Molecular Detection of Francisella spp. in Blood, Milk, and Ticks Infesting Small Ruminants in Urmia, Iran

Background: Zoonotic diseases pose a significant global health challenge, accounting for over half of all newly emerging infectious illnesses. One such pathogenic agent is the bacterium Francisella tularensis, which causes tularemia, a zoonotic disease spread in the Northern Hemisphere through various means, including tick bites. Unfortunately, there is limited literature on tick-borne bacteria affecting human and animal health. This research confirmed the presence of Francisella spp. in ticks in the Urmia region, highlighting the potential for ticks to act as vectors for transmitting the bacteria to livestock and humans. Materials and Methods: A total of 397 ticks, 315 blood samples, and 241 milk samples were gathered from sheep and goats to screen for the existence of Francisella spp. The nested PCR technique revealed the existence of Francisella spp. 16S rRNA gene in the samples. Results: Blood and milk samples from small ruminants did not show the presence of Francisella spp., but the bacteria were detected in 6 tick pools (n = 79; 7.59%; 95% CI: 3.52%-15.59%). The positive ticks identified were Hyalomma asiaticum 2 (n = 24; 8.33%; 95% CI: 2.31%-25.84%), Hyalomma eagyptum 3 (n = 9; 33.33%; 95% CI: 12.06%-64.58%), and Rhipicephalus sanguineus 1 (n = 15; 6.67%; 95% CI: 1.19%-29.82%) and the presence of Francisella tularensis subspecies holarctica was found to be positive in 3 out of 79 tick pools (3.80%; 95% CI: 1.3%-10.58%). The positive ticks identified in this experiment were female Hyalomma aegyptium (1 out of 3; 33.33%; 95% CI: 6.15%-79.23%), male Hyalomma asiaticum (1 out of 14; 7.14%; 95% CI: 1.27%-31.47%) and female Rhipicephalus sanguineus (1 out of 7; 14.29%; 95% CI: 2.57%-51.32%). Conclusion: The study explored the presence of Francisella species, especially the most dangerous, F. tularensis, in small ruminants and the ticks that attach to them using molecular techniques in the Urmia region of northwestern Iran. The research seeks to improve knowledge of Francisella spp. epidemiology. Understanding the risk of human-livestock transmission of this pathogen is crucial for public health, particularly for individuals working in animal-related fields.