Science: West Nile Virus

Washington Post science writer Rick Weiss was online to discuss the West Nile virus and answer other science questions on Monday, June 26 at Noon ET .

Read today's Science feature: Clues on West Nile Sought at Local Bird Paradise .

A transcript follows .

For more of The Post's science coverage, click here .

____________________

Rick Weiss: Hello gang. Welcome back to the Mr. Science hour.

I will be happy to take your questions on today's West Nile science-page story (written by a local freelancer) or other topics of interest.

_______________________

Ocean Pines, Md.: Hi Rick,

As we all should know, West Nile Virus has declined in the eastern U.S. states in the last couple of years, becoming so small that it's statistical significance is virtually nill.

Do you feel that natural immunity developing in birds has contributed to this sharp decline? Unfortunately, today's article in the Washington Post seems to ignore these factors.

Rick Weiss: The experience with West Nile virus in other parts of the world where it has been around longer (such as around Uganda, where it was first identified in the '50s) seems to be that a lot of people develop immunity after an initial, often asymptomatic encounter. I suspect that many people in the Eastern U.S., where West Nile first appeared in '99, have now been exposed and need not worry about serious complications. Some animal species (including crows) seem not to be benefiting from immunity though... though over time, perhaps they will.

_______________________

A general question about viruses...: Why does our government think it's more important to spend money fighting the symptoms rather than finding a cure? I'm thinking specifically of the cuts in funding for AIDS vaccine research.

Rick Weiss: Vaccines are definitely the way to go for widespread, serious viral (and in some cases bacterial) diseases. Problem is, they are very hard to get right (especially when the virus is like HIV and makes its very home in the cells you need to mount an immune response), and until recently, at least, they have proven to be a not very profitable venture, which has dissuaded companies from pursuing them. Lately some drug/vaccine makers have begun to see that they can, in fact, work the economics to their advantage when they get a vaccine that works. How this will affect the overall healthcare economy over time I do not know, but hopefully it will lead to new pushes to develop vaccines for AIDS and other diseases. Meanwhile, medicines that temper symptoms can be a huge help.

_______________________

Charlotte, N.C.: I don't know what to be more scared of: ebola, west nile or bird flu. How do diseases/viruses like these originate?

Rick Weiss: Many of these "new" diseases have their roots in animals, and have leaped to us humans as we've invaded the turf where these animals have been living. Airplanes allow us to spread the relevant viruses or other vectors far more efficiently than we ever could before, which amplifies the spread of trouble. And crowded urban conditions (or suburban, especially when we share space with animals, as so many people do in less developed countries) enhances the odds of a virus jumping species or mutating in a way that can make them deadly to humans. It's basically a big microbial/viral soup out there that we are swimming in daily and especially woith viruses, which are very adept genetically, the odds are these diseases are going to keep popping up for the forseeable future.

_______________________

Washingotn, D.C.: Why are mosquitoes going after Robins as opposed to other types of birds?

Rick Weiss: I don't know the answer to this but wondered it myself. In fact, I wonder how scientists can tell that Robins are the "main meal" for the relevant mosquitoes while the Robins are in town. Are the scientists measuring viral loads in all different species? Counting little red bumps on their skin beneath the feathers? If one of the researchers is reading this, perhaps you could enlighten us?

_______________________

Washington, D.C.: Exactly HOW is this disease contracted?

Rick Weiss: People get West Nile from the bite of an infected mosquito. Mosquitoes get infected by biting infected birds. The disease is believed to have arrived here inside a single infected bird that arrived in New York City in '99 - perhaps one imported as part of the trade in exotic birds. Then again, there is a small chance that one or more infected mosquitoes caught a ride on a plane from the Middle East, where the disease has been endemic for a long time.

_______________________

Arlington, Va.: I'm always fearful of mosquitoes now with the West Nile fear....should I be doing anything else besides shrieking when I see a mosquito buzzing by, to ward this off?

Rick Weiss: I have not seen any published, peer-reviewed studies that have looked at the value of shrieking when approached by a mosquito, but this may be a fine defense. I'd suggest a little mosquito repellent as well, though, just for an extra safety factor. Also, if you are reasonably healthy, you might take my approach (WARNING: I am not licensed to provide medical advice): You could take the philosophy that it is better to finally get exposed to the darn virus and build up some immunity, and take the small chance that your brain will swell up and you will die. What can I say? Life is dangerous.

_______________________

Ocean Pines, Md.: The city of DC has a significant program for larviciding so we're somewhat surprised that some mosquito hot spots were noted in today's article in the Post. And we've heard that their larviciding is working well. Larviciding stops the mosquitoes before they become flying, biting adults. And its essentially non-toxic.

Is it possible that the writer overstated the problem to bolster their organization's research project? Have you been having mosquito problems in your own area?

We've had practically none, and there was an article in a local newspaper commenting on the lack of mosquitoes.

Rick Weiss: My personal experience this summer, for what it is worth, is that there have been fewer mosquitoes than in the previous two or three years at this point in the summer. But it has been pretty dry (until the past day or so -- so perhaps we are abut to have a tremendous blossoming of the critters soon). I have also noticed that ceertain small parts of my large-ish back yard in Takoma Park ('small areas' meaning about four feet by six feet), such as near a few grape vines I have growing, often are mini hot-spots, even though there is no obvious standing water or moisture. I think there is still a lot to learn about micro-environmnets and their effects on insect concentrations and ecology.

_______________________

Washington, D.C.: It is better to experience West Nile virus as an adult than as a senior citizen, so becoming infected sooner rather than later would be preferred if you have a choice. It's my understanding that many people experience West Nile as a summer cold or flu. Is it possible to have been infected and not know it still?

