Hatem el-Gabali, the health minister, said on Monday that cases of the disease had turned up in Minufia, Sharkia and Kafr el-Sheikh provinces in the Nile Delta and in Fayoum, a farming region on a branch of the Nile that runs into the desert southwest of Cairo.
The sudden arrival and spread of the disease over the past four days has caused widespread panic among Egyptians, despite the government's attempts to reassure them that the health risk to ordinary people is minimal.
"Of course I don't buy chicken. I'm afraid, afraid for myself, my family and all the people. Who isn't afraid of disease?" said Om Mohammed, a shopper at a Cairo market.
Newspapers reported suspected cases among humans but officials said all tests on humans had proved negative.
A UN official said the economic effect could be severe because the demand for chicken has collapsed and the industry, which was worth about 17 billion Egyptian pounds ($3 billion) in investments, supports between 2.5 million and three million people.
Chicken, the meat many Egyptians used to eat most regularly, is selling at below five Egyptian pounds a kg, from 14 Egyptian pounds before the disease arrived.
Small poultry merchants have closed up shop and the French-owned supermarket Carrefour in Cairo has removed all chicken meat from its shelves, shoppers said.
Ahmed Abdel Azim, a Cairo poultry seller, said: "It's finished. Nobody's buying chicken ... How are we going to work? It's the same work millions do. The government doesn't pressure us to close, but with bird flu in the news, people are afraid."
Officials say bird flu's health risk
to ordinary humans is minimal
In response, the price of fish has risen 40% but demand has risen faster, shopkeepers said on Monday.
Talib Murad Ali, the Food and Agriculture Organisation's regional officer for animal health, said countries such as Egypt would be hard hit economically.
"Worldwide, poultry accounts for about 20% of the animal protein consumed. But in Egypt it was 45%-50% of all meat and fish and it was a third of the price of red meat.
"It's the only protein to which the poor have access," he said.
Scarce grazing land
The main reason for the prevalence of poultry is that grazing land is so scarce in the arid Middle East, Ali said.
The region is especially vulnerable to animal diseases because it imports so many live animals, sometimes without strict regulation, he said.
"Sometimes we say that every piece of meat on a kebab skewer comes from a different country," he added.
Egypt is also tackling a foot and
mouth outbreak in the Nile Delta
Egypt has been tackling an outbreak of foot and mouth disease in the Nile Delta for the past two to three weeks and this has put pressure on beef and milk supplies, he said.
The government has responded with a vaccination campaign.
The government has promised compensation for people who have to slaughter their chickens but it has not worked out the details and has not made any payments, an official said.
On Friday, the government told people to get rid of the poultry they keep at home or on rooftops, but by Monday not everyone had complied, even in central Cairo.