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Over the coming weeks I will be writing about and commenting on some of my research involving the West Nile Virus here in Dallas, its impact, WHERE it is hitting, and why it may be hitting certain places and not other places.  When we read about a disease (or anything) impacting people living in certain areas, we often think of it as a "blanket result" -- everyone in all parts of the area are equally affected.

The truth is (as you can figure out from your own experiences) is that "it ain't necessarily so."

Last year, the Dallas City Council decided that the way to deal with West Nile Virus was to spray from the air -- in spite of the uproar from citizens.  Organic farmers, beekeepers, naturalists, and a lot of other folks were very upset by this (and many saw some impact from it) and a small coalition has formed to see if we can stop it this year.  Some beekeepers asked me if I would look at the data and see if I can help.

More below the squiggle.

We don't all look at data in the same way, either.   Now, this is a particularly un-handsome image since the only place I could find a zip code map was a fairly low resolution version of it.  I colored in the areas that had the highest number of cases (the black area had THE highest number of cases)... and then I did the one thing that I haven't seen done: colored in the areas where there were NO cases and said, "What's different about these?"

Now, all zip codes have residential areas (even downtown Dallas.)  Population density varies, of course, but the interesting thing is that the virus hits hardest in the wealthiest parts of town.  It could be that this is the area of town where people have enough economic power to go to the doctors and get a diagnosis, but I think that's an over-simplified answer.  I can say from experience that the area with the most cases (the one in black) also had a huge mosquito problem -- big enough that one of the most popular outdoor places in Dallas (a botanical garden called the Arboretum) had enough of a mosquito problem that they had cans of bug spray stationed at the entrance information booth and encouraged people to use the mosquito spray.

Six miles south of that, at the Trinity River Audubon Center, we had very few mosquitoes.  

Both sites have water (one is a big lake, the other has many ponds and lakes that were drying up in the drought) and both have habitats that mosquitoes like (they're not very picky critters.  Give 'em enough water to keep eggs and larvae wet for 10 days and you have a flock of happy mosquitoes flitting around.)

So I'm looking at the areas (walking them... not just sitting on Google Earth and speculating about conditions) and thinking about them.  If we can get enough people involved in being proactive about this then maybe we can keep mosquito numbers down and disease levels down and eliminate the "need" in the minds of the City Council to carpet-bomb the city with insecticide.

It's a crazy plan, but it might work.

Originally posted to Cyberwizard on Sat Dec 29, 2012 at 11:48 AM PST.

Also republished by TexKos-Messing with Texas with Nothing but Love for Texans.

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Comment Preferences

  •  Very interesting - thanks! ....n/t (3+ / 0-)
    Recommended by:
    txcatlin, northsylvania, blueoasis

    ...if only animals could write...

    by Jinnia on Sat Dec 29, 2012 at 12:29:03 PM PST

  •  Republished to TexKos because (5+ / 0-)

    whatever you find out will help us in other parts of the state.

    Those who do not understand history are condemned to repeat it... in summer school.

    by cassandracarolina on Sat Dec 29, 2012 at 12:29:26 PM PST

  •  We live just down the street from the Arboretum (2+ / 0-)
    Recommended by:
    txcatlin, Catte Nappe

    I can attest that mosquitoes were very bad last year. You couldn't set foot outside at any time of the day without being swarmed, and the natural repellent that I normally use hardly slowed the nasty little buggers from eating you alive.  We couldn't sit outside to watch our chickens like we usually do, and I had to resort to long pants/sleeves for my quick trips outside to tend to the chickens twice a day. It was miserable in the summer heat to dress like that.

    I don't like the idea of spraying, but at least in our area, it worked. It was days after the spraying before I saw a single mosquito.

  •  Interesting (1+ / 0-)
    Recommended by:
    Sonofasailor

    Especially since I live in that black colored zip code. Not exactly one of the wealthiest areas in town - not like those red colored ones to the west or the pink of Preston Hollow to the north (maybe impacted by fish ponds and fountains and regular lawn sprinkling?).  I also see a big red blob to the south  that appears to be 75216, which is among the poorest parts of town.
    I look forward to your future findings and suggestions.

    "No one life is more important than another. No one voice is more valid than another. Each life is a treasure. Each voice deserves to be heard." Patriot Daily News Clearinghouse & Onomastic

    by Catte Nappe on Sat Dec 29, 2012 at 04:13:25 PM PST

    •  BTW (1+ / 0-)
      Recommended by:
      Sonofasailor

      It's not just a question of where those infected live. It may have to do with where they work (or play).

      "No one life is more important than another. No one voice is more valid than another. Each life is a treasure. Each voice deserves to be heard." Patriot Daily News Clearinghouse & Onomastic

      by Catte Nappe on Sat Dec 29, 2012 at 04:16:29 PM PST

      [ Parent ]

      •  Exactly! (0+ / 0-)

        That, however, is more difficult to track.  However, since the cases that come to the doctor's attention often occur people with chronically poor health, we can assume SOME correlation there.

