Progress 05/12/05 to 09/30/07
Outputs
A population study of the Gulf Coast tick was conducted using a 303 base pair region of the 16s mitochondrial ribosomal DNA gene for genetic comparison. There is both geographic and seasonal variation exhibited by this tick species across the Southeastern US, and potential genetic diversity could be associated with these and other factors influencing vector capacity of livestock and human disease pathogens. Ticks collected through the National Tick Surveillance Program consisted mostly of specimens from Texas with small numbers from other states, thus field collections by project personnel and collaborating scientists in other states were also used. A portion of the legs of each specimen was used in the preparation of PCR product for the Single Strand Conformation Polymorphism (SSCP)procedure used to analyze the 16s mt rDNA gene. Haplotypes were compared to references previously identified from Gulf Coast ticks specific to locations in Texas, Oklahoma, Kansas, and
Georgia. Livestock census data were collected from each Gulf Coast state and information from wildlife agencies and other sources were compiled to develop information layers on tick host distribution and densities. Information from these studies were presented before the US Animal Health Association, Committee on Parasitic Diseases, and before the Animal Health Committee, subcommittee on exotic diseases, National Cattlemans Beef Association.
Impacts
Results from this project found no new haplotypes among the Gulf Coast tick specimens tested. Tick collected in Texas were expanded to include those from horses and canines, as well as cattle. There were no statistical differences in haplotype frequencies among these host groups for the eastcentral region surveyed. Ticks from Florida exhibited a unique set of haplotypes that were identical to ticks previously tested from Geogria and are different from those in Texas, suggesting that more information is needed from the eastern distribution and the potential for regional variation remains. An outcome of this discovery was a collaborative proposal with Florida to study the genetic variation of this tick species under the USDA, T-Star program. An additional outcome is the interest of scientists at the CDC who are studying human cases of rickettsiosis identified as Rickettsia parkeri, vectored by the Gulf Coast tick. The impact of these studies has increased awareness and
interest of other scientists interested in livestock and human diseases thought to be vectored by the Gulf Coast tick.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
The protocol for DNA extraction and PCR has had to be modified for sample degradation due to alcohol preservation of tick specimens. The modified protocol is being used to test an aged population of ticks in storage with recently collected ticks all from Texas.
Impacts
The Gulf Coast tick is a potential vector of heartwater, an exotic disease of ruminant livestock and wildlife that threatens entry to the US. This study will examine the geographic diversity of the Gulf Coast tick in the Southeastern region of the US and associate that diversity with ecological and epidemiological factors that would improve tick suppression strategies and/or tick surveillance.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
The known haplotypes of the 16s ribosomal gene associated with Gulf Coast ticks from specific sites in Texas, Oklahoma, and Kansas are being developed for reference markers to compare to ticks collected throughout the region. A data file and map of all Gulf Coast tick collections in the Southeastern region were compiled and used to establish a stratified sampling protocol for selection of specimens for molecular analysis. Testing is ongoing.
Impacts
The Gulf Coast tick is a potential vector of heartwater, an exotic disease of ruminant livestock and wildlife that threatens entry to the US. This study will examine the geographic diversity of the Gulf Coast tick in the Southeastern region of the US and associate that diversity with ecological and epidemiological factors that would improve tick suppression strategies and/or tick surveillance.
Publications
- No publications reported this period
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