The erythrokinetics of three baboons were studied over a twelve week period after infection with 3 000 cercariae of S. mansoni and compared with three uninfected control animals. In addition to monitoring changes in haematological and parasitological parameters several radioisotopic techniques were used concurrently to measure alterations in red cell kinetics. In particular 51Cr-labelled red cells and 59Fe-ferric citrate were used to measure red cell production, circulating volume, survival time and routes of loss.

All the animals remained in good condition despite heavy infection and the pathophysiological changes were in general mild and transient in nature. The principle alterations were associated with patency and consisted of a modest fall in haematocrit, some inappetence and the appearance of blood-stained mucus in the faeces. Red cell survival was reduced in the infected animals and this was correlated with an increase in faecal blood loss and haemodilution. There was no evidence of haemolytic factors or depressed erythropoiesis having any aetiological role in the anaemia.

The results confirmed the complexities of schistosomal anaemia as well as the ability of primates to withstand heavy parasitic burdens for short periods with minimal pathophysiological disturbance.