Distribution of Plasmodium falciparum genotypes in clinically mild and severe malaria cases in Orissa, India

A cross-sectional study was conducted in a malaria hyperendemic state of India to ascertain the distribution of Plasmodium falciparum genotypes in patients with mild (n=40) and severe (n=35) malaria. PCR and nested PCR were used to determine the glutamate-rich protein (GLURP), merozoite surface proteins 1 and 2 (MSP1 and MSP2) and knob-associated histidine-rich protein (KAHRP) for characterization of the parasite. The results indicate that (i) the 200bp allele of the MAD20 family of MSP1 and the 550bp allele of the 3D7 family of MSP2 show over-representation in severe malaria cases; (ii) the multiplicity of infection with respect to MSP2 alleles is significantly higher (P<0.001) in severe cases than in mild cases; and (iii) comparison with the findings of other studies leads to the conclusion that the distribution of P. falciparum genotypes between different clinical groups differs geographically.     

Complications and mortality patterns due to Plasmodium falciparum malaria in hospitalized adults and children,Rourkela, Orissa,India

Of 1857 Plasmodium falciparum malaria patients hospitalized from 1995 to 1998, 608 had severe malaria and 83 died. Acute renal failure, jaundice and respiratory distress were common in adults whereas children frequently had severe anaemia. Cerebral malaria occurred equally in adults and children but recovery from coma was quicker in children. Multiple complications caused high mortality in adults.     

Interruption of malaria transmission by chloroquinized salt in Guyana: With observations on a chloroquine-resistant strain of Plasmodium falciparum

Malaria and its local vector, Anopheles darlingi, were eradicated from the coastlands and near interior of Guyana by DDT house-spraying in 1945-51. In the remote interior, where 10% of the population live, only partial control could be achieved, owing to the semi-silvatic habits of A. darlingi and the considerable movement of the sparse population; low malaria endemicity persisted in these areas with occasional localized outbreaks. In the south-west the problem was further complicated by the presence of malaria across the frontier.     

Prioritization of malaria endemic zones using self-organizing maps in the Manipur state of India

Due to the availability of a huge amount of epidemiological and public health data that require analysis and interpretation by using appropriate mathematical tools to support the existing method to control the mosquito and mosquito-borne diseases in a more effective way, data-mining tools are used to make sense from the chaos. Using data-mining tools, one can develop predictive models, patterns, association rules, and clusters of diseases, which can help the decision-makers in controlling the diseases. This paper mainly focuses on the applications of data-mining tools that have been used for the first time to prioritize the malaria endemic regions in Manipur state by using Self Organizing Maps (SOM). The SOM results (in two-dimensional images called Kohonen maps) clearly show the visual classification of malaria endemic zones into high, medium and low in the different districts of Manipur, and will be discussed in the paper.     

Efficacy of amodiaquine for uncomplicated Plasmodium falciparum malaria in Harper,Liberia

In the face of spreading chloroquine and sulfadoxine-pyrimethamine (SP) resistance, amodiaquine remains a cheap and efficacious alternative for treating uncomplicated Plasmodium falciparum malaria in many settings. In Harper, south-eastern Liberia, a previous study we conducted showed very high levels of resistance to both chloroquine and SP. In 2001, in an effort to look for possible alternatives, we measured in the same setting the efficacy of amodiaquine in a 28-d study in vivo, with results corrected by polymerase chain reaction genotyping to distinguish recrudescences from reinfections. In total, 107 children were included in the study and received a 3-d supervised course of 25 mg/kg amodiaquine. Of these, 81 were analysable at day 28. The overall failure rate was 19.8% (95% CI 11.7-30.1%) considering both parasitological and clinical outcomes. These results provide hitherto missing data on amodiaquine in Liberia, and confirm that the drug may still be efficacious in settings where chloroquine and SP are failing. We recommend the introduction of amodiaquine in association with artesunate as a first-line antimalarial in Harper.     

Sulfadoxine-pyrimethamine for the treatment of Plasmodium falciparum malaria in Gabonese children

Chloroquine can no longer be recommended as the first-line treatment for falciparum malaria in several parts of Africa, given the increasing resistance of Plasmodium falciparum to this drug. The sulfadoxine-pyrimethamine combination (SP) is obviously an alternative candidate, that has already been selected as first-line antimalarial treatment by a few African countries. However, the extent of resistance to SP appears to be highly variable within Africa. Therefore, we investigated the efficacy of SP to treat uncomplicated malaria attacks in children from south-east Gabon. Sixty-six children presenting with a P. falciparum malaria attack were given a standard regimen of SP, and were followed at Days 3, 7, 14, and 21. No RIII response was observed, but relatively high prevalences of RII (18.2%) and RI (12.1%) were present. Moreover, analysis of the clinical outcome according to CDC criteria showed that initial clinical response was lacking in 8.5% of children, and that clinical failure occurred in 9.1%.     

