Why quotidian fever is irregular?
Actually, the fever cycles associated with all types of malaria can be irregular. This is particular true in the initial stages of the fever, when the merozoites (the form of the parasite that leaves the liver to infect red blood cells) from different infection broods mature at different rates.
Over a few cycles of reproduction, the maturation synchronises and the parasites burst from the red blood cells in unison, creating more regular cycles of fever (no one really knows how the malaria parasites times emergence so closely!). P. falciparum may also always exhibit irregular cycles of fever, again due to asynchronous destruction of red blood cells.