Pernicious anemia caused by Diphyllobothrium latum, in the light of recent investigations.

By BERTEL VON BONSDORFF, M.D. T HE MACROCYTIC anemia caused by the broad fish tapeworm, Diphyllobothrium latum, has been the subject of extensive investigations in Finland, starting with the pioneer work ofJ. W. Runeberg (1887) and 0. Schauman (1894). The fish tapeworm is extraordinarily common in the country. In certain provinces more than 90 per cent of the population is infested with the parasite. Of the total population of the country, which is about 4,000,000, one half to one million can be considered to be tapeworm carriers. The parasite is found in persons of all ages, even in children under i year of age. For most of these carriers, the worm is a relatively innocent parasite, but in some, it causes a macrocytic anemia. According to earlier investigations (R. Ehrstrom, 192.6) the frequency of anemia was estimated to be i case in 5,000-10,000 worm carriers. But, if the blood of worm carriers is examined systematically, a far greater number of anemia cases can be shown. Among the conscripts of 2.0 years of age admitted to a military hospital in peace time, Seppa (192.7) found i case of anemia in 659 worm carriers. G. T#{246}tterman (1944), in a community strongly infested with tapeworm, noted, in 1942., I case of anemia in 136 carriers; and in 1943, he found the frequency to be i case of anemia in 383 carriers. In a war hospital, from 1941 tO 1944, I found 96 instances of tapeworm anemia in about II,ooo medical cases. The number of worm carriers in this group, composed of men from i8 to 40 years of age, is not known. The above figures give a good idea of the importance of the problem of tapeworm anemia in Finland. This anemia is a typical “pernicious anemia” with a characteristic blood picture and a megaloblastic bone marrow, agreeing in all respects with that found in ‘cryptogenetic” Addisonian anemia. A pernicious tapeworm anemia can also be brought to remission with liver preparations per os or parenterally, or with stomach preparations per os without removal of the worm. In contrast to cryptogenetic pernicious anemia, tapeworm anemia occurs even in people under 2.0 years of age. In most cases there is an achiorhydria after the injection of histamine; though, especially in younger patients, the gastric juice often contains free hydrochloric acid and is secreted in the usual quantities. Signs of spinal cord involvement are less apparent than in cryptogenetic pernicious anemia. That the illness is really due to the worm infestation is proved by the fact that complete remission takes place after the worm is expelled without any further need for antianemic treatment. Since cryptogenetic pernicious anemia is not rare in Finland and worm infestation is common, it is natural that now and then both types of anemia should occur simultaneously in an individual. In such cases, of course, there is no remission after the worm cure. In fact, the anemia often becomes more severe.