Epidemic of Plasmodium falciparum malaria in Central India, an area where chloroquine has been replaced by artemisinin-based combination therapy

India contributes greatly to the global incidence of malaria. The factors influencing malaria in India are highly diverse and vary greatly from the epidemiological setting of any other country. Central India is the most vulnerable area to malaria in India. This study was carried out in three community health centres in Dindori District, Madhya Pradesh (Central India). Dindori District is mesoendemic for malaria, with both Plasmodium falciparum and P. vivax being present in all age groups. Anopheles culicifacies and A. fluviatilis are highly efficient vectors of malaria. In this study, an epidemic of malaria among indigenous ethnic group Baigas was investigated to determine the causes of the epidemic and the population involved in order to aid in disease containment. The existence of sporozoite-positive A. culicifacies and A. fluviatilis indicates either that spraying had not been done properly or the presence of insecticide resistance. A combination of factors propagated the epidemic. Evidence suggests that the non-availability of artemisinin-based combination therapy and rapid diagnostic tests along with an immunogenically vulnerable population each played an important role. As the global prevalence of malaria decreases owing to initiatives to control or eliminate the disease, more areas will become mesoendemic or hypoendemic for malaria. Detection and control of epidemics requires greater attention, and mechanisms to ensure the quality of interventions are essential.     

Quinine for the treatment of uncomplicated Plasmodium falciparum malaria in eastern Sudan

An observational clinical trial was conducted in New Halfa, eastern Sudan, in November and December 2003. Sixty-two patients with uncomplicated Plasmodium falciparum malaria were treated with oral quinine (10 mg/kg thrice daily for 7 d); 47 (76%) of these patients were followed-up to day 28, and 5 (10.6%) of them appeared to have late treatment failures. The parasitological failures were early R1 in two (4.3%) patients and late R1 in three (6.4%) patients. The reappearance of parasites in three of these five patients were true recrudescences rather than a re-infection, based on genetic evidence. The present results and those of earlier investigations indicate that the response to quinine in this area may be faltering.     

Effectiveness of amodiaquine, sulfadoxine-pyrimethamine, and combinations of these drugs for treating chloroquine-resistant falciparum malaria in Hainan Island, China

The study was carried out in 1985-86 in Hainan Island where Plasmodium falciparum is resistant to chloroquine. Fifty cases of falciparum malaria were treated with 1800 mg amodiaquine for 3 days: the cure rate was 65.3%, and the mean time to clear fever and asexual parasitaemia was 30.7 and 60.3 hours, respectively; 34.7% of cases showed RI or RII recrudescence, and one patient''s temperature did not come down to normal within 7 days.     

Polymorphisms in Pfcrt and Pfmdr-1 genes after five years withdrawal of chloroquine for the treatment of Plasmodium falciparum malaria in West Bengal,India

BackgroundThe emergence of resistant power against different antimalarial agents particularly by Plasmodium falciparum is a challenge to combat malaria. Regular monitoring is essential not only to determine the efficacy and development of resistance by the parasite but also to detect early sign of regaining sensitivity to any anti-malarial agent that has been withdrawn for a long period. Studies on molecular markers associated with antimalarial drug resistance of prevailing Plasmodium population play an important role in this aspect. The present protocol was designed to study the polymorphisms in pfcrt and pfmdr-1 gene to determine any sign of regaining sensitivity to chloroquine among P. falciparum after five years of artemisinin combination therapy (ACT) implementation.MethodsClinical isolates were collected from P. falciparum positive patients attending the malaria clinic of Calcutta School of Tropical Medicine during December 2014 to December 2015. Genomic parasitic DNA was extracted and subjected to sequencing of pfcrt and pfmdr-1 gene directly from purified PCR products.ResultsA total of 89 isolates were sequenced for pfcrt and 73 isolates for pfmdr-1 genes. In pfcrt gene mutant K76T was detected in all isolates and all were SVMNT haplotype. Out of three important polymorphisms in pfmdr-1 gene mutant Y184F was detected among all isolates. One synonymous G182G and one non-synonymous S232F/Y, mutation were detected in 99% isolates.ConclusionAll isolates carrying mutant K76T in pfcrt gene, considered as hall mark for CQ resistance, indicate that there is no sign of regaining CQ sensitivity among the prevailing P. falciparum population of the study area after five years of ACT implementation.     

