Edge theories in projected entangled pair state models.

We analyze the low energy excitations of spin lattice systems in two dimensions at zero temperature within the framework of projected entangled pair state models. Perturbations in the bulk give rise to physical excitations located at the edge. We identify the corresponding degrees of freedom, give a procedure to derive the edge Hamiltonian, and illustrate that it can exhibit a rich phase diagram. For topological models, the edge Hamiltonian is constrained by the topological order in the bulk, which gives rise to one-dimensional edge models with unconventional properties; for instance, a topologically ordered bulk can protect a ferromagnetic Ising chain at the edge against spontaneous symmetry breaking.

Frequency of enteroparasitic infections and serum positivity for Toxocara spp. in children from a public day care center in Southern Brazil.

INTRODUCTION: Day care centers play an important social role in children's early education and development. The objective of this study was to investigate the frequency of intestinal parasitic infections and infection with Toxocara spp. in children from a day care center in the city of Rio Grande, Rio Grande do Sul, Brazil. Methods: The study was conducted using fecal samples from 50 children, ages three to six years, using Ritchie, Faust, Rugai, and Kinyoun's techniques. A closed and structured epidemiological questionnaire was used to collect data from the parents/guardians of the children. Serological studies for detection of antibodies to Toxocara spp. by immunoenzymatic assays using Toxocara excretion and secretion antigen (TES) were conducted on sera collected from 41 children. Results: The frequency of enteroparasites was 18%, with 43.9% of the children testing seropositive for Toxocara spp. Low family income and low literacy levels of parents/guardians were common factors between the families of the parasite-positive children. For the children who tested positive for Toxocara spp., most of the parents/guardians reported using only water for sanitizing raw vegetables and fruits. Conclusions: The high seropositivity rates for Toxocara spp. indicate that children were exposed to this parasite, and it is important to reduce the risk of infection. In addition, the seropositivity for enteroparasites and the interviews with the parents/guardians indicate the need to educate the studied population regarding the modes of intestinal parasite transmission and the prophylactic measures needed to prevent their dissemination.

Hansen's disease in a general hospital: uncommon presentations and delay in diagnosis.

BACKGROUND: The question was raised as to why 'obvious' signs of leprosy, Hansen's disease (HD), are often missed by medical doctors working in a HD endemic area. METHODS: This study describes a small sample of patients who were diagnosed with HD during their hospital admission and not before. The discussion is whether the typical early signs and symptoms of HD are just not recognized, or whether unusual presentations confuse the attending physician. RESULTS: A total of 23 HD patients were hospitalized during the study period, of which 6 (26%) were only diagnosed with HD during their admission. All were classified as lepromatous leprosy (LL) with a history of signs and symptoms of HD. In nearly all patients, a suspicion of HD might have been raised earlier if a careful history and dermato-neurological examination had been done. CONCLUSIONS: Multibacillary (MB) HD, especially close to the lepromatous end of the spectrum, may mimic other diseases, and the patient can not be diagnosed without a biopsy or a slit skin smear examination. Clinicians working in a HD endemic area (Rio de Janeiro) do not always include HD in their differential diagnosis, especially when the clinical presentation is unusual. HD should be considered in all patients with skin lesions not responding to treatment, especially when they have neurological deficits, and live or have lived in an HD endemic area. Due to the increase in global travel and immigration, doctors in low endemic areas need to consider HD as a possible diagnosis.

The Role of Baroreflex Sensitivity in Acute Hypotensive Episodes Prediction in the Intensive Care Unit.

A life threatening condition in Intensive Care Unit (ICU) is the Acute Hypotensive Episode (AHE). Patients experiencing an AHE may suffer from irreversible organ damage associated with increased mortality. Predicting the onset of AHE could be of pivotal importance to establish appropriate and timely interventions. We propose a method that, using waveforms widely acquired in ICU, like Arterial Blood Pressure (ABP) and Electrocardiogram (ECG), will extract features relative to the cardiac system to predict whether or not a patient will experience a hypotensive episode. Specifically, we want to assess if there are hidden patterns in the dynamics of baroreflex able to improve the prediction of AHEs. We will investigate the predictive power of features related to the baroreflex by performing classifications with and without them. Results are obtained using 17 classifiers belonging to different model families: classification trees, Support Vector Machines (SVMs), K-Nearest Neighbors (KNNs) replicated with different set of hyper-parameters and logistic regression. On average, the use of baroreflex features in the AHE prediction process increases the Area Under the Curve (AUC) by 10%.

