A team led by researchers at Penn State College of Agricultural Sciences has developed a diagnostic test that identifies violent forms of swine bacterial pathogen Streptococcus equi subspecies zooepidemicus – often referred to as “Strep zoo” – that can cause serious illness and death. in pigs, other animals and rare humans.
Outbreaks of S. zooepidemicus causing high pig mortality were first reported in Asia in 1977, and until recently, the pathogen was not considered a major concern in America. North. However, a major outbreak of Strep juice occurred in pig herds in Canada, Tennessee, Ohio and Pennsylvania in 2019.
Different versions of the pathogen can also cause a number of disease symptoms in horses, retinues, guinea pigs, monkeys, cats, dogs, chickens and humans.
Pigs infected with Strep zoo can have a sudden onset of hazel, weakness, high fever and rapidly increasing mortality that can affect up to 30% to 50% of infected animals. .
However, the bacterium that causes these symptoms poses a diagnostic challenge because brute-force rays are largely different from unnatural strains, according to lead researcher Suresh Kuchipudi, a clinical professor of science veterinarian and biochemical.
Rapid and correct diagnosis is absolutely necessary to control and limit the spread of this disease of pigs. But the lethal version of the bacterium is very similar – with only a few genetic differences – to bacteria commonly found in healthy pigs and other animals. As a result, conventional methods cannot recognize this brutal version. “
Suresh Kuchipudi, Associate Director, Animal Diagnostic Laboratory, Penn State
To address this issue, the team aimed to identify genetic factors that are unique to Strep juice bacteria. Using state-of-the-art equipment incorporating next-generation sequences, the researchers looked at bacterial isolates from a deadly revolution in the Pennsylvania Strep.
Their analysis was incorporated into the SzM gene, which has been identified in previous research as a major feature of S. zooepidemicus violence for pigs but has not been detected in advanced strains of the pathogen.
Focusing on the SzM gene, researchers developed a probe-based real-time polymerase chain reaction, or PCR, diagnostic assay for the detection of virulent Strep juice isolates.
They assessed the specificity and sensitivity of the assay by using it to test a panel of complex bacterial isolates and viral pathogens commonly associated with swine respiratory disease. In addition, they applied the newly developed assay to test advanced strains of S. zooepidemicus.
The team study, recently reported in Limitations in Medical Science, found that the new PCR test reliably identified Strep raspberry juice rays, while yielding negative results when tested for other pathogens may cause swine respiratory diseases, as well as avirulent S. zooepidemicus.
Kuchipudi noted that infectious diseases have the potential to emerge and manifest adverse effects on animal health, food safety and trade.
“A number of animal infectious diseases have a zoonotic potential, meaning that they can have a significant impact on public health,” he said.
“For these reasons, accurate and quick diagnosis is extremely important. This novel assay – which can return results in less than four hours and is the first test to be found S. zooepidemicus virulent selectively in pigs – provides a practical solution to the previously unresolved problem of experiencing Strep zoo in pig herds. “
Kuchipudi said a key unanswered question is whether animals susceptible to other species serve as reservoirs for S. zooepidemicus. “This PCR assay can also be used to answer this question and further investigate the host area of S. zooepidemicus,” he said.
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Magazine Reference:
Kuchipudi, SV, et al. (2021) Modern Real-Time PCR Evaluation for Rapid Virulent Detection Streptococcus equi Subspecies zooepidemicus– Pathogen of emerging pig. Limitations in Medical Science. doi.org/10.3389/fvets.2021.604675.