Rural Poultry in Developing Countries
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Diseases: Fowl Cholera

Introduction

  • Known as Avian Cholera, Avian Pasteurellosis, Avian Haemorrhagic Septicaemia
  • Caused by a bacterium, Pasteurella multocida
  • May cause high morbidity and mortality
  • Often causes chronic infections

 

Clinical Signs

Acute infections

  • birds stop eating
  • feathers ruffled
  • discharge from mouth
  • diarrhoea
  • rapid breathing
  • death may occur in a few hours
  • Chronic infections
  • swollen wattles, sinuses and leg or wing joints

 

Post Mortem Lesions

  • Acute disease: hyperaemia and haemorrhages in lung, intestines and heart
  • Chronic disease: localised infections for example in sinuses or respiratory tract

 

Diagnosis

  • History, clinical signs and necropsy lesions are helpful but the final diagnosis depends on the isolation of the organism in the laboratory.

 

Sample Collection

For isolation of organism:

  • Samples of bone marrow, liver, meninges or lesions
  • Heart blood

To demonstrate the organisms:

  • In acute cases, imprints of the liver on glass slides. stained with Wright's or Giemsa stain.

 

Transmission

  • From bird to bird in water or feed; bacteria in excretions from mouth, nose and conjunctiva
  • Chronically infected birds considered to be a major source of infection
  • Bacteria will survive up to 30 days in water or soil
  • Bacteria are destroyed by disinfectants, sunlight and heat

 

Treatment

  • Treatment cannot be guaranteed to be successful.
  • Sulphur drugs in water, Oxytetracycline (TerramycinTM), AureomycinTM, Novobiocin, Lincomycin, Spectinomycin in feed.  N.B. The withdrawal period is a minimum of 10 days before slaughter for food.

 

Prevention and Control

  • Good flock management – do not introduce sick or new birds
  • Control of rodents (construct elevated chicken houses with an inverted metal or plastic cones on the legs to prevent the entry of predators).
  • Vaccines are available but the results are not always satisfactory. Good results have been obtained in South-East Asia when local isolates are used to prepare a vaccine. More details are given below.

 

Preparation and use of inactivated vaccine against Fowl Cholera

Contributed by:
Dr. Dirk L. Van Aken,
LAO-EU Livestock Project,
dvanaken@loxinfo.co.th

The vaccine should be prepared from a local strain if possible, using an oil adjuvant.

Best vaccination results are obtained when a booster is given 2 weeks after the first vaccination. Serological titres post-vaccination should increase by a factor of log2 after such a booster.

It is very important that the vaccine never freezes. If freezing occurs, the cell walls will burst and Pasteurella endotoxins will be released. Consequently, instead of vaccine pure endotoxin (which is poisonous) will be injected. There have been reports of such incidents where chickens die shortly after vaccination. To avoid such accidents, vaccinate a few birds first, then wait a day or two to check for any harmful reactions.

 

Recommendations:

  • Vaccinate village chickens from 3 months of age onwards
  • Make two rounds per year of double vaccination for the whole village flock. Ideally these rounds of double vaccination should take place every 3 months, but that seems to be impractical under village conditions.
  • Use 26 G needles for intramuscular injection.

 

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