Influence of common variants of TLR4 and TLR9 on clinical outcomes of Plasmodium falciparum malaria in Odisha,India

BackgroundIn malaria, the toll-like receptors (TLRs) have recently emerged as major player of innate immunity. However, implication of TLR variants on clinical manifestations of malaria is conflicting. The present study aims to provide relevant information of growing interest in understanding the role of TLR4D299G, TLR9T-1237C and TLR9T-1486C polymorphisms on clinical outcomes of malaria.MethodsWe genotyped TLR4D299G, TLR9T-1237C and TLR9T-1486C polymorphisms by PCR-RFLP methods and subsequently analyzed in 200 uncomplicated patients and 200 severe patients. Further, the severe malaria categorized into sub-clinical groups such as cerebral malaria (CM), non-cerebral severe malaria (NCSM), single organ dysfunction (SOD) and multi-organ dysfunctions (MODS) are analyzed.ResultThe TLR9-1237CC genotype was observed at significantly low frequency in MODS (p = 0.0008), while in heterozygous state (TC) it was proportionately more frequent in SOD (p = 0.087) as compared to mild malaria. The TLR9T-1486C heterozygote was more common in all categories of severe malaria. However, pair wise LD analysis revealed significant linkage between T-1237C and T-1486C, whereas haplotype analysis showed significantly low frequency of C-T haplotype in CM (p = 0.005, p_c = 0.02) and high frequency of T-C haplotype in NCSM as compared to mild malaria.ConclusionAlthough TLR9-1237C could be a risk factor for severe malaria in heterozygous state, negative association of CC genotype with MODS warrants caution of segregating severe malaria into its sub-clinical groups while interpreting data. Further, clinical outcome in malaria was observed to be apparently modulated by LD between TLR9 promoter variants.     

A national survey of the prevalence of chloroquine resistant Plasmodium falciparum malaria in The Gambia

In The Gambia, 760 children less than 10 years of age with Plasmodium falciparum malaria were treated with chloroquine (25 mg/kg) and followed-up 2 and 9 d after the start of treatment. 700 children (92.1%) completed the study. The level of in vivo resistance to chloroquine varied by area from 0.4% to 16.4%. Of the 28 children found to have chloroquine resistant malaria, none was ill when seen at the 9 d follow-up and only 3 (10.3%) required further treatment with alternative antimalarials because of persistent high levels of parasitaemia. However, the fact that 30.4% of the children who completed the study had chloroquine in their urine at presentation may have masked the true level of resistance and led to underestimation of the clinical significance of these findings. The blood film at day 2 did not usefully predict resistance. 67 isolates were tested in vitro for chloroquine sensitivity. The mean EC50 was 15.5 nmol/litre, an eight-fold decrease in sensitivity from that of isolates tested in 1982. 8 (11%) of the isolates had EC50s above the WHO reference value for sensitive isolates of 18.3 nmol/litre, with values ranging from 22 to 65 nmol/litre of culture medium. Gambian isolates were sensitive to quinine (mean EC50 = 49.6 nmol/litre).     

A randomized trial comparing the efficacy of four treatment regimens for uncomplicated falciparum malaria in Assam state, India

A four-arm drug sensitivity study compared chloroquine, sulfadoxine-pyrimethamine (SP), mefloquine and mefloquine-artesunate in Sonitpur and Karbi Anglong districts in Assam state, India. Two criteria were used to ascertain outcome: success of clinical treatment and parasitologic cure. In Sonitpur, at 14 days, there were 36/56 early and late treatment failures plus late parasitologic failures to chloroquine and 16/56 for SP. In Karbi Anglong, combined treatment failure at 14 days was 16/56 to chloroquine and 8/60 to SP. Mefloquine and mefloquine-artesunate demonstrated 93.9% and 93.6% sustained responses respectively at 42 days. High failure rates to both chloroquine and SP preclude the use of these drugs as first-line treatment for uncomplicated falciparum malaria in this region. A mefloquine-artesunate combination presents an effective alternative utilizing the currently recommended higher dose of mefloquine.     

