Major poultry diseases and their control

Diseases pose a major challenge in poultry farming and can cause significant economic losses if not properly managed.Understanding common diseases, their modes of transmission, symptoms, and control methods is crucial for every farmer.

This article highlights the most critical poultry diseases impacting farms in Kenya and how farmers can prevent and manage them.

 Gumboro disease

 The Gumboro virus is highly resilient. It can survive for a long time in the environment. It resides among wild birds and backyard chickens, poultry manure, farm visitors’ shoes and clothes, and is occasionally brought in by rodents, pets, and darkling beetles. You can introduce infection by allowing sick birds into your healthy flocks.

 How do you recognise Gumboro in your flock? Gumboro only affects young birds. In broilers, the disease affects birds at 21–28 days of age. In long-living birds such as layers and improved kienyeji (indigenous chicken), the disease affects flocks between three and eight weeks old.

Birds already in egg production do not get Gumboro disease. Common signs include sudden loss of appetite, depression, and weakness. Birds will display ruffled feathers (looking cold), huddle together, and discharge whitish, watery diarrhoea.

 If you do not vaccinate your birds, during a disease outbreak, you could lose up to 30 per cent of the flock. How can you control and prevent Gumboro?

 Vaccination remains the most effective and reliable method to control Gumboro. Always follow a proper vaccination schedule recommended by a poultry professional. You can also practise strict biosecurity measures. Other important biosecurity steps include thoroughly cleaning and disinfecting houses after each flock, avoiding keeping birds of different ages on the same farm, and controlling rodents, beetles, pets, and wild birds.

 Respiratory diseases

 There are viral and bacterial diseases that cause respiratory distress in poultry. These diseases often display similar clinical signs, making it difficult for a lay farmer to distinguish them. Such diseases include Mycoplasma, Newcastle disease, infectious bronchitis, Coryza, E. coli, and aspergillosis.

 A nearby veterinarian should be contacted for accurate diagnoses and treatments based on a comprehensive flock examination and laboratory tests. Proper vaccination is a vital part of poultry rearing, with tangible benefits in controlling both viral and bacterial diseases. The main aim of vaccinating any poultry flock is to lower the incidence of clinical disease and support optimal performance.

 In countries where vaccination programmes are mandated by legislation or promoted through awareness campaigns, most respiratory diseases have been entirely eradicated, including coryza, fowl cholera, mycoplasma, Newcastle disease, and chronic respiratory disease.

 Fowlpox disease 

Fowlpox is a disease affecting poultry such as chickens, turkeys, pheasants, and even ducks. It primarily occurs in older birds and is characterised by the appearance of warts or blisters on the skin of the head, wattles, and comb, and can spread to the skin on the back and legs. This form of fowlpox is known as the cutaneous type and is rarely fatal. Affected birds usually recover within two weeks without any treatment. The other form causes similar lesions but on the mucosal (inner) surfaces of the buccal cavity and respiratory linings and, in rare cases, can affect internal organs like the liver and kidneys.

 This is called “Wet Pox” and may result in mortality rates of up to 50 per cent in a non-vaccinated flock.

 There is no specific treatment for Fowl pox disease; affected birds tend to recover naturally if there are no secondary bacterial infections. For severe lesions, spraying the affected areas with iodine or Vetmycin spray can help. To control the disease, it is essential to vaccinate the birds at 5-6 weeks old using live vaccines administered via the wing-web stab.

 Poultry diseases such as Gumboro, respiratory infections, worm infestations, coccidiosis, and fowl pox can significantly reduce farm productivity if not properly managed. Early detection, vaccination, good hygiene, and strict biosecurity measures are crucial for maintaining a healthy flock.

 Farmers who prioritise disease prevention over treatment are more likely to achieve better performance, lower costs, and higher profits.

 [Dr Messo is the company vet, Kenchic; watssonmesso@yahoo.com]