Current information on Newcastle Disease found in birds kept for hobby purposes
The causal pathogen of the disease, paramyxovirus type 1 (PMV-1), has so far been found in six hobby bird facilities. Newcastle disease has not yet spread to a single poultry production farm in Finland. Samples have been taken from several poultry farms and backyard flocks in the vicinity of the infected properties in order to discover a possible spread of the infection. All such samples has proven negative.
At the beginning of June, pigeons were delivered from Outokumpu, Eastern Finland, to Finnish Food Safety Authority Evira for examination as to the cause of death. In the cote in question 20 birds out of 60 had died, most of which were young. The pigeons were found to have Newcastle disease, hence all of the birds in the cote were destroyed and the premises disinfected. Evira is investigating the possible origin and spread of the disease. A significant spreader of the disease was shown to be a cat show held in Pirkkahalli in Tampere on 17.5.2008, where there also were pigeons on show.
All bird species can be infected with PMV-1, but the sensitivity to the disease varies between the different species. Newcastle disease can spread easily amongst birds kept for hobby purposes as the hobby involves different gatherings and the movement of the birds.
In Finland only pigeons are permitted to be vaccinated against Newcastle disease
In Finland the use of vaccines against Newcastle disease is prohibited pursuant to legislation (33/EEO/95; Veterinary Legislation D 39), with the exception of the vaccination of pigeons. All pigeons kept in those cotes from which carrier pigeons, purebred or pigeons kept for ornamental purposes are sent to competitions or exhibitions have to be vaccinated once a year against Newcastle disease. Vaccination of pigeons for other purposes than the abovementioned is voluntary, but it is recommended.
Birds that are to be vaccinated must have identification marking
Birds to be vaccinated against Newcastle disease must have identification marking. The vaccine preparation can be acquired by veterinarians with a special permit. The veterinarian has to report the vaccinations given to the provincial veterinary officer. If the distributor of the vaccine is not a municipal veterinary officer, the vaccination has to be reported also to the municipal veterinary officer. More information on the vaccinations are found on Evira's Internet pages in Finnish at www.evira.fi > Eläintauti- ja elintarviketutkimus > Terveydenhuolto > Rokoteneuvonta.
Pigeons that are taken to a competition or exhibition have to have an individual permanent identification ring or microchip and a valid vaccination certificate stating that the bird has been vaccinated against Newcastle disease. The organiser of the competition or show has to identify each bird and check the accompanying vaccination certificate to see that the bird has a valid vaccination. The organiser of the competition or show also has to report well in advance to the provincial veterinary officer that the event is being organised.
Newcastle disease does not normally transmit to humans
Newcastle disease is caused by paramyxovirus type 1 (PMV-1). Several different forms of Newcastle disease are differentiated and these are caused by viral strains of varying pathogenic ability. Pigeons have their own paramyxovirus strain. Apart from the species, factors affecting the symptoms of Newcastle disease are the pathogenic ability of the viral strain, the age and resistance to the disease of the birds and other infections and environmental factors. The symptoms can be apathy, diarrhoea and symptoms of the central nervous system and the respiratory tract.
In the most serious cases, the mortality rate can suddenly increase to 80–90 per cent without previous symptoms, especially in young birds. The only symptom in adult laying hens can be a decrease in egg production. The incubation time, that is to say the time from picking up the infection until it breaks out, is usually a few days. In a pigeon cote it can even be two weeks. The virus does not usually cause any symptoms in humans, though conjunctivitis has been described in literature.
The virus survives well and spreads easily
PMV-1 survives quite well in the environment and spreads easily from one bird holding facility to the next, for example with birds, feed, humans and transport vehicles. It can also spread with dust. The virus does not spread with the contents of the egg, but it is possible to be infected via a hatchery as the infection can spread with the eggshells.
The exposure of unvaccinated birds to the virus can be examined by looking for serum antibodies. The method is suitable for screening studies and surveys that clarify the disease situation in birds that have been in contact with infected premises. Identification of the virus in organ samples from sick birds or birds that have died is done by using a genetic multiplication technique (RT-PCR). The pathogenicity of the virus is studied using a sequence analysis and/or pathogenicity test on day-old chickens.
Veterinarian, Specialist in infectious animal diseases, Christine Ek-Kommonen, Animal Virology Research Unit, EviraVeterinarian Karoliina Alm-Packalén, Animal Virology Research Unit, Evira