Gastrointestinal parasites of pigeons (Columba livia) in Nawala, Sri Lanka: A comparative coprological analysis between feral and racing pigeons

Pigeons are an integral part of the urban ecosystems and play significant roles in many environmental and historical aspects. Their domestication and distribution ensure greater interaction with humans and livestock, consequently posing threats due to numerous parasitic infections they harbour. Given the potential health risks and their veterinary relevance, this study examined the prevalence and diversity of gastrointestinal (GI) parasites in feral and racing pigeons in Nawala, Sri Lanka, using a descriptive cross-sectional design. In the 60 faecal samples examined, 10 genera of GI parasites were identified, including protozoans, nematodes, a trematode, and a cestode. Eimeria, Heterophyes, Ascaridia, Capillaria and Heterakis were demonstrated in both feral and racing pigeons. Isospora, Choanotaenia, Acuaria, and Tetrameres were reported only from ferals, while Trichostrongylus was observed exclusively in racing pigeons. A total of 76.7% pigeons were infected with GI parasites. The overall parasite prevalence among ferals was 83.3%, compared to 70% in racing pigeons.  Though parasite prevalence did not significantly differ between the two groups (p = 0.227), protozoan (OR = 15.17, p < 0.001), trematode (OR = 6.5, p = 0.04), and mixed (OR = 3.0, p = 0.04), infections were more likely among ferals. To our knowledge, this is the first report on pigeon GI parasites in Sri Lanka. The study demonstrates that both feral and racing pigeons harbour protozoan and helminth parasites, suggesting that they could be a potential source of infection for other closely associated avian and human hosts. The research also reveals that parasite prevalence and co-infection dynamics are affected by poor hygiene conditions in pigeon lofts.