Fowlpox is a slow-spreading viral infection of chickens and turkeys characterized by proliferative lesions in the skin that progress to thick scabs (cutaneous form) and by lesions in the upper GI and respiratory tracts (diphtheritic form). Virulent strains may cause lesions in the internal organs (systemic form). Fowlpox is seen worldwide.
The large DNA virus (an avipoxvirus in the Poxviridae family) is resistant and may survive in the environment for extended periods in dried scabs. Photolyase and A-type inclusion body protein genes in the genome of fowlpox virus appear to protect the virus from adverse environmental conditions.
The virus is present in large numbers in the lesions and is usually transmitted by contact through abrasions of the skin. Skin lesions (scabs) shed from recovering birds in poultry houses can become a source of aerosol infection. Mosquitoes and other biting insects may serve as mechanical vectors. Transmission within a susceptible flock is rapid when mosquitoes are plentiful and the disease tends to persist for extended periods
- The incubation period usually lasts from 4 to 10 days.
- The cutaneous form of fowlpox is characterized by nodular lesions on various parts of the unfeathered skin of chickens and on the head and upper neck of turkeys. Generalized lesions of feathered skin may also be seen. In some cases, lesions are limited chiefly to the feet and legs. The lesion is initially a raised, blanched, nodular area that enlarges, becomes yellowish, and progresses to a thick, dark scab. Multiple lesions usually develop and often coalesce. Lesions in various stages of development may be found on the same bird. Localization around the nostrils may cause nasal discharge. Cutaneous lesions on the eyelids may cause complete closure of one or both eyes. Only a few birds develop cutaneous lesions at one time. Lesions are prominent in some birds and may significantly decrease flock performance.
- In the diphtheritic form of fowlpox, lesions develop on the mucous membranes of the mouth, esophagus, pharynx, larynx, and trachea (wetpox or fowl diphtheria). Occasionally, lesions are seen almost exclusively in one or more of these sites. Caseous patches firmly adherent to the mucosa of the larynx and mouth or proliferative masses may develop. Mouth lesions interfere with feeding. Tracheal lesions cause difficulty in respiration. Laryngeal and tracheal lesions in chickens must be differentiated from those of infectious laryngotracheitis, which is caused by a herpesvirus that produces intranuclear inclusions. In cases of systemic infection caused by virulent fowlpox virus strains, lesions may be seen in internal organs. More than one form of the disease, ie, cutaneous, diphtheritic, and/or systemic, may be seen in a single bird.
- Extensive infection in a layer flock results in decreased egg production. Cutaneous infections alone ordinarily cause low or moderate mortality, and these flocks generally return to normal production after recovery. Mortality is usually high in diphtheritic or systemic infections.
- Vaccination effectively prevents the disease and may limit spread within actively infected flocks.
- Always pay attention to epidemiological situation in local area to timely apply vaccination and strictly comply with schedule.
- Periodically apply antiseptic to the coop to maintain a good biosecurity in the husbandry area.
- Regularly apply adjuvants to enhance natural resistance such as:
- Take the seriously affected and apply mild disinfectants such as Methylene Blue, Cuso4.... or antibiotic oilment (Tetracycline) directly at infected regions.
- Use broad spectrum antibiotics to prevent secondary diseases such as E.Coli, Typhoid, CRD...
- Follow the following treatment regimen suggested by our experts. Treatment period should last from 3 to 5 days.