Newcastle disease is also a dangerous viral disease and must be reported. Due to the very similar clinical picture, it is also called atypical avian influenza. The virus itself belongs to the genus Rubulavirus, which causes mumps in humans or kennel cough in dogs.
[/dv_infobox]The Newcastle virus itself is distributed across all age groups in chickens and can in individual cases lead to conjunctivitis in humans.
Once the viral infection has broken out, control of the disease is extremely cost intense, because the Newcastle disease pathogen has a variety of ways to spread:
- Infected animals excrete the viruses via feces, body fluids, nasal, throat and eye secretions and the air they breathe.
- The pathogens can also be distributed via eggs, fresh meat, frozen meat (can last up to six months) and dried egg (can last for several years).
- Further distribution is also possible via cages, packaging material, stable dust, shoes, clothing and car tyres.
Unspecific changes in dead chickens, i.e. changes that can also occur with other diseases, are:
- Organ swelling
- An increased blood filling of the ovaries
- Nasal and beak fluid retention
Specific changes in dead chickens are primarily selective bleeding on the glandular mucosa and on the surface of the heart, as well as bleeding of the muscle stomach and on the inner wall of the abdominal cavity. In the case of a prolonged infection, there are also crumbly deposits in the intestines.
Due to its similarity to classical avian influenza, it is not easy to see whether it is an atypical avian influenza or the classical one.
Detectable characteristics in the behavior and appearance of the chickens cannot be clearly assigned to either of the two viral infections:
- Drastic decline in laying performance
- Thin-shelled/shellless eggs
- High fever up to over 42 degrees
- Apathy and loss of appetite
- Diarrhea, possibly also bloody
- Shortness of breath, beak and eyes are covered with a thick slime
- Circulatory problems
Only a blood test in the laboratory can clearly clarify whether it is a classical or an atypical avian influenza, i.e. Newcastle disease. If the blood test reveals Newcastle disease in the chickens, the Veterinary Office will set up a restricted area for poultry within a radius of three kilometres.
Furthermore, the breeder is instructed to keep his hens exclusively in the barn for at least three weeks, to slaughter the infected animals immediately, as well as to disinfect the affected stables, buildings and transport vehicles.
In addition, restrictions may be imposed on persons and traffic.
Unfortunately, a cure for Newcastle disease is still not possible.
Strict operational hygiene minimizes the risk of the Newcastle pathogen being introduced:
- Rodent control
- Avoidance of wild birds
- A restriction of vehicle and passenger traffic
- The installation of a disinfection lock (especially for larger farms)
Apart from industrial hygiene, vaccination is of course the most effective method to prevent an outbreak of the infection so far.
According to the Avian Influenza Ordinance, regular vaccination of chickens is compulsory, this also applies to private individuals with small chicken populations and is confirmed by a veterinary certificate. Vaccination usually takes place in drinking water and is repeated several times to ensure adequate protection.
As already described for Marek’s disease, care must be taken not to reassemble freshly vaccinated animals immediately with unvaccinated animals. Vaccine viruses live and can therefore infect unvaccinated chickens with Newcastle disease.