AVIAN METAPNEUMOVIRUS (AMPV) AN EMERGING CHALLENGE IN POULTRY FARMING.
Dr Anil Phadke ,Director, A J Poultry Farm Pvt Ltd
During summer season of 2024 there were lots of complaint of facial oedema, swollen head respiratory rales in broiler , broiler breeder flocks . Many of affected birds latter developed torticollis, opisthotomus, star grazing . Many farmers, field vets confused it with New Castel diseases however it was Avian Metapneumo virus infection ( AMPV)
Clinical signs
Birds of any age can be infected by avian metapneumovirus, although the disease is typically more severe in younger birds. AMPV primarily affects the upper respiratory tract, causing inflammation of the nares (nostrils), sinuses, and trachea. Clinical signs may include coughing, mucus or discharge from the nares, swollen heads, and general signs of an unthrifty bird. In broiler breeders feed consumption reduces & balance feed in feeders is first symptom reported by supervisors. At later stages, disease may progress to induce torticollis (twisted neck or stargazing) or other neurological signs due to involvement of the inner ear. In severe cases, vent prolapse may occur due to straining from coughing. In layers or breeders, there may be reduced egg production and misshapen eggs, soft-shelled eggs, or thin-shelled eggs. Infection by AMPV makes other secondary infections much more likely to occur, such as E. coli. When AMPV is complicated by secondary infections, mortality rates may increase substantially.
Post Mortem lesions
On post-mortem examination, the sinuses or trachea may be filled with excessive mucus. Depending on the severity of the infection, edema (seen as gelatinous fluid) may be present under the skin around the skull or neck. Layers and breeders may have folded egg membranes in the reproductive tract, or yolk peritonitis.
Additional lesions may be observed if secondary infections are present.
Egg peritonitis, air saculitis , are common in birds which die of feed & recumbent position.
TRANSMISSION –Wild birds visitors, trader &feed vehicles bring the infection to farm. Avian metapneumovirus spreads readily through direct contact of respiratory secretions. The virus can survive in rodents for several days, and rodent, human, insect, or inanimate fomites can readily spread infective secretions from one house to another. Although transmission via aerosolization cannot be discounted, it is much less likely to occur than direct contact. There are no published records of direct vertical transmission (spread from breeder hen to chick).
Differential diagnosis
Need to differentiate between Infectious coryza, Mycoplasma infection, new castel diseases, LPAI. For APMV infection facial swelling followed by torticollis are typical signs with low mortality compared to ND.
Treatment & Prognosis
There is no treatment for avian metapneumovirus. However, treatment may be important in controlling secondary bacterial infections. The earlier any secondary diseases are identified and treated, the better the prognosis.
If secondary infections are controlled with good husbandry prognosis is good. Generally flock recovers in 10-15 days with 4-5 % mortality. Birds which develops torticollis need to culled.
