A serosurvey for pathogens in European wild boars

Vet Rec Open. 2015 Aug 28;2(2):e000077. doi: 10.1136/vetreco-2014-000077. eCollection 2015.

A serosurvey for selected pathogens in Greek European wild boar.

Touloudi A¹, Valiakos G¹, Athanasiou LV², Birtsas P³, Giannakopoulos A², Papaspyropoulos K⁴, Kalaitzis C⁴, Sokos C⁵, Tsokana CN², Spyrou V⁶, Petrovska L⁷, Billinis C¹.

Abstract

OBJECTIVES:

Serum samples, collected from 94 European wild boar (Sus scrofa) during the hunting seasons 2006 -2010 from different regions of Greece, were examined in order to estimate the role of these wildlife species as reservoir of pathogens important for livestock and/or public health.

MATERIALS AND METHODS:

The assays used for this purpose were commercial indirect ELISA for the detection of antibodies against porcine circovirus type 2 (PCV-2), porcine reproductive and respiratory syndrome (virus) (PRRSV), Aujeszky's disease virus (ADV), influenza A (IA) virus, Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae, Salmonella species, Trichinella species and indirect immunofluorescence antibody test for the detection of antibodies against Toxoplasma gondii and Neospora caninum.

RESULTS:

Antibodies against PCV-2, PRRSV, ADV, IA virus,A. pleuropneumoniae, M. hyopneumoniae, Salmonella species, Trichinella species, T. gondii and N. caninum were detected in 19.1 per cent, 12.8 per cent, 35.1 per cent, 1.1 per cent, 57.4 per cent, 0 per cent, 4.3 per cent, 6.4 per cent, 5.2 per cent and 1.1 per cent of the samples, respectively. Cluster analysis revealed a hot spot of seropositivity near Bulgarian border; seropositivity to ADV was more common among female animals.

CONCLUSIONS:

These results indicate exposure of wild boar to most of the above-mentioned pathogens, raising concern about the possibility that these species may pose a significant health risk for livestock and/or humans.

KEYWORDS:

GIS; Greece; Infectious diseases; Serology; Wild boar; swine

PMID:26392908 [PubMed]

Genetic diversity of PRRSv collected from air in high pig density regions

Viruses. 2014 Nov 14;6(11):4424-36. doi: 10.3390/v6114424.

Genetic diversity of PRRS virus collected from air samples in four different regions of concentrated swine production during a high incidence season

Brito B, Dee S, Wayne S, Alvarez J, Perez A.

Abstract

Porcine Reproductive and Respiratory Syndrome (PRRS) is one of the most relevant swine diseases in the US, costing the industry millions of dollars per year. Unfortunately, disease control is difficult because of the virus dynamics, as PRRS virus (PRRSV) can be transmitted by air between farms, especially, in regions with high density of swine operations. While long distance airborne transport of PRRSV has been reported, there is little information regarding the dynamics of PRRSV airborne challenge in concentrated regions. The objective of this study was to describe the frequency of detection, dose and diversity of PRRSV in air samples collected across four concentrated production regions during the PRRS-high risk season in the Midwestern US (October-December) in 2012. Between 29% and 42% of the air samples were positive in all four sampling sites. Sequencing of the recovered virus showed a wide diversity of field and vaccine variants. Higher frequency, dose, and diversity of PRRSV were observed in air at locations with higher pig density. These findings suggest that regional spread of PRRSV due to aerosol transmission of PRRSV represents a significant risk to susceptible herds in concentrated regions of domestic pig production where PRRSV is endemic.

PMID:25405592 [PubMed]

Temporal and spatial dynamics of PRRSv infection in the United States

Am J Vet Res. 2015 Jan;76(1):70-6. doi: 10.2460/ajvr.76.1.70.

Temporal and spatial dynamics of porcine reproductive and respiratory syndrome virus infection in the United States

Tousignant SJ, Perez AM, Lowe JF, Yeske PE, Morrison RB.

