Molecular Identification of Dictyocaulus species Isolated from Cattle and Deer

Winona, Minnesota

The purpose of this study was to determine if there were molecular differences between Dictyocaulus species found in cattle (Bos taurus), white-tailed deer (Odocoileus virginianus), and red deer (Cervus elaphus). Dictyocaulus is a genus of nematode parasites found in the bronchial tree of different organisms including cattle and deer. This lungworm has been found to cause disease, specifically pneumonia and bronchitis in infected animals.1 Molecular differences were determined by looking at the second internal transcribed spacer (ITS2) of ribosomal DNA. The second internal transcribed spacer (ITS2) is a region of the nuclear rDNA gene that is commonly used for phylogenetic analyses at both the genus and species levels. This region of DNA has been proven valuable in determining phylogenetic relationships using comparisons of primary sequences.2 In this study the ITS2 was used to determine phylogenetic relationships and genetic differences between different strains of Dictyocaulus that were found in cattle, white-tailed deer, and red deer from different geographical locations. The DNA samples were extracted using the chelex DNA extraction technique and then amplified using PCR followed by gel electrophoresis to determine if the ITS2 gene region were present in the samples. Amplified products were then cloned to create a large pool of the DNA region. The clones were then analyzed using PCR and gel electrophoresis to visualize and determine if the ITS2 gene was present. If the gene was present, the samples were sequenced and analyzed to determine any genetic similarities or differences between DNA samples within the different host animals. To date, DNA sequences isolated from white-tailed deer harvested in Minnesota were identified as D. eckerti and DNA sequences from cattle in Wisconsin have been identified as D. viviparus. Future research will analyze worms isolated from cattle in Missouri, white-tailed deer from another region in Minnesota and red deer from New Zealand.