Kari increases immunity of free range chicken with eyedrop vaccine

A new poultry vaccine has offered a solution to thousands of indigenous poultry farmers in the fight against Newcastle disease, locally known as Kihuruto or Kideri, responsible for over 90 per cent of deaths in free range chickens.

The live thermostable avirulent 1-2 ND vaccine, administered through eye drops, has been hailed by scientists and farmers as a breakthrough in the fight against the disease because previous vaccines have never been suitable for arid and rural areas.

Conventional Newcastle vaccines, like LaSota B1, F and V4-HR, require refrigeration during transportation and storage to be effective and are delivered in expensive packaging in sizes unsuitable for small flocks. However, the new vaccine can withstand harsh temperatures for lengthy periods, making it accessible in caring for the more than 26 million free range chickens reared in the country.

The vaccine also costs just Sh2 a dose, compared with over Sh50 a dose for other vaccines, and requires only one eye drop to protect the bird for four months. Scientists believe a gland in the eye of the chicken is responsible for producing antibodies to the disease, which is why they focused on eye drop administration as opposed to the traditional spraying of the chicken or placing the vaccine in water.

The uptake of the vaccine is now rising swiftly in rural areas due to heightened awareness from the Kenya Agricultural Research Institute (KARI) and Kenya Veterinary Vaccine Production Institute (Kevevapi).

”We realised that free range chickens were at even a higher risk of the disease that their broiler counterparts due to the contact the free range chickens have with the environment and with other chickens, bearing in mind that the disease is spread through contact with infected birds,” said Dr. Ann Mumbi from KARI.

The launch of the vaccine followed a successful trial in several districts in Kenya where indigenous chickens were surveyed over time. Less than 5 per cent of free range chickens in Busia, Nyandarua, Mwea and Mwingi districts had protective antibodies against Newcastle disease before they were vaccinated.

Three weeks after the vaccination, with only a dose of the 1-2 ND vaccine, the rate of protection increased to 62 per cent, and mortality was cut from 90 per cent to 10 per cent in household flocks.

“We also identified something interesting, in that Newcastle is spread through contact, the immunized chicken once in contact with un-immunized birds helped the un-immunized bird boost their immunity, albeit by a small percentage,” said Dr. Mumbi.

The new vaccine underwent laboratory tests in several countries including Mozambique, Tanzania and Vietnam and has proved to be protective against local strains of the Newcastle virus. In Vietnam, it has been officially recognized as the vaccine for local chicken, after extensive local trials.

In Tanzania, it has given protection to rural chicken for at least two months after vaccination, while results from field trials in Mozambique indicate that I-2 ND vaccine provides approximately 80 per cent protection in the face of an outbreak, when given every 4 months via eye drop.

All species of bird of all ages are susceptible to Newcastle, which is an acute to chronic condition and one of the most common poultry respiratory diseases worldwide. The common symptoms include watery eyes and persistent coughing, and gasping.

The disease also affects egg production and quality with brown broiler eggs turning to white eggs. The most catastrophic attack on poultry by the disease was in California and resulted in the death of 20 million birds.

Written by Bob Koigi for African Laughter

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