May 5, 2020

More accurate gilt testing needed to detect Mycoplasma hyopneumoniae


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Sow herds seeking negative Mycoplasma hyopneumoniae (M. hyo) status should use accurate gilt surveillance methods.

Research conducted by Alyssa Betlach, DVM, veterinarian with Swine Vet Center and graduate student at the University of Minnesota, showed differences in the ability to detect a recent M. hyo infection based on sample types used.

“My research is focused on replacement gilt populations and really ensuring, if there was a recent introduction of M. hyo, were we able to detect such introduction with the commonly utilized practices we do today,” Betlach explained.

Maintaining a negative health status for M. hyo in the sow herd is important for reducing the economic toll that this pathogen has on hog production.

Detection differences based on sample type

In the research trial, a naturally infected gilt was introduced into a naïve population. The group was tested periodically for M. hyo using blood samples, oral fluids and other sampling methods including laryngeal swabs and deep tracheal catheters.

“There was one new naïve gilt that became positive at 6 weeks after contact, so you can appreciate that there’s a very slow transmission of M. hyo compared to other pathogens,” Betlach said.

The blood tests did not detect the naturally infected gilt until week 6. But the laryngeal swabs and deep tracheal catheters detected the infected gilt from the beginning of the trial. Oral fluids remained negative.

Different mindset required

The laryngeal swabs and deep tracheal catheters are relatively new sampling techniques. Both require training and practice but are more accurate than other sample types during the early stage of infection.

“If we really want to increase our ability to track M. hyo, we need to have a different mindset and focus in on more sample types that are more sensitive for detecting such pathogens.”

Producers should also understand the advantages and limitations of each sample type and make adjustments as needed in gilt surveillance.

“You could think about even extending your isolation period if you want to take a different sample or less sample sizes,” Betlach suggested.  

The end goal is achieving and maintaining a negative health status in sow herds.

Gilts and sows have a critical role in the transmission of M. hyo. “So it’s really important to minimize the introduction of it…to reduce the cost of M. hyo,” she said.