Dr Kerryn Phelps, Health Editor, with Steve Liebmann, Channel Nine, 'Today'

The West Nile virus is relatively new to the United States but the rate at which it has moved through the American states is causing great concern, and it has scientists searching for answers. Well, joining us now is our Health Editor, Dr Kerryn Phelps. Good morning to you.

PHELPS: Good morning, Steve.

LIEBMANN: Actually, I think the death toll is higher than 28. I think it's up around the 50s now.

PHELPS: Well, it's certainly 28 this year and the number of cases, as you said, have escalated rapidly since 1999. It was first described in the United States in New York, in the Queen's District, when they had seven people die in the one epidemic.

It spread from New York to right across the United States, and in the year 2000 they had 21 cases, and they had two deaths in the year 2001 and it spread further across the United States. This year, there are already 555 reported cases and 28 deaths.

LIEBMANN: What is it and how is it spread? How is it transmitted?

PHELPS: It's carried by a mosquito and the mosquito bites a bird. The bird is infected with the virus, and then the mosquito bites humans, and humans get the virus. Now, this has been known to happen in other continents. It's been known to happen in Asia, in the Middle East, in Africa. But up until 1999 it had never been seen in the United States.

There are other animals that also can be infected; cats, dogs, horses, bats, squirrels, chipmunks, a range of different types of animals as well. But it seems to need the mosquito to bite a human for the human to get it. You can't get it from another human or from an animal.

LIEBMANN: And so far, touchwood, the closest it's got to Australia is India.

PHELPS: India is the closest to Australia so far, but with the migration of birds and the migration of people, I don't think we can be quite so complacent as to think it's not going to happen here, in Australia. And clearly there is going to need to be a very effective public health response both in the United States and elsewhere to try and control this virus.

LIEBMANN: No vaccine?

PHELPS: There is no vaccine available. It's a flavivirus, which is related to Japanese encephalitis and yellow fever, which do have vaccines.

LIEBMANN: Is it at all like the Ross River virus or, I mean, are their similarities?

PHELPS: Well, it does cause an encephalitis which is not really the Ross River type of symptoms, but flu-like symptoms; fever, headache, body ache, skin rash in some people. It's not the same rash as meningococcal. It's a lighter pink rash. Swollen lymph glands, neck stiffness, disorientation and in very severe cases, of course, where the brain is severely infected, coma paralysis, convulsion and in some cases, particularly in older people, death.

LIEBMANN: And all of that, quick, if you don't get treatment?

PHELPS: It certainly can be within 10 days to two weeks of getting the virus that somebody can die, if they don't have a fatal case of it. But seeing the march of it across the United States has, I think, been something that's been quite shocking to American public health authorities.

LIEBMANN: So what do Australian health authorities do to prepare, just in case?

PHELPS: I think we need to obviously put in place the types of public health measures that we need to have in place to prevent the spread of mosquito-borne viruses. And I mean, while it might seem odd to have sprays of mosquito insecticide going through aeroplanes as planes arrive on our shores, I don't think it's such a silly thing when you think that mosquitos could so easily get onto a plane.

Clearly, I think that we need to be on the look out for any signs of this disease here in Australia.

But when you look at all the other different types of mosquito-borne viruses and illnesses around the world, there clearly needs to be a major response. In the United States, people are being advised for example, to not go out unless necessary in the evening, at dusk and in the early morning. To wear long sleeves and long legged pants; to spray insect repellent around those parts, the elbows, the wrists and the feet, and to empty out anything that might contain water like an old car tyre, a pot plant, a puddle in the garden at least once a week. And, of course, for local council areas, to start having mosquito eradication programs if there is a problem in their area. And also to report any dead birds.

LIEBMANN: Okay, well let's cross our fingers and hope we don't get it.

PHELPS: Yes, Steve.

LIEBMANN: Thanks, Kerryn.

Ends