Clinical manifestations of P. vivax infection include high fevers, chills and rigours, nausea, vomiting and diarrhoea. The manifestations are a consequence in part of ruptured erythrocytes and the cytokine response to the sudden release of parasites, haemoglobin and erythrocyte membranes. Untreated and over time, the paroxysms of fever and chills can occur every 48 hours due to synchronicity of the parasite intraerythrocytic growth. Paroxysms can also occur daily. Tertian fever (paroxysm every third day) is not pathognomonic for P. vivax but also occurs with Plasmodium ovale (P. ovale).