Paramyxoviruses are well-known pathogens of the central nervous and respiratory systems of many host species. In the last few decades, many novel paramyxoviruses have emerged causing devastating illnesses in different aquatic and terrestrial animals, including in some cases a species jump to humans . Parainfluenza virus type 3 (PIV3) is an enveloped, single-stranded negative sense RNA virus within the Respirovirus genus of the Paramyxoviridae family [2, 3]. The Respirovirus genus includes human parainfluenza virus types 1 and 3 (HPIV1 and HPIV3, respectively), Sendai virus (murine PIV1) and bovine parainfluenza virus type 3 (BPIV3) . In some instances when animals are subjected to high stressful conditions, infection with BPIV3 can contribute to tissue damage and immunosuppression, resulting in severe bronchopneumonia from secondary bacterial infections . The resulting disease is part of the bovine respiratory disease complex (BRDC) and is considered as the most significant illness associated with feedlot cattle in the USA , and possibly worldwide. Other respiratory viruses such as bovine herpesvirus 1, bovine viral diarrhea virus (BVDV) and bovine respiratory syncytial virus (BRSV) have also been associated with BRDC development in feedlot cattle . The clinical presentation of bovine infections with BPIV3 can vary considerably, ranging from asymptomatic infections to severe respiratory illness. In most cases where BPIV3 is implicated in disease, usual clinical signs include coughing, fever and nasal discharge .
Three genotypes, A (BPIV3a), B (BPIV3b) and C (BPIV3c) have been described, based on genetic and phylogenetic analysis . The BPIV3b genotype could hypothetically be a lineage from a strain that recently crossed from another host species into cattle . PIV3 infections were found in a wide variety of mammals including cattle, humans, sheep , goats , bison , guinea pigs , black and white rhinoceros , moose , bighorn sheep  and camels . Cross-species infections have been reported in numerous instances, including HPIV-3 in guinea pigs , BPIV3 in a human, BPIV3 in sheep, and ovine PIV3 in cattle . In Argentina, serological studies conducted in 1980 and 1984 showed a high incidence of antibodies against BPIV3 (77%) in cattle from the main livestock breeding regions [18, 19]. In addition, positive serology was reported in domestic and wild South American camelids [20–22] and the virus was isolated from cattle and sheep . However, little is known about the circulation of BPIV3 in cattle and other ruminants in Argentina, as well as about the genotypes that are present in this Southern American country.
Production systems have evolved to mixed managements, where alternative production species, such as the water buffalo (Bubalus bubalis), coexist in the same habitat as with cattle. Water buffalo breeding represents an important economic alternative in Argentina, which allows access to national and international markets. This species is susceptible to several viral infections [20, 24, 25] including BPIV3 as reported in a very early in 1966 in Egypt . In addition to its potential relevance with respect to water buffalo health, this finding bears epidemiological significance due to the risk of transmission of the virus to cattle. The aim of this study was to characterize antigenically and genetically BPIV3 isolates from a respiratory and reproductive syndrome outbreak in dairy buffaloes and compare the buffalo isolate with contemporaneous BPIV3 circulating in cattle.