Newcastle disease 2

Clinical symptoms of Newcastle disease

The length of the incubation period varies, depending on the quantity, strength, infection route, and chicken resistance of the virus. The natural infection incubation period is 3 to 5 days.

1. Types

(1) Immediate viscerotropic Newcastle disease: mainly the most acute, acute and fatal infection, usually leading to gastrointestinal bleeding.

(2) Immediate pneumophilic Newcastle disease: It is mainly the most acute, acute and fatal infection, and is mainly characterized by neurological and respiratory system disorders.

(3) Moderate-onset Newcastle disease: characterized by respiratory or nervous system disorders, with a low fatality rate and only young birds dying.

(4) Slow-onset Newcastle disease: mild, mild or unobvious respiratory symptoms, reduced egg production rate.

(5) Asymptomatic slow-onset enterotropic Newcastle disease: only loose stools are seen, and spontaneous recovery occurs after a few days.

2. Typical Newcastle disease

Non-immune or immune-deficient chickens infected with viscerotropic and pneumotropic Newcastle disease strains.

3. Atypical Newcastle disease

Violent or attenuated infection, infected at a certain immune level.