tourist destination of Cancun.
Thomson Holidays rival TUI Travel unveiled a £7 million bill for the May outbreak yesterday.
Despite the disease and later booking trends, Thomas Cook said it was on track to meet management hopes this year with "robust" trading in the summer season.
But chief executive Manny Fontenla-Novoa added: "Looking beyond the current year we are preparing for continued tough market conditions."
In the UK, average selling prices for summer were 8 per cent ahead of last year although bookings were down 11 per cent in line with the company's reduced capacity.
The business has over a third less short-haul flights to sell than at the same stage last year, meaning it has to give away fewer holidays cheaply in the discounted 'lates' market.
Thomas Cook has also been growing share in higher margin medium-haul business, benefiting from a trend towards all-inclusive packages and non-euro destinations. 'All-in' holidays now account for more than 40 per cent of summer capacity, the firm said.
For the coming winter Thomas Cook has seen a 'slow start' with UK bookings 13 per cent down on last year. The firm added that it had already sold 6 per cent of UK capacity for summer 2010 despite a later brochure launch.
When Thomas Cook bought the former Airtours business MyTravel in 2007, management were hoping for operating profits of £480 million by 2010.
But this target was formally dropped today as unrealistic in the depths of the current recession with markets unlikely to recover in time.