Ranikhet Disease in Poultry-Current Scenario

Newcastle disease/Ranikhet disease in poultry is caused by Avian Paramyxo Virus-1. It is an Endemic disease in India.

There are around 22-23 different serotypes/genotypes isolated in different parts of the world and it is/was considered to have cross protection among the strains.

The more popular strains are Serotype-2, 7 and 13B. This  13 B strain of the virus has become recently more popular and of more concern and it is considered to be responsible for recent severe Virulent NDV outbreak in many parts of India.

Current Outbreak–

• The current outbreak of ND in North India started from Commercial layers mainly in Barwala belt in November 2021 , causing around 40% average depletion in growing birds from 3^rd week to 13 week of age.
• Later the outbreak came in commercial broilers causing around 50-70% depletion.
• March and April 2022, broiler breeder also got outbreak from 3^rd to 12^th week of age , causing around 10-15% depletion in female and 20-25% depletion in males.
• Earlier age the outbreak came, more depletion was there as disease got coupled with IBD infection.
• The duration of disease observed is 10 days to even 40 days in some cases.
• Luckily not many cases of NDV outbreak were heard in laying stage of birds as laying birds being more vaccinated and having better protective antibody titers against the virus.
• Sporadic outbreaks still there in layer and breeder growing flocks but severity of disease is somewhat less.

Diagnosis of NDV infection

–The disease can be diagnosed by

• Signs and Symptoms of the disease
• PM Lesions of the disease
• HI and Elisa Titres ( exposed titres)

  RT-PCR

• The disease being per-acute, sudden onset of the disease and high mortality observed.
• Disease showed mainly Viscerotropic Velogenic outbreak initially ,which post 10-12 days of outbreak , got converted to Neurotropic form.
• During Viscerotropic form-we could see severe Proventricular hemorrhage on tips and in some cases , hemorrhage was there in gizzard also.
• There are typical Paint Brush Hemorrhage in  Proventriculus.
  • We could see button ulcers in intestine which are pathognomonic lesion of ND and hemorrhagic and inflamed caecal tonsils also.
• In some cases , kidneys were also severely damaged , might be due to coupled IBD  infection.
• In Neurotropic form , we could see lot of cases of torticollis and circling.

Treatment of disease –

How to prevent losses once outbreak is there-

•    Supportive  treatment-triple salts, antipyretics, immunomodulators etc. helped to reduce losses.
•   Double dose of Lasota live vaccine in drinking water helped in most of the cases.
•   Some tried Lasota live vaccine by  IM injections-  but more mortality were observed due to handling stress  and needle  transmission of disease in higher number of birds.

•   Concentrated  broiler vaccines and Genotype 13 killed vaccine done by changing vaccinator needles also helped to some extent.

Prevention of ND outbreak-

Vaccination is the ultimate protective tool against the disease.

Available vaccines against NDV- Live vaccines mainly Lasota and Cloned Lasota strains, R2B Live vaccine and killed/attenuated vaccine having genotype 2 , 7 and 13B and concentrated ND  killed available from different companies.

• Farm and shed hygiene , sanitation and strict Bio-security measures  are must for preventing the disease.
• Better Immunity of the birds crucial for disease control.
• Suggestive  Vaccination for broiler breeders in   affected area/ farms having recent outbreaks-

–        5-7 days- Lasota live eye drop

–         8-9 days- ND( genotype 2 and 13B) + IB +IBD killed @ 0.25 ml/bird

–       4^th week- ND+IB live eye drop

–       4-5^th week- Broiler concentrated vaccine @ 0.2-0.25ml/bird

–       9-10^th week- ND killed ( genotype 2 and 13B)

( Vaccination schedule is just recommendary  , it can vary from farm to farm and area to area).

Note – the article is based on actual field experience and different technical person might have different opinions on certain disease issues.