Infectious coryza is an acute respiratory disease in chickens caused by a bacterium (Avibacterium paragallinarum – the scientific name of the bacterium that causes Infectious Coryza).
Transmission
- Direct touch.
- Airborne droplets.
- Contaminated drinking water.
Symptoms
- Sneezing and laboured breathing, especially when the birds are roosting at night.
- With blocked nostrils, there is an unpleasant smell and the bird’s breath through its mouth with the result that their tongues go dry.
- If the small canal leading from the mouth to the eye becomes blocked the sinuses cannot drain properly with the result that large swellings are formed under and around the eyes.
- Sometimes lesions are also visible in the throat with a cheesy exudate which plugs the opening to the windpipe and suffocates the bird.
Swelling under and around the eye due to Infectious Coryza
Prevention and Treatment
- Do not keep young and old birds in the same house.
- Strict hygiene and sanitation.
- Keep sick birds separately.
- Practise an all-in/all-out animal flow strategy.
- Replacement hens should come from clean flocks or be grown on the same farm.
- Bacterins/vaccines are available to assist in the prevention and control of infectious coryza. Vaccinate when chicks are 1 month old.
- Antibacterials such as Terramycin and Avisol. Can be used for treatment.
Fowl Typhoid
Fowl typhoid is an infectious disease in chicken and turkeys and rarely in other poultry, game birds and wild birds. The causative agent is the bacterium, Salmonella gallinarum. Fowl typhoid is seen more often in adult birds.
Symptoms
- High temperature
- Loss of appetite and continued thirst
- Yellowish green diarrhoea
- Pall comb
- Enlarged liver and spleen (post-mortem).
Enlarged, bronze to mahogany-coloured liver and mottled and brittle spleen (right) in contrast to normal ones (left)
Prevention and Treatment
- Vaccination
- Produce affected birds and bring in new stock
- As soon as an outbreak of the disease occurs all birds must be vaccinated with the fowl typhoid vaccine.
- You can also use an antibacterial, such as Furasol or Neftin.
Chronic Respiration Disease (CRD)
(Also called ‘Air sac disease’)
Chronic respiratory disease (CRD) refers to respiratory infection of the upper respiratory tract of chickens caused by Mycoplasma gallisepticum.
Symptoms
- Difficult breathing.
- Poor growth.
Prevention
- Draught free house.
- Good management.
- Strict hygiene and sanitation.
- Add some antibiotics to the food or drinking water.
Treatment
- Tylan and Rovamycin – antibiotics.
Avian Chlamydiosis
(Also called Psittacosis, Ornithosis, Parrot Fever)
Ornithosis is an acute or chronic disease of turkeys, ducks, chickens, pheasants and pigeons, and it is caused by Chlamydia psittaci.
Transmission occurs by:
Wild carrier birds and cage birds transmit Chlamydia to their nestling which may survive and become carriers. Carrier birds shed Chlamydia in their secretions and excretions. Chlamydia present in faecal dust may be inhaled or ingested. Pigeons are suspected of being disseminators of infection.
Symptoms
- nasal and ocular discharge
- conjunctivitis
- sinusitis
- green to yellow-green droppings
- fever
- inactivity
- ruffled feathers
- weakness
- inappetence
- weight loss
- drop in egg production
Prevention and Treatment
Human and avian chlamydiosis is a reportable disease; state and local governmental regulations should be followed wherever applicable. No effective vaccine for use in birds is available. Treatment prevents mortality and shedding but cannot be relied on to eliminate latent infection; shedding may recur.
Tetracyclines (chlortetracycline, oxytetracycline, and doxycycline) are the antibiotics of choice. When tetracyclines are administered orally, additional sources of dietary calcium (e.g., mineral block, supplement, cuttlebone) should be reduced to minimize interference with drug absorption.
Appropriate biosecurity practices are necessary to control the introduction and spread of chlamydiae in an avian population. Minimal biosecurity standards include:
- quarantine and examination of all new birds
- prevention of exposure to wild birds
- traffic control to minimize cross-contamination
- isolation and treatment of affected and contact birds
- thorough cleaning and disinfection of premises and equipment (preferably with small units managed on an all-in/all-out basis)
- provision of uncontaminated feed
- maintenance of records on all bird movements
- continual monitoring for the presence of chlamydial infection
The organism is susceptible to heat (it may be destroyed in <5 minutes at 56°C) and most disinfectants (e.g., 1:1,000 quaternary ammonium chloride, 1:100 bleach solution, 70% alcohol, etc) but is resistant to acid and alkali. It may persist for months in organic matter such as litter and nest material; thorough cleaning before disinfection is necessary.
