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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chloroquine-resistant Plasmodium falciparum malaria is an emerging problem in the West African subregion. While chloroquine remains an effective antimalarial agent in some countries of West Africa, the susceptibility patterns of P falciparum strains need to be assessed periodically. This article reviews the literature on chloroquine-resistant P falciparum malaria.
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PMID:Drug resistance in malaria: a review of the west African situation. 129 94

In Central African Republic, the first cases of resistant P. falciparum to chloroquine occurred in 1983 in non immune expatriate residents on regular chemoprophylaxis. From 1984 to 1991, 950 in vivo tests with a seven days observation period were performed in semi-immune autochtonous children living in seven towns of the country. Chloroquine treatments were given at 25 mg/kg over 3 days period to children with P. falciparum parasitaemia > 500 (634 simplified methods) or > 1000/mm3 (316 WHO standard field tests), usually asymptomatic. Until 1988, the surveys show an absence or a low frequency of chloroquine resistance (usually below 10%) according to the town; since 1989, the resistance has been present in all towns but everywhere with a frequency under 20%. None cases of R III level resistance was observed and all children became or remained asymptomatic at day 7. Until further surveys demonstrate a decreased efficacity of chloroquine, it is advised that chloroquine be used at 25 mg/kg over 3 days period as the treatment of choice in uncomplicated acute malaria in the Central African Republic.
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PMID:Persistence of low levels of Plasmodium falciparum resistance to chloroquine in the autochthonous population of the Central African Republic. 130 Mar 52

We have investigated the effects of leaf and bark decoctions of Ocimum gratissimum, Azadirachta indica, Morinda lucida and Enantia chlorantha on (a) the course of Plasmodium yoelii nigeriensis malaria (b) reticulocyte and haematocrit values and (c) nucleated cell numbers in the spleen, bone marrow, peritoneum, liver and peripheral blood of Swiss albino mice. Results obtained showed that normal mice infected with the parasite (10(4)/mouse) suffered fulminant parasitaemia which resulted in death, 7-10 days later. All infected mice treated with chloroquine survived. On the other hand all infected mice treated with the medicinal plants exhibited varying percentages of chemosuppression of early parasitaemia which did not lead to their survival. The total number of nucleated cells in the liver, spleen and peripheral blood of malaria-infected mice increased enormously before the animals died. Such increases were maintained in other groups of mice treated with the medicinal plants. In the non-infected mice, O.gratissimum and E. chlorantha administration increased the number of nucleated cells in the spleen, liver and peripheral blood. Chloroquine on the other hand decreased the number of nucleated cells in both the malaria-infected and un-infected mice. There was also a decrease in reticulocyte numbers in the blood of normal mice injected with chloroquine. Conversely reticulocyte numbers increased in normal mice administered with some medicinal plants. Acute and chronic toxicity tests revealed that some of the medicinal plants were much more toxic than others.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:"Antimalarial" medicinal plants and their impact on cell populations in various organs of mice. 130 80

Artemether is an oil-soluble methyl ether of artemesinin (qinghaosu). It has been studied extensively in China, where it has been shown to be rapidly effective in severe falciparum malaria. Nearly all the patients studied previously were adults. We have investigated the efficacy of artemether in children with moderate or severe falciparum malaria. In the preliminary study of moderately severe malaria, 30 Gambian children were randomised in pairs to receive either intramuscular artemether (4 mg/kg loading dose followed by 2 mg/kg daily) or intramuscular chloroquine ('Nivaquine') 3.5 mg base/kg every 6 h. Both drugs were well tolerated and rapidly effective. The times to parasite clearance were significantly shorter in the artemether recipients (mean 36.7 [SD 11.3] vs 48.4 [16.8] h, p less than 0.05). 43 children with severe malaria were then randomised to receive intramuscular treatment with the same regimens of artemether (n = 21) or chloroquine (n = 22) as used in the preliminary study. 8 children (19%) died. There were no significant differences between the two groups in the clinical, haematological, biochemical, or parasitological measures of therapeutic response in survivors and there was no evidence of local or systemic toxicity. Despite similar parasite counts on admission, clearance times overall were longer in severe malaria than in moderate malaria. Artemether is a well tolerated and rapidly effective parenteral treatment for severe malaria in children, and would be especially valuable in areas with chloroquine-resistant P falciparum.
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PMID:Comparison of artemether and chloroquine for severe malaria in Gambian children. 134 8

Surveys of residents of the Pacific coast of Guatemala revealed a lack of knowledge and many misconceptions about the transmission and treatment of malaria, which could adversely affect malaria control measures and antimalarial therapy. Although mosquitoes are known to play an important role in malaria transmission and are thought to become infected by biting individuals with malaria, 75% of people interviewed believe that the mosquitoes can also acquire infections from contaminated water or by biting snakes and frogs. Furthermore, most residents believe that malaria can be acquired in other ways, such as by bathing too frequently or by drinking unboiled water. Although self-treatment of malaria with oral and injectable drugs purchased at stores and pharmacies is very common, less than 10% of the respondents were aware of the correct curative dose of chloroquine. Chloroquine injections are preferred to tablets and believed to be approximately three times as potent as tablets of the same concentration. Nearly two-thirds of the interviewees believed that pregnant and lactating women with malaria should avoid the use of chloroquine because it may cause a spontaneous abortion or dry up breast milk. Similar surveys of National Malaria Service workers and village malaria workers revealed higher levels of knowledge, although the village workers had many misconceptions about malaria transmission. An educational campaign directed at correcting some of these misconceptions should result in more appropriate self-treatment of malaria and greater acceptance by residents of personal protection methods and vector control and drug treatment programs.
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PMID:Knowledge and beliefs about malaria on the Pacific coastal plain of Guatemala. 134 62

