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WNV Rears Its Ugly Head (1 Viewer)

Beverlybaynes

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My city was the center of the largest human outbreak of West Nile Virus in the summer of 2002. And now it's back.

Today's morning paper has reported our first case -- the second in the country for 2003 -- in the south central part of the city, not far from where I work.

And although our local health boards have formulated a plan for combating WNV that has larvicides as their primary focus, with the emergence of a human case -- a child, unfortunately -- they will begin spraying tonight. :(

To their credit, they will be spraying the neighborhood only within a half-mile radius of the child's home, thereby limited the exposure of others to the spray.

But it's so sad to know that perhaps all the predictions of an outbreak worse than last year's may be coming true.

:-C
 
Oh Beverly I'm so sorry to hear of a child being the first case this year. The news here this morning is a second case of a bird having died from it. In Ontario there have been a number of human cases last year (17 I think). One lady is in a wheel chair as a result. I don't think they have any confirmed this year. We took in a dead bird last year for analysis but it results returned negative. They tell us that the type of mosquitoe carrier is not as common up here in the North. Take care out there.
 
Hi James,

It is a viral disease that attacks birds and, very rarely, people. Spread by mosquitos; originating in the old world (first discovered in Egypt, hence the name), introduced to North America about 4 years ago.

The bad news is that it is present in Britain.

The good news is that it has been present in Britain for so long (probably millenia, if not longer) that all our native birds are pretty resistant to it (both summer visitors arriving from Africa, and also resident species). And since our birds don't get sick with it, the virus doesn't build up enough to reach the high dosage levels necessary to infect people.

The reason it is a problem in N America is that the disease is new over there, so the local birds don't have much resistance to it and can have fairly high death rates. I suspect that this will change in a few years as new generations of American birds evolve resistance.

The nasty thing is that until then, some US authorities still think they can stop the disease by spraying huge amounts of insecticides everywhere to kill all the mosquitos, and the birds that feed on them, and everything else too probably. This mad spraying programme is causing far more damage than the disease does.

Michael
 
Well said, Michael. The city and county sprayed a LOT last summer -- a first knee-jerk response, and of course, a traditional one.

They did, to their credit, spend the winter formulating a new plan, and I applaud them for taking the time and making the effort to find alternate control methods. I know they have been using some form of larvicide, which is the most effective, by dropping pellet larvicide things down in the city's catch basins -- a huge source of mosquito larvae. And there have been fairly consistent reminders in the media of what the general public can do to help: wearing long sleeves and pants, using personal insecticides, emptying containers (buckets, flower pots, tires, etc., etc.) of standing water on their own property.

I lost my neighborhood crows last August, and haven't seen a chickadee or nuthatch in months. Woodpeckers are 'way down (altho I do have a juvie downy coming these days!!). General numbers are just down overall.

That build-up of immunity can't come fast enough!!!
 
My understanding of WNV is that it hits the corvids pretty badly,
while other species (such as American Robins) get sick, but
eventually recover. There's a lot of concern about the raptors,
as well, although its impact on them is still not fully understood.

Unfortunately, immunity is built up primarily through natural
selection - meaning a lot of birds will have to die off, allowing
those that are resistant to WNV to breed and repopulate. And
that's assuming those resistant birds survive the hysteria-
driven mass spraying programs that WNV inevitably inspires.
 
Hi Arnel,

Do you know if a bird (e.g. one of those American Robins) catches it and recovers, does that confer individual immunity (like measles), or can it catch it again another time (like flu or a cold)?

Michael
 
That's a good question. Nothing in the literature I've been
reading answers it one way or the other. Maybe someone
else on the BF has seen something interesting?
 
Hi Arnel,

Thanks; all I know is the results of a study done in Britain last year.

As of last year, WNV had never been recorded in a wild bird in Britain. But it was pointed out that many of Britain's summer-visiting birds winter in WNV endemic areas in Africa.

So some tests were done on various birds. The results were very surprising and totally unexected - ALL the birds tested, resident species as well as summer visitors, had antibodies to WNV. So all had been exposed to the virus.

The conclusion is that WNV has always been present in Britain but just undetected, because our birds are sufficiently resistant to it not to show any symptoms when they catch it.

Yet the virus must also presumably be infecting every fledged juvenile at some point, or they would not develop the antibodies.

