Multiplex Newcastle Disease

Newcastle disease virus (NDV) is a paramyxovirus causing severe respiratory, neurological, and systemic disease in poultry with significant economic impact globally, particularly in developing countries. The virus causes Newcastle disease characterized by fever, respiratory distress, neurological signs including tremors and paralysis, diarrhea, and sudden death. Virulence varies widely depending on virus strain, ranging from asymptomatic infections to highly lethal infections causing 90-100% mortality. Multiple genotypes circulate worldwide with different geographic distributions and virulence profiles. Lentogenic (low virulence), mesogenic (intermediate virulence), and velogenic (high virulence) strains are recognized. Vaccination is widely practiced but vaccine-escape variants continue to emerge.