Tourists who got sick in Las Vegas say they should have been warned that a highly contagious virus causing a gastrointestinal illness is running rampant at several downtown hotels.

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The Health Department in Las Vegas said 1,174 people who stayed at the California Hotel and Casino have reported suffering from Norwalk virus since Dec. 3. The number has been rising as more people come forward after seeing news reports on the outbreak.

Officials say most of those sickened are Hawaii residents. Boyd Gaming Corp., which owns the California Hotel, sells many Las Vegas packages to people in Hawaii.

Norwalk virus, or norovirus, can cause diarrhea, stomach pain and vomiting for 24 to 48 hours. The virus is spread through food, water and close contact with infected people or things they have touched.

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The California Hotel said the numbers are inflated and it's not good for business. Rob Stillwell, a hotel spokesman, conceded the hotel may not be knowledgeable about all of the cases, especially if sick people called the health department after leaving Las Vegas. However, Stillwell said the health department's reporting methods can be inaccurate and vague.

"As an example of how inaccurate the reporting process can be and how vague it is, one gentleman on one flight said 'I'm feeling queasy,' and that's being included in these numbers," Stillwell said.

The California Hotel has stepped up cleaning at its properties, even going so far as to clean public bathrooms every hour.

Robert Silva, who got sick after staying at the California Hotel in February, said all seven people in his party got the virus. Silva said they should have been warned.

As for the virus' impact on the hotel's business, the California said some people have canceled reservations, but it's minimal. A spokesman said he couldn't give any numbers.

But a travel agent told KITV, a Honolulu television station, that with spring break around the corner, the California is usually booked solid. Right now, there are still many openings, according to the agent.

The number of complaints declined last week, KITV reported. But the Clark County Health Department in Nevada said it cannot and will not give a clean bill of health until it has observed a sustained decline for a period of at least one month.