Malaria is endemic in all 17 provinces of Laos. Transmission is perennial with a "seasonal peak" coinciding with the rainy season. The vectors Anopheles minimus and An. balabacensis (=dirus) remain susceptible to DDT. Chloroquine-resistance of Plasmodium falciparum is at the RI-RII level. Multidrug resistance is not yet a problem. Major constraints of the antimalaria program involve logistics and operational problems solutions to which are specifically addressed in the recommendations.
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PMID:The malaria situation and antimalaria program in Laos. 136 66

The effectiveness of antimalarials depends on its pharmacodynamics ie inhibitory effect on the parasites and unwanted effects on the host. It also depends on the pharmacokinetics of the drugs. The ideal antimalarials are drugs that show curative activity in the absence of toxicity to the host. Recommendation for antimalarial dosage regimens should be based on pharmacokinetic and pharmacodynamic studies in appropriate populations ie ethnic groups, adults children, and in pregnancy. Chloroquine remains the drug of choice for treating malaria caused by Plasmodium species other than P. falciparum. Even in the presence of chloroquine resistance the drug may still be quite useful, especially in areas with high communal immunity. In general sulfadoxine/pyrimethamine (S/P) should be used as an alternative antimalarial when chloroquine fails. The decision to change to S/P from chloroquine depends on many factors. Quinine still remains the drug of choice for severe chloroquine-resistant falciparum malaria. Resistance to mefloquine has appeared the exact mechanism being unknown. In general, before the use of any combination of antimalarial drugs the superiority (efficacy and side-effects) over each of the individual drugs should be clearly demonstrated. The combination of mefloquine with sulfadoxine/pyrimethamine was made on the grounds that the combination would delay the resistance to mefloquine. Desferrioxamine will hardly be an agent to be used on its own for treating malaria due to the high recrudescent rate. However, a recent report indicated that its association with antimalarial drugs in the management of severe and complicated falciparum malaria shortens fever and parasite clearance time and resolves complications faster than the standard antimalarial drug alone. Clinical trials with halofantrine has been done in several countries in the region from 1988 to the present with diverse results. Further studies on a larger scale should be carried out to ascertain whether these are due to variation in drug absorption or drug resistance. An improved formulation of halofantrine must be developed to ensure adequate absorption and bioavailability. The artermisinin group of antimalarials is known to be highly effective and independent, in its mode of action, from standard malaria drugs but associated with high recrudescent rate. Phase II studies are needed for determining/optimizing therapeutic dose regimens and to ensure safer and more effective use of these compounds.
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PMID:Overview: clinical pharmacology of antimalarials. 136 73

Several areas of clinical concern and investigation have emerged over the past year in the malaria field. Mefloquine prophylaxis has required a change in its dosing regimen. Continued monitoring for potential mefloquine toxicity has shown this agent to be safe for use for many populations, but not routinely for pregnant women or for young children. Chloroquine-resistant Plasmodium vixax may be geographically limited currently, but its presence in Irian Jaya has serious implications, should be problem spread. The currently available fluoroquinolone antibiotics possess antimalarial activity but they have not proven to be clinically dependable for the treatment of resistant Plasmodium falciparum infections. However, continued investigation of both their mechanisms of action and efficacy should not be abandoned. Adjunctive measures for the control of mosquito vectors and the prevention of human contact with mosquitoes assume greater importance as both pharmacological prophylaxis and therapy for malaria infections become increasingly difficult. Health professionals who advise travelers to endemic regions should emphasize the use of safe topical repellents and residual insecticides, which can be impregnated into bed netting and clothing.
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PMID:Trends and controversies in the prophylaxis and treatment of malaria. 136 30

The prevention of malaria is based on chemoprophylaxis and protection against the vector. Nocturnal mosquito bites can be avoided by individual and collective measures, while chemoprophylaxis involves the use of various agents according to the place and duration of stay. Three endemic zones can be defined on the basis of chemoresistance. Chloroquine, proguanil and mefloquine are the three drugs used in this setting, the latter being contraindicated for pregnant women and children. Travellers making long stays in areas of low-level chemoresistance and short stays in areas of high-level resistance and for whom mefloquine is contraindicated are advised to take antimalarial drugs at the first signs of potentially malarial fever when medical care is unavailable. Quinine, halofantrine and mefloquine are used for the curative treatment of malaria in areas of chloroquine resistance.
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PMID:[Prophylaxis of malaria]. 141 Sep 7

Chloroquine-resistant Plasmodium falciparum has been reported in the Sahel and forest regions of Cameroon since 1985. In vivo response to chloroquine treatment (25 mg/kg) was assessed in 19 patients with malaria in the savanna North-West province. 58% of the cases showed RII resistance to chloroquine. RIII resistance was suspected in one patient. Only 35% of cases showed complete parasite clearance by day 5 of treatment. Chloroquine reduced parasite counts by at least 87% in all patients. Chloroquine resistance now seems to be well established and widespread in Cameroon. Its rapid spread and the prevalence of resistance suggest the existence of sustained drug pressure resulting in rapid selection of less sensitive strains. Unfortunately, similar pressure is also being exerted with quinine.
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PMID:Chloroquine sensitivity of Plasmodium falciparum in vivo in a savanna town in Cameroon. 141 37


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