Causes of death in lethal rat malaria.

The involvement of the brain, lungs and kidneys was studied in a lethal rat malaria. Lewis inbred rats were infected with Plasmodium berghei K173. The disease proved fatal within 10-14 days. Parasitaemia showed an increase of up to 43% parasitised red blood cells on Day 10 p.i. The haematocrit decreased from 50% to 12%. The systolic blood pressure dropped from 99 to 56 mmHg. The lactate dehydrogenase activity rose to 2,543 U/l. BUN and serum creatinine doubled during the course of the disease. The transaminases increased tenfold and the cholinesterase decreased from 943 U/l to 271 U/l. Morphologically the kidneys showed an immune complex glomerulo-nephritis with a normal tubulo-interstitial system. The brain, heart and lungs were normal by light microscopic examination. Marked anaemia and shock were the main causes of death in the above-mentioned specimen rat, showing that the course of the disease is significantly different from lethal infections in humans with Plasmodium falciparum who show severe pulmonary, renal and cerebral complications.