The first survey of endoparasite infection in the brown rat (Rattus norvegicus) from a synanthropic environment in Hungary.

Urban rats are significant reservoirs of zoonotic endoparasites, posing serious health risks to humans. This study aimed to detect common endoparasites in wild brown rats (Rattus norvegicus) in Budapest, addressing the current lack of endoparasite surveys in Hungary. Carcasses of 131 rats collected following extermination were examined. Three zoonotic helminths were identified: Hymenolepis nana and Hymenolepis diminuta in the jejunum, and Calodium hepaticum in the liver. Additionally, non-zoonotic parasites were detected, including Eimeria spp., Entamoeba muris, Heterakis spumosa, Nippostrongylus brasiliensis, Eucoleus gastricus, Aonchotheca annulosa, Syphacia muris (intestine), and Trichosomoides crassicauda (urinary bladder). Helminth infection prevalence was 83.9 %, with no noticeable differences in prevalence or infection intensity between sexes. These findings highlight the potential public health risk posed by zoonotic parasites in urban rat populations, emphasising the importance of surveillance to mitigate possible human infection. This study demonstrates a practical and economical approach to monitoring urban rat populations. Further large-scale studies are recommended to better understand the parasitic landscape in Hungary's rat populations, leveraging data from rat control programs.