Fowl pox is a poultry disease that affects chickens, turkeys, pheasants and even ducks.
It is an old disease mainly seen in adult birds and characterised by the appearance of warts or blisters on the skin surfaces of the head, wattles, and comb and can spread to the skin covering the back and the legs of affected birds.
This form of fowl pox is called cutaneous type and rarely kills. Affected birds recover within two weeks without any need for treatment. The other form will cause similar lesions but on the mucosal (inner) surfaces of the buccal cavity and respiratory linings and in rare cases affect internal organs such as the liver and kidneys. This is called diphtheritic type and may cause mortality of up to 50 per cent or more if the birds fail to recover fully in two weeks. Affected birds completely go off-feed, waste away and eventually die.
How widespread is the disease?
The disease affects poultry worldwide. In Kenya, it is mostly restricted among the local or kienyeji varieties of chickens that are not traditionally vaccinated against fowl pox. Many mushrooming local backyard hatcheries do not vaccinate their breeding lines against the disease and, therefore, the chicks hatched have no maternally derived protective immunity against the disease. Chicks hatched from unvaccinated parents tend to get infected as early as three weeks of life. When buying chicks from local integrators, please insist on seeing their vaccination history. This is the only way we are going to help eradicate this condition among our poultry population.
How is the disease spread?
Fowl pox is mainly spread by biting or sucking insects and directly through contact with infected birds through broken skin, oral or respiratory routes. The causative virus is very resistant and can survive for months in the poultry house if not properly cleaned and disinfected and rested for 21 days. Fowl pox is not by all standards a killer disease and if affected birds are given access to well-balanced feed with plenty of portable water and topical application of 70 per cent tincture of iodine solution, they recover within two weeks. If neglected, such affected birds will feed less, waste away, reduce egg production and eventually die. If slaughtered, the skin may appear as if it has pimples and wart-like growths, and the birds are unappealing to consumers.
Controlling disease by cleaning and sanitation
Cleaning and sanitation are key components of routine biosecurity in a poultry farm. Cleaning and sanitation destroy or reduce the number of disease-causing organisms that might be present on the farm. This will then allow for safe repopulation and allow birds to build up antibodies against the existing micro-organisms. It also prevents further spread of disease-causing organisms during and after an outbreak.
Treatment of fowl pox
There is no known treatment against fowl pox, and affected birds tend to recover on their own if there are no secondary bacterial infections. You can spray the affected wounds with a tincture of iodine or antibiotic spray.
Vaccination against the disease
To control the disease, one must vaccinate the birds at 6-8 weeks using live vaccines applied through the wing web by stabbing. The vaccines were first introduced in 1926, and the good news is that where farmers religiously vaccinate their flocks, fowl pox has been permanently eradicated. It is also important to thoroughly keep your premises clean and disinfected at the end of the cycle and burn any leftover poultry dust and feathers. Finally, ensure you buy your replacement flocks from hatcheries that routinely vaccinate their breeders against the condition.
[The writer is the head vet at Kenchic and can be reached at [email protected]]