Veterinary session

In recent decades, the number of pets has been steadily increasing due to changes in animal husbandry practices. At the same time, urbanization has also provided new habitats and food source for an increasing number of wildlife species in urban environment. While certain corvids (Passeriformes: Corvidae) were previously found primarily in villages, farms and agricultural areas, they are now commonly seen in parks and house yards alike. Based on these environmental changes, the primary goal of our research was to investigate whether some urbanized corvids could potentially serve as sources of protozoan parasitic infections in pets.

In the present study, samples were collected from the brain tissue and oral cavity (oral swab) of 285 individuals. Most of the birds were exterminated for population control around Liszt Ferenc International Airport Budapest and around Dömsöd. The majority of samples originated from Magpies (Pica pica; n = 279), in addition, from some Eurasian Jays (Garrulus glandarius; n = 4) and Hooded Crows (Corvus cornix; n = 2). DNA was extracted from the samples using the QIAamp DNA Mini Kit followed by conventional PCR analysis, and the positive samples were sequenced.

The presence of Toxoplasma gondii (Apicomplexa: Sarcocystidae) in the brain tissues of 10 Magpies was successfully justified. Based on a long sequence of the 18S rRNA gene, this genotype was 100% identical to the highly pathogenic RH and ME49 strains. Another 9 Magpies tested positive for a Lankesterella sp. (Apicomplexa: Lankesterellidae). Among these samples the genotype sharing the same 18S rRNA sequence matched only 98.7% (1021/1034 bp) to the closest genetic variant in the GenBank database (from Common Whitethroat), therefore it probably represents a new species. Based on the PCR targeting Trichomonadida, oral swab samples of 8 Magpies showed positivity. Co-infection was not proven in any of the birds.

Our results show that the increasing presence of corvids in urban environments may provide opportunities for the spread of certain protozoan parasites. Among these, Toxoplasma infection of Magpies can arise from feces of cats or the consumption of intermediate hosts, in addition, dogs and cats can also get infected from infected magpies as prey animals. However, the newly detected species of Lankesterella appears to be host-specific, thus companion birds (e.g. in aviaries) are not at risk from eating vectors that suck blood from infected magpies.