Six-week-old susceptible specific pathogen free chickens were infected intranasally with the virulent Newcastle disease virus strain Herts 33/56 and the levels of virus present in blood, faeces, breast muscle, leg muscle and a pool of heart/kidney/spleen were estimated in birds killed humanely at each day post inoculation. Highest titres were recorded at day 4 post inoculation when titres of virus were 10(6) median egg infectious doses (EID50)/g in the heart/kidney/spleen pool, 10(4.2) EID50/g in the leg muscle and 10(4) EID50/g in the breast muscle and faeces. A median oral infectious dose of Newcastle disease virus strain Herts 33/56 for 3-week-old chickens was estimated to be equivalent to 10(4) EID50.

Newcastle disease virus (strain Herts 33/56) in tissues and organs of chickens infected experimentally.

A survey of Newcastle disease in Swiss laying-hen flocks using serological testing and simulation modelling.

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Persistence of Disease Agents in Carcases and Animal Products Report for Animal Health Australia

La maladie de Newcastle (MN) greve lourdement les productions aviaires malgaches, essentielles a l'alimentation et a l'economie familiales. La MN est une dominante pathologique en l'absence de vaccination generalisee. L'objectif de cette these est la modelisation, la validation et l'analyse mathematique de modeles de transmission de transmission du virus de la MN (VMN) dans les systemes avicoles villageois en general et a Madagascar en particulier. Nous proposons de nouveaux modeles bases sur les connaissances actuelles de l'histoire naturelle de la transmission du VMN. Ainsi, nous presentons deux modeles mathematiques a compartiments de la transmission du VMN dans une population de poules : un premier modele avec transmission environnementale et un deuxieme modele ou la vaccination contre la maladie est prise en compte. Nous presentons une analyse complete de la stabilite de ces modeles a l'aide des techniques de Lyapunov suivant la valeur du taux de reproduction de base R0. Le travail s'est appuye sur des enquetes de terrain pour comprendre les pratiques de vaccination actuelles a Madagascar. (Resume d'auteur)

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Modélisation et contrôle de la transmission du virus de la maladie de Newcastle dans les élevages aviaires familiaux de Madagascar

Poultry products contaminated with pathogenic strains of Newcastle disease virus are a source of virus transmission to susceptible poultry flocks. The probability of contamination varies according to the type of product. Research conducted by various laboratories in Europe has shown that pathogenic virus can be isolated from the carcasses of chickens, whether vaccinated or not, during a brief period after experimental infection. Eggs laid by hens infected with Newcastle disease virus present a very low risk. Furthermore, feathers, bones, blood and offal present potential risks if they are incorporated in poultry feed. Finally, poultry droppings used as a fertiliser can present a major risk of infection in certain circumstances.

H. Le Coq

Papers

Risk for the transmission of Newcastle disease by contaminated poultry products