Colibacillosis is a range of infectious diseases in birds caused by a type of bacteria known as avian pathogenic Escherichia coli (APEC). APEC is a specific strain of the commonly found bacteria E. coli, which can cause localized or systemic infections in birds.
Colibacillosis is a significant concern for poultry farmers, as it can result in various symptoms, including septicemia, a drop in production, and mortality. The disease can manifest in several forms, including colisepticaemia, egg peritonitis, yolk sac infection (also known as “mushy chick disease” and “omphalitis”), and coligranuloma (Hjarre’s disease).
Colibacillosis Management in Chicken
Causes of Colibacillosis Disease
The causes of colibacillosis are multifactorial, with various environmental and infectious factors playing a role in the development of the disease. Here are some of the primary causes of colibacillosis:
- Environmental contamination: Escherichia coli is a normal inhabitant of the digestive tract in birds, and its high numbers can be maintained in the poultry house environment through fecal contamination. The bacteria can live for a long time in the environment and can easily infect birds through direct or indirect contact.
- Predisposing factors: The presence of other infectious diseases such as mycoplasmosis, infectious bronchitis, Newcastle disease, hemorrhagic enteritis, and turkey bordetellosis can weaken the bird’s immune system and make them susceptible to colibacillosis. Poor air quality and environmental stresses can also predispose birds to E. coli infections.
- Hatchery contamination: Initial exposure to pathogenic E. coli may occur in the hatchery from infected or contaminated eggs. A hatching environment that is not sufficiently humid is often associated with a high incidence of yolk sac infection.
- Insect vectors: Beetles can transmit the bacteria, and birds that consume these beetles can become infected.
- Bacterial virulence: Some E. coli are more pathogenic than others, and the severity of the disease can depend on the virulence of the strain.
Symptoms of Colibacillosis Disease
The symptoms of colibacillosis in birds depend on the type and severity of the infection. Here are some common symptoms associated with colibacillosis:
- Respiratory symptoms: Affected birds may exhibit respiratory symptoms such as coughing, sneezing, and wheezing.
- Depression: Birds with colibacillosis often appear lethargic, inactive, and depressed.
- Loss of appetite: Infected birds may exhibit a reduced or complete loss of appetite.
- Diarrhea: Soiling the vent with pasty diarrhoeic feces is a common symptom of colibacillosis in birds.
- Omphalitis/Yolk sac infection: In young chicks, coliform omphalitis or yolk sac infection can cause mortality in the first week of life after hatching. Affected chicks exhibit depression, sleepiness, huddling around heat sources, and distended abdomen with swelling of the naval.
- Swollen Head Syndrome (SHS): This form of colibacillosis causes swelling of the head and face, which can lead to difficulty breathing and eating.
- Drop in egg production: In laying hens, colibacillosis can cause a drop in egg production and poor egg quality.
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Diagnosis of Colibacillosis in Chicken
The diagnosis of colibacillosis in chickens can be challenging, as the symptoms of the disease can be similar to those of other infections. Therefore, clinical s