Field evaluation of the ICT malaria P.f/P.v immunochromatographic test for diagnosis of Plasmodium falciparum and P.vivax infection in forest villages of Chhindwara, central India

A rapid new immunochromatographic test (ICT malaria P.f/P.v) for diagnosis of Plasmodium falciparum and P.vivax was evaluated against thick blood smears in forest villages of Chhindwara, Madhya Pradesh, where both Plasmodium falciparum and P.vivax are prevalent. 344 symptomatic patients (Gond ethnic tribe) in five villages were screened by field staff of the Malaria Research Centre in October 1999. For P.falciparum, the ICT was 97.5% sensitive and 88% specific, with a positive predictive value (PPV) of 87.6% and a negative predictive value (NPV) of 97.6%. For P.vivax the sensitivity was only 72%, the specificity 99%, with a PPV of 92% and an NPV of 96%. Although a negative test result was inadequate to exclude parasitaemia < or = 300/microl for P.falciparum and < or = 1500/microl for P.vivax, the test is potentially useful in remote areas.     

Comparison of the OptiMAL rapid test and microscopy for detection of malaria in pregnant women in Nigeria

Malaria during pregnancy causes anaemia in pregnant women and low birthweight in infants. The purpose of this study was to evaluate the OptiMAL rapid malaria test in comparison with standard microscopy for malaria diagnosis in 268 pregnant women attending antenatal clinics at the Jos University Teaching Hospital and the Federal Medical Centre-Gombe in Nigeria. Positive results by either method were confirmed using a polymerase chain reaction assay for malaria. Although the OptiMAL assay did not detect malaria in the blood of pregnant women with low levels of parasitaemia, it may be useful for the detection of placental malaria which predisposes to low birthweight infants.     

Thrombocytopenia in Plasmodium falciparum,Plasmodium vivax and mixed infection malaria: A study from Bikaner (Northwestern India)

The occurrence, relation and magnitude of thrombocytopenia in different species of malaria are not clearly defined. This study included 1,064 patients admitted with malaria to study thrombocytopenia (platelet count <150,000 /cumm) in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) mono infection and mixed infection (Pf?+?Pv). The species diagnosis was done by peripheral blood film (PBF) and rapid diagnostic test (RDT). Validation by polymerase chain reaction (PCR) was done only in patients with severe thrombocytopenia (platelet count <20,000 /cumm). The breakup of patients was 525 (49.34%) Pf, 460 (43.23%) Pv and 79 (7.42%) mixed malaria (Pf?+?Pv). Thrombocytopenia was observed in 24.6% (262/1064) patients. The risk was greatest in the mixed infections in comparison to monoinfection individually (43.04% [34/79]; mixed vs Pv monoinfection: Odds Ratio [OR]?=?1.675 [95% Confidence Interval (CI) 1.029–2.726], p?<?0.0366; mixed vs Pf monoinfection: OR=3.911 [95% CI 2.367–6.463], p?<?0.0001). Pv monoinfection (31.09% [143/460]) had greater risk compared to Pf monoinfection (16.19% [85/525]; OR?=?2.335 [95% CI 1.722–3.167], p?<?0.0001). The occurrence of severe thrombocytopenia was also higher in Pv monoinfection (18.18% [26/143]) in comparison to either Pf monoinfection (10.59% [9/85], OR?=?1.877 (95% CI 0.834–4.223)) or mixed infection (11.76% [4/34]; OR?=?1.667 (95% CI 0.540–5.142) but this association was statistically not significant. Six patients (3 Pv, 2?Pf and 1 mixed) developed severe epistaxis requiring platelet transfusion. There was no relation between parasite density and platelet count as many patients with severe thrombocytopenia had parasite density similar to patients without thrombocytopenia. We found that the association of thrombocytopenia was statistically more significant with P. vivax monoinfection as compared to P. falciparum.     

