Malaria, tertian

Plasmodium vivax, responsible for the most prevalent form of malaria (benign tertian), has an incubation period of 8—27 days (14 average). A variety seen in northern and northeastern Europe has an incubation period as long as 8—10 months. The disease can cause splenic mpture and anemia. Relapses (renewed manifestations of erythrocytic infection) can occur with this type of malaria. Overall, P. vivax is stiU susceptible to chloroquine however, resistant strains have been reported from Papua New Guinea and parts of Indonesia. Plasmodium malariae the cause of quartan malaria, has an incubation period of 15—30 days and its asexual cycle is 72 hours. This mildest form of malaria can cause nephritis in addition to the usual symptoms. It is a nonrelapsing type of malaria but the ted blood ceU infection can last for many years. No resistance to chloroquine by this plasmodium has been reported. Plasmodium ovale responsible for ovale tertian malaria, has an incubation period of 9—17 days (15 average). Relapses can occur in people infected with this plasmodium. No chloroquine resistance has been reported for this parasite. 

Answer The first and most important step in managing a patient with fever and occasional gastrointestinal symptoms upon return from a malaria-endemic area is to include it prominently in the differential diagnosis. Any delay in the diagnosis and proper treatment places the patient in peril. Untreated P. falciparum in a nonimmune individual can quickly overwhelm the patient in a very short time hence the name malignant tertian malaria. Severe manifestations heralding unfavorable prognosis include... 

Human malaria is caused by four species of Plasmodium namely Plasmodium falciparum, P. vivax, P. malariae and P. ovale. P. vivax is mainly responsible for most of the infections (70%) which results in benign tertian malaria. In P. falciparum and P. vivax infections, the patient has fever with rigors every third day and termed as tertian. The other two, P. ovale and P. malariae are mild in nature in which fever develops every fourth day and termed as benign quartan. Symptoms and complications in P. falciparum malaria are more severe than P. vivax malaria. 

Quartan malaria is caused by Plasmodium malariae (incubation period of 18-40 days), tertian malaria by Plasmodium vivax and Plasmodium ovale (incubation period of 10 to 18 days), and tropical malaria by Plasmodium falciparum (incubation period of 7 to 14 days) ... 

The causal organisms responsible for malaria belong to the genus plasmodium which is of the class of protozoa known as sporozoa. There are four different species which are accepted as being responsible for human malaria. These are Plasmodium malariae, the parasite of quartan malaria Plasmodium vivax, the parasite of benign tertian malaria, Plasmodium falciparum, the parasite of malignant or sub tertian malaria, and Plasmodium ovale, the parasite that causes a mild type of tertian malaria. 

Immunity does not significantly alter the course of the infection due to P. falciparum, which often causes death in untreated cases, earning it the name malignant tertian malaria. Delay in treatment after the demonstration of parasites in the blood may lead to an irreversible state of shock, and death may occur even after the peripheral blood has been cleared of parasites. Parasites of this species multiply rapidly, forming clumps of blood cells and cytoplasm, which block the internal organs. Many secondary changes occur. 

Plasmodium vivax, the cause of benign tertian malaria, produces milder clinical attacks than those of P. falciparum, and death is uncommon even in untreated cases. The build-up of immunity in the host rapidly controls the infection and schizonts disappear from the blood stream. The exo-erythro-cytic forms in the liver, unaffected by immunity, continue asexual division and reinvade the circulation when immunity has fallen once more these relapses are characteristic of vivax malaria and occur for at least two years after the primary infection. Infections due to P. ovale also follow a tertian pattern, but are much milder and more responsive to therapy than those due to P. vivax and relapses are less frequent. Infections due to both these parasites often display a prolonged incubation period between the primary infection and the development of malarial symptoms. P. vivax is widely distributed north and south of the equator, extending from the tropics to the temperate zones, while P. ovale is restricted to tropical Africa and the western Pacific. 

Tertian malaria—Merozoites are released every other day—every 48 hours. 

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