Description Fowl pox is a viral disease which is spread by the bites of mosquitoes. The infection leads to the formation of wart-like nodules on the non-feathered parts of the head and legs and occasionally to similar lesions or canker in the mouth, nose and throat.
Cause/Nature of the disease There are a number of pox viruses which affect different species of birds. Fowls and turkeys are particularly susceptible to fowl pox virus while pigeons suffer most from pigeon pox virus.
Fowl pox virus attacks the skin and the surface of the mouth and throat. Depending on location, pox is referred to as either skin pox or 'wet' pox.
The skin form is most common, showing wart-like eruptions. Fleshy pale lumps form yellow pimples which may enlarge and run together forming masses of yellow crusts. In about a week these scabs darken and fall off.
The 'wet' pox or canker form shows up in the mouth, nose and throat as cheesy masses which interfere with eating and breathing.
Expected course/Spread Nodules appear 5 to 8 days after infection. The scabs clear up in 3 to 4 weeks in simple cases.
The pox virus can be carried and transmitted by intermediate hosts such as mosquitoes and other bloodsucking insects.
Fowl pox can also be spread directly by infection of small wounds in the skin and mouth of the bird. Overcrowding birds increases the risk of injury and may result in fighting and pecking. Correcting this aspect of management will reduce the risk of spread. The virus cannot enter intact skin but can survive for a long time in infected material such as scabs and litter.
Diagnosis In all outbreaks, wart-like lumps are found on many of the birds and this is a reliable guide to diagnosis.
Similar diseases wound scabs
Treatment Treatment is of little value. Lesions normally heal within 4 weeks. In severe cases it may be necessary to remove scabs and treat with antiseptics.
Prevention Prevention is firstly by reducing exposure to mosquitoes. This can be done by screening sheds and by dealing with mosquito habitats. Secondly, vaccination is effective.
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Vaccines Fowl pox 'M' (Mild) strain vaccine and pigeon pox vaccines are available.
The aim of vaccination is to give the birds a mild attack of pox so that after recovery they will be immune to reinfection. Protection is effective 2 to 3 weeks after vaccination.
General recommendations can be made for the various classes of poultry.
Fowls. For vaccination in the face of an outbreak, fowl pox 'M' strain vaccine is used. In birds older than 18 weeks the vaccination reaction may affect laying.
Day-old chicks.Fowl pox 'M' strain can be used as a first vaccination in birds at day-old or up to 6 weeks old. 'M' strain is a field strain which combines mild reaction with strong immunisation. It is applied in the wing by the 'needle stab' or 'stick' method. Birds should be revaccinated at 8 to 12 weeks for full protection through the laying period. Breeder replacements may be done again at 20 weeks.
Pigeons. Pigeon pox vaccine is very effective in preventing pox in pigeons. They may be vaccinated by the follicle method at any age down to squabs of 6 weeks of age.
Turkeys. Poults are vaccinated at day-old and 7 to 8 weeks with 'M' strain vaccine. The vaccine is given by the 'stab' method in the upper thigh rather than the wing. This avoids transfer of pox to the head.
Methods of vaccination
'Needle stab' or 'stick' method. Two grooved needles are bound together to make a double pronged instrument. The instrument is dipped into the vaccine and then thrust through the wing web (the front part of the wing).
The follicle method. Sufficient feathers are plucked from the thigh of the bird to expose about 15 mm of skin. The vaccine is then swabbed into the feather follicles.
Response to vaccination
The birds are inspected at 7-10 days for 'takes'. These are small scabs or swollen follicles that occur at the inoculation site and indicate successful vaccination
Precautions Only healthy, well nourished birds should be vaccinated. When vaccinating day-old chicks, husbandry must be good or the chicks may suffer severe reactions.
this is from the qld dpi http://www.dpi.qld.gov.au/27_2739.htm