Selective activation and functional significance of p38alpha mitogen-activated protein kinase in lipopolysaccharide-stimulated neutrophils.

Activation of leukocytes by proinflammatory stimuli selectively initiates intracellular signal transduction via sequential phosphorylation of kinases. Lipopolysaccharide (LPS) stimulation of human neutrophils is known to result in activation of p38 mitogen-activated protein kinase (MAPk); however, the upstream activator(s) of p38 MAPk is unknown, and consequences of p38 MAPk activation remain largely undefined. We investigated the MAPk kinase (MKK) that activates p38 MAPk in response to LPS, the p38 MAPk isoforms that are activated as part of this pathway, and the functional responses affected by p38 MAPk activation. Although MKK3, MKK4, and MKK6 all activated p38 MAPk in experimental models, only MKK3 was found to activate recombinant p38 MAPk in LPS-treated neutrophils. Of p38 MAPk isoforms studied, only p38alpha and p38delta were detected in neutrophils. LPS stimulation selectively activated p38alpha. Specific inhibitors of p38alpha MAPk blocked LPS-induced adhesion, nuclear factor-kappa B (NF-kappaB) activation, and synthesis of tumor necrosis factor-alpha (TNF-alpha). Inhibition of p38alpha MAPk resulted in a transient decrease in TNF-alpha mRNA accumulation but persistent loss of TNF-alpha synthesis. These findings support a pathway by which LPS stimulation of neutrophils results in activation of MKK3, which in turn activates p38alpha MAPk, ultimately regulating adhesion, NF-kappaB activation, enhanced gene expression of TNF-alpha, and regulation of TNF-alpha synthesis.

Transient Focal Neurologic Symptoms Correspond to Regional Cerebral Hypoperfusion by MRI: A Stroke Mimic in Children.

Children who present with acute transient focal neurologic symptoms raise concern for stroke or transient ischemic attack. We present a series of 16 children who presented with transient focal neurologic symptoms that raised concern for acute stroke but who had no evidence of infarction and had unilateral, potentially reversible imaging features on vascular and perfusion-sensitive brain MR imaging. Patients were examined with routine brain MR imaging, MRA, perfusion-sensitive sequences, and DWI. Fourteen (88%) children had lateralized MRA evidence of arterial tree pruning without occlusion, all had negative DWI findings, and all showed evidence of hemispheric hypoperfusion by susceptibility-weighted imaging or arterial spin-labeling perfusion imaging at presentation. These findings normalized following resolution of symptoms in all children who had follow-up imaging (6/16, 38%). The use of MR imaging with perfusion-sensitive sequences, DWI, and MRA can help to rapidly distinguish children with conditions mimicking stroke from those with acute stroke.

Malaria transmission and the sensitivity of aggressive mosquitoes to insecticides in a poorly urbanized area of the Deido health district in Douala (Cameroon).

The design of an appropriate strategy for mosquito control in urban areas must take into account the local ecoclimate and its particularities. This study sought to determine the dynamics of malaria transmission and the level of insecticide susceptibility of aggressive mosquitoes in Ndogbong, a poorly urbanized district of Douala. Mosquitoes were captured on volunteers in 4 houses and outdoors for 2 consecutive nights a month, from April to September 2014, and identified by molecular and morphologic techniques. The infectivity of vectors was determined by a circumsporozoite protein (CSP) ELISA test. The susceptibility of vectors to DDT, deltamethrin, and permethrin was also assessed. Overall, 3794 mosquitoes belonging to 6 species were captured in 96 person-nights. The aggressive mosquito fauna comprised : Culex pipiens (57.83%), Cx. poicilipes (1.45%), Anopheles gambiae s.l. (39.01%), Aedes albopictus (1.51%), and An. paludis (0.10%). An. coluzzii accounted for 97% of members of the Gambiae complex captured and was the only species found to be infected with P. falciparum, with an average infection rate of 1.9% (95% CI : 0.82-4.41). The mean entomological inoculation rate was estimated at 0.3 ib/p/n. Susceptibility testing on female An. gambiae s.l. and Cx. pipiens revealed mortality rates lower than 85 % and thus suggested strong resistance to insecticides. An. Coluzzii develops well in poorly urbanized built-up areas of Africa and appears to be the major malaria vector in Ndogbong, especially during the rainy season. The high resistance to insecticides observed requires the development of new formulations for insecticides.