Michael
 
Sounds like the common cold for your birds, if that.

It would be interesting to see why some of the species here succumb to
the disease, while others do not. Could the American Robins, some time in
their distant past, have been subjected to a similar virus which renders them
immune to WNV? In human beings, it has been demonstrated that survivors
of the Black Plague passed on to their descendants an immunity to not only
the Black Plague, but also to other diseases caused by similar viruses, such
as AIDS.
 
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I am really sorry to hear that Beverly. My city has not been enlightened yet and are still spraying rather than using the larvicides. I wonder how many years it will take for the butterflies and dragonflies to recover from the spraying.

BTW, what birds are primarily affected in your area?
 
In Virginia the crow is the biggest indicater - personally I'll take the spraying vs. the disease - we also have numerous horses that contract the WNV here in the USA - besides I don't like cats either "the only good cat is a dead one", they come to my feeders and kill my birds. A cruel world we live in.
 
An intriguing point . . .

The Northern Wheatears that breed in NE Canada, cross the Atlantic to Europe, and move south to winter in AFRICA.
The Northern Wheatears that breed in Alaska, cross the Bearing Straits, go right across Asia, to winter in AFRICA.
These birds will certainly resist the virus well. But juveniles arriving in the wintering grounds will (theoretically) be free of infection, and 'catch up' with it sometime through their first winter.
What surprises me, is that these birds have never carried the disease to North America in the course of their normal migration.

Same can be said for the Red Knots that breed in NE Canada and winter in NW Europe.

Hi Arnel,
Sorry, but what you've read there about Black Death / Bubonic Plague (caused by the bacterium Yersinia pestis) and AIDS (caused by a virus), isn't true!

Michael
 
Hi Michael,

I actually mis-remembered the PBS program where I got
the information. What the program stated was that survivors
of the Black Plague had a genetic mutation which made it
impossible for the bacterium to kill them. Because survivors
of the Black Plague repopulated Europe, they passed on this
mutation. The mutation was then discovered to give these
descendents immunity to AIDS, as the virus causing AIDS
tries to trick the immune system in much the same way as
the bacterium that causes Black Plague.

It had been about 6 months since I saw the program, so
my recollection of it had cobwebs. Here's the link the program
in question:

http://www.pbs.org/wnet/secrets/case_plague/index.html


Sorry about the mixup.


- Arnel


:egghead:
 
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We lost TONS of corvids and raptors, especially Great Horned Owls and Red-tailed Hawks, last year. My personal observations show fewer woodpeckers, chickadees and titmouses, too.

There were a LOT of horses lost, too, as northern Indiana is home to the 3rd largest Amish community in the country (which is centered north of here, but there is a large community here in the county too).

The saddest, closest loss was Sullivan, a 12-year-old Golden Eagle, who was an education bird for a raptor rehab organization I'm involved with.

Ron, I'm afraid I cannot agree at all with you. The effects of spraying -- aside from being the LEAST effective method of mosquito control known -- are just too wide-spread. The effect on insects (including butterflies and dragonflies, et al), on other mammals, and on humans, especially those with respiratory illnesses, is just too harsh and/or deadly. The residues filter into the soil and the water, so who knows what kind of effects it may be having on reptiles and amphibians? Can we afford these kinds of ripple effects? I don't think so.

There is hope that North American birds, the survivors, will develop the same kinds of antibodies found in British birds and pass them to their offspring. What we don't know is how long it will take.
 
The larvicides that Beverly mentioned above struck my curiosity,
so I did a quick Google search for it and came up with some
interesting information, the best of which is at the following
link (from Oregon State University):

http://ace.orst.edu/cgi-bin/mfs/01/pips/bacillus.htm?57#mfs

Apparently, these larvicides are quite effective, with minimal
damage to the environment.

In the search, I also stumbled upon a number of websites for
various mosquito abatement districts throughout the country.
At least one or two of these websites state that targeting adult
mosquitoes through the use of spraying is the least effective
method of control. They would prefer to target the mosquito
larvae rather than the adults. Here's one example:

http://www.msmosquito.com/moscontr.html

So.....I don't think we have an either/or scenario here.....

Just my 2 cents' worth.....


- Arnel Guanlao
 
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