A longitudinal study of Plasmodium falciparum malaria in the West African savanna using the ELISA technique

Malarial antibody levels were measured by the enzyme-linked immunosorbent assay (ELISA) in two West African populations, one exposed to intense malaria transmission and the other protected. The results reflected the transmission of maternal antibody and, in the unprotected population, the subsequent increase of the ELISA values with age reflected the development of the immune response to malaria. Malaria control activities reduced ELISA values in the protected population. The limitations of the ELISA test used in this study are shown by the fact that numerous infants with previous proven parasitaemia were ELISA-negative. Purified antigens are needed to improve the ELISA test for use in serological surveys of malaria.     

A randomized comparison of oral chloroquine and sulfadoxine-pyrimethamine for the treatment of uncomplicated Plasmodium falciparum malaria in Laos

Between June and October 2000 we conducted the first randomized trial in Laos comparing chloroquine (CQ) with sulfadoxine-pyrimethamine (SP) in the treatment of uncomplicated Plasmodium falciparum malaria (n = 29, 42-d follow-up, age > 5 years). The proportion of patients with treatment failure was high (CQ = 78%, RIII 46%; SP = 36%, RIII 15%). The treatment policy for uncomplicated P. falciparum malaria in Laos needs to be reviewed urgently.     

Rapid spread of the new clone of Vibrio cholerae O1 biotype El Tor in cholera endemic areas in India.

Using molecular techniques, we investigated whether the clone of Vibrio cholerae O1 biotype El Tor which appeared in Calcutta, India, in 1994 has spread to other cholera endemic areas in the country. The ribotype of 31 of the 33 strains isolated from different parts of India during 1996 and 1997 was identical to the ribotype displayed by the new clone of V. cholerae O1 which emerged in Calcutta in 1994. Likewise, 12 of the 15 strains examined by pulsed-field gel electrophoresis (PFGE) showed identical profile to that exhibited by the new clone of O1. The restriction fragment length polymorphism (RFLP) of CTX genetic element of these strains also matched with the new clone of O1 which emerged after the outbreak of V. cholerae 0139 in Calcutta. However, two strains (AH042 and AH046) isolated from an outbreak in Ahmedabad (western India) showed different CTX RFLP but had the same ribotype and PFGE profile as the new clone, whereas one strain from Goa (G2) showed distinct ribotype and PFGE profile and the CTX RFLP was identical to the O1 strains which prevailed before the genesis of 0139 in Calcutta. The drug resistance pattern of most of the O1 strains examined in this study, except strain G2, was similar to that of the new clone of V. cholerae O1. None of the strains in this study carried plasmids. Molecular studies clearly show that the new expanded drug resistant clone of V. cholerae O1 has spread to all cholera endemic areas in India and also provide evidence for the evolution of new clones of the O1 serogroup.     

A comparison of two DNA probes, one specific for Plasmodium falciparum and one with wider reactivity, in the diagnosis of malaria

The sensitivity and specificity of 2 probes for the detection of malarial infection was studied. 399 blood samples from Gambian children were tested in a deoxyribonucleic acid (DNA) hybridization assay, and the results compared with the microscopical findings from thick blood films. 8 additional pure Plasmodium malariae and 14 pure P. vivax samples were also assayed. One probe, containing a 21 base pair tandem repeat and highly specific for P. falciparum, detected this species in all except 2 of 74 samples with a parasitaemia of 250 per microliter or more; the overall sensitivity of the probe was 76%. The other probe, a 6 kilobase pair organelle DNA, is conserved in all Plasmodium species so far tested. Its sensitivity for P. falciparum was lower than the 21 base pair repeat, but it detected P. vivax and P. malariae at low levels of parasitaemia, and thus could be useful in field studies.     

Meteorologic influences on Plasmodium falciparum malaria in the Highland Tea Estates of Kericho,Western Kenya

Recent epidemics of Plasmodium falciparum malaria have been observed in high-altitude areas of East Africa. Increased malaria incidence in these areas of unstable malaria transmission has been attributed to a variety of changes including global warming. To determine whether the reemergence of malaria in western Kenya could be attributed to changes in meteorologic conditions, we tested for trends in a continuous 30-year monthly malaria incidence dataset (1966-1995) obtained from complete hospital registers at a Kenyan tea plantation. Contemporary monthly meteorologic data (1966-1995) that originated from the tea estate meteorologic station and from global climatology records were also tested for trends. We found that total hospital admissions (malaria and nonmalaria) remained unchanged while malaria admissions increased significantly during the period. We also found that all meteorologic variables showed no trends for significance, even when combined into a monthly suitability index for malaria transmission. We conclude that climate changes have not caused the highland malaria resurgence in western Kenya.