Newcastle Disease In Poultry: Prevention, Signs And Treatment
On a cool winter morning in Tsholotsho, a farmer walks into her chicken run and finds six indigenous hens dead, wings stretched, necks twisted. By sunset, half the flock is gone. Within three days, the yard is silent. For many Zimbabwean households, this is the familiar, painful story of Newcastle Disease.
Newcastle Disease (ND) is the most devastating poultry disease in Zimbabwe and across sub-Saharan Africa. It kills commercial broilers and village chickens alike, spreads fast, and once clinical signs appear, there is no cure. Yet for less than US$5 per 100 birds, a simple vaccine can stop this disaster before it starts.
What Is Newcastle Disease?
Newcastle Disease is caused by a virus called Avian Paramyxovirus type 1 (APMV‑1). There are several strains, ranging from mild to very severe.
- Mild strains may cause only slight respiratory signs.
- Velogenic (highly virulent) strains can kill up to 100% of unvaccinated birds within days.
It is the velogenic strain that is responsible for the sudden, large outbreaks seen in many parts of Zimbabwe, from rural homesteads in Gokwe to peri-urban broiler projects around Harare.
FFA Explainer:
“Velogenic” means a virus strain that causes severe disease and high death rates. With Newcastle Disease, these strains can wipe out an unvaccinated flock in three to five days — which is why vaccination is described by vets as non‑negotiable for sustainable poultry production.
How Does Newcastle Disease Spread?
The Newcastle virus is highly contagious and moves quickly between birds and farms.
Main routes of spread include:
- Direct contact: Healthy birds mixing with sick or carrier birds.
- Droppings and secretions: Infected faeces and mucus contaminate feed, water, and equipment.
- People: Virus carried on shoes, clothing, hands, and equipment from one flock to another.
- Wild birds and free-ranging chickens: Birds from neighbouring homesteads or surrounding areas can introduce infection.
- Live bird markets: Birds from many farms mix in crowded, uncontrolled conditions, making these markets a major source of spread.
For smallholders who sell and buy at township markets, basic hygiene — such as changing shoes and clothes before entering the chicken run — can slow this invisible movement of disease.
What Are The Signs Of Newcastle Disease?
Clinical signs vary with the strain, but some patterns are common.
Watch for the following signs:
- Sudden death of several birds with no prior warning.
- Respiratory signs: gasping, coughing, and rattling sounds when breathing.
- Nervous signs: twisted neck (torticollis), paralysis of wings and legs, circling or difficulty standing.
- Green or yellow‑green watery droppings.
- Swollen head and face in some birds.
- Sharp drop in egg production in laying birds.
- Depression, loss of appetite, birds huddling together and looking dull.
In outbreaks caused by velogenic strains, many birds may simply die overnight with few obvious early symptoms. If multiple birds die within 24–48 hours, especially when some show breathing or nervous signs, Newcastle Disease must be suspected immediately.
What Should You Do If You Suspect Newcastle Disease?
Speed is critical. Once ND enters a flock, every hour of delay increases losses and the risk of spreading it to neighbours.
If you suspect Newcastle Disease:
- Isolate immediately: Close off the affected house. No movement of birds, people, or equipment in or out.
- Contact experts: Call your nearest Agritex veterinary officer or a private veterinarian. A post‑mortem examination confirms the diagnosis.
- Report the outbreak: Newcastle Disease is a notifiable disease in Zimbabwe. Inform Agritex or the Veterinary Department so they can advise and monitor spread.
- Increase disinfection: Disinfect footwear, doorways, equipment, and any surfaces that may have come into contact with sick birds.
- Vaccinate unaffected birds: If there are birds on the property or nearby that have not yet been vaccinated, consult a vet or Agritex officer about emergency vaccination.
- Dispose of dead birds safely: Bury carcasses at least 60 cm deep and at least 30 metres away from any water source, or burn them. Never throw dead birds into rivers, dams, or open rubbish pits.
There is no antiviral treatment for Newcastle Disease. Antibiotics can sometimes help with secondary bacterial infections, but they do not kill the virus and will not stop an outbreak.
How Can Vaccination Prevent Newcastle Disease?
Vaccination is the only effective way to control Newcastle Disease. Without it, village flocks and broiler projects remain at constant risk. With it, outbreaks become rare and much less severe.
In Zimbabwe, the LaSota and V4 strains of ND vaccine are commonly used. They are available from suppliers such as Agricura, ZFC, and other veterinary outlets across the country.
Recommended vaccination schedules:
- Commercial broilers: Vaccinate at day 7–10 using eye‑drop or drinking water method, then give a booster at day 21.
- Layer pullets and hens: Vaccinate on arrival at the farm, boost at 8 weeks, then repeat every six months during the laying period.
- Indigenous village chickens: Organise mass vaccination of all birds in the village twice per year. Community‑level campaigns, often coordinated by Agritex or local NGOs, have been highly effective in reducing ND losses in communal areas.
For women and youth in districts like Mutoko or Zaka, who rely on chickens for school fees and household cash, these community vaccination days can mean the difference between growing a flock and starting again every dry season.
Why Is Vaccine Handling So Important?
Even the best vaccine fails if it’s handled incorrectly. Live ND vaccines are sensitive to heat, light, and time.
Key handling rules:
- Store vaccine in a refrigerator at 2–8°C.
- Never freeze live vaccines — freezing destroys them.
- Keep vaccine cool and shaded when travelling from the shop to the farm.
- Once mixed (reconstituted), use within the time stated on the package — usually within a few hours.
- Discard any leftover mixed vaccine; do not keep it for the next day.
Improperly stored or outdated vaccine will not protect birds. Farmers in parts of Mashonaland East have learnt to coordinate purchases so that several households vaccinate on the same day, sharing a vial and reducing waste.
Building Stronger Poultry Flocks
Newcastle Disease will remain a threat in Zimbabwe as long as unvaccinated birds move freely between homesteads, markets, and villages. Yet the solution is already in farmers’ hands — a low‑cost vaccine and simple biosecurity steps.
By working with Agritex officers, organising village vaccination days, and treating ND as the serious, notifiable disease it is, communities can protect their flocks, incomes, and nutrition. For the Tsholotsho farmer who has seen her yard emptied by ND more than once, the plan now is clear: vaccinate early, vaccinate regularly, and keep that chicken run door firmly closed to disease.
Article prepared by FFA Research Team | Farm Future Africa | farmfutureafrica.co.zw
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