Epithelial cells as phagocytes: apoptotic epithelial cells are engulfed by mammary alveolar epithelial cells and repress inflammatory mediator release.

Clearance of apoptotic cells is critical to tissue homeostasis and resolution of inflammatory lesions. Macrophages are known to remove dying cells and release anti-inflammatory mediators in response; however, many cells traditionally thought of as poor phagocytes can mediate this function as well. In the lactating mammary gland following weaning, alveolar epithelial cell death is massive, yet the gland involutes rapidly, attaining its prepregnancy state in a matter of days. We found histologic evidence of apoptotic cell phagocytosis by viable mammary epithelial cells (MEC) in the involuting mouse mammary gland. Cultured MEC were able to engulf apoptotic cells in vitro, utilizing many of the same receptors used by macrophages, including the phosphatidylserine receptor (PSR), CD36, the vitronectin receptor alpha(v)beta3, and CD91. In addition, MEC, like macrophages, produced TGFbeta in response to stimulation of the PSR by apoptotic cells or the anti-PSR ab 217G8E9, and downregulated endotoxin-stimulated proinflammatory cytokine production. These data support the hypothesis that amateur phagocytes play a significant role in apoptotic cell clearance and its regulation of inflammation.

Complete amino acid sequence of the major component myoglobin from the goose-beaked whale, Ziphius cavirostris.

The complete primary structure of the major component myoglobin from the goose-beaked whale, Ziphius cavirostris, was determined by specific cleavage of the protein to obtain large peptides which are readily degraded by the automatic sequencer. Over 80% of the amino acid sequence was established from the three peptides resulting from the cleavage of the apomyoglobin at its two methionine residues with cyanogen bromide along with the four peptides resulting from the cleavage with trypsin of the citraconylated apomyoglobin at its three arginine residues. Further digestion of the central cyanogen bromide peptide with S. aureus strain V8 protease and the 1,2-cyclohexanedione-treated central cyanogen bromide peptide with trypsin enabled the determination of the remainder of the covalent structure. This myoglobin differs from the cetacean myoglobins determined to date at 12 to 17 positions. These large sequence differences reflect the distant taxonomic relationships between the goose-beaked whale and the other species of Cetacea the myoglobin sequences of which have previously been determined.

Complete amino acid sequence of the myoglobin from the Pacific spotted dolphin, Stenella attenuata graffmani.

The complete amino acid sequence of the major component myoglobin from the Pacific spotted dolphin, Stenella attenuata graffmani, was determined by the automated Edman degradation of several large peptides obtained by specific cleavage of the protein. The acetimidated apomyoglobin was selectively cleaved at its two methionyl residues with cyanogen bromide and at its three arginyl residues by trypsin. By subjecting four of these peptides and the apomyoglobin to automated Edman degradation, over 80% of the primary structure of the protein was obtained. The remainder of the covalent structure was determined by the sequence analysis of peptides that resulted from further digestion of the central cyanogen bromide fragment. This fragment was cleaved at its glutamyl residues with staphylococcal protease and its lysyl residues with trypsin. The action of trypsin was restricted to the lysyl residues by chemical modification of the single arginyl residue of the fragment with 1,2-cyclohexanedione. The primary structure of this myoglobin proved to be identical with that from the Atlantic bottlenosed dolphin and Pacific common dolphin but differs from the myoglobins of the killer whale and pilot whale at two positions. The above sequence identities and differences reflect the close taxonomic relationship of these five species of Cetacea.

