Queenstown has been hit by an outbreak of Newcastle poultry disease, the Eastern Cape agriculture department said on Thursday.

"Several districts have been hard hit by a highly virulent Newcastle disease," said head of department's veterinary services Dr Luba Mrwebi in a statement.

Mrwebi said there had been two flocks with confirmed cases so far, one at a commercial poultry establishment near the town, the other in Mlungisi township.

Newcastle disease affects all birds including poultry, waterfowl, pigeons, cage birds, ostriches, emus and wild birds including guinea fowl.

"The disease is caused by a paramyxo virus and spreads very rapidly through an area by airborne transmission... as well as via nasal discharges, contaminated feed and water, faeces, carcasses, wild birds and via infected eggs."

He said the strain of virus causing the present outbreak appeared to be particularly virulent. Affected birds showed severe respiratory distress with blue to black combs, coughing and gasping followed by rapid death.

"A large percentage of fowls in unvaccinated flocks may die of the disease when infected," Mrwebi said.

He said young birds were particularly susceptible and mortality could be up to 100 percent.

Laying hens would show a dramatic drop in egg production, adding that eggs could have abnormal shape, colour or texture.

Owners were advised to contact the nearest state veterinary services or private veterinary surgeon where they suspected cases of the disease.

"All owners of poultry establishments, pigeons, ostriches and cage birds in the Queenstown district are advised to vaccinate their birds as soon as possible to prevent further spread of the outbreak."

Sapa