I agree that this is on-topic for us. There is more to this issue than the surface would indicate and their has been a little hysteria in both camps. The attached links will help us get to the real scoop and come to a sensible decision on this. While the Anti-chemical position is absurd by definition, it does appear that we are overreacting to West Nile Virus. More people have drowned in their own swimming pools this year than have succumbed to WNV in the previous five. Please see the two attached links and the letter that follows.
Nicola Cataldo http://www.cdc.gov/ncidod/dvbid/westnile/insects.htm http://www.cdc.gov/ncidod/dvbid/westnile/mosquitoSpecies.htm ----- Original Message ----- From: Maryann Whitman To: [EMAIL PROTECTED] Sent: Wednesday, April 16, 2003 11:49 AM Subject: RE: [vernalpool] Re: Mosquito control I thought some of you might appreciate reading the information below on mosquitoes and West Nile Virus. NB: something that is not mentioned by Dr Walker in this letter that he mentions elsewhere is that the bird-feeding species of Culex, feed 15-30 feet above ground, ie in the nesting area of birds. That they are not frequently found at ground level may be related to why they don't typically bite humans. Maryann Whitman, southeast Michigan, am learning a lot about vernal pools from this list-serve ```````````````````````````````````````````````````````````````````````````` ```````````````````````````````````````````````````````````````````````````` ``````````````````````````` Hello Ms. Whitman, Our research in Michigan, and that elsewhere, shows that of all the mosquito species we have in the temperate areas of the eastern United States, certain species of Culex are important vectors of West Nile virus. In particular, Culex pipiens and Culex restuans have the highest infection rates amongst all mosquitoes sampled from the field, and tested for virus infection by virus isolation, antigen captures methods, or by PCR. Both of these species of mosquitoes feed primarily on birds, so whether indeed they can "bridge" the virus to humans by biting humans is unclear. They are very rare in human biting collections, but evidence from a New York city study suggests that a small proportion of their populations in late summer and early fall do indeed bite humans and other mammals. Thus, WNV transmission to humans could occur this way, but the data for a firm conclusion are weak. Whether Culex transmission alone could explain the 644 confirmed cases of West Nile virus infection in Michigan from 2002 is hard for me to believe. This is further complicated by an urban "form" of Cx. pipiens called Culex molestus, which does not require blood meals for egg production, but may occasionally take them and then from mammals and birds. I know very little about the status of this species in Michigan. It would be important to study. Culex salinarius is a fourth species that is also important as it will bite both birds and mammals including humans. However, it is very spotty in Michigan and we know little about where it occurs in the state, or how frequently it bites people in the areas where it does occur. From its name, you can see that it is associated with saline habitats as larvae, and of course in parts of Michigan where salt mining and brine pumping were part of the historical industrial development of the state, this species may be common (e.g., downriver Detroit; Midland area; etc.). I have collected it in Michigan and have been bitten by it, in SE Jackson County. The observations above then beg the question: what other mosquitoes might be involved as bridge vectors? These would be those species that can and will bite birds (and in doing so acquire virus infection) and at a later blood feeding transmit the virus to a human or other mammal such as a horse. Such species as Aedes vexans, Coquillettidia perturbans, or Ochlerotatus trivittatus might qualify. We had WNV positive detections in all of these species last summer, but only one each. Because many birds that acquire infection by mosquito bite run very high viremias and become very sick before they die, they are vulnerable to mosquito bites owing to their loss of anti-mosquito behaviors. Crows for example fall and flop to the ground for a few days before they die. So, I think the virus cycle is maintained by Culex-bird-Culex-bird transmission through the course of the summer. As birds get sick, they become vulnerable to feeding by other species of mosquitoes, which then at later blood feedings may (by chance) bite people. I hope these comments are useful to you. Sincerely, Ned Walker Edward D. Walker, PhD Associate Professor Dept of Microbiology and Molecular Genetics 2215 Biomedical Physical Sciences Michigan State University East Lansing, MI 48824-4320 office: Room 6169 517-355-6463 x1595 lab: Room 6154 517-355-6463 x 1589 fax: 517-353-8957 email: [EMAIL PROTECTED] -----Original Message----- From: ohop [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 15, 2003 9:09 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: [vernalpool] Re: Mosquito control Culex sp, correct? ---------- Original Message ---------------------------------- From: "Karro A Frost" <[EMAIL PROTECTED]> Reply-To: [EMAIL PROTECTED] Date: Tue, 15 Apr 2003 15:48:48 -0400 >I remember hearing a story last year on the WNV on NPR. It seems that the >mosquito most likely to carry it is a common "house" mosquito - one that >breeds in containers around homes, not one that breeds in our wetlands >(including vernal pools). I do notice that some pools have more mosquito >larvae and some fewer - definitely the most are found in pools where there >are no other inverts to be found. The spraying of pesticides is very >aggravating. > >Karro > -----Original Message----- > From: Jennifer Ohop [mailto:[EMAIL PROTECTED] > Sent: Tuesday, April 15, 2003 2:21 PM > To: [EMAIL PROTECTED] > Subject: [vernalpool] Re: Mosquito control > > > I just wanted to add a few things on the BTI Discussion. I had researched > this topic in response to an editorial in our local newspaper. It