Sheep measles, which is common in New Zealand, is not a human health risk, but rather a product quality issue. True hydatids, on the other hand, is much more serious. The parasite can only mature in dogs, but to complete its life cycle it also needs an intermediate host. In New Zealand, the main intermediate host is sheep. Sheep become infected by grazing on pasture contaminated with tapeworm eggs passed in dog faeces.
Hydatids disease in man usually follows close contact with infected dogs.
Such dogs are most likely to infect their owner or owner's children. The effect on the health of people can vary from no symptoms to severe illness and death, depending on the number of cysts, their site and size. Every year there are around 30 million sheep and lambs and three to four million cattle, calves and deer slaughtered and inspected in New Zealand. The absence of cysts provides strong assurance that the parasite is almost beaten. Whenever they are found, they are followed up with a detailed investigation of the property to make sure no hidden pockets of the disease remain.