Distribution of Leptospira spp. in Norway rat population in Belgrade, Serbia

Abstract

Leptospirosis is a bacterial infection, a disease of global concern which is directly transmittable to humans and animals by many rodents, of which Norway rat (Rattus norvegicus) is one of the most important. The fact that Norway rats are exceptionally adaptable to a variety of habitats, especially to those in close proximity to humans, creates a high risk of bacterial transmission. The idea of this study was to examine the presence of Leptospira spp. bacteria in populations of Norway rat in the broad environs of Belgrade City. Animals were collected predominantly in their urban and suburban habitats over the past three years. The bacterium was identified by molecular analyses of kidney tissues from the collected animals. After homogenization, bacterial DNA was isolated using the commercial isolation kit Quick DNA MiniPrep. Primers and specific sequence probe were used to detect the bacteria in Real Time PCR. A total of 278 specimens of Norway rat were analysed. Samples with the highest concentrations of bacteria were selected for further analysis and sequencing. The analyses included animals of different stages of growth with body weight ranging from 30 to 490 g. Considering the sampling periods (2020, 2021 and 2022), the percentage of Norway rats infected with Leptospira bacteria was steady, ranging between 31.73 and 40 %. In total, bacterial presence was detected in 35.61 % of the animals.