First molecular identification and phylogenetic analysis of <i>Neospora caninum</i> in dogs from Sulaymaniyah province, Iraq

Abstract Introduction Neospora caninum is a cosmopolitan intracellular coccidian parasite causing paralysis and neuromuscular problems in dogs, as well as abortion in cattle. This study investigated the molecular prevalence of neosporosis in Sulaymaniyah, Kurdistan, Iraq, and characterised the genetic diversity of the N. caninum Nc5 gene in isolates from that region. Material and Methods From July to December 2024, a study was conducted in Sulaymaniyah province in which 258 canine blood samples were collected and analysed for N. caninum infection. Conventional PCR and Nc5 gene sequencing were used to detect the parasite and assess its genetic diversity. Results The rate of infection with N. caninum was 3.87% and the disease was significantly (P &lt; 0.05) higher in stray dogs (6.38%) than in kept dogs (0.85%), in dogs (6.45%) than in bitches (1.49%) and in adults (6.30%) than in juveniles (1.52%). Analysis of partial Nc5 gene sequences from the protozoa resulted in the isolation and identification of 10 local isolates in the study region. Six of these isolates matched sequences previously deposited in GenBank, while four novel isolates, characterised by six new mutations, were identified for the first time in the research area. Phylogenetic analysis indicated a close relationship between N. caninum isolates from different countries. Conclusion The current research provided a useful molecular dataset for N. caninum species, which is crucial for the assessment of phylogenetic associations and the molecular identification of these protozoans.