Malaria Plasmodium ovale

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. 

Malaria is transmitted from person to person by a certain species of the Anopheles mosquito. The four different protozoans causing malaria are Plasmodium falciparum, P. malariae, P. ovale, and P. vivax. Drugp used to treat or prevent malaria are called anti malarial drags. Three antimalarial drugs are discussed in the chapter chloroquine, doxycycline, and quinine sulfate. Other examples of antimalarial drugs in use today are listed in the Summary Drug Table Antimalarial Drugs. 

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. 

The malarial parasite is a single-cell protozoan (plas-modium). Although more than 100 species of plasmodia have been identified, only four are capable of infecting humans Plasmodium malariae, P. ovale, P. vivax, and P. falciparum) the rest attack a variety of animal hosts. P. falciparum and P. vivax malaria are the two most common forms. 

Mecfianism of Action A quinolone-methanol compound structurally similar to quinine that destroys the asexual blood forms of malarial pafhogens, Plasmodium falciparum, P. vivax, P. malariae, P. ovale. Therapeutic Effect Inhibifs parasite growth. Pharmacokinetics Well absorbed from fhe gasfroinfesfinal (GI) tract. Protein binding 98%. Widely distributed, including cerebrospinal fluid (CSF). Metabolized in liver. Primarily excreted in urine. Half-life 21-22 days. 

Four species of plasmodium typically cause human malaria Plasmodium falciparum, P vivax, P malariae, and P ovale. A fifth species, P knowlesi, is primarily a pathogen of monkeys, but has recently been recognized to cause illness, including severe disease, in humans in Asia. Although all of the latter species may cause significant illness, P falciparum is responsible for the majority of serious complications and deaths. Drug resistance is an important therapeutic problem, most notably with P... 

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). 

The total dose of chloroquine base over 3 days should be approximately 25 mg/kg base. This is sufficient for Plasmodium malariae infection but, for Plasmodium vivax and Plasmodium ovale eradication of the hepatic parasites is necessary to prevent relapse, by giving ... 

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) ... 

Malaria is a vector-borne infectious disease caused by protozoan parasites. Human malaria is usually caused by the infection of Plasmodium falciparum, P. malariae, P. ovale, and P. vivax (Mendis et al, 2001). It is widespread in tropical and subtropical regions, including Asia, Africa, and parts of the Americas. Each year there are about 350-500 million cases of malaria, and more than 1 million people die (CDC, 2009). A series of gossypol derivatives with modified aldehydic groups and hydroxyl groups (Figs. 6.10 and 6.11) have been shown to inhibit the growth of P. falciparum (Razakantoanina et al, 2000 Royer et al, 1986). Table 6.3... 

Baert, C. B., Deloron, P., Viscogliosi, E., Delgado-Viscogliosi, P., Camus, D., and Dive, D. (1999). Cloning and characterization of iron-containing superoxide dismutase from the human malaria species Plasmodium ovale, P. malariae and P. vivax. Parasitol. Res. 85,1018-1024. 

Hydroxychloroquine sulfate is a 4-aminoquinoline compound that interferes with parasitic nucleoprotein (DNA/ RNA) synthesis and parasite growth or causes lysis of parasite or infected erythrocytes. In rheumatoid arthritis, it may suppress formation of antigens responsible for symptom-producing hypersensitivity reactions. It is indicated for prophylaxis and treatment of acute attacks of malaria caused by Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale, and susceptible strains of Plasmodium falciparum. It is also used for treatment of chronic discoid and systemic lupus erythematosus (SLE) and acute or chronic rheumatoid arthritis in patients not responding to other therapies. 

Malaria parasites have a complex life cycle that permits drug action at several points. Plasmodium species that infect humans P falciparum, P malariae, P ovale, P vivax) tire spread by the female Anopheles mosquito and, after inoculation into the human host, undergo a primary developmental stage in the liver (primary tissue phase). They then enter the blood and parasitize erythrocytes (erythrocytic phase). P falciparum and P malariae have only one cycle of liver cell invasion thereafter, multiplication is confined to erythrocytes. The other species have a dormant hepatic stage (in which they become bypnozoites) that is responsible for recurrent infections and relapses after apparent recovery of the host from the initial infection. 

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. 

Chloroquine is an excellent suppressive agent for treating acute attacks of malaria caused by Plasmodium vivax and Plasmodium ovale. The drug also is effective for cure and as a suppressive prophylactic for the treatment of Plasmodium malariae and susceptible Plasmodium falciparum. 

As a result, the drug combination (Fansidar) appears to have improved drug-mediated disruption of folic acid in Plasmodium sp. (35,43). This combination has been used with quinine for the treatment and prevention of chloroquine-resistant malaria Plasmodium falciparum, Plasmodium ovale, Plasmodium vivax, and Plasmodium malaria). The combination therapy (Fansidar) has the added advantage of being inexpensive, which is essential for successful therapy in developing countries. When used on its own, pyrimethamine is a blood schizonticide without effects on the tissue stage of the disease. 

The variety of malaria parasites is almost as confusing as their nomenclature since the first observation of the living parasite by Laveran in 1880, there have been described over 100 different types, and the number of anopheline vectors is of the same order. Fortunately, only four plasmodial species infect man, namely Plasmodium falciparum, P. malariae, P. ovale and P. vivax, but numerous others parasitise various species of mammals. 

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