The classic ones are those of malaria, one of the three great medical killers of mankind (the others being TB
and HIV, plus, of course, war and organized religion).
Intermittent malarial fevers vary considerably, based on organism involved:
Quotidian fever: From the Latin quotidianus, daily. This is a fever whose paroxysm (and resolution)
occurs every day. It is usually caused by a double tertian malaria, due to infection by two distinct
groups of Plasmodium vivax, alternately sporulating every 48 hours. It may also be caused by the most
pernicious malarial parasite (P. falciparum), combined with vivax, or by two distinct falciparum
generations that mature on different days, thus resulting in a fever that occurs twice a day. Note that
a double quotidian fever is a daily two-spikes fever that is not malarial, but gonococcal. It used to be
present in 50% of endocarditis cases, but today is mostly extinct.
Tertian fever: From the Latin tertianus, third. This is a P. vivax fever that recurs every third day, counting
the day of an episode as the first. Hence, it occurs every 48 hours (every other day).
Quartan fever: From the Latin quartanus, fourth. This is a P. malariae fever that recurs every fourth
day, counting the day of an episode as the first. Hence, it occurs every 72 hours. Note that a double
quartan is instead an infection with two independent groups of quartan parasites, so that the febrile
paroxysms occur on two successive days, followed by one without fever.
Malignant tertian fever: This is the fever of P. falciparum (falciparum fever, or aestivo-autumnal
fever, or Roman fever because it was a common ailment in the countryside of Rome up to World War
II). It is characterized by 48-hour paroxysms of a severe form of malaria, occurring with acute cerebral, renal, or gastrointestinal manifestations. These are usually due to clumping of the infected red blood
cells, causing secondary capillary obstruction and ischemia
and HIV, plus, of course, war and organized religion).
Intermittent malarial fevers vary considerably, based on organism involved:
Quotidian fever: From the Latin quotidianus, daily. This is a fever whose paroxysm (and resolution)
occurs every day. It is usually caused by a double tertian malaria, due to infection by two distinct
groups of Plasmodium vivax, alternately sporulating every 48 hours. It may also be caused by the most
pernicious malarial parasite (P. falciparum), combined with vivax, or by two distinct falciparum
generations that mature on different days, thus resulting in a fever that occurs twice a day. Note that
a double quotidian fever is a daily two-spikes fever that is not malarial, but gonococcal. It used to be
present in 50% of endocarditis cases, but today is mostly extinct.
Tertian fever: From the Latin tertianus, third. This is a P. vivax fever that recurs every third day, counting
the day of an episode as the first. Hence, it occurs every 48 hours (every other day).
Quartan fever: From the Latin quartanus, fourth. This is a P. malariae fever that recurs every fourth
day, counting the day of an episode as the first. Hence, it occurs every 72 hours. Note that a double
quartan is instead an infection with two independent groups of quartan parasites, so that the febrile
paroxysms occur on two successive days, followed by one without fever.
Malignant tertian fever: This is the fever of P. falciparum (falciparum fever, or aestivo-autumnal
fever, or Roman fever because it was a common ailment in the countryside of Rome up to World War
II). It is characterized by 48-hour paroxysms of a severe form of malaria, occurring with acute cerebral, renal, or gastrointestinal manifestations. These are usually due to clumping of the infected red blood
cells, causing secondary capillary obstruction and ischemia