Hydatids Prevalence Not Reduced

Press, Volume XCVIII, Issue 28793, 14 January 1959, Page 9

Hydatids Prevalence Not Reduced

(From Our Own Reporter)

WELLINGTON, January 13.

Cases of hydatids by head of population are as prevalent now as they were 30 years ago, according to the figures of the medical statistics branch of the Department of Health, published in the New Zealand Medical Journal.

The figures show also that incidence of the disease is spread over a number of occupations and is not, as had been thoujght, confined to those ftftbn-~ tact with stock and sheep dogs.

Maoris appear to be much more susceptible to the disease than Europeans. A conclusion based on the study of hospital statistics over 10 years is that on a population basis, death by hydatids is three times more likely in New Zealand than it is in Australia, 20 times more likely in New Zealand than in England i and Wales, 28 times more likely than in Scotland, and 125 times more likely than in the United States. The New Zealand average annual number of deaths by, hydatids is 13.2, or 6.23 a million inhabitants. This compares with other countries as follows:—Australia, 2.22 a million; England and Wales, 0.31; Scotland, 0.08; United States, 0.05. In 957 cases of hydatids occurring in New Zealand between 1946 and 1956 it was found that the disease was 27.2 per cent, more common in men than in women. Males outnumber females in every age group except that under 10 in the disease statistics. The figures record hydatids cases as young as two and as old as 93. Incubation Period Some authorities have long held that the incubation period of the disease is from 10 to 20 years, yet the medical statistics record 148 cases in the under 10 group (seven aged two, 14 aged three, 19 aged four, 20 aged five, 21 aged six, 23 aged seven, 20 aged 8, and 24 aged 9). More than 80 per cent, of hydatids occurs in the vicinity of the liver or lungs. In 902 cases notified over the last 10 years in New Zealand, 432 occurred in the liver or its vicinity, 329 in the lungs or vicinity, and only 27 in the next most prevalent area, the abdomen. Although the over-all figures show the liver to be involved in 47.8 per cent, of the total, compared with the lung in 36.5 per cent., there is a continuing change in percentages related to age. In the under 20 group the disease appears to seat itself in the lung for preference. Over 20, the liver

become increasingly the dominant site.

In the 50-59 age group there are 1J times as many liver cases as lung cases. In the 60-69 group the incidence is twice as many liver cases as lung cases and in the over 70 group there are three times as many liver cases as lung cases. Maoris and Europeans The disease is shown to be six times more prevalent in Maori males than in European males, and four times more prevalent in Maori females than in European females. About five in every 100,000 New Zealanders in the working years are admitted to hospital annually with hydatids. In New Zealand 15 hospital beds are continuously occupied by hydatids patients. The statistics show that the farmer and the farm labourer are not the primary sufferers from the disease. In a table computed on the annual incidence of the disease for 100.000 people in each group, the following head the list: forestry and related trades, 18: spinners, weavers, and related trades, 16: labourers, 16; farmers, 9; production process workers, 8; farm workers, 7. v “The fact that the rates for forestry workers and for spinners, etc., are higher than those for farmers and farm workers is somewhat surprising, when it is remembered that a close association with dogs which 'are fed on raw sheep offal is generally considered to be the principal method of becoming infected with the disease,” says the report. Notifications It is also noted that less than half the new cases were notified to the respective district health offices. In the percentage of actual cases occurring in the district which were actually notified. Timaru leads New Zealand, but Invercargill and Dunedin are at the bottom of the list. The percentages of cases in each district that were actually notified were:—Timaru, 91.7; Gisborne, 86.8; Wellington, 86; Christchurch, 71; Greymouth, 58; Nelson, 52; Dunedin, 19; Invercargill, 6.3.