Lizards Lessen Lyme Disease
Updated October 09, 2014.
This article is part of the Arthritis Archives.
Dateline: April 21, 1998
University of California at Berkeley scientists may have found the reason there is less tick-borne Lyme disease in California than in the eastern United States, where it was first discovered and given its name.
Scientists have found that ticks who feast on the blood of the common western fence lizard are purged of Lyme disease bacteria within their gut.
It is thought that a protein in the lizard's blood destroys the bacteria that would otherwise thrive in the belly of the tick and would later be transmitted to humans. The protein is yet to be identified.
Robert Lane, an insect biologist at UC Berkeley and his colleague conducted laboratory experiments using young Lyme disease-infected ticks and fence lizards. The ticks are about the size of a poppy seed in the nymphal stage, during which they feed on the blood of the lizards. Commonly found are 30 to 40 ticks at one time sharing the blood of a single fence lizard. Though the infected adult female ticks threaten to transmit Lyme disease to humans, the smaller nymphal ticks are most jeopardous because they are hard to find and also capable of transmitting the disease.
Eight years ago, Lane had determined that lizards appeared immune to Lyme disease even though infested with tick nymphs. His latest research and experiments help explain why.
The experiments first ruled out that antibodies produced by the lizard's immune system could neutralize Lyme disease bacteria.
Test tube experiments revealed that Lyme disease bacteria soaked with lizard's blood died within one hour, compared to samples grown in mouse blood which lasted three days. Researchers heated lizard blood to the boiling point and discovered it no longer killed the bacteria in the test tube. Lab tests showed that after infected nymphs fed on lizards and then metamorphosed into adult ticks, they were no longer infected.
The sum of these results indicates what Lane called a "spirochete-killing factor" which is likely a large protein. Researchers are now attempting to determine the exact nature of the Lyme disease killing protein. Once found, the hope is it will be useful in creating a treatment for the disease.
California health officials have long been both pleased and puzzled by the low incidence of Lyme disease in the state despite an abundance of ticks. Lane reiterates that eastern regions with higher incidence of Lyme disease are areas without fence lizards.
The percentage of infected deer ticks in high Lyme disease areas such as Connecticut is 30 to 60 percent. The percentage of black-legged ticks, the closely related cousins that carry Lyme disease in California, is only 1 to 2 percent and only as high as 6 percent in Mendocino county where Lyme disease is most prevalent in California.
In California, about one in every 200,000 persons is infected with Lyme disease. The rate in Connecticut is 100 times higher.
Lyme Disease Guide To Lyme Disease How To Protect Yourself Against Lyme Disease
Source: San Francisco Chronicle, 4/17/98
First published: 4/21/1998
This article is part of the Arthritis Archives.
Dateline: April 21, 1998
Lizards May Lessen Lyme Disease
University of California at Berkeley scientists may have found the reason there is less tick-borne Lyme disease in California than in the eastern United States, where it was first discovered and given its name.
Scientists have found that ticks who feast on the blood of the common western fence lizard are purged of Lyme disease bacteria within their gut.
It is thought that a protein in the lizard's blood destroys the bacteria that would otherwise thrive in the belly of the tick and would later be transmitted to humans. The protein is yet to be identified.
Robert Lane, an insect biologist at UC Berkeley and his colleague conducted laboratory experiments using young Lyme disease-infected ticks and fence lizards. The ticks are about the size of a poppy seed in the nymphal stage, during which they feed on the blood of the lizards. Commonly found are 30 to 40 ticks at one time sharing the blood of a single fence lizard. Though the infected adult female ticks threaten to transmit Lyme disease to humans, the smaller nymphal ticks are most jeopardous because they are hard to find and also capable of transmitting the disease.
Eight years ago, Lane had determined that lizards appeared immune to Lyme disease even though infested with tick nymphs. His latest research and experiments help explain why.
The experiments first ruled out that antibodies produced by the lizard's immune system could neutralize Lyme disease bacteria.
Lyme Disease Killing Protein
Test tube experiments revealed that Lyme disease bacteria soaked with lizard's blood died within one hour, compared to samples grown in mouse blood which lasted three days. Researchers heated lizard blood to the boiling point and discovered it no longer killed the bacteria in the test tube. Lab tests showed that after infected nymphs fed on lizards and then metamorphosed into adult ticks, they were no longer infected.
The sum of these results indicates what Lane called a "spirochete-killing factor" which is likely a large protein. Researchers are now attempting to determine the exact nature of the Lyme disease killing protein. Once found, the hope is it will be useful in creating a treatment for the disease.
California health officials have long been both pleased and puzzled by the low incidence of Lyme disease in the state despite an abundance of ticks. Lane reiterates that eastern regions with higher incidence of Lyme disease are areas without fence lizards.
The percentage of infected deer ticks in high Lyme disease areas such as Connecticut is 30 to 60 percent. The percentage of black-legged ticks, the closely related cousins that carry Lyme disease in California, is only 1 to 2 percent and only as high as 6 percent in Mendocino county where Lyme disease is most prevalent in California.
In California, about one in every 200,000 persons is infected with Lyme disease. The rate in Connecticut is 100 times higher.
Related Resources
Source: San Francisco Chronicle, 4/17/98
First published: 4/21/1998
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