First-time detection of porcine reproductive and respiratory syndrome virus (PRRSV) infection in Uruguay

Abstract

Within the last two decades, several high-impact viruses have emerged in the global swine population, including porcine reproductive and respiratory syndrome virus (PRRSV). In Uruguay, the more recent serological survey for PRRSV and other notifiable diseases such as Aujeszky's disease virus (ADV) and classical swine fever virus (CSFV) dated from year 2000. The main purpose of this study was to update our information on the infection status of PRRSV, ADV and CSFV in Uruguayan pig herds, in order to keep informed about the epidemiological situation of these notifiable infections in the country. For serological testing, a total of 524 swine serum samples collected during the period 2014-2016 were assayed by commercial ELISAs. Our results revealed the (unexpected) presence of PRRSV antibodies in Uruguayan domestic swine herds and confirmed the absence of ADV and CSFV antibodies in all of the assessed samples. Following such initial finding, PRRSV antibodies were further investigated in 23 retrospective samples collected during 2010-2014. Thirteen of these 23 samples resulted seropositive. Subsequently, a molecular detection approach in frozen serum samples was implemented to confirm PRRSV infection, and viral RNA was identified by reverse transcription-nested polymerase chain reaction (RT-nPCR). Fourteen of 86 evaluated 2014-2016 samples resulted positive for viral RNA, while molecular analysis of four retrospective samples also revealed the presence of PRRSV type 2. Viral isolation of selected samples was carried out in porcine alveolar macrophages (PAM) and MARC 145 simian kidney cells, and the virus identity was confirmed by cytopathic effect (CPE) and immunofluorescence assay (IFA) using specific monoclonal antibodies for PRRSV nucleocapsid. Data reported here evidence for the first time the circulation of PRRSV type 2 in Uruguay, and retrospective serology results suggest that the virus has been infecting pigs in this country at least since 2011.

Detection of porcine reproductive and respiratory syndrome virus ( PRRSV ) 1‐7‐4‐type strains in Peru

“…While differences in virulence were reported for US PRRSV 1-7- Figure 1) (Neira et al, 2017;Ramos et al, 2018). Importantly, the later reported the first detection of PRRSV in 2017 (Ramos et al, 2018).…”

“…The factors underlying the increased disease incidence remain poorly understood. It is important to note, however, that other countries in South America, including Chile and, most recently, Uruguay also recently reported PRRSV outbreaks (Figure ) (Neira et al., ; Ramos et al., ). Importantly, the later reported the first detection of PRRSV in 2017 (Ramos et al., ).…”

“…It is important to note, however, that other countries in South America, including Chile and, most recently, Uruguay also recently reported PRRSV outbreaks (Figure ) (Neira et al., ; Ramos et al., ). Importantly, the later reported the first detection of PRRSV in 2017 (Ramos et al., ). As the strains detected in these countries are genetically different, the expansion of PRRSV in South America seems likely a result of multiple virus introductions in the region rather than dissemination of the virus within the continent.…”

“…The PRRSV strains recently reported in Chile and Uruguay diverge from the strains identified in Peru here. Sequence analyses of the ORF7 of the Uruguayan PRRSV strains revealed a close relationship of the virus with the historical PRRSV strain VR2385 (Ramos et al., ). Whereas the virus recently circulating in Chile is related to PRRSV strains detected in the US in 2012 (Neira et al., ).…”

“…In 2013, however, the virus was re-introduced in Chile (Neira et al, 2017). Additionally, PRRSV was also recently detected for the first time in Uruguay (2017-2018) (Ramos et al, 2018).…”