Molecular Characterization of the Horn Fly Haematobia irritans Infesting Horses in Central Anatolia Region in Turkey.

The study examines the horn fly infestations present in horses raised in the Sultan Marshes wetland ecosystem in Central Anatolia, Turkey. It identifies the flies as a unique type of Haematobia irritans, through morphological identification and sequence analyses of the mitochondrial cytochrome oxidase I gene.

Study Design and Collection of Specimens

• The research focused on seven horses that were raised together and each was found to host over 500 horn flies.
• A total of 376 fly specimens were collected using nets for further laboratory examination and species identification.
• This large sample size allowed for a wider understanding of the scope and nature of the infestation.

Morphological Identification

• All collected flies were examined and identified based on their physical characteristics.
• It was determined that all flies were adults of the species Haematobia irritans, commonly known as horn flies.

Mitochondrial Cytochrome Oxidase I (mt-COI) Gene Analysis

• Partial fragments of the mt-COI gene from a subset of 50 isolates were amplified to perform sequence and phylogenetic analyses.
• The analysis showed no genetic variation among the isolates, indicating that they all belonged to the same unique sub-strain of Haematobia irritans.

Haplotype and Nucleotide Diversities

• The researchers determined the mean haplotype and nucleotide diversities within the mt-COI data set of H. irritans.
• These measurements allow us to understand the genetic diversity within a species population. In this case, H. irritans showed a mean haplotype and nucleotide diversities of 0.8571 and 0.00695, respectively.
• The newly identified fly haplotype from Turkey differed genetically by 1.0 compared to all other published sequences of isolates from various countries.

Comparison with Haematobia exigua

• The mt-COI dataset also allowed for a comparison between the genetic difference of H. irritans and another species, namely Haematobia exigua.
• It was found that there is a mean interspecific genetic difference of 1.7, which gives us insights into the evolutionary distance between the two species.

The research provides valuable insights into the horn fly populations affecting horses in Central Anatolia, which can help develop effective control measures. The identification of a unique haplotype for H. irritans also contributes to our broader understanding of the species genetic diversity globally.