Abstract
Background:
Borrelia burgdorferi is a Gram-negative bacterium that causes Lyme disease or borreliosis in domestic and wild animals including dogs, with the possible transmission to humans.
Aim:
This study was conducted to investigate the infection rate of Spirochetes and B. burgdorferi in stray dogs in Nineveh province, Iraq.
Methods:
During the period from May to October (2022), a total of 55 stray dogs were selected randomly from different areas in Nineveh province, Iraq. Blood samples were collected from cephalic venous and tested molecularly using the conventional polymerase chain reaction (PCR) technique.
Results:
The present study revealed that the total infection rates of Spirochetes and B. burgdorferi were 41.82% and 27.27%, respectively. Concerning age, values of infection rate, Odds ratio, and relative risk of B. burgdorferi were increased significantly in dogs aged  4 months (42.86%, 3.505 and 2.438, respectively) while decreased in dogs of  1-3 (12.5%, 0.337 and 0.42, respectively) and  3 (13.33%, 0.32 and 0.409) years old when compared to dogs aged 5-12 months (27.27%, 1 and 1, respectively). While concerning dogs sex, a significantly higher infection rate, Odds ratio and relative risk of B. burgdorferi were shown in females (32.56%, 5.495 and 6.792, respectively) compared to males (8.33%, 0.182 and 0.147, respectively).
Conclusion:
To our knowledge, this represents the first Iraqi study on the prevalence of spirochetes, in particular B. burgdorferi, in stray dogs in Nineveh province (Iraq). However, additional studies of B. burgdorferi infection in other animals as well as vectors such as ticks in different geographic areas appear necessary to detect variation in the distribution patterns of infection. In addition, owners and veterinarians should be aware of zoonotic diseases transmitted from wild and domestic animals, in particular those with tick-bite histories.

Key words: Spirochetes, Lyme disease, Borrelia burgdorferi, Tick-transmitted diseases, Iraq