Genome characterization, prevalence and tissue distribution of astrovirus, hepevirus and norovirus among wild and laboratory rats (Rattus norvegicus) and mice (Mus musculus) in Hungary.

Abstract

Rodents including rats are reservoir of several pathogens capable of affecting human health. In this study, faecal and different organ specimens from free-living Norway rats (Rattus norvegicus) (N=18) and faecal samples from laboratory rodents (rats N=21 and mice N=20) collected from different geographic areas in Hungary between 2017 and 2020 were investigated by viral metagenomics and conventional RT-PCR methods. The complete genome of three different RNA viruses, rat astrovirus, rat norovirus and rat hepevirus were characterized and analysed in detail. Rat norovirus was detected in faecal (17.6%, 3/17) and kidney (7.1%, 1/14) samples; rat astrovirus in faecal (23.5%, 4/17) and spleen (13.3%, 2/15) samples, and rat hepevirus in 43% to 67% the faecal, liver, kidney, lung, heart, muscle, brain and blood samples from Norway rats, respectively. Rat norovirus was also identifiable in 5% (1/21) of laboratory rats and rat astrovirus in 40% (8/20) of faecal samples from laboratory mice. Co-infections were found in 28% (5/18) wild Norway rats. The highest RNA viral load of astrovirus (1.81×108 copy/g) and norovirus (3.49×107 copy/g) were measured in faecal samples; while the highest RNA viral load of hepevirus (1.16×109 copy/g) was found in liver samples of Norway rats, respectively. This study confirms the wide geographic distribution and high prevalence of astrovirus, norovirus and hepevirus among wild rats in Hungary with confirmation of different organ involvement of as well as the detection of norovirus and astrovirus in laboratory rats and mice, respectively. This finding further strengthens the role of rodents in the spread of viral pathogens especially infecting human.