Decrease in platelet survival and total platelet sialic acid concentration in rats infected with Plasmodium bergei bergei.

Suckling Wistar rats aged 3-5 weeks were infected through their dorsal tail vein with P. berghei berghei passed in Swiss albino mice. Platelet recovery and platelet survival using 51Cr-labelled heterologous platelets obtained from adult Wistar rats were determined in the infected animals on different post-infection days and on a group of non-infected rats as controls. Total platelet sialic acid was also determined in the same groups of animals. The results showed reduced platelet recovery, shortened survival and reduced total platelet sialic acid content in the infected animals compared with control values. The reduction in total platelet sialic acid content was related to the degree of parasitaemia and reached significant levels on the 5th post-infection day. It is concluded that the shortened platelet survival and reduced total platelet sialic acid content observed in the P. berghei infected rats were causally related and may account for the thrombocytopaenia reported in experimental and natural malaria infections of animals and man.