The following is the forwarding message. Please spread it out to others and local newspapers.
OT: Pigeons and the Avian Flu Scare
Everyone, please spread the word to all animal lovers you know and to all your contacts at whatever animal protection organizations you have any:
The H2N1 Asian avian influenza concern is URGENT. Pigeons are probably being killed right now this minute by people who don't know they don't spread it.
Pigeons have been studied and appear to be immune to the Asian "avian flu" virus (H5N1 virus). After innoculating the virus into pigeons, scientists were not able to find any virus in the pigeons and the pigeons did not get sick. So the virus appears to be unable to survive in pigeons and these birds cannot spread the disease. The
presence of antibodies to the Asian Bird Flu virus only means the pigeon was exposed. The bird does not harbor communicable virus:
Avian Influenza in Pigeons
Various studies have been carried out to determine the role of | pigeons in the spread of avian influenza. These studies have determined that pigeons are resistant or minimally susceptible to infection with HPAIV or NPAIV and probably play a minimal epidemiological role in the spread of the viruses.
For further information see the following two articles:
Pathogenicity of a Hong Kong-origin H5N1 highly pathogenic avian influenza virus for emus, geese, ducks, and pigeons. Perkins LE, Swayne DE
Pigeons were inoculated intranasally with A/chicken/Hong Kong/220/97 (H5N1) highly pathogenic avian influenza virus. They seemed resistant to infection not showing any clinical signs or gross and histologic lesions and the virus was not re-isolated.
Susceptibility of pigeons to avian influenza. Panigrahy B, Senne DA, Pedersen JC, Shafer AL, Pearson JE Pigeons were inoculated with non-pathogenic avian influenza virus
To date, however, the body of scientific evidence indicates strongly that pigeons are not involved in the transmission of Avian Influenza to domestic poultry.
During an outbreak of Avian Influenza (H5N2) nine years earlier (1983-84), again in the north-eastern USA, scientists conducted a survey of wildlife to determine the potential of wild birds to spread disease locally among farms, or to carry the virus to more distant locations.
Included in this survey were
- wild and free-flying domestic ducks and geese,
- wild or free-flying domestic birds closely associated with poultry farms, poultry manure, or poultry carcasses,
- mice and rats found inside and around houses containing infected poultry, and
- wild birds of any species reported sick or dead within the quarantine zone.
Tracheal (windpipe) and vent swabs from birds and lungs from mice and rats were examined for virus. As well, in some instances, toes from birds and rodents were also collected for the same purpose. When feasible, blood samples were also obtained from birds and small rodents. Attempts to isolate virus were conducted on 4,132 birds and rodents collected within the quarantine zone. Included in this number were 473 pigeons (92.6% of these pigeons were obtained from known infected farms), 81 pigeon feet (all of them from influenza-affected premises), and seven mourning doves. None of the 4,132 samples was positive for influenza virus. Blood samples from 2,147 non-aquatic birds, including 383 pigeons, were negative for antibodies to Avian Influenza - an indication that infection by this virus had not occurred in these birds. An additional 313 birds, including 50 pigeons, collected from the quarantine zone, were also negative for influenza virus. It is important to note that experimental attempts to infect pigeons with this strain of Avian Influenza did not result in either multiplication of the virus in these pigeons, or evidence of antibodies in the blood. The results of all of these studies indicated that pigeons were not infected with Avian Influenza and did not spread it.
In the 1993 outbreak in the USA, in the period from February to May, blood samples were collected from 17 flocks of meat varieties of pigeons, mainly White Kings located within the quarantine area, for evidence of antibodies to Avian Influenza. Flock sizes varied from 2000 - 3000 birds, and represented a total of about 34,000 - 51,000 birds. Approximately 10 birds per flock were sampled, for a total of 160 birds. In every instance, all pigeons tested were negative for antibodies to Avian Influenza.
Another study published in 1996 on the susceptibility of pigeons to Avian Influenza, found that groups of pigeons inoculated with two strains of highly pathogenic influenza virus or two strains of non-pathogenic virus remained healthy during the 21-day trial period, did not shed virus, and did not develop antibodies to this disease - further evidence that pigeons are not a factor in the spread of this disease.
More recent evidence from experimental work in 2001/02 has shown that pigeons infected experimentally with the highly pathogenic form of the virus (designated H5N1, and of Hong Kong origin) did not develop signs of this disease and did not have detectable changes to this disease in their tissues. As well, virus was not found in their tissues and neither was it re-isolated from swabs of tissues. These findings indicated once again that pigeons (along with starlings, rats and rabbits used in these studies), are largely resistant to infection with this virus.
Despite these reassuring findings, fanciers should be aware of the very slight possibility that if a returning race bird, or any wild bird for that matter, drops into a poultry farm on which the chickens are infected with Avian Influenza; it could pick up the influenza virus on its feet as it walks through droppings from these infected chickens. If this bird were to fly to another poultry farm, in theory it could be a mechanical means of spreading the virus on its feet to chickens on the second farm. The importance of this fact is that Type A influenza viruses can remain viable for long periods at moderate environmental temperatures, for four days in water at 22oC (72oF), and for over 30 days at 0oC (32oF). However, as noted in earlier studies, the feet of pigeons collected from affected poultry farms were examined for influenza virus and all were found to be negative.
Given this information from the scientific literature, it is important to note the non-role of pigeons in the spread of Avian Influenza, and the fact that pigeons themselves are not infected by this virus.
The reasons for the understandable caution and concern by regulatory agencies when they are faced with outbreaks of Avian Influenza include the fact that it can be a very costly disease. For example, the US government spent over $60 million in 1983-84 to eradicate a highly pathogenic H5N2 virus in poultry flocks (both chickens and turkeys).
I hope that this brief look at Avian Influenza and the non-role of pigeons in the spread of this disease to poultry will be of some assurance to concerned fanciers. Further information on this disease can be obtained from federal or provincial/state governmental agencies.