Monday, April 29, 2019

Assessment of biosecurity practices and development of a scoring system in swine farms using item response theory.


 2019 Jun 1;167:128-136. doi: 10.1016/j.prevetmed.2019.03.020. Epub 2019 Apr 10.

Assessment of biosecurity practices and development of a scoring system in swine farms using item response theory.

Author information

1
Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Veterinary Diagnostic and Production Animal Medicine Department, Iowa State University, Ames, IA, United States.
2
Department of Statistics, Institute of Mathematics and Statistics and Post-Graduate Program of Epidemiology, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
3
Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Department of Agriculture and Livestock of Rio Grande do Sul (SEAPI), Porto Alegre, Brazil.
4
Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
5
Veterinary Diagnostic and Production Animal Medicine Department, Iowa State University, Ames, IA, United States.
6
Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil. Electronic address: luis.corbellini@ufrgs.br.

Abstract

Brazil is the fourth largest producer and exporter of pork in the world, but has never reported yet the occurrence of some economically important diseases such as porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED). Most of the swine farms in Brazil are characterized by intensive production being part of large integrated companies, where biosecurity practices help to prevent the introduction and spread of disease-causing infectious agents. The assessment of biosecurity in farms is not straightforward because of the large number of practices that constitute an on-farm biosecurity program. It is therefore necessary to combine the measurement of several parameters in order to characterize the level of biosecurity on a given farm. Thus, the objective of the study was to develop a biosecurity score to estimate the biosecurity level (theta or θ) in swine farms using the item response theory (IRT) and explore the relationship between the scores and independent variables. The IRT is a latent trait method extensively used in other fields, and offers the advantage to quantify the latent trait, here the biosecurity level, and to identify the practices that discriminate the farms avoiding the use of extensive questionnaires and redundant questions. In this study, 604 farms were evaluated in the main swine production regions of the state of Rio Grande do Sul, Brazil. Thirty-five practices were considered in order to quantify the biosecurity level on a given farm. After a recursive process 14 practices were selected to compose the biosecurity score to estimate the biosecurity level (θ). The variables identified with greater capacity of distinguishing the farms as to their biosecurity level were if the farm has 'feed bin outside of the barn limit (external feed loading)', has 'perimetral fence around the farm or barn', and if 'transit of trucks inside the farm is prohibited'. The biosecurity level was associated with some independent variables, e.g. the farm operation type, the integrated company and some owner characteristics. In addition, the results demonstrated that biosecurity practices related to management (internal biosecurity) are adopted with higher frequency compared to segregation and sanitation practices (external biosecurity). The IRT model proved useful and valid to estimate the biosecurity level in swine farms. Moreover, the biosecurity score described here has a relatively low number of items, which makes the application of this tool easier and faster compared to other previously described biosecurity assessment.

KEYWORDS: 

Biosecurity assessment; Biosecurity score; Herd characteristics; Item response theory; Swine farms
PMID:
 
31027714
 
DOI:
 
10.1016/j.prevetmed.2019.03.020

Tuesday, April 16, 2019

PRRSV: web-based interactive tools to support surveillance and control initiatives in Canada

 2019 Mar 28;5:10. doi: 10.1186/s40813-019-0117-x. eCollection 2019.

Porcine reproductive and respiratory syndrome virus: web-based interactive tools to support surveillance and control initiatives.

Author information

1
Laboratoire d'épidémiologie et de médecine porcine (LEMP), Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec Canada.

Abstract

BACKGROUND: 

Control of porcine reproductive and respiratory syndrome (PRRS) represents a tremendous challenge. The trend is now toward managing the disease collectively. In Quebec, area and regional control and elimination (ARC&E) initiatives started in 2011; diagnostic testing, including ORF5 sequencing, and sharing of information among stakeholders are largely promoted. At the provincial level, a data-sharing agreement was signed by Quebec swine practitioners allowing PRRS virus (PRRSV) sequences to be transferred to a database maintained by the Laboratoire d'épidémiologie et de médecine porcine (LEMP-DB). Several interactive tools were developed and are available to veterinarians to allow comparison of PRRSV ORF5 sequences within ARC&E projects or provincially while managing confidentiality issues.

RESULTS: 

Between January 1st 2010 and December 31st 2018, 4346 PRRSV ORF5 sequences were gathered into the LEMP-DB, involving 1254 sites and 43 practicing veterinarians. Approximately 34% of the submissions were from ARC&E projects. Using a novel web-based sequence comparison tool, each veterinarian has access to information on his/her client sequences and can compare each sequence with 1) commercial vaccine strains, 2) historical samples from the same site, and 3) all sequences submitted to the database over the last 4 years. Newly introduced PRRSV into breeding herds can be monitored using a new sequence comparison tool based on comparison of sequences at the provincial level. Each month, graphs providing the number of introductions per month and the yearly cumulative are updated. Between August 1st 2014 and December 31st 2018, 233 introductions were detected on 180 different breeding sites. Following a data-sharing agreement, veterinarians involved in ARC&E projects have access to an interactive mapping tool to locate pig sites, compare sequence similarity between participating sites and visualize the results on the map.

CONCLUSIONS: 

The structure developed in Quebec to collect, analyse and share sequencing data was efficient to provide useful information to the swine industry at both provincial and regional levels while dealing with confidentiality issues.

KEYWORDS: 

ARC&E; Control; Epidemiology; Molecular; ORF5; PRRS; Sequence; Similarity; Surveillance
PMID:
 
30976454
 
PMCID:
 
PMC6437942
 
DOI:
 
10.1186/s40813-019-0117-x


Thursday, April 11, 2019

Comparison of four commercial PRRSV MLV vaccines in herds with co-circulation of PRRSV-1 and PRRSV-2


 2019 Apr;63:66-73. doi: 10.1016/j.cimid.2018.12.010. Epub 2019 Jan 9.

Comparison of four commercial PRRSV MLV vaccines in herds with co-circulation of PRRSV-1 and PRRSV-2.

Author information

1
Seoul National University, College of Veterinary Medicine, Department of Veterinary Pathology, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
2
Seoul National University, College of Veterinary Medicine, Department of Veterinary Pathology, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea. Electronic address: swine@snu.ac.kr.

Abstract

The efficacy of four commercial porcine reproductive and respiratory syndrome virus (PRRSV) modified-live virus (MLV) vaccines against respiratory disease was evaluated and compared in pig farms suffering from co-infection with PRRSV-1 and PRRSV-2. All vaccinated groups on average exhibited improved growth rate compared to the unvaccinated pigs. Interestingly, the two groups vaccinated with either of the PRRSV-2 MLV vaccines had a better overall growth rate compared to the pigs vaccinated with either of the PRRSV-1 MLV vaccines. Vaccination of pigs with either of the PRRSV-1 MLV vaccines did not result in reduction of PRRSV-1 or PRRSV-2 viremia whereas vaccination of pigs with either of the PRRSV-2 MLV vaccines resulted in the reduction of PRRSV-2 viremia only. Taken together, the results of this field study demonstrate that a PRRSV-2 MLV vaccine can be efficacious against respiratory disease caused by co-infection with PRRSV-1 and PRRSV-2.

KEYWORDS: 

Co-infection; Porcine reproductive and respiratory syndrome; Vaccine; Virus
PMID:
 
30961820
 
DOI:
 
10.1016/j.cimid.2018.12.010