Pernicious Plasmodium vivax as a Historical Cause of Malarial Cachexia?

Prior to the understanding of malaria as a parasitic disease, malaria cachexia was a loosely defined syndrome consisting of severe anemia and splenomegaly in a chronically wasted individual living in a malarious area. Entire rural populations in diverse areas such as the Thames estuary, Marseilles marshes, and the Mississippi valley were said to have cachexia on the basis of chronic malaria "poisoning," which accounted for their poor socioeconomic health. Malaria cachexia appeared to disappear as the marshes were drained, agriculture improved, and quinine or iron treatments were administered. Malaria cachexia's association with plasmodia in the blood was uncertain once blood smears were examined in the twentieth century. Modern studies have raised the question of chronic Plasmodium vivax in the spleen as a possible etiology; historical specimens could be examined to clarify malaria cachexia.