Frequency of enteroparasitic infections and serum positivity for Toxocara spp. in children from a public day care center in Southern Brazil / Frequência de enteroparasitos e de soropositividade para Toxocara spp. em crianças de uma creche pública do Sul do Brasil

Abstract Introduction Day care centers play an important social role in children's early education and development. The objective of this study was to investigate the frequency of intestinal parasitic infections and infection with Toxocara spp. in children from a day care center in the city of Rio Grande, Rio Grande do Sul, Brazil. Methods: The study was conducted using fecal samples from 50 children, ages three to six years, using Ritchie, Faust, Rugai, and Kinyoun's techniques. A closed and structured epidemiological questionnaire was used to collect data from the parents/guardians of the children. Serological studies for detection of antibodies to Toxocara spp. by immunoenzymatic assays using Toxocara excretion and secretion antigen (TES) were conducted on sera collected from 41 children. Results: The frequency of enteroparasites was 18%, with 43.9% of the children testing seropositive for Toxocara spp. Low family income and low literacy levels of parents/guardians were common factors between the families of the parasite-positive children. For the children who tested positive for Toxocara spp., most of the parents/guardians reported using only water for sanitizing raw vegetables and fruits. Conclusions: The high seropositivity rates for Toxocara spp. indicate that children were exposed to this parasite, and it is important to reduce the risk of infection. In addition, the seropositivity for enteroparasites and the interviews with the parents/guardians indicate the need to educate the studied population regarding the modes of intestinal parasite transmission and the prophylactic measures needed to prevent their dissemination.

Resumo Introdução As creches desempenham um importante papel social na educação e desenvolvimento inicial das crianças. O objetivo deste estudo foi investigar a frequência de infecções parasitárias intestinais, além de infecção por Toxocara spp. em crianças de uma creche na cidade do Rio Grande, Rio Grande do Sul, Brasil. Métodos: Para o estudo, foram coletadas amostras fecais de 50 crianças de três a seis anos, analisadas pelas técnicas de Ritchie, Faust, Rugai e Kinyoun, sendo aplicado um questionário epidemiológico fechado e estruturado aos pais/responsáveis ​​das crianças. Também foi realizada uma pesquisa sorológica de anticorpos para Toxocara spp. em 41 crianças, pelo ensaio imunoenzimático, associado ao antígeno de excreção e secreção (ES), com soros pré-adsorvidos com antígeno somático de Ascaris lumbricoides. Resultados: A frequência de enteroparasitos foi de 18%, enquanto que 43.9% das crianças foram soropositivas para Toxocara spp.. Baixa renda familiar e baixo nível de alfabetização dos pais/responsáveis ​​foram fatores comuns entre as famílias das crianças parasitadas. A maioria dos pais ou responsáveis das crianças, com diagnóstico positivo para enteroparasitos ou para Toxocara spp., relatou utilizar apenas água para a higienização de verduras e frutas. Conclusões: As altas taxas de soropositividade para Toxocara spp. indicam que as crianças foram expostas a esse parasito, sendo importante minimizar o risco de infecção. Além disso, a positividade de 18% para enteroparasitos e os dados obtidos com as entrevistas realizadas com os pais ou responsáveis demonstram a necessidade da realização de trabalhos com a população estudada que visem a divulgação sobre as parasitoses intestinais, especialmente sobre medidas profiláticas especificas.

[Anopheles gambiae, major malaria vector in Logbessou, a peri-urban area of Douala (Cameroon)]. / Anopheles gambiae, vecteur majeur du paludisme à Logbessou, zone péri-urbaine de Douala (Cameroun).

An entomological survey was carried out from August to November 2013, in order to determine the vector system of a building site for social housing in a coastal periurban district of Douala (Cameroon). Mosquito larvae were collected and adult endophilic mosquitoes captured on volunteers, for a total sample of 4897 mosquitoes. Morpho-taxonomic techniques alongside molecular techniques enabled the identification of 4 species, all aggressive to humans: Cx. pipiens (22.3%), Ae. albopictus (0.3%), An. coluzzii and An. gambiae (77.4%). The overall average biting rate recorded was 41.73 bites/person/night (b/p/n). An. gambiae s.l. represents 90.82% of this aggressive fauna, followed by Cx. pipiens (8.58%) and Ae. albopictus (0.6%). The detection of CSP showed that An. gambiae was responsible for 100% of P. falciparum transmission. The overall mean Entomological Inoculation Rate (EIR) was 3.94 ib/p/n. Female An. gambiae mortality rates were 14.47%, 82.5% and 100% respectively with DDT, permethrin and deltamethrin. The proliferation of An. gambiae in this area during raining season, at the detriment of An. coluzzii Coetze & Wilkerson and An. melas Theobald known to be major malaria vectors in island and coastal areas of Africa, may owe to the forest that still colonises this coastal peri-urban locality. Residents should therefore make use of deltamethrin based protective measures.

