BLACKWATER FEVER. So far this disease, which oc curs in all tropical countries and occasionally elsewhere, and is often classed with malaria, has defied the efforts of research to trace its cause. Its geographical distribution covers tropical Africa, where it is perhaps most prevalent, parts of Asia, the `'Vest Indies, the southern United States, Greece, Sicily, and Sardinia. Its range is not co-extensive with malaria since it is found in places where malaria is unknown or infrequent. Accord ing to Webster it is "a malarial fever marked by bloody urine." It is characterized by irregular febrile paroxysms, accompanied by rigors, bilious vomiting, jaundice and haemoglobinuria, the victim being anaemic in proportion to the severity of the case. The kidneys are clogged, the urine being more discoloured in some cases than in others.
The association of blackwater fever with malaria (q.v.) is a question which still divides expert opinion. Dr. J. G. Thomson in his Report on Southern Rhodesia has pointed out that blackwater fever occurs principally among persons living in houses un protected and careless about mosquito nets, and he supports his case by statistics given by Stephens, Nakayawi and Hoctori with percentages of 73, 85 and 96 in which malarial parasites were found in blackwater fever cases. Some authorities, including Koch, have believed that excessive use of quinine taken to combat malaria was responsible. If that were correct, one would expect blackwater fever to be regularly prevalent in malarial countries and more or less co-extensive with the use of quinine, which is not the fact. Moreover Thomson says cases of blackwater fever have occurred among Europeans who are known never to have taken quinine. The modern school of tropical parasitology rejects both theories, and regards blackwater fever as a specific disease due to a protozoal parasite akin to that which causes the redwater fever of cattle.
Yet Dr. Andrew Balfour, the great authority on hygiene, in his Health Problems of the Empire (British Empire Series), argues that the view now "most generally held" is that blackwater fever is "merely a concomitant of malaria" and continues : "If so, it is a most serious complication, which has slain many a pioneer of empire. Even if, as some believe, blackwater fever is a disease sui generis and due to a parasite of its own, yet there can be little doubt that it is in some way or other associated with malarial infection. Perhaps malaria renders the red blood cells more frag ile so that they are readily acted upon by some other poison, and so yield up their colouring matter, which, set free in the blood, is voided in the urine. It colours this secretion a shade of red, varying from that of a light claret to that of dark port wine, and it is this change, striking and fear-inspiring, which has given the condition its name of blackwater." See J. G. Thomson Preliminary Report on the Results of Investiga tions into the Causation of Blackwater Fever in Southern Rhodesia . (C. H.; E. S.)