For the first time in New Zealand, an exotic parasite has been found in ostriches, which were imported for farming into New Zealand in the 1990s.
The wireworm parasite, which sucks the ostrich’s blood causing inflammation and anemias, was first found in New Zealand in late April. So far it has been found on two North Island ostrich farms and one South Island farm.
In their native African home, the wireworm disease is called “vrotmaag” or rotten stomach and can kill up to 50 per cent in juvenile birds. In New Zealand, the parasite has had the same impact, with one farmer estimating that over the past 18 months half of his chicks have died, 20 per cent of his juvenile birds and 10 per cent of his adult birds.
Even though the parasite was only recently discovered, the Ministry of Agriculture and Fisheries believes it must be here for some time as live ostriches were last imported into New Zealand in 1996. MAF also thinks that, because of a history of active transport in the ostrich industry, the parasite is probably widespread.
While there are no food safety or public health issues with wireworm, there is concern for its local cousin, New Zealand’s flightless bird, the kiwi. The possibility of interaction with wild kiwis is remote, but in places such as zoos and aviaries, MAF says that ostrich-derived eggs or larvae could come into contact with kiwis by contaminated footwear or other mechanical means.
According to a report prepared for MAF by Palmerston North veterinarian Phil McKenna there are a few incidences of transfer of the parasite from one ratite to another. In Australia, where ostriches have been farmed for more than 100 years, and where the wireworm is quite widespread, there is little evidence of any infection of Australia’s native ratites, suggesting that if such cross-transmissions do occur, it is likely to be only infrequently. But McKenna cautions that a report of the parasite being found in the emu in Sweden, which raises the possibility that other ratites such as kiwis could also become infected.
So MAF is stressing that people who work with both ostriches and kiwis, such as zoo workers, should practice good biosecurity measures such as changing or disinfecting boots and outerwear if contaminated. Also, MAF suggests kiwi should not be housed in enclosures that have a history of access by other birds. MAF is also telling ostrich farmers that they should be aiming to contain the parasite by clearing their ostrich enclosures of faces and by reducing the exposure of younger, more susceptible birds to infection.
Local conservation lobby group Forest and Bird wants more than just containment of the parasite. “We need to have this eradicated in ostriches, rather than simply have its numbers kept down with a cheaper control programmed,” Forest and Bird conservation manager Kevin Hackwell was quoted in the New Zealand Herald as saying.
Ostriches, the largest, heaviest, tallest bird and over time, the swiftest animal, were first farmed in New Zealand at the turn of the century for the feather fashion trade, MAF says. Modern ostrich farming commenced in 1993 with the importation of eggs followed by birds in 1995. Nowadays there are about 14,000 ostriches in New Zealand; about 75 percent of the ostrich meat is exported.