        But you're absolutely right about that.

  •  as a person who contracted West Nile here in (1+ / 0-)
    Recommended by:
    blueoasis

    Chicago, from a mosquito that was in our house, the only positive thing I have to say about the virus, is that I won't get it again.

    i was very lucky. others weren't...a Chicago fireman passed away not long ago from bites he got in October, during a trip to Wisconson.

    i'm working on a diary about my experience. it been rough.

    Al Qaeda announced its dissolution, “our mission of destroying the American economy is now in the capable hands of the U.S. Congress.” Andy Borowitz

    by dear occupant on Sat Dec 29, 2012 at 04:29:36 PM PST

  •  The epidemiology is much more complicated. (1+ / 0-)
    Recommended by:
    Sonofasailor

    First, very few species of mosquitos will transmit WNV (or and other arbovirus such as Eastern, St Louis, and so on).

    The virus is present in the wild bird population and in order for it to be transmitted to a human, a female mosquito has to bite an infected bird, become infected herself, and then bite you. So the mosquito, the bird, and the human have to be in the same habitat.

    There are hundreds of species of mosquitos in the US. 90% don't bite people and 90% of those don't bite birds. You can get the crap bit out of you and not be at risk, depending on what the species is that is doing the biting. Culex nigripalpus is the main problem, IIRC.

    Not all mosquitos are susceptible to the virus, so they won't ever transmit.

    The reporting of arbovirus infections is suspect. Most infected people have mild cases and at worst think that they have a cold or the flu. Generally seroconversions outnumber reported cases by two or three orders of magnitude (I am not sure of the exact number for WNV). If there is a lot of publicity then more people will get tested and the fraction of reported cases will go up.

    If you seroconvert, you are immune for life.

    I have never worried about it myself. I spend a lot of time outside and I figure that I will eventually get exposed (if I haven't been already). I am willing to trade the small risk of a serious infection for reducing my exposure to DEET and pesticides. But if you are immunocompromised, elderly, or have an infant that is probably not a good idea.

    I spent 12 years doing research on malaria-transmitting mosquitos so I know a bit about tihs. It has been 15 years since then, so anyone who is more current can correct me.

    •  You're correct! The transmission cycle is not (1+ / 0-)
      Recommended by:
      Andrew F Cockburn

      so simple. This is what makes managing mosquitoes for public health so difficult.

      There is abundant evidence implicating the significant role Culex mosquito species play as WNV vectors. That tells public health officials where they should be looking to identify breeding habitats for source reduction.

      WNV continues to be an underreported disease. Most infected people, about 80% or 4 out of 5 people, don't show symptoms and will never know they have it. About 20%, however, develop West Nile fever, which causes flu-like symptoms, including headache, fever, body aches, and swollen lymph glands. Less than 1%, or 1 out of 150 infected people develop severe West Nile disease, WNND, the neuroinvasive form of the infection, which can lead to meningitis or encephalitis and death.

      Perhaps someone whom has experienced WNND can persuade you to reconsider your exposure risk decision. I've found a number of DEET free repellents, formulated with natural oils, which are quite effective and seem to work longer than any DEET based products I've ever tried.

      "Life is tough. It's even tougher if you're stupid." --John Wayne

      by Sonofasailor on Sat Dec 29, 2012 at 09:17:04 PM PST

      [ Parent ]

      •  Which ones are you using? (1+ / 0-)
        Recommended by:
        Andrew F Cockburn

        I want to include them in my report to the working group when we meet back in January.  Some of the folks there undoubtedly know about these products, but some of them are office workers and wouldn't have a clue about this.

        •  There are many DEET free formulations... (0+ / 0-)

          two that I'm fond of are Naturapel® and Liquid Net®.

          These products use herbal oils, which are generally recognized as safe and my experience is that they perform better than DEET formulations in high mosquito landing pressure environments.

          "Life is tough. It's even tougher if you're stupid." --John Wayne

          by Sonofasailor on Tue Jan 01, 2013 at 07:52:36 AM PST

          [ Parent ]

      •  I went through a major Eastern epidemic (0+ / 0-)

        in Florida in the 1990s. Dozens of people died and hundreds were hospitalized. At the time I worked in one of the most prominent mosquito laboratories in the world (USDA/ARS Medical and Veterinary Research Laboratory). I suspect that our scientists were happy to go on TV and talk about how dangerous mosquitos were (scientists always need more funding) However, I don't remember anybody in the lab talking about taking additional precautions when we were in the field and certainly no one stopped having barbecues.

        I tihnk that the fear of WNV is an example of us being concerned about a rare and spectacular danger and ignoring much greater mundane dangers. The classic example is someone who drives rather than flying because they see a big plane crash on the news. In this case I think that the cumulative risk from constantly putting chemicals on my skin or staying inside to avoid mosquitos is greater than the risk from arboviruses.

