Newcastle disease (Ranikhet)
The disease behind most sudden "the whole flock died in three days" losses in backyard poultry — and one that a few rupees of vaccine per bird prevents.
- Cause
- Avian paramyxovirus type 1
- Flock death rate
- Up to 100% unvaccinated
- Tell-tale sign
- Twisted neck, paralysis
- Control
- Lasota / R2B vaccine schedule
Overview
Ranikhet disease is caused by a paramyxovirus that infects chickens of all ages and many other birds. Virulent strains spread explosively: an infected bird sheds virus in its breath, droppings and eggs, and it travels on dust, feed bags, crates, footwear, wild birds and the wind. Village flocks are often infected from live-bird markets and newly bought birds.
With a virulent strain the first sign in an unvaccinated flock is often simply dead birds, with death rates approaching 100% over a few days. Birds that last longer show breathing distress — gasping, coughing, sneezing, a rattling wet sound — greenish watery diarrhoea, swelling round the eyes and neck, and a sharp fall or complete stop in egg laying, with soft-shelled and misshapen eggs.
A day or two later come the nervous signs that point strongly to Ranikhet: twisting of the neck so the head is upside-down or turned over the back (torticollis), circling, tremors, and paralysed wings and legs. There is no treatment. Control is a lifelong vaccination schedule — the cheapest and most important intervention in any poultry enterprise — backed by basic biosecurity.
This is a general guide, not a substitute for a veterinarian. Always call a vet for diagnosis, dosage and treatment of a sick animal.
Signs to look for
- Sudden deaths with no warning — often several birds found dead each morning, rising fast day by day.
- Breathing distress: gasping with the beak open, coughing, sneezing, and a wet rattling or gurgling sound, worse at night.
- Greenish or whitish watery diarrhoea, staining the vent feathers.
- A sudden drop or total stop in egg production, with thin, soft-shelled, rough or misshapen eggs.
- Swelling and puffiness around the eyes and neck; dullness, ruffled feathers, huddling.
- Nervous signs after a few days: neck twisted so the head is upside-down or over the back, walking in circles, tremors, wings and legs paralysed.
How it spreads
- Inhaling virus in dust and droplets in the shed; infected birds shed virus before they look sick.
- Droppings contaminating feed, water, litter and the ground; the virus survives for weeks in cool conditions.
- On crates, egg trays, feed sacks, vehicles, footwear and clothing moved between flocks.
- New birds from markets or other farms brought in without quarantine — the commonest way it enters a village flock.
- Wild and free-flying birds, rodents and flies; contaminated eggs and, rarely, day-old chicks.
Vaccination schedule
- A widely used backyard and layer schedule: Lasota (F1) strain by eye-drop or drinking water at 5–7 days, repeated at 4–5 weeks, then the R2B (Mukteswar) strain by injection at 8–10 weeks.
- Layers and breeders: a booster every 8–10 weeks, or R2B every 6 months, to hold immunity through the laying period.
- Backyard birds: at minimum, R2B once or twice a year for the village flock; align rounds with the pre-monsoon and post-monsoon high-risk periods.
- Give live vaccine in cool hours, use clean non-chlorinated water with skim-milk powder as a stabiliser for drinking-water vaccination, and use it up within a couple of hours.
- Only vaccinate healthy birds; a flock already incubating disease will not be saved by vaccinating during an outbreak.
Biosecurity and outbreak response
- Quarantine every new or returned bird for 2–3 weeks away from the flock.
- Keep a footbath with disinfectant at the shed door; limit visitors; do not share crates and equipment with other flocks untreated.
- Keep feed and water clean and covered; control rats and keep wild birds out.
- In an outbreak: report it (Ranikhet is notifiable), stop all bird and egg movement, isolate or cull affected groups on veterinary advice.
- Dispose of dead birds by deep burial with lime or burning — never throw carcasses onto a field or dump.
- Clean out litter, wash and disinfect the shed, and leave it empty for 2–3 weeks before restocking; vaccinate the new batch on schedule.
Animals affected
Open an enterprise page for its full feeding, breed and vaccination-calendar guide.
Frequently asked questions
My birds are dying fast. Can I treat Ranikhet with antibiotics?
Antibiotics do nothing against the virus. They are sometimes given to slow secondary bacterial infection, but they will not stop the outbreak. Vaccinating during an outbreak also rarely helps because birds are already infected. The response is isolation, movement control, safe carcass disposal and reporting — and then vaccinating the next batch properly.
Is it safe to eat eggs or meat from the flock during a Ranikhet outbreak?
Do not eat or sell birds that are sick or dying, and do not move eggs off an affected farm. Ranikhet can cause a mild, short-lived eye infection (conjunctivitis) in people who handle heavily infected material, so wear gloves and wash your hands. Thorough cooking destroys the virus, but during an outbreak the priority is containment.
How is Ranikhet different from bird flu?
Both cause sudden heavy poultry deaths and look similar in the shed. The nervous signs — twisted neck, paralysis, circling — are more typical of Ranikhet. Only a laboratory can tell them apart for sure, so any sudden large die-off should be reported to the veterinary department, which will arrange testing.
I vaccinate my chicks once. Why did laying hens still get Ranikhet?
One or two chick doses do not last a whole laying life. Immunity fades, and layers need a booster every couple of months or R2B twice a year. An unboosted flock, plus new birds brought in without quarantine, is the usual reason a "vaccinated" flock breaks with disease.
Signs, prevention and treatment follow ICAR, DAHD and state veterinary-university practice; vaccine schedules are the commonly notified ones and may vary by region or outbreak status. Always confirm with a veterinarian before treating an animal. editorial policy.