Avian Metapneumovirus (aMPV): Frequently Asked Questions (FAQs)
Madhusudan Timilsina DVM, MS, and Mostafa Ghanem DVM, MS, Ph.D., Department of Veterinary Medicine, University of Maryland
Why is aMPV Important?
aMPV is a highly contagious respiratory disease affecting turkeys and chickens. It causes significant economic losses due to reduced egg production, increased mortality rates, and decreased performance in infected flocks.
What Causes aMPV?
aMPV is caused by a negative-sense, single-stranded, enveloped virus of the Paramyxoviridae family. There are four subtypes (A, B, C, and D). Three subtypes have been reported in the United States in 2024, with subtype B responsible for the recent 2024 outbreak in the eastern states, including Delmarva.
Where do aMPV Outbreaks Occur Historically?
aMPV outbreaks occur worldwide in major poultry-producing areas. Historically, Subtypes A and B are more common in Europe, South America, and Africa, while subtype C is predominantly found in the United States, China, Canada, and South Korea. Subtype D is exclusive to France. In 2024, subtypes A, B and C have been reported in the United States.
How can poultry growers quickly identify aMPV symptoms in their flocks?
Poultry growers can quickly identify aMPV symptoms in their flocks by looking for the following signs:
1. Respiratory symptoms: Watch for sneezing, coughing, nasal discharge, and respiratory rales (abnormal breathing sounds).
2. Eye-related issues: Look for frothy eyes, conjunctivitis, and wet eyes.
3. Behavioral changes: Observe for depression, ruffled feathers, and head shaking.
4. Swollen head: In severe cases, birds may develop swollen sinuses or faces.
5. Egg production issues: For laying hens and breeders, watch for a marked decrease in egg production (up to 70%), poor shell quality, and misshapen eggs.
6. Rapid spread: aMPV can spread quickly, potentially affecting an entire flock within just one day.
7. Age consideration: While birds of all ages are susceptible, the disease is most commonly seen in birds between 3 to 12 weeks old
It's crucial to note that these symptoms may be accompanied by secondary bacterial infections, making the birds more susceptible to pathogens like E. coli, ORT, and cholera. Infected birds may exhibit variable signs depending on age, gender and concurrent infections. If you observe these signs, contact your veterinarian immediately for proper diagnosis and management.
B) Turkey with swollen sinuses. Credit AAAP.
How is aMPV Transmitted?
aMPV spreads primarily through:
· Direct contact with infected birds
· Indirect contact via contaminated equipment, vehicles, or personnel
· Potentially through aerosol transmission (less likely)
· Migratory wild birds may be potential sources of infection
· The virus can remain infective for long periods of time under cool and moist environmental
conditions, e.g., in poultry litter for three days at 20 to 25°C and for 14 to 30 days at 8°C.
When does aMPV Occur?
aMPV outbreaks can occur at any time of the year, especially when birds are stressed or have compromised immune systems. Seasonal surges in infections have been observed around fall and spring months. Factors influencing outbreaks include bird density, ventilation, temperature, biosecurity and management conditions.
How is aMPV Diagnosed?
Diagnosis is made through:
· Clinical signs and Postmortem findings although may overlap with other respiratory diseases therefore laboratory confirmation is necessary.
· Laboratory testing:
o RT-PCR from choanal or Tracheal swabs or tissues
o Serological tests (e.g., ELISA)
How do you Control aMPV?
Control measures include:
· Strict biosecurity protocols
· Reducing bird density
· Improving ventilation
· Vaccination
Managing secondary bacterial infections
How do you Prevent aMPV?
Prevention strategies include:
· Implementing robust biosecurity measures
· Proper cleaning and disinfection between flocks
· Adequate downtime between flocks
· Vaccination
Are there vaccines for avian metapneumovirus (aMPV) available in the USA?
As of December 2024, vaccine options for avian metapneumovirus (aMPV) in the USA are limited and as follows:
1. No USDA-approved live vaccines for aMPV
2. Four special approvals for inactivated (killed) vaccines have been granted:
o Two imported vaccines (TUR-3 by Boehringer Ingelheim and one by Hipra) for aMPV subtype B
o Two experimental autogenous vaccines (by MSD and Ceva) using U.S.-origin subtype B isolates
The USDA Center for Veterinary Biologics is expediting the availability of experimental autogenous inactivated vaccines. While vaccine development continues, poultry growers should focus on strong biosecurity measures and consult their veterinarians for the best prevention strategies against aMPV.
Who Should You Contact When You Suspect a Case?
If you suspect an aMPV outbreak in your flock:
1. Contact your veterinarian immediately
2. Maryland residents with inquiries regarding bird health and avian metapneumovirus (aMPV) are encouraged to reach out to the Maryland State Department of Agriculture's Animal Health Diagnostic Laboratories. You can contact them at 410-543-6610 or 301-600-1548 for assistance.
3. Report to the United States Department of Agriculture (USDA), as aMPV is reportable at the federal level (though not actionable)
It's important to note that while aMPV is reportable, it does not cause disease in humans. early detection and rapid response are crucial in controlling aMPV outbreaks and minimizing their impact on your flock and the poultry industry.
References:
1. American Association of Avian Pathologists, & Boulianne, M. (Eds.). (2013). Avian disease manual (7th ed.). American Association of Avian Pathologists, Inc.
2. S. Clark, aMPV Working Group meetings. 2024