Pullorum
The historical name for this disease is bacillary white diarrhoea. Pullorum disease is caused by Salmonella enterica Pullorum.
Symptoms
- Affected birds huddle near the heat source
- Anorexia
- Weakness and depression
- White faecal material can be found pasted to the vent area.
- Respiratory disease
- Blindness
- Swollen joints
Prevention and Treatment
- Freedom from infection and elimination of positive birds and flocks is key to control. Treatment will not eliminate the carrier state and is never recommended.
- Control is based on routine serologic testing of breeding stock to assure freedom from infection.
- Management and biosecurity measures should be taken to reduce the introduction of S enterica Pullorum from feed, water, wild birds, rodents, insects, or people.
- Birds should be purchased from sources free of S enterica
Fowl Cholera
Fowl cholera is a contagious, bacterial disease of birds caused by Pasteurella multocida. It affects domestic and wild birds worldwide. The disease is more prevalent in turkeys than in chickens. It occurs more frequently in stressed birds associated with parasitism, malnutrition, poor sanitation and other conditions. P multocida is easily destroyed by sunlight, heat, drying and by most disinfectants. However, it will survive several days of storage or transportation in a humid environment. It persists for months in decaying carcasses and moist soil. The agent is frequently carried in the oral cavity of wild and domestic animals.
Transmission occurs by:
- If birds are bitten by infected animals such as rodents and carnivores, the disease could be disseminated in the flock.
- Contaminated feed, water, soil and equipment are also considered potential factors in the spreading of the disease.
Symptoms
Acute septicaemic form:
- High morbidity and mortality and sudden death.
- Dead birds may be found on dropping boards or in nests.
- Depressed, cyanotic and loss of appetite
- Nasal and oral discharge
- Greenish diarrhoea
- The comb may be swollen and discoloured.
- Emaciated
Chronic fowl cholera:
- Swelling of wattles, sinuses, joints, footpad and tendon sheaths
- Cheesy exudate in the conjunctival sac
- Twisting of the head and neck may be observed in some birds.
- A middle ear infection is rare but occurs when the bacterial agent reaches the middle ear through the nasal cavity.
- The bird may lose its sense of balance with the head and neck twisted to one side.
- If both ears are infected, the bird’s head and neck are pulled back over the body and between the legs.
Prevention and Treatment
- Good management practices, including a high level of biosecurity, are essential to prevention.
- Rodents, wild birds, pets, and other animals that may be carriers of P multocida must be excluded from poultry houses. The organism is susceptible to ordinary disinfectants, sunlight, drying, and heat.
- Bacterins – a suspension of killed or attenuated bacteria for use as a vaccine.
- Attenuated live vaccines are available for administration in drinking water to turkeys and by wing-web inoculation to chickens. These live vaccines can effectively induce immunity against different serotypes of P multocida. They are recommended for use in healthy flocks only.
Treatment may involve:
- Eradication of infection requires depopulation, followed by thorough cleaning and disinfection.
- Antibiotics may reduce mortality but won’t eliminate P multocida from a flock.
Tuberculosis in Poultry
Tuberculosis, caused by Mycobacterium avium, can affect all birds, although susceptibility varies by species. Poultry tuberculosis is predominately caused by Mycobacterium avium subsp. avium (M avium).
M avium infection is transmitted through contact with contaminated environments. The larger the infected population and the longer they remain on those premises, the higher the bacterial contamination level in the environment.
- M avium is typically ingested, although infection may occur via aerosol.
- M avium may persist in soil for many years. It is therefore important not to use contaminated premises to raise poultry, swine, or other susceptible species.
Symptoms
- Depressed and progressive loss of weight leads to emaciation.
- The skin of the face, wattles and comb is pale.
- Dull, ruffled feathers.
- Diarrhoea
- Unilateral lameness.
Prevention and Treatment
Because avian tuberculosis is treated with the same drugs used to treat human infection, treatment is not recommended for fear of producing resistant strains. Control includes prevention, so previously contaminated premises should not be used to raise poultry. Infected flocks should be depopulated so as not to perpetuate flock infection, nor continue to contaminate the environment. Using all-in/all-out management practices, in which birds of only one age are kept and when production is completed, they are depopulated, may help prevent infection.