Updated: Nov 15, 2019
We trust you learnt a lot from the last week post, we are excited to share premium information on how you can prevent and control diseases in a poultry farm. As promised, this week we are looking at the Fowl Pox and Egg drop Syndrome diseases in poultry. Enjoy and Learn!
EGG DROP SYNDROME.
There are no reliable signs other than the effects on egg production and egg quality.
Healthy-appearing hens start laying thin-shelled and shell-less eggs. Once established, the condition results in a failure to achieve egg production targets.
Transient diarrhoea and dullness occur prior to egg shell changes.
Note: Fertility and hatchability are not affected
Cause and transmission: Egg drop syndrome is caused by an adenovirus. It is believed that the syndrome was first introduced into chickens from contaminated vaccines. Vertical transmission occurs from infected breeders to chicks. Newly hatched chicks excrete the virus in the faeces.
Note* Similar egg production impacts can be caused by failures in husbandry such as a lack of food or water or infectious diseases such as infectious bronchitis, avian influenza or Newcastle disease.
Treatment: There is no successful treatment of infected birds. Induced moulting will restore egg production.
Prevention: Prevention involves a good biosecurity program. Vaccination of subsequently placed birds will prevent the occurrence of disease.
Note: The Egg drop virus is very stable in the environment and thus, it is difficult to eradicate once a place has housed infected birds.
Symptoms: There are two forms of fowl pox.
The dry form is characterized by raised, wart-like lesions on un-feathered areas (head, legs, vent, etc.). The lesions heal in about 2 weeks. If the scab is removed before healing is complete, the surface beneath is raw and bleeding. Not growing and retarded growth are typical symptoms of fowl pox. In laying hens, infection results in a transient decline in egg production.
In the wet form there are ulcer-like lesions in the mouth, pharynx, larynx, and trachea. The wet form may cause respiratory distress by obstructing the upper air passages. Chickens may be affected with either or both forms of fowl pox at one time.
Cause, transmission, and epidemiology:
Fowl pox is a viral disease affecting most species of poultry. Chickens, turkeys, pheasants, quail, ducks, psittacine, and ratites of all ages (except newly-hatched chicks) are susceptible.
It is transmitted by direct contact between infected and susceptible birds or by mosquitoes.
Virus-containing scabs also can be sloughed from affected birds and serve as a source of infection. The virus can enter the blood stream through the eye, skin wounds, or respiratory tract. Mosquitoes become infected from feeding on birds with fowl pox in their blood stream.
Mosquitoes are the primary reservoir and spreaders of fowl pox on poultry ranges. Several species of mosquito can transmit fowl pox.
Treatment: No treatment is available. However, fowl pox is relatively slow-spreading. Thus, it is possible to vaccinate to stop an outbreak.
Fowl pox outbreaks in poultry confined to houses can be controlled by spraying to kill mosquitoes.
However, if fowl pox is endemic in the area, vaccination is recommended. Do not vaccinate unless the disease becomes a problem on a farm or in the area.
Chickens may be vaccinated at 4-6 weeks of age using the wing web-stick method, and turkeys older than 8 weeks by the thigh-stick method.
Recovery: Most individuals with fowl pox will recover and will clear the virus. Recovered birds are not reservoirs of infection. Flocks can recover from infection, but the environment must be cleaned before new birds are introduced.
In our next post, we will be sharing about Gout and the effect of stress on diseases. If you would like to know about a disease, tell us in the comment section. We have your back. Till next time.
Source: Handbook of Poultry Diseases Important in Africa