Topic: Community ecology and disease risk: lizards, squirrels, and the lyme disease... in CA
Melanie Reber
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Salkeld DJ, Lane RS Community ecology and disease risk: lizards, squirrels, and the lyme disease spirochete in California, USA. [Journal Article, Research Support, N.I.H., Extramural] Ecology 2010 Jan; 91(1):293-8.
Vector-borne zoonotic diseases are often maintained in complex transmission cycles involving multiple vertebrate hosts and their arthropod vectors. In the state of California, U.S.A., the spirochete Borrelia burgdorferi, which causes Lyme disease, is transmitted between vertebrate hosts by the western black-legged tick, Ixodes pacificus.
Several mammalian species serve as reservoir hosts of the spirochete, but levels of tick infestation, reservoir competence, and Borrelia-infection prevalence vary widely among such hosts. Here, we model the host (lizards, Peromyscus mice, Californian meadow voles, dusky-footed wood rats, and western gray squirrels), vector, and pathogen community of oak woodlands in northwestern California to determine the relative importance of different tick hosts.
Observed infection prevalence of B. burgdorferi in host-seeking I. pacificus nymphs was 1.8-5.3%, and our host-community model estimated an infection prevalence of 1.6-2.2%. The western gray squirrel (Sciurus griseus) was the only source of infected nymphs. Lizards, which are refractory to Borrelia infection, are important in feeding subadult ticks but reduce disease risk (nymphal infection prevalence). Species identity is therefore critical in understanding and determining the local disease ecology.
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Pinelady
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Interesting articles Miss Melanie. I have studied a lot of lizards around here
It would be interesting if they could find out more about the lizard things they know and suspect.
Such as could a population be rendered borrelia free by feeding on a Bb immune lizard. Like I suspect why possum may show immunity.
-------------------- Suspected Lyme 07 Test neg One band migrating in IgG region unable to identify.Igenex Jan.09IFA titer 1:40 IND IgM neg pos 31 +++ 34 IND 39 IND 41 IND 83-93 + DX:Neuroborreliosis Posts: 5850 | From Kentucky | Registered: Dec 2008
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Melanie Reber
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Hmmm, like fried lizard? Hey, if it would work... I would be the first in line! Posts: 7052 | From Colorado | Registered: Mar 2003
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hshbmom
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Dr. Kerry Clark of the University of North Florida
Dr. Kerry Clark, Lyme disease researcher and Associate Professor of Epidemiology and Environmental Health at the University of North Florida, began collaborating with Dr. Jim Oliver in the 1990's.
Dr. Clark's studies led to the first isolation and characterizations of B. burgdorferi in South Carolina (24). He has since documented the presence of three separate Lyme Borrelia species infecting ticks, lizards and small mammals in Florida and South Carolina (25; 26).
Dr. Clark was the first ever to report finding Lyme disease spirochetes infecting wild reptiles, finding Bb in 8 of 9 lizard species from southeastern states (26).
Clark's work, published in 2005, was a breakthrough in understanding the ecology of Lyme disease in the Southeast. Prior to this, many in the scientific community assumed that we couldn't have much Lyme disease here because studies have documented that the blood of a few species of lizards kills a few strains of B. burgdorferi.
The hypothesis was that because ticks often feed upon lizards in the South, the lizard blood helped to halt the infection's transmission cycle here. While this may be true of some species of lizards, many researchers and public health officials seemed to jump on the bandwagon and assumed that the blood of all lizard species kills all Lyme spirochetes.
These assumptions seemed to be made even about strains that haven't been cultured and studied yet. Dr. Clark's research proved that many lizard species in the Southeast can, indeed, harbor Lyme disease bacteria, and for long periods of time.
(His research showed evidence of Bb transmission from broad-headed skinks to feeding larval ticks five months after infection.) Other studies have since documented similar findings in lizards (27; 28; 29).
This important work helps explain the enzootic transmission cycle of the spirochete, or how the Lyme disease bacteria may be maintained in nature, here in the Southeast.
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Melanie Reber
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Hey there Miss Alabama,
Your work above is very accurate. I know that in CA, it is the Western Fence Lizard (Sceloporus occidentalis)that seems to have all the anti-bugg properties. Whereas, the Western Grey Squirrel is highly infested with Bb. Robert Lane has been studying them both for a long time.
Posts: 7052 | From Colorado | Registered: Mar 2003
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I heard Bob Lane say that maybe up to 80% of the squirrels are infected here. If that's true, that's pretty high. I hope they don't feel sick.
Add one more lizard that reverses Lyme: the southern alligator lizard, with a range of Washington State through N Baja California.
When ticks feed upon these lizards, there's a protein complement in lizard blood that kills bacteria in the tick's gut.
And yes, I think most of us have asked Bob Lane the million dollar lizard question about whether they could help us out,
but so far, do not expect any lizard burgers on the horizon - the protein complement effectiveness does not appear to jump species.
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Melanie Reber
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Hello Miss Robin, Yes, that 8 out of 10 figure came up in the lecture I saw too. Interesting about the Southern lizard. Now I HAVE eaten alligator, and it is rather good (in a chicken sort of way). Posts: 7052 | From Colorado | Registered: Mar 2003
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Pinelady
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Do they have some kind of bacteria that inhibits it from growing in the possum or just prevents it from being able to be seen on testing.
Or is it that the species of ticks the possums carried-Dermacentor variabilis was the only tick species found on opossums.
Prevalence of B. burgdorferi by tick species was 24.4% (141/577) in D. variabilis, 40.6% (13/32)
You would think with such high prevalence in ticks-they could have at least got some positive.
And I was wondering about the reported immune lizards. If it could be the same.
-------------------- Suspected Lyme 07 Test neg One band migrating in IgG region unable to identify.Igenex Jan.09IFA titer 1:40 IND IgM neg pos 31 +++ 34 IND 39 IND 41 IND 83-93 + DX:Neuroborreliosis Posts: 5850 | From Kentucky | Registered: Dec 2008
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Pinelady
Frequent Contributor (5K+ posts)
Member # 18524
-------------------- Suspected Lyme 07 Test neg One band migrating in IgG region unable to identify.Igenex Jan.09IFA titer 1:40 IND IgM neg pos 31 +++ 34 IND 39 IND 41 IND 83-93 + DX:Neuroborreliosis Posts: 5850 | From Kentucky | Registered: Dec 2008
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