seems >the > editor of the local paper has some unrealistic fear of death from West >Nile > and called for our rural towns to spend thousands of dollars (which we >don't > have) to spray. > > BtI is a microbial insecticide, the active ingredient is a microorganism. > The bacterium destroys the lining of the gut of the mosquito larvae. It >is > considered, to date, "safe" by the EPA > > One thing I am very curious about is what vector they are using to deliver > the BTI into the environment, that is to say, what are the "Inert" > ingredients? > > I recall that it is a common practice to spray BTI, but then use >methoprene > or some other larvicide in detention basins. > > What sorts of effects will this have on our wetlands? I guess we will >find > out. One paper (Effects of BTI on nontarget macroinverts in MN wetlands, > Hershey et al in Ecological Applications, 8(1)1998) states "detecting > negative treatment effects on the invert community required a 2-3 year lag > time, depending on the taxon" and " three years may not be adequate to >fully > evaluate the importance of these changes to vertebrate species because >they > are likely to have longer response times" > > The authors point out that overall diversity of insect species at the BTI > study sites went down, while individual species became dominant at that > site. Isn't it ironic that we celebrate biodiversity days while we work >to > eliminate it from our wetlands? > > I find it very, very aggravating that people are using West Nile paranoia > excuses to spray for mosquitoes. At a time when we are cutting gym, music > and libraries from our school budgets, $50,000 is an awful lot of money > spent to kill bugs! Less than one percent of people infected with WNV will > develop severe illness, mostly the very old or very young. If you can't > take a few bites, than go inside and watch tv! > > I have noticed that the healthy woodland pools here have less mosquito > larvae in them, percentagewise, than the pile of old tires I found off a > dirt road the other day. > > My two cents- > > Jen Ohop > > > > ----- Original Message ----- > From: "dennis.panu01" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Tuesday, April 15, 2003 1:16 PM > Subject: Re: [vernalpool] (no subject) > > > > I heard an unsubstantiated report from a friend that Cambridge MA has > > stopped the practice of putting donuts in storm drains because the > pesticide > > was detected in tidal marshes (where all the storm drains drain) and > causing > > off target kill. This might just be a rumor but it emphasizes why we > treat > > even non-toxics (to us!) as pesticides. > > > > Dennis Panu > > > > Dennis Panu > > ----- Original Message ----- > > From: "Carol Childress" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Tuesday, April 15, 2003 10:18 AM > > Subject: Re: [vernalpool] (no subject) > > > > > > > Yes, that's why they can throw pesticide donuts into the storm sewers, > > which > > > in most cases, empty into our lakes and ponds. This is also good > practice, > > > no? > > > > > > Carol Childress > > > > > > ----- Original Message ----- > > > From: "Matt Burne" <[EMAIL PROTECTED]> > > > To: <[EMAIL PROTECTED]> > > > Sent: Tuesday, April 15, 2003 7:56 AM > > > Subject: Re: [vernalpool] (no subject) > > > > > > > > > > Mosquito control is exempt from the Wetlands Protection Act, so your > > > > commission may well be unaware of the spraying. That's why they can > > > > ditch and drain vernal pools, and other good wetlands practices. > > > > > > > > Matt Burne > > > > > > > > [EMAIL PROTECTED] wrote: > > > > > > > > >The warm sun brought out both wood frogs and aerial mosquito >sprayers > > > > >today(!!!!!). > > > > > > > > > >Helicopter spent a few hours thoroughly spraying a several hundred > acre > > > swamp > > > > >that is a major part of our water supply...........I'm checking >with > > > ConCom > > > > >to see what the sprayed and what process they went through for > > > permission. > > > > > > > > > >Heard the most clucking of wf today so far this season, but still >not > > > alot. > > > > >Did find wf eggs in one pool, (sal. eggs in every pool, but not >large > > > > >numbers) and wf calling at two others. Last year wasn't a good year > for > > > them > > > > >either here in Scituate. With a life span of 2-3 years I wonder how >a > > > couple > > > > >of bad years affect the population. > > > > > > > > > >2 years ago I had the pleasure of sitting next to a pool, (or >series > of > > > > >pools), where the wf's had stopped calling when I first arrived. I > sat > > > > >quietly, and the calling resumed, and got so loud and so strong >that > I > > > > >actually had to cover my ears for a minute or two! I also found a > > > correlation > > > > >between wf's that utilize pools right next to the road and their > > > > >"shyness"....flashlights bother them not a bit, and the ones deep >in > > the > > > > >woods go quiet as soon as you turn one on. > > > > > > > > > >Thanks for all the great info everyone. > > > > >Shan Morrissey > > > > > > > > > > > > > > >To unsubscribe from this group, send an email to: > > > > >[EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > >Your use of Yahoo! Groups is subject to > > http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > To unsubscribe from this group, send an email to: > > > > [EMAIL PROTECTED] > > > > > > > > > > > > > > > > Your use of Yahoo! Groups is subject to > > http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > > > To unsubscribe from this group, send an email to: > > > [EMAIL PROTECTED] > > > > > > > > > > > > Your use of Yahoo! Groups is subject to > http://docs.yahoo.com/info/terms/ > > > > > > > > > > > To unsubscribe from this group, send an email to: > > [EMAIL PROTECTED] > > > > > > > > Your use of Yahoo! Groups is subject to >http://docs.yahoo.com/info/terms/ > > > > > > > > > Yahoo! Groups Sponsor > > > > To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > > > Your use of Yahoo! Groups is subject to the Yahoo! 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