Evaluation of the Abbott Cell-Dyn 4000 hematology analyzer for detection and therapeutic monitoring of Plasmodium vivax in the Republic of Korea

The Cell-Dyn 4000 automated hematology analyzer (CD4000) has the ability to detect malaria patients, but it remained unclear whether it could detect persistent malaria post-treatment. To investigate this, we used the CD4000 to evaluate 68 Korean patients with Plasmodium vivax malaria, and control groups of 50 patients with fever and 50 asymptomatic patients. The results from the instrument-generated scatter plot (derived by laser light depolarization) were compared with microscopy results. During the initial diagnosis, the sensitivity of the CD4000 in detecting malaria was 91.2%. On day 3 of follow-up, the CD4000 results matched those from microscopy by 96.7%. Malaria was not detected by either method beyond 14 days post-presentation. Interestingly, the atypical depolarizing events, which typify the presence of malaria in the analyzer, were highly correlated with the levels of parasitaemia in serially diluted samples of the leucocyte-depleted blood, and the CD4000 detected parasites down to the level of 288 +/- 17.7/microl. Our findings suggest that the phenomenon of atypical light depolarization could be influenced by parasitaemia levels, and be used as a screening method for P. vivax malaria patients, as well as for the therapeutic monitoring.     

Comparison of chloroquine, sulfadoxine/pyrimethamine, mefloquine and mefloquine-artesunate for the treatment of falciparum malaria in Kachin State, North Myanmar

Multi-drug resistant falciparum malaria is widespread in Asia. In Thailand, Cambodia and Vietnam the national protocols have changed largely to artesunate combined treatment regimens but elsewhere in East and South Asia chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) are still widely recommended by national malaria control programmes. In Kachin State, northern Myanmar, an area of low seasonal malaria transmission, the efficacy of CQ (25 mg base/kg) and SP (1.25/25 mg/kg), the nationally recommended treatments at the time, were compared with mefloquine alone (M; 15 mg base/kg) and mefloquine combined with artesunate (MA; 15:4 mg/kg). An open randomized controlled trial enrolled 316 patients with uncomplicated Plasmodium falciparum malaria, stratified prospectively into three age-groups. Early treatment failures (ETF) occurred in 41% (32/78) of CQ treated patients and in 24% of patients treated with SP (18/75). In young children the ETF rates were 87% after CQ and 35% after SP. Four children (two CQ, two SP) developed symptoms of cerebral malaria within 3 days after treatment. By day 42, failure rates (uncorrected for reinfections) had increased to 79% for CQ and 81% for SP. ETF rates were 2.5% after treatment with M and 3.9% after treatment with MA (P > 0.2). Overall uncorrected treatment failure rates at day 42 following M and MA were 23% and 21%, respectively. Chloroquine and SP are completely ineffective for the treatment of falciparum malaria in northern Myanmar. Mefloquine treatment is much more effective, but three day combination regimens with artesunate will be needed for optimum efficacy and protection against resistance.     

Malaria epidemiology in a rural area of the Mekong Delta: a prospective community-based study

Over the past 10 years, the Mekong Delta region in Vietnam has experienced fast socio-economic development with subsequent changes in malaria vectors ecology. We conducted a 2-year prospective community-based study in a coastal rural area in the southern Mekong Delta to re-assess the malaria epidemiological situation and the dynamics of transmission. The incidence rate of clinical malaria, established on 558 individuals followed for 23 months by active case detection and biannual cross-sectional surveys, was 2.6/100 person-years. Over the 2-year study period, the parasite rate and malaria seroprevalence (Plasmodium falciparum and P. vivax) decreased significantly from 2.4% to almost 0%. Passive case detection (PCD) of clinical cases and serological follow-up of newborns carried out in a larger population confirmed the low and decreasing trend of malaria transmission. The majority of fever cases were seen in the private sector and most were unnecessarily treated with antimalarials. Training and involvement of the private sector in detection of malaria cases would greatly improve the quality of health care and health information system.     

Paracheck-Pf: a new, inexpensive and reliable rapid test for P. falciparum malaria

We compared the performance of Paracheck-Pf, a new and cheap rapid malaria test, with ICT-Pf/PvR and microscopy in two malaria surveys in Thai villages on the Thai-Burmese border. The specificity, sensitivity, predictive positive and negative values of the Paracheck-PfR and ICT-PfR tests were calculated taking microscopy results as the gold standard. The 294 ICT-Pf/Pv tests resulted in two invalid (no control line) and 11 doubtful results. Both the ICT-Pf/PvR and Paracheck-PfR tests reliably detected P. falciparum infections. However, Paracheck-PfR failed to detect three P. falciparum cases and likewise, ICT-Pf/PvR failed to detect the same three cases and an additional four cases. These seven cases were detected by microscopy and had a parasitaemia under 150 parasites/microl. At a cost of c. US $1.00, the Paracheck-PfR test, based on the detection of the P. falciparum specific HRP-2 protein, is a reliable, easy to use and affordable tool for the diagnosis of P. falciparum malaria.     

