Newcastle disease in poultry
Recognising Ranikhet disease, why vaccination timing decides the outcome, and biosecurity that actually works.
Newcastle disease, known locally as Ranikhet, is the most destructive viral disease of poultry in Pakistan. Velogenic strains can take an unvaccinated flock to near-total mortality within a week.
Signs
- Sudden deaths with no preceding illness
- Gasping, coughing, rattling breathing
- Greenish watery droppings
- Twisted neck, tremors, paralysis in survivors
- In layers: a sharp drop in production, soft-shelled and misshapen eggs
There is no treatment
Once a bird is infected, nothing cures it. Antibiotics are sometimes given to control secondary bacterial infection, but they do nothing to the virus. Everything that matters happens before the outbreak.
Vaccination
A typical broiler programme uses a live lentogenic vaccine at day 5-7, a booster around day 18-21, and an inactivated vaccine where a longer-lived flock justifies it. Layers need a more extensive programme carried through the laying period. Exact timing depends on maternal antibody levels and local challenge, so set the programme with a veterinarian rather than copying a neighbour's.
Biosecurity that actually works
- One age group per site where possible; all-in, all-out
- Footbaths at every shed entrance, with the disinfectant actually changed
- No visitors into sheds, and no shared equipment between farms
- Control wild birds and rodents - they move the virus between sites
- Dispose of dead birds by burial or burning, never by dumping
- Clean and disinfect thoroughly between batches, and leave the shed empty for a period
If you suspect an outbreak
Stop all movement of birds, people and equipment off the farm, and contact a veterinarian immediately. Moving apparently healthy birds out of an infected flock is how a farm outbreak becomes a district outbreak.