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

In the North Fly region of the Western Province of Papua New Guinea 491 cases of Plasmodium falciparum infection were monitored in vivo for sensitivity to chloroquine and amodiaquine over a 2-year period; 41% resistance was detected. The RI type accounted for 74% of the resistant strains detected; 43% of these recrudesced on day 28 or shortly thereafter. 22% of resistant strains were RII type and 4% R III. The infections were categorized as imported or locally acquired. Imported infections accounted for 58% of the cases monitored and showed a resistance rate of 49%. Resistance was detected in 24% of the cases indigenous to the North Fly region (13% in the Kiunga-Ningerum area and 38% in the Ok Tedi-Star Mountains area). Linguistic groups immediate to the Ok Tedi mining operation, the Wopkaimin and Kamfaiwolmin, showed an increase in resistance from 28% in 1986 to 55% the following year. This increase was associated with renewed construction activity within the mine's development area. Two falciparum malaria outbreaks were experienced during this study, the second being attributed to introduced strains. The study showed the impact of age and variation of malaria endemicity in suppressing resistance. The study also demonstrated a possible cross-resistance problem between imported cases of P. falciparum treated with amodiaquine and chloroquine, with resistance rates of 58% and 60%, respectively, demonstrated in children under 10 years of age. The 61% amodiaquine resistance rate in locally acquired infection in children was attributed to drug pressure, since chloroquine resistance in the same group was reported at 19%. RIII-type resistance in children was only detected in those treated with amodiaquine. The efficacy of amodiaquine in clearing only 41% of the P. falciparum infections in children was a major concern. All 201 resistant P. falciparum infections detected over the 24-month monitoring period responded to treatment with quinine and Fansidar.
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PMID:Resistance of Plasmodium falciparum to chemotherapy with 4-aminoquinolines in the Ok Tedi area of Papua New Guinea. 266 76

In-vitro lymphoproliferative responses to malaria antigens are suppressed in patients with acute Plasmodium falciparum infection. Studies with other parasitic diseases have suggested that monocyte/macrophage-derived prostaglandins may be responsible for immunosuppression. Since acute malaria infection is characteristically associated with fever it is likely that prostaglandin E production will also be enhanced in these patients. In this study, indomethacin, a cyclooxygenase inhibitor which blocks the synthesis of prostaglandins, was added to the culture medium during assays of lymphoproliferative responses to malaria antigens and other soluble proteins. Responses to several antigens were enhanced in the presence of indomethacin, indicating that prostaglandins may have a generalized immunosuppressive role in malaria-infected individuals. However, responses to malaria antigens were particularly enhanced by indomethacin, suggesting that malaria-specific T-cells are especially sensitive to the effects of prostaglandin, possibly due to prior activation in vivo by circulating malaria antigens.
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PMID:Suppression of in-vitro lymphoproliferative responses in acute malaria patients can be partially reversed by indomethacin. 268 16

We report suppression of T-cell proliferative responses to P.falciparum specific antigen and mitogens. T-cells derived from malaria patients were co-cultured with P.falciparum antigen or mitogens and the T-cell activity determined by radioactive thymidine incorporation assay system. We found inhibition of T-cell responses to P.falciparum antigen in 13 out of 24 malaria patients studied. The suppression ranged from 4%-60%. Results of mitogenic responses of T-cells showed a wide variation. Suppression of concanavalin A (Con A) responses ranged from 48%-64% (4 out of 10 patients) while phytohaemagglutinin (PHA) responses varied from 4%-60% (8 out of 10 patients) and those of purified protein derivative (PPD) antigen from 12%-44% (3 out of 6 patients). Together, these preliminary results show a marked impairment in T-cell responses to parasite antigen and mitogens in P. falciparum infected patients.
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PMID:Suppression of T-cell proliferative response in Plasmodium falciparum malaria patients--preliminary results. 269 67

Various pernicious syndromes in Plasmodium falciparum infection are being reported with increasing frequency from tropical countries. A rare case of fatal pancytopenia associated with falciparum malaria is described. The patient developed fulminant aspiration bronchopneumonia which was unresponsive to antibiotic therapy and contributed to the development of adult respiratory distress syndrome. He also had severe uncontrolled gastrointestinal bleeding and possibly an intracerebral haemorrhage. Anaemia and thrombocytopenia are well known in malaria but severe leucopenia is very rare and pancytopenia has not been reported.
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PMID:Fatal pancytopenia in falciparum malaria. 269 48

In the treatment of severe Plasmodium falciparum infection antimalarial drugs should, ideally, be given by controlled rate intravenous infusion until the patient is able to swallow tablets. In cases where infection has been acquired in a chloroquine resistant area, and where it has broken through chloroquine prophylaxis or where the geographical origin or species are uncertain, quinine is the treatment of choice. When access to parenteral quinine is likely to be delayed, parenteral quinidine is an effective alternative. A loading dose of quinine is recommended in order to achieve therapeutic plasma concentrations as quickly as possible. In the case of chloroquine sensitive P. falciparum infection, chloroquine, which can be given safely by slow intravenous infusion, may be more rapidly effective and has fewer toxic effects than quinine. There is limited experience with parenteral administration of pyrimethamine sulphonamide combinations such as Fansidar, and resistance to these drugs has developed in South East Asia and elsewhere. Mefloquine and halofantrine cannot be given parenterally. Qinghaosu derivatives are not readily available and have not been adequately tested outside China. Supportive treatment includes the prevention or early detection and treatment of complications, strict attention to fluid balance, provision of adequate nursing for unconscious patients and avoidance of harmful ancillary treatments. Anaemia is inevitable and out of proportion to detectable parasitaemia. Hypotension and shock ('algid malaria') are often attributable to secondary gram-negative septicaemia requiring appropriate antimicrobial therapy and haemodynamic resuscitation. Many patients with severe falciparum malaria are hypovolaemic on admission to hospital and require cautious fluid replacement. Failure to rehydrate these patients may lead to circulatory collapse, lactic acidosis, renal failure and severe hyponatraemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Treatment of severe malaria. 269 26

