The purpose of treatment for uncomplicated malaria is to produce a radical cure using the combination of: artesunate (4 mg/kg/day) plus mefloquine (8 mg/kg day) for 3 days; a fixed dose of artemether and lumefantrine (20/120 mg tablet) named Coartem (4 tablets twice a day for three days for adults weighing more than 35 kg); quinine 10 mg/kg 8-hourly plus tetracycline 250 mg 6-hourly for 7 days (or doxycycline 200 mg as an alternative to tetracycline once a day for 7 days) in patients aged 8 years and over; Malarone (in adult 4 tablets daily for 3 days). In treating severe malaria, early diagnosis and treatment with a potent antimalarial drug is recommended to save the patients life. The antimalarial drugs of choice are: intravenous quinine or a parenteral form of an artemisinin derivative (artesunate i.v./i.m. for 2.4 mg/kg followed by 1.2 mg/kg injection at 12 and 24 hr and then daily for 5 days; artemether i.m. 3.2 mg/kg injection followed by 1.6 mg/kg at 12 and 24 hrs and then daily for 5 days; arteether i.m. (Artemotil) with the same dose of artemether or artesunate suppository (5 mg/kg) given rectally 12 hourly for 3 days). Oral artemisinin derivatives (artesunate, artemether, and dihydroartemisinin with 4 mg/kg/day) could replace parenteral forms when patients can tolerate oral medication. Oral mefloquine (25 mg/kg divided into two doses 8 hrs apart) should be given at the end of the artemisinin treatment course to reduce recrudescence.
Adult ; Antimalarials/*administration & dosage ; Child ; Clinical Trials as Topic ; Drug Administration Routes ; Drug Administration Schedule ; Drug Therapy, Combination ; Humans ; Malaria/*drug therapy ; Recurrence/prevention & control ; Severity of Illness Index ; Thailand ; Time Factors

Objective: To determine the frequency of malaria parasite detection from the buffy coat blood ilms by using capillary tube in falciparum malaria patients with negative conventional thick ilms. Methods: Thirty six uncomplicated falciparum malaria patients confirmed by conventional thick and thin films were included in the study. The patients were treated with artemisinin combination therapy at Hospital for Tropical Diseases, Bangkok, Thailand for 28 day. Fingerpricks for conventional blood films were conducted every 6 hours until negative parasitemia, then daily fingerpricks for parasite checks were conducted until the patients were discharged from hospital. Blood samples were also concurrently collected in 3 heparinized capillary tubes at the same time of fingerpricks for conventional blood films when the prior parasitemia was negative on thin films and parasitemia was lower than 50 parasites/200 white blood cells by thick film. The first negative conventional thick films were compared with buffy coat thick films for parasite identification.Results:Out of 36 patients with thick films showing negative for asexual forms of parasites, buffy coat films could detect remaining 10 patients (27.8%) with asexual forms of Plasmodium falciparum. Conclusions: The study shows that buffy coat thick films are useful and can detect malarial parasites in 27.8% of patients whose conventional thick films show negative parasitemia.

We retrospectively examined the charts of travelers admitted to the Hospital for Tropical Diseases, Bangkok, Thailand, with malaria during the years 2000-2005. Twenty-one cases of malaria were identified, of which 12 (57%) were Plasmodium vivax infections and 9 (43%) were P. falciparum infections. There was one mixed case with vivax and falciparum infection. Only 1 P. falciparum case had complications. All cases were successfully treated with standard antimalarial drugs. Only 3 of the 21 cases were thought to be acquired in Thailand, the rest were regarded to be imported.
*Travel ; Thailand/epidemiology ; Retrospective Studies ; *Plasmodium vivax ; *Plasmodium falciparum ; Middle Aged ; Male ; Malaria/*epidemiology/*parasitology ; Humans ; Animals ; Adult

The AnaeroPack^® malaria culture system with a portable thermostat incubator was evaluated in a field laboratory on the Thai-Myanmar border conducting in vitro drug susceptibility tests on blood samples from 5 Karen children infected with P. falciparum. Only one isolate was susceptible to chloroquine; the others were highly resistant. The IC₅₀ value of an isolate was only resistant to mefloquine, whereas the values of the 3 patients who presumably showed recrudescence were slightly elevated in the susceptible ranges. These results suggested that chloroquine should no longer be used for P. falciparum malaria in this geographic area, and that mefloquine should be carefully monitored for its in vivo effectiveness. In this study, the AnaeroPack^® malaria culture system with portable thermostatic incubator is a powerful and useful mobile tool, which aids in providing detailed evidence-based distribution data concerning of drug resistant malaria in the field.

The NOW^® Malaria Test, an immunochromatographic test (ICT), was evaluated to determine its ability to quantitatively detect malaria parasites using 100 blood samples from Thailand, including 50 Plasmodium falciparum (Pf) infections and 50 P. vivax (Pv) infections. Intensities of the thickness of the visible bands of the positive ICT were compared with the parasite densities. In cases of Pf infection, the intensities of both HRP-2 bands (T1 bands: Pf specific bands) and aldolase bands (T2 bands: pan-Plasmodium bands) correlated with the parasite densities. The intensities of T2 bands in Pf positive samples showed better correlation with the parasite densities than the T1 bands. In the cases of Pv infection, the intensities of T2 bands were also well correlated with parasite density. These results suggest that the ICT is useful not only for rapid detection of malaria parasites but also for estimating parasite density.

