Falciparum malaria parasitemia index for predicting severe malaria

Introduction: While hyperparasitemia is considered an important indicator for the development of severe malaria, there is currently no consensus on the quantitative definition of hyperparasitemia. This study was conducted to establish a cutoff point for peripheral parasitemia among patients with Plasmodium falciparum malaria, to define severe malaria. Methods: The clinical presentations of 200 uncomplicated P. falciparum malaria, and 189 severe P. falciparum malaria, patients, admitted to the Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, were analyzed. Results: A peripheral parasitemia of 0.5% was found to be the optimal cutoff point for defining severe malaria, demonstrating highest sensitivity (85.1%), specificity (62.0%), and accuracy (73.2%). Conclusion: Symptoms of severe falciparum malaria depend on many factors. For the definition of hyperparasitemia in areas of low or seasonal transmission, peripheral parasitemia of 0.5% might be considered a cutoff point for discrimination between severity levels. This value might be useful for the clinical management of malaria, particularly in hypo‐endemic areas, unstable transmission areas, and other areas with similar transmission patterns.     

Falciparum malaria presenting with pruritic rashes

Rash is not generally believed to be a symptom of malaria. Two cases of acute falciparum malaria in non-immune residents of Mozambique who presented with pruritic rashes are reported. One case exhibited classical urticaria, the other a pruritic papular rash. Review of the literature reveals cases of malaria from India, East Africa, France, and the USA presenting with urticaria or a pruritic rash. Previous exposure to malaria may be a factor in these presentations. Physicians should not discount the diagnosis of malaria in patients with a history of exposure if they present with a rash. This may be of particular importance in travellers returned from malarious areas to developed countries.     

Falciparum malaria: current therapeutic challenges

PURPOSE OF REVIEW: Malaria remains a major cause of death in much of the world. The routine treatment of malaria is currently threatened by rising rates of drug resistance. Moreover, mortality among children with severe and complicated malaria remains unacceptably high. Here we review trends in antimalarial drug resistance and report on the progress of newer drugs and drug combinations. We then review some recent literature regarding the pathological processes involved in the aetiology of severe malaria that may lead to improvements in the management of children with severe disease. RECENT FINDINGS: Resistance to first line therapies, including chloroquine and sulphadoxine/pyramethamine, continues to rise in many parts of the world. The availability of newer and more effective drugs and fixed drug combinations is hampered by financial and political considerations. Nevertheless, a number of promising drugs and supportive treatments for both mild and severe malaria are at various stages of development. SUMMARY: A range of newer drugs and fixed drug combinations are now available that are safe and effective. However, these drugs remain expensive and their introduction will require political and financial support at every level. Considerable work is still required to achieve a better understanding of the processes involved in the pathogenesis of severe and complicated malaria. Only then will it be possible to develop new and appropriate therapies that will be widely applicable.     

Falciparum malaria and beta-thalassaemia trait in northern Liberia

In a study in northern Liberia of the malaria and beta-thalassaemia hypothesis, the frequencies of beta-thalassaemia and HbS traits were 9.1 and 3.4% in the Mano and 9.5 and 1.7% in the Gio tribal samples. HbC and HbN were present at low frequency. G6PD deficiency was found in 16% of males. An observed increase with age of beta-thalassaemia trait frequencies was consistent with the selection hypothesis. However, we could not entirely exclude that associated iron deficiency influenced the results in the six to 11 month age group. Malaria was holoendemic; Plasmodium falciparum predominated, P. malariae and P. ovale were also identified. Plasmodium falciparum prevalence rates were similar in normal and beta-thalassaemia trait children but parasite densities were consistently lower in the latter. Using the criterion of a falciparum parasite density of 1 x 10(9) 1(-1) or greater to indicate a potentially important infection, the relative risk in beta-thalassaemia traits one to four years old from the cross-sectional study was 0.45 (upper 95% confidence interval 0.79) and 0.41 (0.61) in two to nine year trait carriers from a longitudinal study. Plasmodium falciparum gametocyte rates were lower in beta-thalassaemia trait children (P less than 0.005). The geometric mean titre of P. falciparum antibodies was lower in beta-thalassaemia trait children from the one to four year group (P less than 0.05). Otherwise immunological studies showed little difference between the different Hb types. Parasitological findings were consistent with relative resistance of HbS trait carriers towards P. falciparum infection. We found no evidence for relative resistance of beta-thalassaemia traits towards P. malariae infection nor that G6PD deficient males were more resistant to P. falciparum than those with normal activity. We conclude that the results are consistent with relative resistance of beta-thalassaemia trait carriers to P. falciparum malaria.     

