The confirmation of a bird-flu outbreak is likely to hit the Thai economy hard.
Economists fear the effects could spread
Following the news of two human cases of the disease, the EU is to join Japan in banning Thai poultry imports.
Thai poultry exports are worth at least 16bn baht (£222m; $410m) a year, and the agriculture ministry says the flu may cost the sector $2.6bn.
The news caused further sharp falls in the shares of poultry exporters, and knocked 2% off the value of the overall Thai stock market.
Thailand is one of the world's top five poultry exporters.
Japan takes more than 60% of Thailand's poultry exports, with most of the rest going to the European Union.
Most of Thailand's main customers have now banned imports, with the EU joining the list on Friday.
Japanese households seem unlikely to go short of chicken, however, as Thailand accounts for just one-third of the country's total supply.
Poultry alone is far from crucial to the Thai economy, accounting for less than 1% of the country's total merchandise exports.
And among the country's farm exports, it comes way behind the main earners such as rice and seafood.
It is growing fast, however: unofficial figures say the trade has more than doubled in value since the last statistics were published for 1999.
And there are fears that the economic impact could spread to crucial sectors such as tourism, Thailand's biggest foreign-exchange earner.
The tourism sector is notoriously vulnerable to health scares, as Asian countries found last year during the outbreak of the Sars virus.
In Thailand in particular, the effect could be underscored by fears of government cover-ups.
Thailand has a poor reputation on this score, having for years denied the existence of terrorists in an attempt not to alarm tourists.
There are now persistent reports of a cover-up over avian flu, following an official slaughter of the birds to combat a poultry disease which officials said was cholera.