A strategic approach to identifying and combating porcine reproductive and respiratory syndrome virus outbreaks and other porcine viral diseases

This project aims to develop a strategic approach to identify and combat porcine reproductive and respiratory syndrome virus (PRRSV) outbreaks and other porcine viral diseases in the Philippines. The Philippines are the world's 8th largest producer of pork producing over 1,700 mega tons of pork meat per year. However, the pork production still relies largely on backyard farms, which, in 2016, were reported to house 64% of the roughly 12.5 million animals in the country. This divergence in farming practises between backyard and commercial farms requires a robust strategic approach to prevent pathogen spread across farms and systems. The backyard farms often use crossbred commercial western/indigenous breed pigs, with few biosafety measures in place, rarely rely on veterinary consultation, lack diagnostics, and allow fairly liberal and unsupervised access to antibiotics. In contrast, the commercial farms rely on commercial highly bred western pig breeds, mostly Landrace/Large White/Duroc crosses brought in from leading breeding companies, such as PIC and Topigs Norsvim, amongst others. The commercial farms, despite little usage of diagnostics to support clinical diagnoses, are employing extensive vaccination schemes; however, currently this isn't always effective in preventing disease. Improved diagnostics, monitoring, surveillance and reviewing of current biosafety and vaccination strategies are essential to employ a targeted approach to disease control.

Therefore, this project aims to assess the current health situation in commercial and backyard farms, to identify current vaccination strategies, and to identify circulating strains and subtypes of PRRSV and PEDV. We will use traditional Sanger and next generation sequencing of field samples to conduct phylodynamic and phylogeographic analysis, which will help to inform the spread and source of PRRSV and PEDV outbreaks, and which will further aid disease prevention strategies. The outcomes will give us an overview of the current health and biosafety situation in the Filipino pig industry and will allow us to develop specific, easy-to-use diagnostic tools that will enable farmers to specifically identify diseases present in their stock and advise targeted vaccination and biosafety measures. We aim to develop differential diagnostic tools based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) or reverse transcription recombinase polymerase amplification (RT-RPA) for systemic viral diseases including PRRSV, CSFV, PCV2, and IAV-S, and for enteric viral diseases including PEDV, TGEV, and rotaviruses. We will employ easy-to-use flow strip detection methods to develop multiplex tests that allow differentiation between viruses and/or subtypes. From our results, we aim to generate targeted advice for both commercial and backyard farms in order to prevent and combat viral diseases in pigs.

Who will benefit from this research?

The potential non-academic beneficiaries of this research include pig diagnostic labs, pig health companies, pig breeding companies, pig producers and ultimately the entire chain of users of pig products, including meat packers, processors, retailers and consumers. There are also potential benefits to the pig vaccine sector.

How will they benefit from this research?

Porcine viral disease is of major impact to pigs of all ages. Clinical manifest disease often leads to high mortality in suckling and weaned piglets and slower weight gain in animals of all ages. Therefore, this has an immediate effect on feed efficiency, productivity and the livelihood of farmers. Accurate and fast diagnostic will allow to take the correct biosafety and biosecurity measures to prevent disease spread, advise the use of appropriate vaccination where available, and in consequence improve the health of one farm and prevent spread to other farms. This benefits the pig producers, as well as the pig product chain immediately. Pig diagnostic labs and pig health companies can be involved in the commercialisation and distribution of such diagnostic tools and the pig breeding companies are benefiting from wealthier farmers that can afford high breed animals, but also their own elite and producer farms will be benefiting from these tools.