Namibia: Know About Poultry Diseases – Part 2


FOWL cholera is a contagious, bacterial disease that affects chickens worldwide. It usually occurs as a sudden onset with high morbidity and mortality, however, asymptomatic infections also occur.


The symptoms include ruffled feathers, loss of appetite, diarrhoea, coughing, nasal, ocular and oral discharge, swollen wattles and face, sudden death, swollen joints, lameness.


▩ Good management practices such as high levels of biosecurity are essential to prevention. Rodents, wild birds and pets must be excluded from poultry houses.

▩ Vaccination of healthy flocks

▩ Use of prescribed antibotics

▩ In extreme cases, farmers may need to cull all chickens and start afresh after several weeks

Disinfect all poultry houses

A number of drugs will lower mortality from fowl cholera; however, deaths may resume when treatment is discontinued, showing that treatment does not eliminate fowl cholera completely from a flock. Eradication of infection requires depopulation and cleaning and disinfection of buildings and equipment. The premises should then be kept free of poultry for a few weeks.


Farmers are advised to visit their local veterinarian for advice


Fowl pox is a highly contagious viral infection that causes painful sores on the chicken’s skin. Fowl pox occurs in two forms, namely wet and dry. While there is no cure, the symptoms of fowl pox can be managed.

Dry fowl pox is a viral inflation that affects a chicken’s skin in non-feathered areas such as the combs, wattles, face and eyelids. On the other hand, wet fowl pox affects a chicken’s upper respiratory systems such as the mouth, throat and tends to be more life threatening than the dry fowl pox.

The disease is highly contagious and spreads slowly from one chicken to the next within the flock. Birds usually become infected when dry scabs are ingested, inhaled and through contact with skin wounds. The initial stages of fowl pox often:

▩ Ash covered blisters on the comb, wattles and face,

▩ Blisters evolve and develop into larger yellow bumps and finally dark coloured looking scabs,

▩ Some chickens become immune to fowl pox.

Symptoms of fowl pox

▩ Drop in egg production

▩ Loss of appetite or weight loss

▩ Lesions on the skins (dry fowl pox) and inside the mouth (wet fowl pox)

Methods of prevention

Practise good biosecurity through the adoption of the following practices:

▩ Do not mix old and new flocks,

▩ Clean and disinfect chicken houses monthly

▩ Control mosquitoes

▩ Vaccinate against fowl pox

▩ Clean feeders and drinkers daily during an outbreak

▩ Install footbaths on chicken houses to avoid cross infections


Farmers are advised to vaccinate their flocks as there is no cure for this disease


Ascites is when fluid builds up in the lower abdomen of a chicken due to pulmonary hypertension and heart failure. Ascites is also referred to as water belly or dropsy. The condition is more common in broilers and aging layers.

Causes of Ascites

In broilers, the fast rate of growth these chickens experience typically causes the condition, according to Damerow. The immature heart and lungs simply can’t keep up with the demand, and the heart responds by pumping more blood into the lungs. This results in increased blood pressure between the heart and lungs.

The rigid chicken lungs can’t handle the increased pressure, so the heart works harder to keep the blood pumping. Eventually, the heart enlarges and thickens until the right valve can no longer close. This results in blood building up into the liver, and fluid from the liver leaks out into the body cavity.