Avian metapneumovirus (aMPV) poses a significant threat to the global poultry industry as a cause of acute respiratory infections in avian species.
In the poultry sector, aMPV infections can lead to severe economic repercussions, manifesting as drops in egg production and increased mortality, which lead to costly veterinary interventions and biosecurity measures.
Part of the Paramyxoviridae family, aMPV has a high degree of genetic diversity, which complicates efforts to control its spread. There are multiple subtypes of aMPV — aMPV-A, aMPV-B and aMPV-C — currently circulating in different parts of the world.
Because aMPV can spread rapidly and asymptomatically, timely and accurate diagnosis of subtypes present in an outbreak is essential for effective disease management and containment. Traditional diagnostic methods, such as serology and conventional polymerase chain reaction (PCR), may be limited by turnaround time, sensitivity and specificity, according to a group of researchers in China who have developed a multiplex real-time PCR assay.
In a recent edition of Poultry Science, these researchers described the development of their assay, which was found to be capable of concurrently detecting and distinguishing among aMPV-A, aMPV-B and aMPV-C.
The novel assay was developed to include high-throughput capability with enhanced specificity and sensitivity for use in China, where the three subtypes have been frequently identified in waterfowl and live-poultry markets.
The researchers analyzed all available aMPV sequences in GenBank to improve primer detection efficiency and designed primers and probes for detecting the conserved SH gene of aMPV-A and aMPV-B, as well as the P gene for aMPV-C. They validated the assay using various primer and probe combinations against aMPV subtypes as well as other respiratory virus samples, including human metapneumovirus, Newcastle disease virus, infectious bronchitis virus and infectious laryngotracheitis virus.
Results from the validation tests indicated that the multiplex real-time PCR assay effectively identified the target pathogen while yielding negative results for all other viruses, suggesting strong specificity for aMPV-A, aMPV-B and aMPV-C. The assay was also found to be sensitive to a minimum concentration of
8.5 x 102 copies per microliter.
The research team concluded that their diagnostic tool addresses key challenges previously faced in the field, notably the need for high specificity and sensitivity in aMPV detection within mixed infections.
Also, the assay’s capacity to differentiate among the three subtypes without cross-reactivity with other avian respiratory pathogens overcomes shortcomings of traditional methods, which require separate testing for each subtype.
What does this mean for producers?
- A novel multiplex real-time PCR assay improves aMPV diagnostics in a single
- Use of this novel assay may enhance aMPV surveillance and control, particularly in settings like live-poultry markets.
- Future research will focus on validating the assay across different regions and in different types of poultry populations.
The full paper, “Establishment and application of a one-step multiplex real-time PCR assay for detection of A, B, and C subtypes of avian metapneumovirus,” can be found in Poultry Science and online here.
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