Parasite multiplication potential and the severity of Falciparum malaria

The multiplication rates and invasiveness of Plasmodium falciparum parasites isolated from adult Thai patients hospitalized with uncomplicated malaria (n=34) were compared with those from persons with severe malaria (n=42). To simulate severe malaria and control for host effects, the in vitro cultures were adjusted to 1% parasitemia and used the same red blood cell donor. P. falciparum isolates from persons with severe malaria had initial cycle multiplication rates in vitro that were 3-fold higher than those from uncomplicated malaria (median [95% confidence interval], 8.3 [7. 1-10.5] vs. 2.8 [1.7-3.9]; P=.001). Parasites causing severe malaria exhibited unrestricted red blood cell invasion, whereas those from uncomplicated malaria were restricted to a geometric mean of 40 (31%-53%) of red blood cells. P. falciparum parasites causing severe malaria were less selective and multiplied more at high parasitemias than those causing uncomplicated malaria.     

Haemoglobinuria in a case of Falciparum malaria treated with co-artemether

The first reported case of haemoglobinuria in a patient treated with co-artemether for falciparum malaria is described.     

Falciparum malaria transmitted by a thick blood smear negative kidney donor

This report describes a case of P. falciparum transmission by a recent-immigrant renal donor. The donor tested negative upon microscopy of a thick blood smear. The diagnosis was made after analysis of a Quantified Buffy Coat. In our opinion, a renal donor from a malaria endemic country should be pre-treated with antimalarials.     

Chloroquine- and sulfadoxine-pyrimethamine-resistant Falciparum malaria in vivo - a pilot study in rural Zambia

BACKGROUND: Chloroquine (CQ) and Sulfadoxine-Pyrimethamine (SP) are the predominantly used antimalarials in Zambia and other parts of East Africa, but increasing resistance of P. falciparum is a major concern. METHODS: Seventy consecutive patients with uncomplicated falciparum malaria were enrolled. In 43 patients, no prior CQ use could be demonstrated by history and urianalysis (qualitative test, Dill & Glazko) and these patients were given CQ; the other 27 had taken CQ before and received SP. RESULTS: Combined R-II and R-III CQ-resistance was 58% (60% in under-fives), which is the range previously reported from Zambia. By contrast, SP-resistance (R-II and R-III) was much higher (26%) than previously reported (3% - 17%). The history of prior CQ intake correlated well with the results of the Dill-Glazko test; there was no evidence for prior SP intake to explain these results. CONCLUSION: If our findings of SP resistance are confirmed, other drugs such as quinine, atovaquone/proguanil and artemisinin are required to treat malaria in Zambia.     

蒿甲醚伍用伯氨喹治疗恶性疟的研究

目的　观察蒿甲醚伍用伯氨喹治疗恶性疟的疗效和副作用。　方法　在中非共和国选择恶性疟12 1例 ,随机分为两组。伍用组 :口服蒿甲醚 80mg ,qd× 5d ,首日蒿甲醚 16 0mg加服伯氨喹 3片 (含基质 7 5mg ,qd× 3～ 4d)治疗 32例 ;肌注蒿甲醚加服伯氨喹 ,治疗 2 9例 ;对照组 :单用口服蒿甲醚治疗 33例和肌注蒿甲醚治疗 2 7例 ,B组、C组和D组所用剂量与疗程均同A组。上述病例于用药前及后 6、 14、 2 1、及 2 8d各随访1次 ,密切观察病例的临床症状与体征变化。　结果　A组、B组、C组和D组病例的平均退热时间分别为(47 6± 15 7)、 (36 9± 10 7)、 (48 5± 18 4 )和 (42 2± 9 5 )h。其临床治愈率依次为 84 4 %、 10 0 %、 90 1和96 3% ,其复燃率依次为 6 3%、 3 4 %、 2 1 2 %和 18 5 %。 4组药物副作用均轻。　结论　蒿甲醚伍用伯氨喹及单用蒿甲醚 (口服或肌注 )对恶性疟治疗作用均良好 ,但联合使用药物能降低恶性疟的复燃率