Abstract

OBJECTIVE:

To measure incidence and estimate temporal and spatial dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) infection in US sow herds.

ANIMALS:

371 sow herds in the United States from 14 production companies.

PROCEDURES:

The exponentially weighted moving average was used to monitor incident PRRSV infections for onset of an epidemic. The spatial scan statistic was used to identify areas at significantly high risk of PRRS epidemics. A χ(2) test was used to estimate whether there were significant differences in the quarterly and annual PRRS incidence among time periods, and a bivariable logistic regression model was used to estimate whether PRRSV infection during a given year increased the odds of that herd being infected in the following year.

RESULTS:

During the 4-year period of this study, 29% (91/319; 2009 to 2010), 33% (106/325; 2010 to 2011), 38% (135/355; 2011 to 2012), and 32% (117/371; 2012 to 2013) of the herds reported new infections. Weekly incidence was low during spring and summer and high during fall and winter. The exponentially weighted moving average signaled the onset of a PRRSV epidemic during the middle 2 weeks of October each year. Disease incidence was spatially clustered. Infection in the previous year increased the odds of infection in 2010 to 2011 and 2011 to 2012.

CONCLUSIONS AND CLINICAL RELEVANCE:

Results indicated a striking repeatability in annual PRRSV temporal and spatial patterns across 4 years of data among herds from 14 production companies, which suggested that efforts to control PRRSV at a regional level should continue to be supported.

PMID:25535663 [PubMed - indexed for MEDLINE]

Production outcomes following exposure of gestation gilts to attenuated PRRSv vaccine

Vaccine. 2014 Aug 6;32(36):4639-43. doi: 10.1016/j.vaccine.2014.06.073. Epub 2014 Jun 24.

Reproductive, productivity, and mortality outcomes in late-gestation gilts and their litters following simulation of inadvertent exposure to a modified-live vaccine strain of porcine reproductive and respiratory syndrome (PRRS) virus.

Schelkopf A¹, Nerem J¹, Cowles B², Amodie D², Swalla R², Dee S¹.

¹Pipestone Veterinary Clinic, 1300 S. Highway 75, Pipestone, MN 56164, USA. ²Outcomes Research, Zoetis Inc, 100 Campus Drive, Florham Park, NJ 07932, USA.

Abstract

The study evaluated the safety of a modified live-virus (MLV) porcine reproductive and respiratory syndrome (PRRS) vaccine in susceptible, pregnant gilts. To simulate inadvertent exposure secondary to postvaccination shedding of PRRS-MLV, seronegative gilts (n=51) were exposed by IM vaccination at 90 days of gestation. Vaccinated and nonvaccinated, seronegative control gilts (n=25) were maintained in separate facilities. The PRRS-MLV vaccine was given in a 2mL dose on day 0. On day 7 all vaccinated gilts were PRRSV-PCR-positive for PRRSV and had responded serologically as determined by an ELISA. All control gilts remained PRRSV-PCR- and ELISA-negative throughout the study. Abortions did not occur in gilts from either group. The difference between vaccinated and control gilts in average number of piglets per litter (12.43 and 12.16, respectively), number of live births per litter (11.21 and 11.54), and mean piglet birth weight (3.22 and 3.26 lbs) were not significantly different. Piglets in the control group had significantly greater average daily gain versus piglets from vaccinated gilts (0.52 vs. 0.46 lbs, P<0.0001). Preweaning mortality was significantly greater (P=0.0023) in piglets from the vaccinated gilts (19.7% vs. 10.9%). A single gilt accounted for 18.2% of stillbirths in the vaccinated group. Air samples were borderline PRRSV-PCR-positive for PRRSV on days 29 and 32, after more than 98% of gilts had farrowed. Results demonstrated that vaccination of pregnant gilts at the time of peak fetal susceptibility was non-abortigenic and that the PRRS-MLV agent did not significantly affect reproductive outcomes. Lower ADG in piglets from vaccinated gilts may be due to PRRS-MLV viremia following transplacental or post-farrowing exposure. Air sampling results indicated that environmental contamination with PRRS-MLV shed from vaccinated gilts was minimal.
Copyright © 2014 Elsevier Ltd. All rights reserved.