In acute uncomplicated falciparum malaria, there is a continuum from mild to severe malaria. However, no mathematical system is available to predict uncomplicated falciparum malaria patients turning to severe malaria. This study aimed to devise a simple and reliable model of Malaria Severity Prognostic Score (MSPS). The study was performed in adult patients with acute uncomplicated falciparum malaria admitted to the Bangkok Hospital for Tropical Diseases between 2000 and 2005. Total 38 initial clinical parameters were identified to predict the usual recovery or deterioration to severe malaria. The stepwise multiple discriminant analysis was performed to get a linear discriminant equation. The results showed that 4.3% of study patients turned to severe malaria. The MSPS = 4.38 (schizontemia) + 1.62 (gametocytemia) + 1.17 (dehydration) + 0.14 (overweight by body mass index; BMI) + 0.05 (initial pulse rate) + 0.04 (duration of fever before admission) - 0.50 (past history of malaria in last 1 year) - 0.48 (initial serum albumin) - 5.66. Based on the validation study in other malaria patients, the sensitivity and specificity were 88.8% and 88.4%, respectively. We conclude that the MSPS is a simple screening tool for predicting uncomplicated falciparum malaria patients turning to severe malaria. However, the MSPS may need revalidation in different geographical areas before utilized at specific places.
Adolescent ; Adult ; Animals ; Disease Progression ; Female ; Humans ; Malaria, Falciparum/*diagnosis/pathology/physiopathology ; Male ; Multivariate Analysis ; Prognosis ; Sensitivity and Specificity ; Severity of Illness Index ; Thailand ; Treatment Outcome

Artemesinin-combination therapies (ACT) for falciparum malaria reduce gametocyte carriage, and therefore reduce transmission. Artemisinin derivatives will act against only young gametocytes whereas primaquine acts on mature gametocytes which are present usually in the circulation at the time when the patient presents for treatment. Both artemisinin derivatives and primaquine have short half-lives, less than 1 hr and 7 hr, respectively. Therefore, asexual parasites or young gametocytes remain after completed ACT. A single dose of primaquine (0.50-0.75 mg base/kg) at the end of ACT can kill only mature gametocytes but cannot kill young gametocytes (if present). Remaining asexual forms after completion of ACT course, e.g., artesunate-mefloquine for 3 days, may develop to mature gametocytes 7-15 days later. Thus, an additional dose of primaquine (0.50-0.75 mg base/kg) given 2 weeks after ACT completion may be beneficial for killing remaining mature gametocytes and contribute to more interruption of Plasmodium falciparum transmission than giving only 1 single dose of primaquine just after completing ACT.

INTRODUCTIONChloroquine, in combination with primaquine, is used as the firstline treatment for uncomplicated P. vivax malaria in Thailand. In view of the declining efficacy of chloroquine in many P. vivax endemic areas, the possibility of emergence of chloroquine- resistant P. vivax in Thailand is a concern. The aim of this study was to assess the trends in therapeutic efficacy of chloroquine and primaquine for the treatment of uncomplicated P. vivax malaria and to assess the utility of parasite clearance times as a measure of efficacy.

MATERIALS AND METHODSThis study consisted of: 1) review of medical records of patients who were hospitalised for a period during their treatment for uncomplicated P. vivax malaria at the Hospital for Tropical Diseases, Bangkok, Thailand between 2004 and 2013. Treatment consisted of chloroquine (1500 mg base administered over 3 days) or chloroquine (as before) plus primaquine (15 to 30 mg base/daily for 14 days from day 2); and 2) systematic review of the literature in English to assess current standards in the reporting of parasite clearance times.

RESULTSThe 28-day cure rate was 99.1%. The range of median parasite clearance time over the 10-year period was 46 to 59 hours, and there was statistical evidence for an increasing trend in parasite clearance times between 2009 and 2013. Heterogeneity was noted among previous chloroquine efficacy studies in the measurement and reporting of parasite clearance.

CONCLUSIONThe treatment of P. vivax infection with a combination of chloroquine and primaquine has remained efficacious in Thailand. Increasing rates of parasite clearance in a population over time may be a useful early warning mechanism for the emergence of chloroquine resistance. The utility of monitoring time-trends in parasite clearance to detect resistance may be enhanced if parasite clearance measurements are standardised.

Antimalarials ; therapeutic use ; Chloroquine ; therapeutic use ; Drug Resistance, Microbial ; Drug Therapy, Combination ; Humans ; Malaria, Vivax ; drug therapy ; Plasmodium vivax ; Primaquine ; therapeutic use ; Thailand ; Time Factors ; Treatment Outcome

Peripheral gangrene, characterized by distal ischemia of the extremities, is a rare complication in patients with falciparum malaria. Patients with this complication have generally undergone early amputation of the affected areas. In this report, we describe 3 adult Thai patients presented at the Hospital for Tropical Diseases, Bangkok, with high grade of fever ranged 6-9 days, jaundice, acute renal failure, respiratory failure, alteration of consciousness and shock. Two patients had gangrene developed at the lower extremities on day 1 of hospitalization and 1 patient had gangrene developed on day 3. Blood smears revealed hyperparasitemia with Plasmodium falciparum. These patients were diagnosed as having severe malaria with peripheral gangrene. The resolution of gangrene was successfully achieved by treatment with artesunate and conservative treatment in 2 of 3 cases.
Middle Aged ; Male ; Malaria, Falciparum/*complications/drug therapy ; Humans ; Gangrene/*etiology ; Female ; Antimalarials/therapeutic use ; Adult

Mixed infections of Plasmodium falciparum and Plasmodium vivax is high (~30%) in some malaria hypoendemic areas where the patients present with P. falciparum malaria diagnosed by microscopy. Conventional treatment of P. falciparum with concurrent chloroquine and 14 days of primaquine for all falciparum malaria patients may be useful in areas where mixed falciparum and vivax infections are high and common and also with mild or moderate G6PD deficiency in the population even with or without subpatent vivax mixed infection. It will be possibly cost-effective to reduce subsequent vivax illness if the patients have mixed vivax infection. Further study to prove this hypothesis may be warranted.