Rick Weiss: Yes, many people feel only mild fluish symptoms and no doubt many don't even realize they have any particular infection at all, but perhaps simply feel a little worn out for a day or three -- as any of us would under the circumstances of living in Washington, in the summer, at a time in history when, let's face it, few people are feeling really chirpy. (No pun intended, all you Robins out there.)

_______________________

Fairfax, Va.: So from reading some of the questions and answers to this chat, so far, I'm beginning to realize that West Nile isn't the crazy fearful virus it was a few years ago. Do I have the right impression or have other viruses such as SARS and the Bird Flu trumped West Nile making the world come back down to earth a bit and realize it's not something we should fret about?

Rick Weiss: My read so far has been that West Nile is not going to be the major blowout human disease problem that some had predicted, and it certainly does not pose the kind of risk (theoretical though it remains for now) of avian flu. But that does not mean it will not have devastating effects in North America, especially if it continues to take heavy tolls on various bird species (including raptors, which are important predator species all across the country). I think it is still too early to see what the real impacts are going to be, given this virus's ability to erase certain key trophic levels in the ecological web. Horses also remain threatened, though there are vaccines now in use for valuable horses, (captive) birds, and other animals.

_______________________

Ocean Pines, MD: Perhaps the person who was shreiking needs some additional advice.

Fans help as mosquitoes are weak fliers and don't like strong air currents.

Citronella candles are somewhat useful. Vicks vapor rub has some repellent effects (for a little while) and most people already have some on hand, without going out to buy a new product. Long sleeves and slacks are another defense. Dark cloored clothing is said to be an attractant, so wearing lighter colors can help.

Rick Weiss: Reasonable advice from a reader ...

_______________________

Washington, D.C.: I have seen a number of dead birds on sidewalks over the past week. Is this anything, or just normal birds flying into windows kind of thing?

Rick Weiss: I have not noted a burst of dead bird-dom out there myself and would not hazard a guess as to what you may be documenting -- Do you live near some big plate glass windows? Are you near Dick Cheney's office window? I did see a fair number of dead crows the first couple of years after WNV arrived here. And in the past two years or so, although I see an occasional crow or two (there used to be scads of them in my neighborhood) those few disappear within a few days -- many, I presume, killed by West Nile, which has a paticular predilection for corvids such as crows and jays.

_______________________

Springfield, Va.: We see with West Nile, that viruses can be transmitted by mosquitoes, why not AIDS?

Rick Weiss: Despite early fears that AIDS could be transmitted by mosquitoes or other living links, no such transmission has ever been documented or even seriously believed to have occurred, as far as I know. I don't know the specifics in the case of HIV, but viruses tend to be pretty specific in terms of the kinds of cells they can hijack for their purposes. HIV seems to like mammalian cells.

_______________________

Bethesda, Md.: We found a dead bird (sparrow?) in our driveway. Should we have called someone? There was also another dead bird (small) down the street.

Rick Weiss: Last time I checked on this the relevant authorities were not interested in hearing about dead birds. The presence of these corpses (and subsequent testing for West Nile virus in their blood) was a useful way of tracking the virus's arrival in our area. But now that it is here, there is little else to say. That said, some scientists in the U.S. are looking for genetic variations in viral samples taken from birds to see if the virus is changing in significant ways. It was through studies such as those that scientists were able to determine that the entire North Amercian pandemic almost certainly arose from a single entry, probably a single bird.

_______________________

Fairfax, Va.: We live on a cul-de-sac surrounded by wooded areas. Is there any reason to discard our bird feeder out of fear of bird-borne diseases, or is that unlikely to have any effect?

Rick Weiss: I think the major risk of a bird feeder is that teetering step ladder you're probably using to refill it. Life is short. Look at as many birds as you can.

_______________________

Washington, D.C.: One study featured on television showed that mosquitoes like stinky cheese, and dirty feet because they smell like stinky cheese. I have heard cheese as you would find on a cheeseburger or in a ham and cheese sandwich is enough to attract mosquitoes. The most savage attacking I've ever experienced by mosquitoes was after using Pert shampoo, but this also taught me to select a soap that smells like Off. I can't name it thought because it was in Europe, but the principle translates.

Rick Weiss: This being Washington, I can only assume this was written by a vegan lobbyist who also has an account with a shampoo company competing with Pert. But maybe I have lived here too long. Anyone want to do the melted cheese experiment and write back?

_______________________

Burke, Va.: What about mosquito repellents like OFF? Are they helpful? Also what about the 'after-bite' medications? Do they provide any help with West Nile? They do relieve the itching and pain.

Rick Weiss: Studies I have seen have repeatedly found that repellants with the ingredient abbreviated as DEET are strongest. And though I've not seen any research on the topic, it is hard for me to believe that an anti-itch product would help prevent West Nile fever. Once the virus is there, in your bloodstream, I don't believe itching or not itching is likely to change the course of the disease.

_______________________

Rick Weiss: Well, the hour has passed quickly. During our chat, I have become extremely itchy, have had flashes of a possible fever, swatted at a fly near my workstation out of fear it might give me AIDS, been told that my feet smell like rotten cheese and have decided that Robins, rather than being a happy sign of Spring, are the ornithological equivalent of the devil. Thanks a ton for making my day!

Tune in next Monday for another Science Chat.

_______________________

Editor's Note: washingtonpost.com moderators retain editorial control over Live Online discussions and choose the most relevant questions for guests and hosts; guests and hosts can decline to answer questions. washingtonpost.com is not responsible for any content posted by third parties.