The role of adrenal hyperandrogenism, insulin resistance, and obesity in the pathogenesis of polycystic ovarian syndrome.

Hyperandrogenism, insulin resistance, and obesity are common features of polycystic ovarian syndrome (PCOS). This study was designed to investigate the relationship among these factors and how they might contribute to ovulatory dysfunction in PCOS. Adrenal androgen secretion and insulin resistance were quantified in oligomenorrheic women with PCOS and in three groups of eumenorrheic women: weight-matched hirsute women, obese nonhirsute women, and thin nonhirsute women. Adrenal androgen secretion was defined as the androstenedione response to synthetic corticotropin. Insulin resistance was estimated by calculating the area under the curve for serum insulin levels in response to a 75 g oral glucose load. The mean serum androstenedione response (nmol/L) to corticotropin in PCOS (5.6 +/- 1.3) was greater than that in eumenorrheic hirsute women (3.4 +/- 0.5; P < 0.10), obese nonhirsute women (1.8 +/- 0.8; P < 0.05), and lean nonhirsute women (1.9 +/- 0.5; P < 0.05). The serum androstenedione response was not correlated with body mass index (BMI). The area under the curve for serum insulin (mU/L.min/1000) in PCOS (29.1 +/- 5.3) was greater (P < 0.001) than in eumenorrheic hirsute women (9.1 +/- 1.7), obese nonhirsute women (5.8 +/- 1.0), and lean nonhirsute women (4.5 +/- 0.4). The serum insulin response was highly correlated with BMI (P < 0.001) in the three groups of obese women, but women with PCOS became significantly more insulin resistant with increasing BMI (P < 0.02). There was no correlation between adrenal androgen secretion and insulin resistance in any of the groups. We conclude that adrenal hyperandrogenism and insulin resistance are independent predictors of anovulation in hirsute women. These conditions are present in both oligomenorrheic and eumenorrheic hirsute women, but are present to a greater extent in anovulatory women. Obese women with PCOS also differ from eumenorrheic controls by developing a greater degree of insulin resistance as body mass increases.

The cloning and functional characterization of the nifH gene of Rhodospirillum rubrum.

Dinitrogenase reductase (the nifH product) from Rhodospirillum rubrum is regulated by a post-translational modification system encoded by draTG. As demonstrated in this report, the cloning, sequencing, and functional characterization of the nifH gene provides a basis for further analysis as well as revealing interesting features of gene organization. The coding regions of nifH and draT are separated by only 400 bp, though the genes are divergently transcribed and differentially regulated. The construction of a nifH insertion caused a Nif- phenotype and destroyed the mutant's ability to synthesize both dinitrogenase and dinitrogenase reductase, verifying functionality and transcriptional organization of the nifHDK genes.

Malaria chemotherapy trial at a minimal effective dose of mefloquine/sulfadoxine/pyrimethamine compared with equivalent doses of sulfadoxine/pyrimethamine or mefloquine alone.

In murine malaria the addition of mefloquine to sulfadoxine/pyrimethamine has been shown to exert an additive effect and to significantly slow the emergence of resistance to the individual components. In a pilot study carried out in Gabon, a reduced dosage of the triple combination with a mean of 1 mg/kg of mefloquine/2 mg/kg of sulfadoxine/0.1 mg/kg of pyrimethamine (Fansimef; Roche, Basel, Switzerland) had previously been shown to achieve high cure rates in Plasmodium falciparum malaria. To evaluate the additive effect, a randomized, double-blind trial in school children with mild P. falciparum malaria was performed in Gabon. Two hundred thirty-one patients evaluated received a single dose of either the triple combination with a mean of 1.07 mg/kg of mefloquine/2.14 mg/kg of sulfadoxine/0.11 mg/kg of pyrimethamine (group MSP), or 1.07 mg/kg of mefloquine alone (group M), or 2.14 mg/kg of sulfadoxine/0.11 mg/kg of pyrimethamine alone (group SP). In the MSP group and the SP group, 67% and 69% of the patients were parasitologically cured, respectively, compared with only 13% in the M group (P < 0.001). A significantly higher parasitemia was found in the M group compared with the MSP group or the SP group on days 2 and 3 after the start of treatment. The high efficacy of the low dose sulfadoxine/pyrimethamine regimen was the most surprising finding of this study.

