Abstract
Introduction: Avian haemoparasites pose significant threats to poultry health and productivity. While microscopy is traditionally used for parasite identification, molecular methods, such as polymerase chain reaction (PCR), offer enhanced sensitivity and specificity. The present study aimed to determine the prevalence of haemoparasites in poultry species in Ibadan, Nigeria, and to compare the diagnostic performance of microscopy and nested PCR for detection and identification.Materials and methods: Blood samples were obtained from 390 healthy birds, including commercial layers chickens (153), turkeys (75), broiler chickens (69), local chickens (60), pigeons (30), and ducks (3), randomly selected from 10 farms in Ibadan, Nigeria. Thin blood smears were Giemsa-stained and examined microscopically. Genomic DNA was extracted and subjected to nested PCR targeting the mitochondrial cytochrome b gene of haemosporidian parasites. Positive amplicons were sequenced and phylogenetically analyzed. Results: The haemoparasites were microscopically detected in 44.6% (174/390) of samples, including Plasmodium (P.) spp. (18.2%), Haemoproteus spp. (15.9%), Leucocytozoon spp. (5.6%), Babesia spp. (2.8%), and microfilariae (2.1%). The PCR detected infections in 53.3% (208/390), confirming P. gallinaceum (12.3%), Haemoproteus spp. (19%), Leucocytozoon spp. (9%), Babesia spp. (3.3%), and additional unidentified haemosporidian lineages (8.7%). The PCR demonstrated significantly greater sensitivity than microscopic analysis. Infections were more prevalent among females (60.3%), adult birds (55.2%), and during the rainy season (54%). Sequencing confirmed the presence of P. gallinaceum as the most prevalent pathogen (97.87-97.94%). Phylogenetic analysis supported the molecular identification and revealed evolutionary relationships among detected lineages. Conclusion: The present study confirmed a high prevalence of haemoparasites in poultry in Ibadan, Nigeria, and underscored the superior sensitivity of PCR over microscopy for detection. The integration of molecular and morphological approaches enhanced diagnostic accuracy and provided deeper insights into parasite diversity and epidemiology.