A randomized, double-blind field trial was carried out to compare the effectiveness of mefloquine plus sulfadoxine-pyrimethamine (MSP) with that of sulfadoxine-pyrimethamine (SP) in chemoprophylaxis against malaria. The study was conducted in 193 migrant workers in the eastern rural areas of Thailand which are known to be highly endemic for multidrug-resistant Plasmodium falciparum infection. MSP was found to be more effective than SP in the suppression of both P. falciparum and P. vivax parasitaemias, when administered weekly for 12 weeks (P = 0.0014). Complete suppression of P. falciparum was achieved by MSP while 8 subjects receiving SP developed parasitaemia. One subject in the MSP group developed P. vivax parasitaemia, compared with 4 in the SP group. However, in view of the reported complications associated with the use of long-acting sulphonamides, some of which can be life threatening, prophylactic regimens containing sulfadoxine, though proved efficacious, must be used with extreme caution.
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PMID:The effectiveness of chemoprophylaxis against malaria for non-immune migrant workers in eastern Thailand. 269 63

After treatment with chloroquine and pyrimethamine/sulfadoxine, 118 school children aged 6 to 10 years living near the Kenyan coast were enrolled in a malaria chemoprophylaxis study and followed up for 20 weeks. Children were randomly assigned to receive either chlorproguanil 20 mg weekly (n = 78) or placebo (n = 37). The attack rate of Plasmodium falciparum infection was 42% in chlorproguanil recipients (39.8 episodes per 1000 person-weeks of prophylaxis) and 73% in placebo recipients (69.2 episodes per 1000 person-weeks, p less than 0.02). Sensitivity tests on 36 isolates successfully cultured in vitro showed that all 21 isolates from chloroproguanil recipients were resistant to dihydrofolate-reductase inhibitors, whereas only 3 of 15 isolates from the placebo group were resistant (p less than 10(-6)). Chlorproguanil in a weekly adult dose of 40 mg does not provide adequate prophylaxis against P falciparum in Kenya, probably because drug levels between doses fall below those required to suppress parasites resistant to dihydrofolate-reductase inhibitors.
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PMID:Inadequacy of chlorproguanil 20 mg per week as chemoprophylaxis for falciparum malaria in Kenya. 287 70

Malaria sporozoite infection rates in a mixed species group of 244 Anopheles gambiae Giles sensu lato and 115 An.funestus Giles wild female mosquitoes were compared using three methods to determine cut-off absorbance values for positivity of a Plasmodium falciparum Welch enzyme-linked immunosorbent assay (ELISA). Positive controls were based on P.falciparum circumsporozoite protein. As negative controls, four wild male Anopheles were included on each microtitre plate; tests were repeated on four consecutive days for each plate. Infection rates were estimated at 13.1-22.8% using the mean absorbance value of negative controls plus three standard deviations, 11.7-12.8% using double the mean and 12.5-13.6% using the fixed cut-off value of 0.20 (allowing for 20% variation in negative control absorbance values). Observed agreement for positivity or negativity among samples tested four times was 98.6% for the 2 x mean method, 97.2% for the fixed cut-off 0.20 value, but only 82.7% for the mean + 3 SD method. It was concluded that the 2x mean cut-off method is most reliable for field studies. P.falciparum sporozoite rates of 12.2% in An.funestus and 11.9% in An.gambiae s.l. were thus determined on the basis of the 2x mean cut-off method. This comparative evaluation demonstrates that vector infectivity rates can be seriously over-estimated from sporozoite ELISA tests, by as much as 87% in one case considered here, depending on the absorbance cut-off method applied for negative controls.
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PMID:ELISA absorbance cut-off method affects malaria sporozoite rate determination in wild Afrotropical Anopheles. 298 Jan 82

There is no indigenous mosquito-borne transmission of malaria in Kuwait. However, in a five year period at a district general hospital, the number of laboratory-diagnosed cases of malaria increased annually from 25 to 84, a rise of 336%. Except for two induced infections, all were imported, mainly from the Indian subcontinent. Plasmodium vivax was responsible for 87.29% of the cases; P.falciparum (12.05%), a mixed infection of P.vivax and P.falciparum (0.33%) and a case of P.ovale (0.33%) were also identified. Rapid preparation of acetone-fixed, Giemsa-stained thick blood films, a heightened awareness of the infection, examination of multiple samples of blood from patients and the general resurgence of malaria in endemic areas were some of the factors responsible for the high number of cases diagnosed. Most patients were young males and presented with clinical malaria due to P.vivax between May and October each year, an apparent seasonal peak. However, many were already resident in the country for a variable period. Patients with P.falciparum though, presented clinically within two weeks of arrival in the country. Parasite densities were calculated to monitor the progress of treatment and identify quickly any possible chloroquine-resistant P.falciparum strains. A policy of active prophylaxis is suggested to stem the tide of imported malaria.
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PMID:Aspects of imported malaria at a district general hospital in non-endemic Kuwait, Arabian Gulf. 304 48

Malaria should be considered in a patient with unexplained fever and a history of travel to an endemic area. Aggressive therapy must be started if Plasmodium falciparum infection is a possibility. Travelers must be educated about mosquito bite protection and appropriate chemoprophylaxis. Travelers can, however, acquire malaria despite chemoprophylaxis, and symptoms may appear up to one year after the trip.
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PMID:Malaria: chemoprophylaxis and therapy. 304 49


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