        •  I agree...the risk is slight... (1+ / 0-)
          Recommended by:
          Andrew F Cockburn

          but I also wouldn't want to join those in the unlucky <1% that have experienced the life altering, or worse yet life ending, arbovirus infections.

          It's hard to imagine the USDA/ARS occupational health and safety protocols would not discuss use of insect repellents in their work hazard analysis and safety plan for field work in elevated arboviral infection areas as a means of hazard mitigation.

          Surely using a botanical oil based insect repellent will not guarantee that you won't get bitten by an infected mosquito and contract an arbovirus, but it can't hurt. I've discovered the cumulative effects of slathering myself with these products is that I smell pleasant and my skin has a wonderful smooth texture.

          I look at applying insect repellent like wearing a seatbelt in a car or looking both ways before you cross a street. Not everyone does it, and some are lucky, but others...not so much. Personal protection is a personal choice and we are all free to decide what risks each of us are willing to expose ourselves to.

          "Life is tough. It's even tougher if you're stupid." --John Wayne

          by Sonofasailor on Tue Jan 01, 2013 at 08:32:06 AM PST

          [ Parent ]

    •  Exactly! (1+ / 0-)
      Recommended by:
      Andrew F Cockburn

      I didn't go into this in my first diary, but according to the research I've seen, the birds that are most implicated in this are the blue jay, crow, and robin.  Of those, the robin is considered to be the biggest problem, since it can live the longest with the disease.

      Dallas is a place full of environments that the robins love.

      Culex is one of the species implicated in transmission... and we have a lot of them here.

      I'd love to see some of your publications and commentaries on what you uncovered.  

      •  Your information on birds is what I remember also. (0+ / 0-)

        Here in WV almost all the crows and ravens were wiped out when WNV went through a few years ago. I gather that was the case across the country. This year I notice that they are coming back. I wonder if they have been selected for resistance or if the virus has mutated so that it isn't so lethal to them.

        I have also heard that robins were the primary carrier.

  •  You were living within a public health disaster! (0+ / 0-)

    That outbreak was serious business and it could have been much worse. The drought modified certain water features which are typically unsuitable mosquito larval habitats turning them into highly productive breeding grounds. The sustained elevated temperatures accelerated brood development and also reduced the time it takes for the virus to infect the host reservoirs and mosquito vectors.

    We have some experience with WNV here in CT and it will take  time for the TX public health network to develop a fully coordinated response system. Fortunately, they can benefit from the experiences of others while we get used to endemic WNV and prepare for other emerging infectious tropical diseases to arrive in the US as our climate becomes suitable for them and their vectors.

    As you investigate the planned public health response to this outbreak in depth, I believe you may appreciate exactly what these professionals were dealing with. A decision to deploy a wide area aerial mosquito adulticide application is not made lightly and never doubt that it did save a significant number of lives. There is a tremendous amount of effort and resources required to conduct such an operation and it is always done under the extreme pressures of an emergency response. Several weeks worth of work is compressed into a 2 or 3 day schedule with many people working around the clock to prepare for it. Aerial applications are regarded as a last line of defense in public health mosquito management and only used when it is considered absolutely necessary.

    I followed the WNV outbreak in TX this summer on a professional level and have some detailed knowledge of the vector management response, including a briefing on the aerial application operation. The contractors hired to perform the aerial application are highly qualified and conduct an operation that is well refined by experience. You may be surprised by the level of sophistication used in controlling the application coverage on target and the ground monitoring to ensure the integrity of any no spray areas was maintained. These were not the crop dusters the local TV news stations kept showing in the run up to hype the spraying.

    Hopefully, the city and county vector management districts will develop a comprehensive integrated management program that promotes monitoring and source reduction in the larval habitats, using cultural and biological controls as a first line. There are more effective and less invasive techniques for managing localized mosquito infestations before they increase in number and become widespread. Truck mounted and aerial adulticide applications should be reserved for last line options. You can play an important role in encouraging political support for the sustained funding necessary to maintain a comprehensive program to avoid the knee-jerk reaction of throwing a pile of money at an emergency.

    I'll look forward to your updates in the weeks ahead.

    "Life is tough. It's even tougher if you're stupid." --John Wayne

    by Sonofasailor on Sat Dec 29, 2012 at 11:16:26 PM PST

    •  Heh. You anticipated my next diary (0+ / 0-)

      It is, indeed, drought conditions and the black area has a huge lake that was impacted by the drought (and the predators couldn't get to the larva and eggs.)

    •  And by the way, thanks for your comments! (0+ / 0-)

      You're right that this area is completely unprepared for it and they're acting in panic mode.  The city isn't thinking long-term, and that's one of the big problems -- they're in knee-jerk mode.

      (Your comments will be brought back to the citizens committee, as will those of my other DKos commenters.  Perhaps together we can all do some good.)

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