Malaria 621 



development of the condition, since blackwater fever lias followed treat- 

 ment with other drugs such as atebrin. The onset is often marked by 

 rigors, bilious vomiting, jaundice, black urine, and general prostration. 

 The characteristic feature is intravascular hemolysis, followed by passage 

 of hemoglobin in the urine. The pathological effects are essentially those 

 of severe chronic malaria, with the complication of sudden and extensive 

 hemolysis. The only known preventive is adequate treatment of patients 

 in areas where blackwater fever is known. An extensive treatise on black- 

 water fever has been published by Stephens (107). 



Laboratory diagnosis of malaria 



Final diagnosis depends upon the detection of parasites in ma- 

 terial from the patient.^ Although certain serological techniques (Chapter 

 XIV) seem to be useful, they are not yet adequate substitutes for direct 

 demonstration of the parasites. Smears of bone marrow, obtained by 

 sternal puncture, have been used for diagnosis of chronic malaria, but 

 blood films are the preparations usually examined. 



Both thick and thin films are often prepared for examination. Most 

 routine descriptions of the parasites are based upon thin-film prepara- 

 tions. The thick film, in which a large drop of blood is spread over a 

 small area of the slide, is the more efficient, both in saving time and in 

 insuring detection of the parasites. Since the thick-film techniques — the 

 rapid method of Field (45), the method of Barber and Komp (2), and 

 others — destroy the corpuscles, the technician must depend upon careful 

 microscopy and morphology of the parasites. With either type of films, 

 it may be necessary to examine slides prepared at successive intervals if 

 parasites are not detected at first. In any case, it is not sound practice to 

 base a negative report upon examination of thin films alone if malaria 

 is suspected. 



Chemotherapy 



Although malariologists seem to agree that P. falciparum should 

 be eliminated promptly, opinions have differed concerning the treatment 

 of quartan and benign tertian cases. Advocates of the "short-term" treat- 

 ment have disapproved attempts to eradicate P. vivax and P. malariae 

 during primary attacks, preferring clinical prophylaxis and suppressive 

 treatment during residence in malarial territory. Such recommendations 

 are based upon the assumption that individuals with sub-clinical infec- 

 tions will gradually develop an effective immunity, whereas prompt elim- 

 ination of the parasites will leave the individual susceptible to reinfection. 

 In presenting objections to the short-term treatment, Craig (35) has 

 stressed the shortcomings of active immunization in India, where the 



* Comprehensive discussions of laboratory diagnosis have been published by Craig 

 (36) and Wilcox (118a). 



