Abstract
Dogs implicated in zoonotic transmission of numerous pathogens as Francisella tularensis that endemic among most countries; however, no previous or recent Iraqi evidences. The aims of study to molecular investigation of F. tularensis in stray dogs, sequencing and phylogenetic analyses of study isolates, and serological evaluation of immunity in positively and negatively infected cases. A total of 87 stray dogs were subjected to collection of venous blood samples that tested molecularly by the conventional polymerase chain reaction to estimate the incidence rate of F. tularensis, and serologically by specific quantitative enzyme-linked immunosorbent assay to measurement the concentrations of immune markers. Additionally, DNAs of positive dogs were sequenced, submitted in the NCBI-GenBank database, and analyzed phylogenetically to indicate the relationship of study isolates with the global NCBI-BLAST isolates / strains. Molecular data revealed that the incidence rate of F. tularensis infection was 17.24%. Sequencing data and phylogenetic analysis of all positive F. tularensis isolates detected its identity to the global NCB-BLAST F. tularensis Italian strain (MG432686.1) at a rate of similarity ranged from 98.64% to 100%. In comparison to negatives, the findings of positive dogs to F. tularensis infection were shown a significant elevation in values of IFN-α and IL-6 but a marked reduction in values of IL-1, IL-10, and TNF-α. However, insignificant variation was observed in values of IL-8 and TNF-. This might represent first study in Iraqi and Asian of the dog which demonstrated molecularly the incidence rate of F. tularensis and confirmed phylogenetically the identity of study isolates to global NCBI-GenBank F. tularensis isolates / strains. Also, the present study identified serologically variation in levels of immune response among the positively and negatively infected animals. Thus, moreover molecular phylogenetic studies are greatly required in dogs as well as other animals and humans throughout various Iraqi areas.

Key words: Canine febrile diseases, Deer fly fever, Iraq, Rabbit fever; Tularemia