The medical indicators are sometimes delicate, however could be exacerbated by secondary bacterial pathogens
8 Could 2024
3 minute learn
[Edited version of a presentation by Silke Rautenschlein, DVM, PhD, University of Veterinary Medicine Hannover, Germany, during the 2024 Western Poultry Disease Conference]
Whereas the medical indicators of avian metapneumovirus (AMPV) are sometimes delicate and have an effect on solely a part of the flock, they are often exacerbated by secondary bacterial pathogens, which is then the primary set off for veterinary investigations.
AMPV infections could also be tough to diagnose within the area on account of a brief detection interval in choanal and tracheal swabs relying on the virus pressure and host.
The virus appears to be unstable in diagnostic materials, which impacts the detection fee and the possibility for virus isolation, explaining the low variety of obtainable laboratory and AMPV vaccine strains.
Numerous in-house procedures and industrial (q) RT-PCR techniques can be found to detect the completely different subtypes in multiplex assays. Nevertheless, it’s attainable that newly rising subtypes could also be missed, relying on the design of the RT-PCR response.
AMPV subtypes
Totally different subtypes (A-D) of AMPV have been described in poultry in numerous areas on the planet. Totally different poultry in addition to wild chook species present variable susceptibility to the completely different subtypes.
New subtypes have been advised not too long ago for viruses detected in gulls and parakeets. AMPV exhibits a powerful tropism for epithelial cells within the trachea and turbinates in addition to within the reproductive tract, which ends up in respiratory signs and reproductive problems, and subsequently vital financial losses.
Whereas subtype D was detected solely retrospectively in samples from the Eighties, subtype A and B nonetheless flow into in lots of areas on the planet since their first description on the finish of the Seventies.
Totally different subtype C strains emerged in america in the course of the Nineties and later in Asia and Europe, the latter persevering with to unfold additional.
AMPV management methods
Relying on the chook’s species and density of the poultry inhabitants in a particular area management methods might differ. In poultry dense areas, biosecurity appears to be much less environment friendly for the management of the virus and due to this fact, vaccination is moreover carried out.
In areas with fewer poultry flocks and low area stress, eradication methods and biosecurity might management AMPV unfold.
It is very important perceive the circulation of the AMPV viruses in wild chook populations, particularly those having their habitat in or close to farming areas, as they might help virus presence.
AMPV vaccination
To this point, solely attenuated stay vaccines and inactivated vaccines are commercially obtainable to guard towards completely different subtypes, particularly to be used in laying hens to forestall losses in egg manufacturing. The comparatively brief period of native immunity after the appliance of stay vaccines might require frequent booster vaccinations, particularly in long-living birds.
Cross-protection has been noticed between subtype A and B vaccinations. Vaccine utilization might drive virus evolution within the area. The reversion of vaccine strains to extra virulence has been noticed.
New technology vaccines have been examined experimentally. The event of reverse genetics techniques for various subtypes of AMPV might enable the design of recent candidate vaccines sooner or later with diminished security issues and long-lasting safety, in comparison with the at present obtainable vaccines.
