Viral Diseases of Poultry: Symptoms, Control, and Treatments

June 2, 2023 Agric4Profits

These are poultry diseases caused by a virus. Some examples of viral diseases of poultry include Newcastle disease, fowl pox, leucosis complex, and avian encephalomyelitis.

A disease is an unhealthy or abnormal physical state and/or appearance. It can be caused by living organisms (infectious agents) or faulty environments due to poor management. Chickens, like human beings, are subjected to many diseases and parasites.

There are even some poultry diseases with the same names like cholera, pox, typhoid, hepatitis, etc. Chickens are also known to suffer from internal and external parasites. Some poultry diseases and parasites can be prevented while others cannot be prevented.

Some cannot be controlled and cause death when contracted; others can be isolated and controlled. Some are present in the country and others are from foreign sources.

Unless diseases and parasites are accurately identified and prevented or controlled, they can cause huge losses of chickens and consequently loss of money.

The key is to prevent rather than to control. Poultry farmers need to be familiar with the causes and symptoms of the various common poultry diseases to plan an effective control program.

Viral Diseases of Poultry

These are poultry diseases caused by a virus. Some examples include Newcastle disease, fowl pox, leucosis complex, and avian encephalomyelitis.

1. New castle Disease/ Ranikhet Disease

It is a highly infectious and fatal viral disease. It attacks poultry of all ages. It is widely feared by those raising chickens worldwide.

When it occurs, the mortality rate can be as high as 100% in young chickens but lower in adult birds. The virus is transmitted through contact with chickens and other birds.

Symptoms – The most obvious symptom is a sudden high number of deaths. Other symptoms are nervousness, incoordination, and paralysis; respiratory distress (coughing, gasping for air, wheezing); greenish diarrhea with fowl odor; drooping head, inactivity, and drowsiness; distended crop; eventually, death.

In adult laying birds, symptoms may be loss of appetite, decreased water consumption, and a rapid drop in egg production.

Control – Vaccinate chicks for one day against it and re-vaccinate again at 6 to 8 weeks. Newcastle disease is preventable by vaccination.

Treatment – There is no treatment for this disease once the outbreak occurs. Affected birds should be isolated and destroyed immediately. Antibiotics may be administered for 3 to 5 days to prevent bacterial infections.

2. Fowl Pox

This disease is very prevalent mostly among extensively managed flocks. It affects poultry of all ages, especially growers and adults. The virus is very hardy and can remain viable in scabs for up to ten years.

It is mechanically transmitted by mosquitoes and other blood-sucking arthropods from infected birds to other birds.

Birds can also become infected by ingesting an infective scab. Fowl pox manifests in two forms: the wet form which affects the mouth, oesophagus, trachea, and pharynx, and the dry form which affects the skin (mostly the hairless sites like combs and wattles, face, and the feet).

The wet form is more serious than the dry form, causing high mortality.

Symptoms – The eyes, beak, comb, and head will be covered with scabs and/or swellings. In the wet form, nodules are present in the mouth, along the digestive and respiratory tracts.

Control – Vaccination is the most reliable method of preventing fowl pox and this is done by the hatcheries.

Treatment– There is no drug to use when there is an outbreak. Treating the dry form is easier than the wet form. It involves scrapping warts and cleaning the surface with disinfectant. When a few birds are affected, isolate them and use a tincture of iodine to dab the raw bleeding surface.

Administration of antibioticss to combat secondary bacterial infection and environmental stress is appropriate. Affected birds can also be destroyed.

3. Gumboro Disease (Infectious Bursal Disease)

It is a highly contagious viral disease affecting young chicks (3 to 6 weeks) with attendant grave economic losses.

Symptoms – Affected birds produce white watery droppings; have soiled vent feathers, and ruffled feathers. Other symptoms are loss of appetite, vent pecking, reluctance to move, and death.

Control– Vaccines are now available as a preventive measure.

Treatment – There is no known effective treatment. However, increased ventilation is recommended with antibiotic medication.

4. Marek’s Disease

This is a viral disease affecting mostly birds between 6 to 26 weeks of age. The virus is spread from an infected chicken to a non-infected one through the air, poultry dust, contact, and sometimes feces.

Symptoms – include lameness or paralysis of the legs, droopy wings, blindness, poor respiratory rate, and death of 10-30% of the flock.

Control – prevention of Marek’s disease is by vaccination by the hatcheries at day old. Also, procure genetically resistant chicks and main high sanitation standards.

Treatment – There is no treatment, thus affected chickens should be destroyed.

5. Avian Encephalomyelitis (Epidemic Tremor)

This viral disease affects all ages of chickens with mortality as high as 50%. Mostly chicks from day old to about 4 weeks of age are affected.

This disease may symptomatically be confused with Newcastle disease. It is transmitted by chicken eating infected feed and litter materials. It can also come through eggs laid and hatched from infected stock.

Symptoms – Affected chicks have ataxia (lack of coordination of the leg muscles). The chickens cannot walk, lose muscle control, and are paralyzed. The first signs are shivering of the muscles, head, neck, and legs. Death follows after a few days due to starvation and thirst.

Control – The chickens are vaccinated at the hatcheries before dispatching.

Treatment – No treatment is available. Affected chickens should be isolated and destroyed.

Viral Diseases of Poultry: Symptoms, Control, and Treatments