Chloe Combra
Congratulations to Chloe Combra, this year’s recipient of the Sheriff’s Meadow Foundation award at the Martha’s Vineyard Regional High School science fair. Sheriff’s Meadow sponsors an award as a part of our education program to be given to a student project focused on the environment. This year, the science fair was held virtually. Chloe is a senior and will be attending college next year in the United Kingdom.
Research: Long term investigation of Lyme bacteria infection rates in adult male and female deer ticks (Ixodes scapularis) collected over multiple years from Chilmark, MA, using PCR and molecular markers specific for Borrelia, the bacteria causing Lyme disease in humans.
Lyme disease is the most commonly reported vector-borne illness in the United States. Few areas are as afflicted as the Island of Martha’s Vineyard. My experiment investigates changes in annual Lyme bacterial infection rates in adult male and female deer ticks between the years of 2018-2020, from Chilmark, MA, a small town on the Island of Martha’s Vineyard. A total of 68 adult ticks were collected and documented digitally. Tick DNA, along with potential Lyme bacterial DNA was extracted and analyzed using Polymerase Chain Reaction and molecular markers specific for the OspA gene. The PCR products were subsequently analyzed by gel electrophoresis and ticks infected with the Lyme bacteria identified.
The results from this study indicate that the overall infection rate for both male and female ticks rose between 2018 and 2019 from 35.7% to 55% and stabilized at 55% in the year 2020. More interesting perhaps, is that infection rates in males and females differed significantly as the infection rate of male ticks averaged 31% over the three years while that of females averaged 61%. This long term dataset represents the first ever long-term dataset of Lyme infection rates of deer ticks over multiple years and was compiled in the MVRHS Tick Lab, the only lab on Martha’s Vineyard that tests ticks for the Lyme bacteria.
-Chloe Combra