Incidence Of Infection

Press, Volume CVI, Issue 31131, 6 August 1966, Page 10

Incidence Of Infection

A REVIEW of the recent incidence of infection of tapeworms in dogs, as shown by faecal samples examined by the National Hydatids Testing Station during the year ended March 31, 1966, is given in the annual report of the National Hydatids Council. The report says: True Hydatids: “The East Coast area of the North Island remains heavily infected. The predominantly dairying areas of Northland, Auckland, and Taranaki have a relatively low incidence, while remaining areas vary from moderately low to relatively high incidence. North and South Canterbury show a relatively low incidence, which is surprising in an area devoted to sheep farming, but the remainder of the South Island shows a variation up to the moderately high rate of 2.75 per cent in Westland. A very high rate of infection is found in the Chatham Islands.”

False hydatids: “A fairly similar picture, but at considerably higher rates of infection, is evident in both islands. Marked variations in incidence in neighbouring areas may be due to differences in type of farming, but in some instances indicate the unreliability of the lower figure concerned.” Sheep measles: “Increasingly high rates of infection are centred in North Canterbury, but Southland, Otago, Westlaml and East Coast and central North Island areas are also showing considerable increase. Even city areas show a marked rise. A few county figures are inconsistently low compared with similar neighbouring areas and are considered unreliable. “There are two distinct theories concerning the steady rise in incidence of infection in dogs over the past

several years” says the council’s report in referring to sheep measles. “The first is that a change in dog-feeding practice—from the feeding of offal to the feeding of carcase meat—is entirely responsible. The second relies on the evidence of Gemmell’s work on the production of immunity to cystic infection in sheep. This suggests that if a sheep

ingests eggs of one species of tapeworm, cysts of this species will develop and cause a resistance to the subsequent development of cysts of the same or any other related species. Thus it is possible that a reduction in the number of eggs of true and false hydatids on pastures may give a greater chance of infection with sheep measles....”