BLACKWATER FEVER, a disease occurring in tropical countries and elsewhere, which is often classed with malaria (q.v.). It is characterized by irregular febrile paroxysms, accompanied by rigors, bilious vomiting, jaundice and haemoglobinuria (Sambon). It has a wide geographical distribution, including tropical Africa, parts of Asia, the West Indies, the southern United States, and - in Europe - Greece, Sicily and Sardinia; but its range is not coextensive with malaria. Malarial parasites have occasionally been found in the blood. Some authorities believe it to be caused by the excessive use of quinine, taken to combat malaria. This theory has had the support of Koch, but it is not generally accepted. If it were correct, one would expect blackwater fever to be regularly prevalent in malarial countries and to be more or less coextensive with the use of quinine, which is not at all the case. It often resembles yellow fever, but the characteristic black vomit of yellow fever rarely occurs in blackwater fever, while the black urine from which the latter derives its name is equally rare in the former. According to the modern school of tropical parasitology, blackwater fever is neither a form of malaria nor produced by quinine, but a specific disease due to a protozoal parasite akin to that which causes the redwater fever of cattle.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)