Molecular detection of paramyxovirus and coronavirus in fecal samples of shorebirds from Southern Brazil.

Wild birds are an important source of viral infection since it is considered a reservoir for a number of viruses, such as Paramyxovirus and a range of Gammacoronavirus and Deltacoronavirus. Avian paramyxovirus 1 (APMV-1), the causative agent of Newcastle Disease (ND), poses significant threats to both wild and domestic avian populations. Gammacoronaviruses, such as the Infectious Bronchitis Virus (IBV), primarily affect poultry, leading to respiratory, enteric, reproductive, and neurological disorders. The aim of this study was to monitor the presence of paramyxovirus and coronaviruses in shorebirds in the middle coast of southern Brazil, between May and December of 2023, by analyzing fecal samples for the presence of viral genome. Two hundred and eighty-nine fresh fecal samples were collected monthly between May and December of 2023 in the middle coast of Rio Grande do Sul state, Brazil. RNA was extracted from the samples following the protocol of PREVIR and cDNA was synthesized. All samples were screened for APMV-1 M gene by qRT-PCR and for the RdRp gene of coronavirus by nPCR. Positive samples were confirmed by Sanger Sequencing. Five samples out of 289 (1.73%/100%) contained APMV-1 RNA, while all samples were negative for coronavirus RNA. APMV-1 RNA was detected in feces of the American Oystercatcher (Haematopus palliatus) (1/5) and Kelp Gulls (Larus dominicanus) (2/5). To our knowledge, this is the first report of APMV-1 infection in American Oystercatcher and Kelp Gulls. Although at a low frequency, we demonstrate the presence of APMV-1 in the coast of Brazil, posing a risk of infections in an area in South Brazil which is visited by thousands of wild birds each year during migration. These studies should continue in order to keep surveillance and anticipate outbreaks which could impact both wild and domestic birds health.