Newcastle Disease

NCD

Changed on: 14.12.2020
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Newcastle disease (NCD, avian pneumoencephalitis) is a highly contagious, acute to chronic disease of birds caused by highly virulent strains of avian avulavirus 1 (so-called avian paramyxovirus 1, APMV-1).

Occurrence

Newcastle Disease occurs worldwide

Host animals

All species of birds, wild birds and poultry

Mode of transmission

Direct transmission via all body fluids (faeces, eye, nose and throat secretions), indirect transmission via air and objects. The virus can also be transmitted to the chick already in the egg.

Incubation period

4 to 7 days

Symptoms

Cold symptoms, diarrhea. The clinical picture is reminiscent of avian influenza ("bird flu").

Therapy

There is no treatment for Newcastle Disease.

Prevention

Newcastle Disease is an animal disease that is notifiable under the Animal Diseases Act. Prophylactic vaccination is permitted in Austria and is also carried out on chickens, turkeys and pigeons (carrier and breeding pigeons).

Situation in Austria

Newcastle Disease was last detected in poultry in Austria in 1997, but is observed sporadically in wild pigeons.

Newcastle Disease is a notifiable disease. The occurrence of clinically suspicious symptoms must be reported to the official veterinarian, who takes samples and sends them for diagnosis. Only highly pathogenic types of virus are declared as a disease if the virus has a pathogenicity index (ICPI) of 0,7 or higher and if sequencing is used to identify a velogenic pathotype of the virus strain. Different control provisions apply to commercial poultry than to pigeons kept for breeding purposes (carrier pigeons).


Legende

    Professional information

    The causative agent of Newcastle Disease is the Newcastle Disease Virus (Avian Avulavirus 1, APMV-1), a single-stranded RNA virus from the Paramyxoviridae family. NDV is assigned to the genus Avulavirus. A distinction is made between apathogenic, lentogenic (low virulence), mesogenic (moderate virulence) and velogenic (high virulency) virus types. The symptoms depend on the virulence of the pathogen.

    In bone marrow and muscles of slaughtered poultry, the NCD virus remains infectious at -20 ⁰C for 6 months, at 1 ⁰C up to 134 days. In contaminated henhouses the virus remains infectious for 30-25 days, depending on the ambient temperature. Dried virus particles can be infectious for years.

    The virus is spread directly, by air or by objects. The spread of the disease is favoured by the high tenacity of the virus and the wide host spectrum. Sources of infection are often clinically inapparently infected, diseased animals or animals in the incubation period.

    NDV is shed in large quantities in faeces, eye, nose and throat secretions and all other body fluids. Shedding lasts for about 26 days; in vaccinated animals about 40 days. The pathogens are spread directly from animal to animal as well as indirectly via all equipment, stable dust and air, shoes and vehicles. Transovarian virus transmission plays a major role, with infected chicks hatching from NCD virus contaminated eggs.

    Trading with live or slaughtered poultry or poultry products plays a role in the new introduction of the disease into disease-free regions (also via frozen poultry!). Virus transmission is also possible via feeding of kitchen waste, litter, feed, housing equipment and transport containers. In comparison, the probability of transmission via wild birds is low. With regard to wild birds, waterfowl and wild poultry are a natural reservoir for epidemics.

    Newcastle Disease is spread worldwide. Due to control measures, the disease has lost importance in recent years. In July 2018 an outbreak was reported in Belgium in domestic chickens.

    Diagnostics

    Laboratory diagnosis is based on pathogen detection from tracheal/oropharyngeal (throat) and cloacal swabs as well as from animal bodies (CNS, lung, liver, kidney, heart, intestine) using specific molecular biological methods (RT-qPCR, RT-PCR and additional pathotyping) and by virus cultivation in egg culture followed by haemagglutination (HA) and haemagglutination inhibition (HAH) tests. The detection of antibodies by ELISA and HAH is possible, but can be evaluated depending on the situation if vaccination is allowed.

    Diseases that should be considered for differential diagnosis:

    • Acute increase in mortality
    • Respiratory disorders
    • Disorders of the CNS
    • Drop in laying performance
    • Reduction of weight gain
    • Petechial hemorrhages on seroses

    e.g. infectious bronchitis, infectious laryngitis, avian influenza, Marek's disease, avian cholera, mycoplasmosis, deficiency symptoms.

    In case of slightest suspicion, the official veterinarian in charge must, after contacting the National Reference Laboratory by telephone (+43 50555 38112, 0664 9670940), send the required samples to the National Reference Laboratory.

    Type of sample for sampling:

    Live animals:

    • Throat and cloacal swabs (no bacteriological swab transport medium)
    • Serum

    Samples from dead animals:

    • Organ material, especially brain, lung, liver, kidney, heart, intestine

    Sample transport and short-term storage: at +4 °C

    OIE detection methods:

    Direct pathogen detection:

    • Rapid diagnosis: quantitative RT PCR, conventional RT-PCR
    • Typing by sequencing: determines pathogenicity of the virus (low or high pathogenicity)
    • Virus detection via egg culture and haemagglutination: Pathogen detection is performed by inoculating organ suspensions from brain, lung, liver, kidney and heart of diseased animals into the allantoic cavity of 9-11 day old chicken embryos

    Indirect virus detection (antibody detection):

    Antibodies can be detected in chronic diseases, but the vaccination status of the animals must be taken into account.

    • Hemagglutination inhibition

    Contact/Forms

    Institute of Veterinary Medicine Mödling (= National Reference Laboratory)

    Robert Koch-Gasse 17
    2340 Mödling

    Tel: +43 50 555-38112
    E-mail: vetmed.moedlingno@Spam@agesno.Spam.at

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