Avian Influenza (AI) type A viruses have been found in over 40 species of wild and domestic birds and cases occur every year throughout the world.
Low pathogenicity AI occurs periodically in the US. High pathogenic avian influenza (HPAI) is an extremely infectious and fatal form of the disease that, once established, can spread rapidly from flock to flock. However, some LPAI virus strains are capable of mutating under field conditions into HPAI viruses. The virus is shed in fecal droppings, saliva and nasal discharge of some avian wildlife species and infected domestic poultry. Contaminated water has become a common source of infection for birds.
The clinical signs of birds affected with all forms of AI may show one or more of the following:
- Sudden death without clinical signs
- Lack of energy and appetite
- Decreased egg production
- Soft–shelled or misshapen eggs
- Swelling of the head, eyelids, comb, wattles, and hocks
- Purple discoloration of the wattles, combs, and legs
- Nasal discharge
- Coughing, sneezing
- Lack of coordination
Although different subtypes of type A AI have been identified, the subtypes most often associated with high pathogenicity avian influenza (HPAI) with high morbidity and mortality in birds are H5 and H7. There has been an H5N1, HPAI subtype circulating in Southeast Asia since 1997. It is of concern to public health because it has spread from birds to people. However, H5N1 has accounted for only a relatively small number of human illnesses. H5NI is considered to have the potential to become pandemic , since it is a novel strain for the human population (with no human immunity), and it has resulted in severe morbidity and mortality in the diagnosed human cases. The subtype would need to be capable of spreading easily from person to person, to become a human pandemic and that capacity has not yet been demonstrated.
High pathogenicity AI is a reportable disease nationally. Multiple agencies with oversight responsibilities for domestic birds and wildlife in North Dakota are currently tailoring an Avian Influenza Response Plan. The plan includes surveillance and monitoring activities as well as draft response procedures in the event high pathogenicity AI should ever be diagnosed in North Dakota.
Frequently asked questions
1. Are the flu viruses of human and birds the same?
In most cases, the influenza viruses that infect birds do not infect humans and vice versa. The first case in both humans and birds was discovered in Hong Kong in 1997.
2. What are the risks of getting avian influenza from waterfowl?
Avian influenza virus infections are widespread in wild birds, especially ducks. Migrating waterfowl are a significant source of avian influenza viruses especially in the major flyways. Turkeys on open ranges in Minnesota, a state in the major flyway for migrating ducks, frequently experience low pathogenicity avian influenza problems. But the prevalence of avian influenza in turkeys has been high in some years and minimal in others. The reason why influenza viruses come and go is not known. The risk of transmission of Avian Influenza to susceptible birds from contact with waterfowl must be considered, although it may vary from year to year for unknown reasons.
3. Why can't I prevent infection by vaccinating my flocks?
Vaccines effectively prevent clinical signs of influenza infections in many species including poultry. However, the vaccines are not cross-protective for the 15 virus subtypes that can infect poultry. Since there is no way to predict which type will infect a flock, vaccines are generally not practical to prevent infections.
4. What should I do if I suspect avian influenza in my birds?
You should contact your veterinarian if you observe any of the signs of avian influenza, especially if they are accompanied by a drop in feed consumption and/or a significant drop in egg production. Because the signs of avian influenza are so variable, it is important to get the help of an expert for diagnosis.
If wanting more information concerning Avian Influenza, please contact Jeanne David, ND Avian Influenza Coordinator at 701-220-0151 or call our office at 701-328-2655.