Ranikhet disease

 

Introduction :

• Ranikhet disease, also known in the West as Newcastle disease. Newcastle disease is an infectious several virus disease of birds, caused by Paramyxovirus 1 and characterized by characteristic respiratory, alimentary and nervous signs.

• Although all the Newcastle diseases virus strains and isolates were considered to form a serologically homogenous group but recently developed monoclonal antibodies techniques have shown that considerable antigenic variation exists in the different strains of Newcastle diseases virus.

• Newcastle diseases virus has however, three strains viz (a) Highly virulent strains (b) Medium strength strains and (c) Mild strains.

• Newcastle diseases virus. has been demonstrated in at least 236 species from 27 of the 50 orders of birds.

• Although Newcastle diseases affects all the species of domestic poultry but outbreaks are mainly reported in chickens. 

• Although all ages and breeds of chickens are susceptible to Newcastle diseases but it produces severe disease in young's.

• Newcastle disease virus infect sischarge from the infected birds through infected droppings and respiratory discharges.

• Newcastle disease virus affected birds shed virus through respiratory discharge and droppings, transmitted to susceptible birds through inhalation and ingestion. Spread from infected farms to susceptible farms through equipment, trucks, personnel, wild birds of air.

Clinical signs :

• The severity of the Newcastle disease depend on the infecting virus , the host species and its age and immune status, confection with other organisms, environmental conditions, route of exposure and dose.

(a). Infection with the highly virulent viruses : 

• It may produce per-acute infections of fully susceptible chickens where the first indication of disease is sudden death.

• Typically, disease signs such as depression, prostration, diarrhoea, oedema of the head and nervous signs my occur with mortality reaching 100%.

(b). Infection with moderately virulent virus :

• These viruses usually cause severe respiratory disease, followed by nervous signs.

• Laboured breathing with wheezing and gurgling, accompanied by the nervous signs like paralysis of twisted necks are the main signs.

• The appearance of shell-less of soft shelled eggs, followed by complete cessation of egg laying may be an early signs in adult fowl.

(c). Infection with low virulence virus :

• These viruses may cause no disease, or mild respiratory sistress for a short time in chickens and turkeys.

Diagnosis :

• Although the history of outbreak, clinical signs and pathological changes are suggestive for Newcastle disease but none of the clinical signs of lesions of Newcastle disease may be regarded ad pathognomonic.

• Virus isolation and identification are the common methods for the diagnosis of Newcastle disease.

• Diagnosis is made by virus isolation from tracheal of cloacal swabs.

Treatment :

• There is no satisfactory treatment due to viral etiology but some poultry raisers use potassium per manganet 0.01% in drinking water, some farmers use sulphadiazine of sulphamethazin 0.5%  in feed to cheek secondary infection.

Control :

• Vaccination against Newcastle disease with live or inactivated adjuvant vaccines is the only reliable control method.