Plasmodium vivax

Malaria is transmitted by the bite of an infected female Anopheles mosquito, one of the few species of the insect capable of carrying the human malaria parasite. The responsible protozoa ate from the genus P/asmodium of which only four of some 100 species can cause the disease in humans. The remaining species affect rodents, reptiles, monkeys, birds, and Hvestock. The species that infect humans are P/asmodium falciparum Plasmodium vivax Plasmodium malariae and Plasmodium ovale. Note that concomitant multiple malaria infections are commonly seen in endemic areas, a phenomenon that further compHcates choice of treatment. 

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. 

Horuk R, Chitnis CE, Darbonne WC, et al. A receptor for the malarial parasite Plasmodium vivax the erythrocyte chemokine receptor. Science 1993 261 1182-1184. 

Craig, A.A. and Kain, K.C. (1996) Molecular analysis of strains of Plasmodium vivax from paired primary and relapse infections. Journal of Infectious Diseases 174, 373-379. 

Hazlett F et al. Emergence of FY A (null) in a Plasmodium vivax-endemic region of Papua New Guinea. Proc Natl Acad Sci USA 1999 96 13973-13977. 

A 27-year-old female has just returned from a trip to Southeast Asia. In the past 24 hours, she has developed shaking, chills, and a temperature of 104°E A blood smear reveals Plasmodium vivax. Which of the following agents should be used to eradicate the extraerythrocytic phase of the organism ... 

A8. Alving, A. S., Johnson, C. F., Tarlov, A. R., Brewer, G. J., Kellermeyer, R. W., and Carson, P. E., Mitigation of the hemolytic effect of primaquine and enhancement of its action against exoerythrocytic forms of the Chesson strain of Plasmodium vivax by intermittent regimens of drug administration. Bull. World Health Organization 22, 621-631 (1960). 

Malaria For the suppressive treatment and treatment of acute attacks of malaria caused by Plasmodium vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum. 

Chloroquine is a rapidly acting blood schizonti-cide with some gametocytocidal activity. It is used with primaquine for Plasmodium vivax and Plasmodium ovale infections. It has been widely used prophylactically by traveler s to endemic areas. Its mechanism of action is unclear. It is believed to hinder the metabolism of hemoglobin in the parasite. Presumably chloroquine prevents the formation in the plasmodia of polymers out of free heme which then builds up and becomes toxic. Resistance occurs as a consequence of the expression of a membrane phospho-glycoprotein pump in the plasmodia which is able to expel chloroquine from the parasite. Plasmodium falciparum is the most likely to become resistant. 

Halofantrine, a 9-phenanthrenemethanol derivative, is a blood schizonticide and is active against Plasmodium vivax and chloroquine sensitive as well as chloroquine resistant strains of Plasmodium falciparum. As no parenteral preparation is available it cannot be used for severely ill patients. Oral absorption is slow and incomplete and is increased by a fatty meal. 

P aeruginosa—Pseudomonas aeruginosa P carinii—Pneumocystis carinii P kellicotti—Paragonimus kellicotti P mirabilis—Proteus mirabilis P vivax—Plasmodium vivax PABA— p-aminobenzoic acid PAS—para-aminosalicylic acid Pb—lead... 

Ling J et al Randomized, placebo-controlled trial of atovaquone/proguanil for the prevention of Plasmodium falciparum or Plasmodium vivax malaria among migrants to Papua, Indonesia. Clin Infect Dis 2002 35 825. [PMID 12228819]... 

Reticulocyte binding protein 1 precursor-Plasmodium vivax (330217.5 Da) Titin-rabbit (fragment) (751113.32 Da)... 

Four principal species from the genus Plasmodium cause natural human infection Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium falciparum. P. falciparum is the most lethal as it causes approximately 90% of malaria-related deaths (1). An additional species, Plasmodium knowlesi, which generally infects macaques, has also been shown increasingly to infect humans as well (4). As more sophisticated diagnostic tests are now able to easily distinguish one species of Plasmodium from another, it is thought that infection with P. knowlesi has heretofore been underreported because this species morphologically resembles other Plasmodium species in blood smears (5). 

Chaudhuri, A., Polyakova, J., Zbrzezna, V., Williams, K., Gulati, S., and Pogo, A. O. (1993) Cloning of the gpD protein cDNA, the major subunit of the Duffy blood group system and the receptor for the Plasmodium vivax malaria parasite. Proc. Natl. Acad. Sci. USA 90, 10,793-10,797. 

Her hemoglobin level was 10.9 g/dL (moderately anemic), white blood cell count was 5200/p.L (normal), and her platelet count was 103,000/pL (the lower limit of normal for platelet count is 140,000/pL). Examination of a peripheral blood smear revealed clear evidence of malaria due to Plasmodium vivax (Figure A.4). 

Question A.7 In general, what are the drugs of choice for the treatment of malaria due to Plasmodium vivax ... 

Plasmodium vivax—is the most geographically widespread and the cause of the most malaria cases in the United States. This species produces less severe symptoms. Relapse is possible as well as the potential for chronic disease. 

Alphonse Laveran, a French Army physician working in North Africa in the 1880s, was the first to observe malarial parasites in human blood. Their mode of transmission was not understood, however, until Ronald Ross, a British medical officer in India, found the organisms within the bodies of Anopheles mosquitoes. Malaria is caused by four species of parasitic protozoa Plasmodium vivax, P. ovale, P. malariae, satid P. falciparum. These organisms have complex life cycles involving several different developmental stages in both human and mos-... 

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