"To date, they all tested negative," said Colin D'Cunha, adding that the tests were ordered by family doctors after patients showed West Nile symptoms, which can include, fever, headaches and body aches.

D'Cunha suggested, however, that only those who show possible signs of the disease should be tested.

"You've got to ask yourself, why .?.?. you want to get tested," he said.

"If the answer is you want to get tested out of curiosity, clearly that's not a good use of resources."

Stung by criticisms about their handling of the SARS crisis, Ontario's Conservative government has launched a detailed public health strategy to help fight West Nile.

The plan's progress was updated Thursday at a conference attended by D'Cunha and Health Minister Tony Clement.

"Any one of us are at risk, so precautions are vital," said Clement, adding that a teleconference will be held later this month involving public health officials from Ontario, Manitoba, New York and Illinois to discuss the most effective ways of keeping the virus at bay.

West Nile virus is carried and spread by mosquitoes and can cause fatal inflammation of the brain or the membranes covering the brain or spinal cord. In the vast majority of cases, those who are bitten by an infected mosquito show mild symptoms or none at all.

There is no vaccine to prevent West Nile infections.

Health Canada says that when infection does cause illness, symptoms will usually appear within two to 15 days.

In the case of a positive result, D'Cunha said, laboratories are required to provide notification to doctors within 48 hours of receiving the specimen, or faster if requested.

In the past, the government has been criticized for not having the resources to conduct speedy testing.

D'Cunha said that 19 crows have tested positive for West Nile this year. Crows and blue jays are considered indicator species for the virus in Ontario, because they are immune to bites from infected mosquitoes.

West Nile first arrived in the New York area in 1999, 62 years after it first appeared in a region of Uganda.

Health Canada, which gets its information on confirmed and suspected cases of West Nile from the provinces, has reported that Canada has 20 confirmed deaths from the disease - 18 in Ontario and two in Quebec.

Last year, the first Ontario resident tested positive for the virus in late August.

D'Cunha said larviciding - which involves the placing of pellets or granuals into mosquito breeding sites to kill the eggs before they hatch - is being conducted by 10 public health units.

A dozen people affected by West Nile virus announced last month they are suing the Ontario government, saying the province did not take appropriate measures to warn the public about the disease, and did not ensure there was speedy testing for the virus.