Susceptibility to PRRSV infection among Chinese native pig breeds

Arch Virol. 2018 Apr 24. doi: 10.1007/s00705-018-3821-y. [Epub ahead of print]

Different susceptibility to porcine reproductive and respiratory syndrome virus infection among Chinese native pig breeds.

Meng C1,2, Su L1,3, Li Y1,2, Zhu Q3, Li J3, Wang H1,2, He Q1, Wang C3, Wang W3, Cao S4,5,6.

Author information

Abstract

China is rich in native pig breeds, yet information regarding the susceptibility/resistance of local breeds to porcine reproductive and respiratory syndrome virus (PRRSV) infection is lacking. In the present study, an in vitro method based on assessing PRRSV replication in porcine alveolar macrophages (PAMs) was established to evaluate PRRSV susceptibility/resistance in a commercial pig breed (Landrace) and five native pig breeds from Jiangsu and Anhui provinces in China. Expression levels of cytokines (IL-8, IL-10, TNF-α and IFN-γ), Toll-like receptor 3 (TLR3), CD163 (PRRSV receptor), and sialoadhesin (Sn, PRRSV receptor) in infected pigs were determined using real-time PCR, and the association between PRRSV susceptibility/resistance and the abundance of the cytokines and receptors was investigated. The viral replication rate and titer at 0, 6, 12 18, 24 and 36 hours postinfection (hpi) were determined to assess the proliferation dynamics of PRRSV NJGC in PAMs. Based on the PRRSV proliferation dynamics, the results indicated that Dingyuan pigs were the most susceptible to PRRSV infection, whereas Jiangquhai pigs were the least susceptible to PRRSV infection among the six pig breeds tested, as indicated by measuring PRRSV replication and the viral load in PAMs. The different levels of susceptibility to PRRSV infection in PAMs may be associated with differences in the abundance of CD163 (PRRSV receptor), cytokines IL-8, IFN-γ, and TNF-α in Jiangquhai and Dingyuan pig breeds after viral inoculation.

PMID:

 

29691704

 

DOI:

 

10.1007/s00705-018-3821-y

Assessing PRRS area spread

Transbound Emerg Dis. 2018 Apr 14. doi: 10.1111/tbed.12875. [Epub ahead of print]

Assessment of area spread of porcine reproductive and respiratory syndrome (PRRS) virus in three clusters of swine farms.

Arruda AG1, Sanhueza J2, Corzo C2, Vilalta C2.

Author information

Abstract

Despite decades of porcine reproductive and respiratory syndrome (PRRS) research, outbreaks with emerging and re-emerging PRRS virus (PRRSV) strains are not uncommon in North America. The role of area spread, commonly referred but not limited to airborne transmission, in originating such outbreaks is currently unknown. The main objective of this study was to explore the role of area spread on the occurrence of new PRRSV cases by combining information on genetic similarity among recovered PRRSV isolate's open-reading frame (ORF) 5 sequences and publicly available weather data. Three small regions were enrolled in the study for which high farm-level participation rate was achieved, and swine sites within those regions were readily sampled after reporting of an outbreak in a sow farm. Oral fluid PCR testing was used to determine PRRSV status of farms, and wind roses were generated for assessment of prevailing wind directions during 2-14 days preceding the outbreak. Under the conditions of this study, the data did not support the area spread theory as the main cause for these outbreaks. We suggest that for future studies, analysis of animal movement and other links between farms such as personnel, equipment and sharing of service providers should be incorporated for better insights on source of the virus. Furthermore, the development of rapid and easy diagnostic methods for ruling out resident PRRSV is urgently needed.

KEYWORDS: 

PRRS area spread; PRRS epidemiology; PRRS risk factors; porcine reproductive and respiratory syndrome; swine

PMID:

 

29654632

 

DOI:

 

10.1111/tbed.12875

Time series analysis for PRRS in the US

PLoS One. 2018 Apr 3;13(4):e0195282. doi: 10.1371/journal.pone.0195282. eCollection 2018.

Time-series analysis for porcine reproductive and respiratory syndrome in the United States.

Arruda AG1, Vilalta C2, Puig P3, Perez A2, Alba A2.

Author information

1

Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, Ohio, United States of America.

2

Department of Veterinary Population Medicine, University of Minnesota, St. Paul, Minnesota, United States of America.

3

Department of Mathematics, Autonomous University of Barcelona, Barcelona, Spain.

Abstract

Industry-driven voluntary disease control programs for swine diseases emerged in North America in the early 2000's, and, since then, those programs have been used for monitoring diseases of economic importance to swine producers. One example of such initiatives is Dr. Morrison's Swine Health Monitoring Project, a nation-wide monitoring program for swine diseases including the porcine reproductive and respiratory syndrome (PRRS). PRRS has been extensively reported as a seasonal disease in the U.S., with predictable peaks that start in fall and are extended through the winter season. However, formal time series analysis stratified by geographic region has never been conducted for this important disease across the U.S. The main objective of this study was to use approximately seven years of PRRS incidence data in breeding swine herds to conduct time-series analysis in order to describe the temporal patterns of PRRS outbreaks at the farm level for five major swine-producing states across the U.S. including the states of Minnesota, Iowa, North Carolina, Nebraska and Illinois. Data was aggregated retrospectively at the week level for the number of herds containing animals actively shedding PRRS virus. Basic descriptive statistics were conducted followed by autoregressive integrated moving average (ARIMA) modelling, conducted separately for each of the above-mentioned states. Results showed that there was a difference in the nature of PRRS seasonality among states. Of note, when comparing states, the typical seasonal pattern previously described for PRRS could only be detected for farms located in the states of Minnesota, North Carolina and Nebraska. For the other two states, seasonal peaks every six months were detected within a year. In conclusion, we showed that epidemic patterns are not homogeneous across the U.S, with major peaks of disease occurring through the year. These findings highlight the importance of coordinating alternative control strategies in different regions considering the prevailing epidemiological patterns.

PMID:

 

29614099

 

DOI:

 

10.1371/journal.pone.0195282