Herd-level infectious disease surveillance of livestock populations using aggregate samples

Abstract

All sectors of livestock production are in the process of shifting from small populations on many farms to large populations on fewer farms. A concurrent shift has occurred in the number of livestock moved across political boundaries. The unintended consequence of these changes has been the appearance of multifactorial diseases that are resistant to traditional methods of prevention and control. The need to understand complex animal health conditions mandates a shift toward the collection of longitudinal animal health data. Historically, collection of such data has frustrated and challenged animal health specialists. A promising trend in the evolution toward more efficient and effective livestock disease surveillance is the increased use of aggregate samples, e.g. bulk tank milk and oral fluid specimens. These sample types provide the means to monitor disease, estimate herd prevalence, and evaluate spatiotemporal trends in disease distribution. Thus, this article provides an overview of the use of bulk tank milk and pen-based oral fluids in the surveillance of livestock populations for infectious diseases.

Use of oral fluids for efficient monitoring of influenza viruses in swine herds in Colombia

“…A sample of two OF per group was required to have a 90% probability to find at least 10% virus prevalence in the sampled subpopulation. For the purpose of this study an OF sample was described as a penbased specimen or aggregate sample (Rotolo et al, 2018) collected from a group of >20 animals per pen and/or >20 animals per barn if they were housed individually but having close contact between them, i.e. stall-housing pigsty in a breeding herd facility.…”

“…IAV affect pig performance, reducing feed conversion ratio, feed intake and weight gain (Olsen et al, 2002;Myers et al, 2007). Sampling methods to detect SIAV infected individuals in large populations require high number of resources (Muñoz-Zanzi et al, 2000), but aggregation of samples has been proposed as a cost-efficient tool for detection of diseases in these populations (Rotolo et al, 2018). Effectiveness of pathogen detection in pooled samples is highly dependent on the dilution effect (Arnold et al, 2009), however, several studies demostrated a no dilution effect when detecting SIAV in OF by molecular methods (Panyasing et al, 2016;Gerber et al, 2017).…”

Feasibility of pooled oral fluid collection from pre-weaning piglets using cotton ropes

“…Although OF collection was introduced to swine health surveillance relatively recently, it has been widely studied as the potential application of OF-based diagnosis is substantial ( Prickett & Zimmerman, 2010 ). Detection of nucleic acids or antibodies in OF have been reported for most swine pathogens ( Bjustrom-Kraft, 2018 ; Rotolo, Main, & Zimmerman, 2018 ). OF samples are easy to obtain with non-invasive procedures, which utilize the natural behavior of pigs ( Kittawornrat & Zimmerman, 2011 ).…”

Advances in oral fluid antibody-based surveillance for porcine reproductive and respiratory syndrome virus (PRRSV)

“…Among possible alternative samples, oral fluids have been widely accepted for PRRSV surveillance in commercial systems because they are easily collected from individual pigs or group-housed animals (Fablet et al, 2017;Kuiek et al, 2015) and testing protocols for PRRSV RNA and PRRSV-specific antibodies (IgA, IgM, and IgG) are well-documented (Kittawornrat et al, , 2012aRotolo et al, 2018aRotolo et al, , 2018b. The first commercial PRRSV antibody ELISA specifically designed for antibody detection in swine oral fluid specimens was released in Europe in 2012, in the United States in 2015, and at least three additional commercial PRRSV oral fluid…”