DNA Prevalence of Eukaryotic Parasites with Zoonotic Potential in Urban-Associated Birds

Abstract

Synanthropic birds might play an important role as reservoirs of many zoonotic endoparasites; however, little information is available on many parasites and their prevalence. Here, we use an approach based on targeted metagenomic detection through the use of DNA metabarcoding of faecal samples to screen for circulating parasites in alien parakeets (Myiopsitta monachus and Psittacula krameri) and urban landfill-feeding storks (Ciconia ciconia) and gulls (Larus fuscus). We focus especially on potentially zoonotic parasites, with the aim of better understanding the zoonotic risk that these birds’ faeces may pose. We detected a total of 23 genera of eukaryotic parasites: six fungi, three protists, five nematodes, two cestodes and seven trematodes. Among them, six stood out for their relevance to human health: Cryptococcus spp., Aspergillus spp. and Candida spp. (fungi); Cryptosporidium spp. (a protist); and Ascaris spp. and Halicephalobus spp. (nematodes). In parakeets, we detected Cryptococcus spp. and Ascaris spp., the latter being detected in 10–20% of the samples. In the White Stork and the Lesser Black-backed Gull, we found a high prevalence of Aspergillus spp. (in 15% and 50% of the samples, respectively) and Candida spp. (in 63% and 82% of the samples, respectively), and the presence of Cryptosporidium spp. in 10% of the samples. We detected Halicephalobus spp. in one gull sample (2%). Our results show that synanthropic birds may act as vectors and reservoirs of zoonotic parasites and their faeces could pose a risk to human health associated with the zoonotic parasites present in them. This should be taken into account when developing management plans for urban populations of these bird species.