多重PCR种特异性检测恶性疟原虫和间日疟原虫方法的建立

目的建立恶性疟原虫和间日疟原虫种特异性检测的多蕈PCR方法,用于疟疾的检测和诊断.方法根据疟原虫18S核糖体小亚基ssRNA的基因序列设计合成8对11条引物,通过对恶性疟、间日疟患者及健康对照者血样的DNA进行扩增,选择出敏感性和特异性最佳的引物用于建立多重PCR方法,并用梯度变化的方法分别对引物浓度、复性温度、延伸温度和循环次数等反应参数进行比较分析,优化PCR反应条件.利用优化后的多重PCR埘采自云南和上海的139份疟疾患者血样和32份非疟疾患者血样进行检测,以镜检方法为金标准,分析多重PCR方法检测患者血样的敏感性和特异性.结果从8对11条引物中优选出2对共3条引物用于建立多重PCR.利用这3条引物进行多重PCR,一次反应即可完成对恶性疟原虫和间日疟原虫的种特异性鉴定.对疟疾和非疟疾患者血样检测结果显示,该方法检测患者血样的敏感性为97.8%,特异性为100%.结论多重PCR方法敏感、特异、可进行批量检测,适用于对人群的疟疾监测和疑似疟疾病例的诊断,并能鉴定恶性疟原虫和间日疟原虫虫种.     

Plasmodium chabaudi: a rodent malaria model for in-vivo and in-vitro cytoadherence of malaria parasites in the absence of knobs

The ability of Plasmodium chabaudi infected erythrocytes to bind to endothelial cells in vivo and to various murine cell lines in vitro is described. A procedure for the selective recovery of a sequestering subpopulation of schizont-infected erythrocytes from hepatic sinusoids of BALB/c mice, using a combination of body perfusion, trypsin treatment and Percoll density centrifugation was developed. The serial subinoculation of such a subpopulation was used to select for a clone of parasites (strain AJJ) with considerably better cytoadherent characteristics than the parent line (strain AJ). In contrast, it was demonstrated that another clone (PC7), showed no cytoadherence in vivo or in vitro. This study shows that parasite induced alterations occurred on the surface of erythrocytes infected with late developmental stages of P. chabaudi. The antigenicity of these molecules in the infected mouse was demonstrated using immune serum and affinity chromatography. Cytoadherence and surface antigenic changes in P. chabaudi schizont-infected erythrocytes were demonstrated in the absence of the submembranous 'knobs' associated with cytoadherence in P. falciparum.     

Very young children with uncomplicated falciparum malaria have higher risk of hypoglycaemia: a study from Suriname

Objective To measure glucose kinetics and the influence of age, nutritional status and fasting duration in children with uncomplicated falciparum malaria (UFM) under the age of 5 years. Methods Plasma glucose concentration, endogenous glucose production (EGP) and gluconeogenesis (GNG) were measured using [6,6‐²H₂]glucose and ²H₂O in 17 very young (<3 years) and 7 older (3–5 years) Surinamese children with UFM admitted to the Distrikt Hospital Stoelmanseiland and Diakonessen Hospital Paramaribo over 17 months. Results Plasma glucose concentration was lower in the group of very young children than in the older children (P = 0.028). There were no differences in EGP and GNG between the groups. Overall GNG contributed 56% (median, range 17–87%) to EGP, with no differences between the groups (P = 0.240). Glucose clearance was lower in the older children (P = 0.026). Glucose concentration did not differ between children with weight for length/height less than ?1.3 SD and children with weight for length/height greater than ?1.3 SD (P = 0.266). Plasma glucose concentration was not predicted by fasting duration (P = 0.762). Conclusions Our data suggest a higher risk of hypoglycaemia in very young children with uncomplicated malaria as plasma glucose concentration was lower in this study group. Since this could not be attributed to an impaired EGP, and because glucose clearance was lower in the older children, we presume that older children were better capable of reducing glucose utilization during fasting. Studies on glucose kinetics are feasible in very young children with malaria and give more insight in the pathophysiology of hypoglycaemia.     

