HYDATIDS RESEARCH—I Groundwork At aieri For Vital Campaign

Press, Volume C, Issue 29436, 11 February 1961, Page 8

HYDATIDS RESEARCH—I Groundwork At aieri For Vital Campaign

At the former Royal New Zealand Air Force station at Taieri the Hydatids Research Unit is doing the groundwork for one of the most intensive public health schemes instituted in this country.

Some 150 persons contract hydatids every year in New Zealand from dogs and the annual economic loss in condemned sheep and lamb livers has been estimated at £2m.

The research unit was formed at the Medical School of the University of Otago in 1934 but was disbanded about 1940. Some research work was, however, still continued after the unit ceased to function. That of Dr. Edith Batham on arecoline hydrobromide has been described by the present director, Mr M. A. Gemmell, "as a world classic of its type.” Among those who have played a notable part in the history of the unit have been Sir Louis Barnett and Sir Charles Hercus, and the present research programme followed the approach of Sir Charles Hercus to the Government and the two producer boards in 1957.'

A grant of £130,000 was received for research over five years and with this the unit was reconstituted. It is controlled by the National Hydatids Research Committee under the chairmanship' of' Sir Charles Hercus on behalf of the New Zealand Medical Research Council.

In 1958 the unit took over its present premises at Taieri and the survey of the incidence of hydatids disease in domestic animals in New Zealand was begun. In this survey some 200,000 sheep and lambs, about 10,000 dogs, 80,000 cattle and calves and 10,000 pigs were examined. Mr Gemmell carried out the survey in the South Island and in the North Island was assisted by Mr L. S. Forbes, veterinary surgeon of the unit. Meat inspectors of the Department of Agriculture also assisted with the survey.

The survey showed the incidence of Echinococcus granulosus (the true hydatid) to vary from 0.1 per cent, in young calves to as high as 90 per cent, in old cattle; from 3 per cent, in lambs to 90 per cent, in old sheep; and from 7 per cent, in young pigs to 25 per cent, at three years of age. Up to 60 per cent, of the livers of the lambs examined in the survey, which had been killed at freezing works, were found to be damaged by Taenia hydatigena (the false hydatids). While both tapeworms have similar life cycles T. hydatigena shows a greater incidence in the younger sheep and E. granulosus in the adult. T. hydatigena is also much more common in dogs. The survey showed that 9 per cent, of the dogs in New Zealand in 1958-59 were infested with E. granulosus. In areas where there was no voluntary control scheme operating one dog in three was infested and where there was a good scheme the proportion fell to one in 18. Throughout the country every fifth dpg was harbouring T. hydatigena. Subsequently the unit’s senior parasitologist (Dr. G. K. Sweatman) carried out a survey of wild animals to determine the relative incidence of the disease. Within two years the unit completed its field work and was able to plan its research programme on the basis of the factors made known in the survey. The research team then split into groups, each working along a separate and apparently unrelated, path.

In 1962, at the conclusion of its present five-year research programme, the unit will make a further complete survey of New Zealand domestic and wild animals to compare with the position in 1958-59.

One field experiment which has been maintained by the unit since 1941, foith a break between 1951 and 1957, has been the examination of all dogs in the Styx area, on the Maniotqto Plain in Central Otago, and the inspection of all lambs killed from this area. This experiment is giving valuable information on the problems and relationship of infected dogs to infected sheep. In Hangar The Taieri unit is housed in a large hangar at the airfield, which also houses the national hydatids testing unit which examines all purge samples sent in from control officers throughout the country. In the year to July 31, more than a quarter of a million samples were tested.

In one corner of the hangar there is a large concrete block building, as big as a house, in which lambs, taken from their mothers at birth, are reared on sterilised foods. To enter the building, the visitor has to put on gumboots and pass through a formalin foot bath. Two doors provide an airlock between the lambs and the outside world.

This is to prevent eggs being carried in on footwear or feed—even the hay is sterilised. From the lambs reared in the building the research team can obtain uninfected sheep for experimental work.

In another section a room filled with cages houses rabbits, opossums and hedgehogs and a cage in the storeroom encloses a very active wallaby. Across the airfield in one of the old ammunition dumps is Lucy, a red deer which was formerly a pet on a Banks Peninsula farm, and two fallow deer for companionship, with a compound of dogs being housed in another dump.