Various types of poultry disease / chicken disease and their controls

POULTRY DISEASE / CHIKEN DISEASE

Poultry are kept all over the world for various reasons. They are one of the cheapest sources of meat and can be kept by anyone, even in backyards. Two very important factors that should be addressed to ensure that you have a healthy flock of chickens are management and environment. 

A disease can spread rapidly among chickens because they are usually kept together in a cage or chicken house. They also share the same food and water bowls, which can spread disease and infections from sick to healthy chickens. In an intensive system we place a great deal of pressure on the chickens to grow fast and to lay many eggs. This situation can cause disease to spread resulting in a lot of damage because of the stress the chickens experience.

Avian Pox/Fowl Pox:

Fowl Pox is a highly infectious skin disease. It is characterized by typical pox lesions in the form of wart-like scabs on the face, comb and wattles.

Symptoms: White spots on skin; combs turn into scabby sores; white membrane and ulcers in mouth, on trachea; laying stops; all ages affected.

Treatment: Supportive care, warm dry quarters, soft food; many birds with good care will survive.

Fowl Cholera

The disease is caused by pasteurellaavicida, a microorganism that multiplies very rapidly in the blood causing poisoning.  Sick birds, wild birds, human, animals or utensils transmit the disease.

Symptoms

The disease spreads very rapidly in a flock.  There is yellowish colouration on birds’ droppings, which is followed by yellowish or greenish diarrhoea.  Infected birds become droopy, feverish and sleepy. The birds also sit with the head down or turned backwards or rested in feathers about the wing.

Control

Birds with acute type should be destroyed and burned. House should be thoroughly cleaned and disinfected.  Treatment with recommended sulphur drugs is effective.  Ensuring there is no wet litter is important, which provides ideal conditions for coccidian.

Coccidiosis

Causes

The disease is caused by coccidian, which multiply very rapidly in the intestines.  It usually occurs at 8 to 10 weeks of age and normally expresses itself in acute and chronic forms.  In the acute type, death occurs in 5 to 7 days.  The chronic type does not kill immediately but persists for long.

Symptoms

Infected birds or chicks become droopy, look unthrifty, and usually have ruffled feathers, pale beaks and shanks.  Caecal coccidiosis has bloody droppings.  Mortality may be high and sudden.

Control

Sulphur drugs are normally used for treatment, use of coccidiostat in feed and always ensuring dry litter are other controls.

Lymphoid leucosis

Lymphoid leucosis is a disease that affects chickens, caused by the retrovirus Avian leukosis virus.

It is a neoplastic disease caused by a virus, which may take the form of a tumor of the bursa of Fabricius and may metastasize to other tissues of the chicken and cause enlargement and swelling of the abdomen.

Symptoms

Symptoms include enlargement of abdomen, bursa, weight loss, weakness and emaciation, and depression. The disease is more likely to affect chicken around five to eight months of age who are more vulnerable. Green diarrhea tends to develops at the terminal stage.

Treatments

Diagnosis based on flock history and tumors, confirmed by typical progression of disease and differentiation from other diseases. There is no treatment. Prevention is to obtain chicks from LL-free sources, rear birds in isolation with adequate ventilation and biosecurity, prevent stress and control other diseases.

Air Sac Disease

Air sac disease is a respiratory disease like CRD, but usually occurs in chicks about 6-9 weeks old, instead of adult birds.

Symptoms

It can be caused either by E. coli bacteria or mycolpasmagallisepticum.  The symptoms are weight loss, coughing, nasal discharge, watery eyes and difficulty breathing.  It can also weight loss and a loss of appetite which in turn causes uneven growth of the chicks.

Treatments

Try to avoid dusty litters and make sure the chicks have good ventilation.  Also avoid letting them get chilled.  If your birds do get infected, make sure they stay warm and feed them a high protein feed with plenty of vitamin E, which is found in sunflower seeds.  Be aware, however, that the survivors will now be carriers and can potentially infect other birds in the future.

Infectious Bronchitis

Infectious bronchitis is a highly contagious respiratory disease.  It can be more obvious in chicks, but older birds will have a rattling noise in the throat when they are on the roost at night.  

Signs of Infectious Bronchitis

Chicks will cough, sneeze, and have rattling sounds in the throat.  Symptoms are less noticeable in older birds, but you may notice them at night.  Chicks may even die.

Managing Infectious Bronchitis

There is a vaccine available, but it is not successful against all strains.  If infectious bronchitis has become an big problem in your flock, the best way to handle it is put all the birds down, disinfect, and start over with a fresh flock.

Infectious Coryza

Infectious Coryza is the equivalent of a chicken cold, and is spread the same way, by droplets propelled by coughing and sneezing.

Signs of Infectious Coryza

This looks like a respiratory infection, so it may be hard to pinpoint what specifically is the cause.  Your chicken will have nasal discharge, sticky eyes, or a swollen face.

Managing Infectious Coryza

There is a vaccine but it must be redone every two years, so it’s best to use it only after you know your flock has had an outbreak. 

Marek’s Disease

Marek’s disease is caused by a herpesvirus, and it is also so common that virtually all chickens have it, even though it may be dormant.

Signs of Marek’s Disease

The signs can vary widely, depending on the form it is, but a common symptom is leg paralysis.  You will see young chickens with one leg stretched forward and the other back behind itself.

Managing Marek’s Disease

There is a vaccine available, and most hatcheries offer vaccinated chicks.  It’s not a hundred percent effective, and the birds may still infect other birds, especially if they are stressed or their immune system is not in tip-top shape.