Serum Vitamin B12Levels and Incidence of Tapeworm Anemia in a Population Heavily Infected with Diphyllobothrium Latum

In order to elucidate the incidence of D. latum infection, tapeworm anemia and low serum vitamin B12levels, a population in Eastern Finland was subjected to a mass examination. Of the 1,345 subjects examined, 27.2 per cent were found to have tapeworm ova in their feces. Among those who had no tapeworm ova 0.3 per cent had a combination of anemia and low serum vitamin B12level, but none had megaloblastic bone marrow. Among the worm carriers 1.9 per cent had verified (megaloblastic), and another 1.1 per cent suspect (nonmegaloblastic) vitamin B12deficiency anemia. The incidence of tapeworm anemia in worm carriers is at least 1:50. The mean serum vitamin B12levels in the tapeworm carrier and control groups were 116.4 and 273.8 g./ml., respectively, the difference being statistically highly significant. More than fifty per cent of the worm carriers had a serum vitamin B12concentration below 100 g./ml., whereas this occurred in less than 5 per cent of the control subjects. It is concluded that the incidence of tapeworm anemia is much higher than has hitherto been supposed, that vitamin B12deficiency is extremely common in D. latum carriers and that the D. latum endemy in Finland is thus to be regarded as a serious public health problem.