Deltamethrin-impregnated bednets as an operational tool for malaria control in a hyper-endemic region of Burundi: impact on vector population and malaria morbidity

Within the framework of the National Malaria Control Programme Burundi, impregnated bednets were promoted through health care facilities, schools and local administration in Nyanza Lac district. The decision to buy a bednet was left to the inhabitants and, as a result, coverage rates between 6 and 65% were observed at sub-district level. Three intervention regions were specified based on the intervention start date. From November 1992 until March 1995, bi-monthly parasitological and entomological surveys were carried out in two areas each of Region 1 and Region 2. After introduction of impregnated bednets in Region 1 the proportions of children under 5 with high parasitaemia were reduced by 42 and 53% in the 2 parasitological survey areas, where the average bednet coverages were 55 and 44% respectively. In the survey areas of Region 2 (control) no significant change occurred during the same period. During the second part of the intervention from September 1994, when intervention was also operational in Region 2, significant decreases in the proportion of high parasitaemia (63 and 42%) among children under 5 years were obtained in both parasitological survey areas of Region 2 (average coverages of 51 and 29%). The positive output of the intervention was maintained and even reinforced in the survey areas of Region 1. Bednets as a tool for malaria control entail specific problems such as coverage, daily use, reimpregnation, and renewal of old and torn nets. Further evaluation has to point out the possible shift of the clinical spectrum and the age-specific admission of malaria cases to assess the long-term benefit of this control method.     

Therapy of uncomplicated malaria in children: a review of treatment principles, essential drugs and current recommendations

Understanding the optimal treatment of uncomplicated malaria in children is challenging because of the availability of new drugs and the shift to combination therapies. This is a review of the guiding principles for the treatment of uncomplicated malaria, the essential anti-malarial drugs for children, and the treatment regimens currently recommended.     

Antibodies against Plasmodium falciparum vaccine candidates in infants in an area of intense and perennial transmission: relationships with clinical malaria and with entomological inoculation rates

Serum immunoglobulin (Ig)G1, IgG3 and total IgG were assessed by immunoabsorbent assay in 198 infants from a Tanzanian village highly endemic for Plasmodium falciparum. Antibodies were measured against epitopes of the circumsporozoite protein (the repetitive epitope (NANP)50 and a construct of the flanking regions (CS27IC)), the malaria vaccine SPf66, and two constructs of the merozoite surface protein-1 (MSP-1), a 19-kDa fragment from the C-terminal domain (MSP-119) and an N-terminal fragment spanning blocks 1-6 (H6-p190 M-1/6-H6). IgG1 and total IgG titres showed similar age profiles, all decreasing for the first 2 months of life. Anti-(NANP)50 titres remained very low throughout the first year of life, while anti-CS27IC antibody appeared to peak around 7 months of age. Only a slight tendency to increase with age was observed for levels of the other antibodies studied. IgG3 titres except for H6-p190(1/6), were very low initially and remained very low throughout the first year of life. Clinical malaria incidence at the village dispensary was analysed prospectively in relation to antibody. No IgG1 or total IgG titre showed protective effects, but low IgG3 against p190(1/6) appeared to be a risk factor in some age groups. Given the large number of antibodies tested, this single indication of possible protection could merely be chance. There were no strong associations between antibody titres and entomologically assessed sporozoite exposure suggesting that transmission-reducing interventions may have little effect on antibody levels in such children.     

Environmental, socio-demographic and behavioural determinants of malaria risk in the western Kenyan highlands: a case–control study

Objective  To identify risk factors for uncomplicated malaria in highland areas of East Africa at higher risk of malaria epidemics, in order to design appropriate interventions.
Methods  Prospective, population-based, case–control study in the Nandi Hills, a highland area of western Kenya, to identify environmental, sociodemographic and behavioural factors associated with clinical malaria. Data were collected using field observation, a structured questionnaire, and a global positioning system device.
Results  We interviewed 488 cases of slide-confirmed malaria and 980 age-matched controls. Multivariate analyses associated higher malaria risk with living <250 m of a forest [OR = 3.3 (95% CI 1.5, 7.1)], <250 m of a swamp [2.8 (1.3, 5.9)], <200 m of maize fields [2.0 (1.2, 3.4)], in the absence of trees <200 m [1.6 (1.2, 2.2)], on flat land [1.6 (1.2, 2.2)], in houses without ceilings [1.5 (1.1, 2.2)], in houses with a separate kitchen building [1.8 (1.4, 2.3)] and in households where the female household head had no education [1.9 (1.1, 3.1)]. Travelling out of the study site [2.2 (1.2, 4.1)] was also associated with increased risk.
Conclusions  In this East African highland area, risk of developing uncomplicated malaria was multifactorial with a risk factor profile similar to that in endemic regions. Households within close proximity to forest and swamp borders are at higher risk of malaria and should be included in indoor residual spraying campaigns.     

