Vaccination is a crucial practice in poultry farming. It helps protect the flock from disease transmission and outbreaks. Vaccination involves introducing antigens or vaccines into the body to create immunity from a certain disease. Administering vaccines to poultry birds prevent them from contracting different forms of chicken diseases. However, vaccines are often limited to one type of illness.
Poultry farmers in Kenya vaccinate their flock against several common illnesses including:
Marek’s Disease (MD)
Marek or fowl paralysis is a highly infectious airborne illness. It is caused by chicken herpes virus. Affected flocks carry the virus throughout their life. Due to the high susceptibility of young birds to Marek’s disease, it is necessary to vaccinate the newborn chicks in the hatchery on the day they hatch.
Transmission
Infection occurs when birds inhale virus-laden dander. The dander could be spread by the poultry handlers on shoes, clothing, skin, hair, and hands. This virus can live in the dander for years. Therefore, once the disease is in the poultry house, the coop can remain contaminated for years even when all birds are gone.
Signs
- Bird sits in a splay-legged position (Legs stretched to the side)
- Legs stretch in opposite directions (forward and back)
- Death due to starvation or trampling by other birds
- Tumors in internal organs such as liver, lung, heart, ovary. Sometimes, the tumors may be present in the feather follicles, eyes, and the nervous system Weight loss, emaciation, and eventually death
Gumboro
Also known as the infectious bursal disease, the viral illness is highly infectious and causes severe death in young flocks. The infectious bursal disease virus can survive in the poultry environment for long period up to four months.
Transmission
Transmission occurs mainly via the oral-fecal route when the poultry ingests contaminated faeces and other organic materials. The disease affects the immune system of young flocks by damaging the B lymphocytes in their immature stages in the Bursa. The bursa is a lymphoid organ that offers a favorable microenvironment of B lymphocytes, the types of cells responsible for antibody production.
Birds are highly susceptible between the third and sixth weeks of age. At this age, the bursa is developing at the peak rate and filled with B cells.
Signs
- Watery, whitish diarrhoea
- Inflammation of the cloaca
- Soiled vents (a vent is the opening where the bird releases waste and eggs)
Newcastle
Newcastle is a devastating viral disease that spreads rapidly. The causal organism is a paramyxovirus. This highly contagious illness can lead to the death of many birds without showing any signs of infection.
Transmission
Transmission can occur through direct contact with dropping and discharges from the nose, mouth, and eyes of infected birds. Human can spread the virus carrying material from the infected flock to the healthy one through their shoes and clothing. Other potential routes of transmission include contaminated feed, water, equipment, and vehicles. The virus enters the body through the mucosal membrane, rapidly multiplies in the epithelium, and spreads through the bloodstream to other organs.
Signs
The main signs include:
- Sneezing
- Discharge from the nostrils
- Coughing
- Greenish, watery diarrhoea
- Depression
When the disease is severe, you may notice the following signs:
- Muscular tremors
- Drooping wings
- Complete paralysis
- Twisted neck
- Sudden death
- For the laying birds, you may realize a partial to complete decline in egg production; and the production of thin-shelled eggs
Fowl Pox
Fowl pox is a viral illness caused by a DNA virus of the genus Avipoxvirus and the family Poxviridae. The milder form (dry fowlpox) affects poultry in the non-feathered areas, especially the wattles, comb, face, and eyelids. A more severe form of the disease (wet fowlpox) affects the diphtheritic (wet) membranes lining the upper respiratory system.
Transmission
Biting insects such as mosquitoes are culprits in transmitting the fowlpox virus into backyards. The disease may then spread within the flock through infected skin dander, scab secretions and blood, sloughed-off scabs, feathers, and feather debris.
Symptoms
Dry Fowlpox
- Dry, crusty scabs on featherless areas which start as blisters, before turning yellow and then brown or black
Wet Fowlpox
- Lesions in the mouth and throat that resemble infected ulcers
Fowl Typhoid
Fowl typhoid is a bacterial disease caused by Salmonella enterica Gallinarum. The disease is observed in the later growth stages and in mature birds.
Transmission
The disease can be transmitted vertically or horizontally. Vertical transmission occurs when infected breeder hens lay eggs resulting in infected chicks. Horizontal transmission can occur through dropping or dead carcasses of infected birds.
Signs
- Loss of appetite
- Ruffled feathers
- Dehydration
- Sticky diarrhea (yellow-green)
- Pale shrunken comb/wattles
Immunization
Farmers may build a vaccination schedule around two fundamental concepts. These include:
- The poultry farm’s requirements
- A disease that is common in the area around the farm
For more information on the appropriate poultry vaccination program in Kenya, you can visit https://www.kenchic.com/health-management/. Besides, seek help from your nearest registered vet for assistance.
Appropriate administration of immunizations helps in the development of immunity that makes the birds resistant to the illnesses against which they have been vaccinated. However, immunization works in tandem with other practices including appropriate biosecurity, proper hygiene, and sanitation.