Probing researchers strike gold to stop pigs from trotting

Gold nanorod probes combined with an optical microscope can now be used to detect signs of a highly contagious and deadly virus that poses a major threat to the swine industry worldwide.

The cutting-edge technology was developed by Chinese and Australian biomedical scientists to diagnose Porcine Epidemic Diarrhea Virus (PEDV), a disease that has wreaked economic havoc on pig farms in recent years.

Researchers from Yangzhou University and the University of South Australia say the gold nanoparticle probe, which was developed for use in the field, could replace existing PEDV detection techniques, which are costly, time-consuming and performed in laboratories.

PEDV is a devastating disease causing severe diarrhea and/or vomiting, dehydration and high mortality rates in suckling piglets. Outbreaks in the US in 2014 and China in 2016-2017 cost local producers millions of dollars, compounded by the lack of an effective vaccine and slow diagnosis.

UniSA bioengineer Dr. Chih-Tsung Yang, senior author of a recent article describing the technology, says early diagnosis is crucial to prevent future PEDV outbreaks.

“The current diagnostic gold standard involves taking samples from pigs and transporting them to a laboratory, which is expensive and tedious but accurate,” says Dr. Yang.

“Our method uses a biofunctionalized chip and a gold nanorod probe to capture and label PEDV pathogens. Under a darkfield microscope, PEDV can be identified by counting software. It can be performed on-site in rural areas at minimal cost, making it very accessible and sensitive, delivering results within an hour.

“We anticipate this technology will be invaluable to biosecurity systems, helping to stem the spread of the virus in Australia and elsewhere, keeping pigs healthy and protecting the industry from economic loss. There are no effective vaccines against PEDV, so early diagnosis is key.”

The study was published in the latest issue of biosensors.

PEDV is a single-stranded RNA virus that belongs to the coronavirus family. The disease was discovered in England and Belgium in 1971 and has since caused severe economic losses in China, East Asia and North America. Initial vaccines provided adequate immunity, but in 2020 a new wave of PEDV swept across China, rendering existing vaccines ineffective.