Comparison of invasive methods and two different stool antigen tests for diagnosis of H pylori infection in patients with gastric bleeding

AIM: To compare two different H pylori stool antigen tests as noninvasive diagnostic methods. METHODS: The study population consisted of 22 upper gastrointestinal system bleeding patients. Urea breath test (UBT), rapid urease test (RUT) and histopathological examination were applied to all patients. Stool specimens from these patients were examined by rapid STRIP!HpSA and one step simple H pylori antigen cassette test for the detection of H pylori antigens. RESULTS: For these 22 patients, 15 (68.2%) were diagnosed as positive and seven (31.8%) were diagnosed negative for H pylori infection by the gold standard methods. Whereas 10 (45.5%) were positive and 12 (54.5%) were diagnosed negative by the rapid STRiP!HpSA test. The sensitivity, specificity, positive and negative predictive values were 60%, 86%, 90% and 50%, respectively. When compared to the gold standard methods, these differences were not significant. However, six patients (27.3%) were positive, and 16 (72.7%) were negative by the simple H pylori stool antigen cassette test. The sensitivity, specificity, positive and negative predictive values were 33%, 86%, 83% and 38%, respectively. Compared to the gold standard methods, the simple H pylori stool antigen cassette test results were significantly different (P = 0.012). CONCLUSION: Rapid STRIP! HpSA test could be used as a routine diagnostic tool in the microbiology laboratory for assessing clinical significance and eradication control of H pylori in upper gastrointestinal system bleeding patients.     

结核分枝杆菌特异性38kD多肽抗原提纯及其血清学诊断价值的研究

目的提纯结核分枝杆菌特异38kD多肽抗原,建立基于38kD多肽抗原(P38)的斑点金免疫渗滤法(DIGFA)检测结核病人血清标本,评价38kD多肽用于结核病血清学诊断抗原的实际价值。方法采用超声破碎、SDS-PAGE、切胶浸泡回收法提取结核分枝杆菌H37Rv株的38kD多肽抗原。建立以38kD多肽为包被抗原的DIGFA(P38-DIGFA),并检测147例临床确诊的活动性肺结核病人血清标本。同时建立以结核分枝杆菌脂阿拉伯甘露糖(LAM)为包被抗原的DIGFA(LAM-DIGFA)作为对照。结果结核分枝杆菌H37Rv株38kD多肽抗原提取物经SDS-PAGE后仅显示为单一的条带,并可与临床确诊的肺结核病人阳性血清标本呈阳性免疫印迹反应。P38-DIGFA和LAM-DIGFA检测肺结核病人血清标本的总阳性率分别为84.4%(124/147)和76.2%(112/147),其中59份痰涂片及培养均阳性的肺结核病人血清标本P38-DIGFA和LAM-DIGFA阳性率分别为88.1%(52/59)和84.7%(50/59),88份痰涂片及培养均阴性的肺结核病人血清标本P38-DIGFA和LAM-DIGFA阳性率分别为81.8%(72/88)和70.5%(62/88),60例气管炎病人血清标本阳性率分别为13.3%(8/60)和6.7%(4/60),120例健康人血清标本阳性率分别为5.8%(7/120)和5.0%(6/120)。各P38-DIGFA和LAM-DIGFA检测阳性率之间均无显著性差异。结论结核分枝杆菌38kD多肽作为抗原用于结核病血清学检测时,其敏感性和特异性与LAM相似,可应用于研发结核病血清学诊断试剂盒。     

Diagnosis of Helicobacter pylori infection in dyspeptic patients by stool antigen detection: Usefulness of a new monoclonal enzyme immunoassay test