KEYWORDS:

Fostera; Porcine; Reproductive; Respiratory; Syndrome; Vaccine; Virus

Chimeric PRRSv confers cross-protection in pigs

Virology. 2015 Sep 2;485:402-413. doi: 10.1016/j.virol.2015.08.021. [Epub ahead of print]

Chimeric porcine reproductive and respiratory syndrome virus containing shuffled multiple envelope genes confers cross-protection in pigs.

Tian D¹, Ni YY¹, Zhou L¹, Opriessnig T², Cao D¹, Piñeyro P³, Yugo DM¹, Overend C¹, Cao Q¹, Lynn Heffron C¹, Halbur PG⁴, Pearce DS⁵, Calvert JG⁵, Meng XJ⁶.

Author information

Abstract

The extensive genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) strains is a major obstacle for vaccine development. We previously demonstrated that chimeric PRRSVs in which a single envelope gene (ORF3, ORF4, ORF5 or ORF6) was shuffled via DNA shuffling had an improved heterologous cross-neutralizing ability. In this study, we incorporate all of the individually-shuffled envelope genes together in different combinations into an infectious clone backbone of PRRSV MLV Fostera^® PRRS. Five viable progeny chimeric viruses were rescued, and their growth characteristics were characterized in vitro. In a pilot pig study, two chimeric viruses (FV-SPDS-VR2,FV-SPDS-VR5) were found to induce cross-neutralizing antibodies against heterologous strains. A subsequent vaccination/challenge study in 72 pigs revealed that chimeric virus FV-SPDS-VR2 and parental virus conferred partial cross-protection when challenged with heterologous strains NADC20 or MN184B. The results have important implications for future development of an effective PRRSV vaccine that confers heterologous protection.
Copyright © 2015 Elsevier Inc. All rights reserved.

KEYWORDS:

Cross-protection; DNA shuffling; Envelope genes; Heterologous strains; Porcine reproductive and respiratory syndrome virus (PRRSV); Vaccines

PMID: 26342466 [PubMed - as supplied by publisher]

Persistence and Retention of PRRSv in Stable Flies

J Med Entomol. 2015 Jul 12. pii: tjv096. [Epub ahead of print]

Persistence and Retention of Porcine Reproductive and Respiratory Syndrome Virus in Stable Flies (Diptera: Muscidae).

Rochon K1, Baker RB2, Almond GW3, Gimeno IM3, Pérez de León AA4, Watson DW5.

Author information

Abstract

We investigated the acquisition of porcine reproductive and respiratory syndrome (PRRS) virus by the stable fly (Diptera: Muscidae; Stomoxys calcitrans (L.)) through a bloodmeal, and virus persistence in the digestive organs of the fly using virus isolation and quantitative reverse-transcription PCR (qRT-PCR). Stable flies were fed blood containing live virus, modified live vaccine virus, chemically inactivated virus, or no virus. Stable flies acquired PRRSV from the bloodmeal and the amount of virus in the flies declined with time, indicating virus did not replicate in fly digestive tissues. Virus RNA was recovered from the flies fed live virus up to 24 h postfeeding using virus isolation techniques and 96 h using qRT-PCR. We further examined the fate of PRRSV in the hemolymph of the flies following intrathoracic injection to bypass the midgut barrier. PRRSV was detected in intrathoracically inoculated adult stable flies for 10 d using qRT-PCR. In contrast to what we observed in the digestive tract, detectable virus quantities in the intrathoracically inoculated stable flies followed an exponential decay curve. The amount of virus decreased fourfold in the first 3 d and remained stable thereafter, up to 10 d.

© The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

KEYWORDS: 

Stomoxys calcitrans; intrathoracic inoculation; midgut barrier; virus persistence

PMID:

 

26336236

 

[PubMed - as supplied by publisher]