BACKGROUND: Helicobacter pylori antigens can be measured in human stools with an enzyme immunoassay, which may prove to be a valuable non-invasive diagnostic tool. Aim. To evaluate the usefulness of a new monoclonal enzyme immunoassay for detecting H. pylori antigens in dyspeptic patients' faeces (FemtoLab H. pylori, Connex, Martinsried, Germany). PATIENTS: H. pylori infection was determined in 75 patients (49 men, 26 women, mean age 52 + 16.5) for histology and rapid urease test. METHODS: H. pylori status was established by concordance of the reference tests. FemtoLab H. pylori was measured in triplicate. In addition, two determinations of a polyclonal faecal antigen test (HpSA, Platinum Premier HpSA, Meridian Diagnostic Inc., Cincinnati, USA) were also performed. Sensitivity, specificity, positive and negative predictive values were calculated. Concordance between different measurements was estimated by Kappa statistics. RESULTS: The sensitivity of the FemtoLab H. pylori immunoassay ranged from 98 to 100% and its specificity was 76%. Positive and negative predictive values were 91 and 94-100%, respectively. Concordance coefficients ranged from 0.81 to 0.92. Corresponding HpSA values were 69, 86, 92 and 53%, respectively. Concordance coefficient was 0.61. CONCLUSIONS: FemtoLab H. pylori is a very sensitive, specific, highly reproducible and easy-to-perform tool for diagnosis of H. pylori infection.     

Antigen persistence of rapid diagnostic tests in pregnant women in Nanoro,Burkina Faso,and the implications for the diagnosis of malaria in pregnancy

Objectives To evaluate persistence of several Plasmodium antigens in pregnant women after treatment and compare diagnostics during treatment follow‐up. Methods Thirty‐two pregnant women (N = 32) with confirmed malaria infection by a histidine‐rich protein 2 (HRP2)‐based rapid diagnostic test (RDT) and microscopy were followed for 28 days after artemisinin‐based combination therapy (ACT). A Plasmodium lactate dehydrogenase (pLDH)‐based RDT and two ELISAs based on the detection of dihydrofolate reductase–thymidylate synthase (DHFR‐TS) and haeme detoxification protein (HDP) were compared with each other and to RT‐PCR at each visit. Results The mean visit number (95% confidence interval) on which the HRP2‐based RDT was still positive after treatment was 3.4 (2.7–4.1) visits with some patients still positive at day 28. This is significantly later than the pLDH‐based RDT [0.84 (0.55–1.1)], microscopy (median 1, range 1–3), DHFR‐TS‐ELISA [1.7 (1.1–2.3)] and RT‐PCR (median 2, range 1–5) (P < 0.05), but not significantly later than HDP‐ELISA [2.1 (1.6–2.7)]. Lower gravidity and higher parasite density at day 0 resulted in significantly longer positive results with most tests (P < 0.05). Conclusions HRP2 can persist up to 28 days after ACT treatment; therefore, this test is not suitable for treatment follow‐up in pregnant women and can generate problems when using this test during intermittent preventive treatment (IPTp). DHFR‐TS is less persistent than HRP2, making it a potentially interesting target for diagnosis.     

Prevalence of point mutations in the dihydrofolate reductase and dihydropteroate synthetase genes of Plasmodium falciparum isolates from India and Thailand: a molecular epidemiologic study

Pyrimethamine-sulfadoxine (PS) is used as a second-line treatment for P. falciparum malaria patients who fail to respond to chloroquine. Resistance to these drugs has been shown to encode with point mutations in dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) genes. Our aim was to assess the comparative rate of point mutation occurring in DHFR and DHPS genes among P. falciparum isolates from India and Thailand where the use of PS is at a different rate. We used the mutation-specific polymerase chain reaction (PCR) technique and mutation-specific restriction digestion to determine the prevalence of DHFR and DHPS gene mutations at codons 16, 51, 59, 108, 164 and at 436, 437, 581 and 613, respectively. In the 89 clinical isolates from India, in the case of the DHFR gene, we found 71 of S108N, 10 of N51I, 28 of C59R and four of I164L types. Among the 50 isolates from Thailand the rate of point mutations in the DHFR gene was higher at four codon positions. We found 47 of S108N, 18 of N51I, 23 of C59R and 12 of I164L types. None of the isolates from either country possessed the paired mutations S108T and A16V. Mutations of the DHPS gene were less frequent among the Indian isolates: 4.5% showed DHPS gene mutation, two of S436F, A437G, A613T and two of S436F, A613T; whereas 66% (33/50) of the Thai isolates had mutated at codons 436, 437, 581 and 613 which include 13 of S436F, 15 of A437G, 19 of A581G and 25 of A613S/T, ranging from single to quadruple mutant types. Among the Indian isolates, DHFR point mutations were very frequent and 85/89 had a wild type DHPS genetic profile. The pattern of mutations in the samples from Thailand was different, as most were associated with point mutations in DHFR and DHPS genes.