Antibody responses to Plasmodium falciparum: evolution according to the severity of a prior clinical episode and association with subsequent reinfection.

We measured sporozoite- and total parasite antigen-specific IgG and IgM antibodies before and after treatment in matched groups of Gabonese children who presented with either mild or severe Plasmodium falciparum malaria. We investigated the influence of various parameters on these antibody responses, including clinical presentation, age, and post-treatment reinfection profiles. IgG but not IgM responses were strongly influenced by both clinical and parasitological status. IgG responses to the repeat region of the circumsporozoite protein, which were low at admission, particularly so in those with severe anemia, increased after treatment but showed no association with either age or reinfection profiles. Total parasite antigen-specific IgG responses were strongly influenced by parasitological status, and also differed significantly when segregated according to clinical status at admission, age, and reinfection histories. Most notably, anti-parasite IgG responses measured when children were parasite-free were higher and a good indicator of recent reinfections in those who presented with mild rather than with severe malaria. The profile of responses in the latter group suggests some immune system dysfunction, which may reflect the induction of tolerance to parasite antigens.

Dose-response effect of depot leuprolide acetate on serum androgens in hirsute women.

OBJECTIVE: To determine the dose of leuprolide acetate (LA) needed to maximally suppress serum androgens in hirsute women. DESIGN: Prospective, dose-escalation study. SETTING: Outpatient endocrinology clinic. PATIENTS: Eight hyperandrogenic women with moderate to severe hirsutism. INTERVENTIONS: A LA dose-response study was done in women receiving depot LA plus estrogen-progestin replacement. MAIN OUTCOME MEASURES: Serum concentrations of T, androstenedione (A), and basal and GnRH-stimulated LH. RESULTS: The lowest LA dose (3.75 mg/mo) suppressed serum T by 62% +/- 6% and A by 56% +/- 7%. No further decrease in serum androgens was seen with doses up to 15 mg/mo. Maximal suppression of basal and stimulated LH was also seen with the lowest dose of LA. CONCLUSIONS: As opposed to results previously published in children with precocious puberty, the 3.75 mg dose of depot LA is sufficient to maximally suppress serum androgens in hyperandrogenic women.

No influence of socioeconomic factors on severe malarial anaemia, hyperparasitaemia or reinfection.

Malaria is responsible for nearly 500 million clinical cases per year, only a small proportion of whom will become severely ill. Socioeconomic risk factors may play a role in the development of severe malaria in African children and in their susceptibility to reinfection. In Gabon, 100 children suffering from severe malaria, defined as hyperparasitaemia and/or severe anaemia, were matched for sex, age and provenance to 100 children with mild malaria. Socioeconomic factors were assessed using a standard questionnaire and compared between the 2 groups. The children were followed-up and the time to first reinfection was recorded. No significant influence of socioeconomic factors could be detected on the severity of disease or the time to first reinfection. Socioeconomic factors are not major determinants of severe malarial anaemia and hyperparasitaemia in children in Gabon.

Merozoite surface antigen 1 and 2 genotypes and rosetting of Plasmodium falciparum in severe and mild malaria in Lambaréné, Gabon.

We present a case-control study to investigate the distribution of Plasmodium falciparum genotypes in patients with severe and mild malaria. We compared clinical and parasitological data with the parasites' genotype and rosetting. The study group consisted of 100 children suffering severe malaria, defined as severe anaemia and hyperparasitaemia. These children were matched by age, sex and provenance with 100 children with mild malaria. For characterization of the parasites we used the polymerase chain reaction to determine merozoite surface antigen (MSA) 1 and 2 genotypes and the phenomenon of rosette formation. We found a significant association between rosette formation and disease severity, and a significant association of severe anaemia with the presence of the MSA-1 allele K1. Infections with 2 genotypes in the severely affected group were significantly associated with severe anaemia and the presence of MSA-1 allele K1. Comparison with the findings of other groups led to the conclusion that the occurrence of P. falciparum genotypes seems to differ geographically.

Molecular analysis of recrudescent parasites in a Plasmodium falciparum drug efficacy trial in Gabon.

Recrudescent Plasmodium falciparum parasites were sampled from 108 children taking part in a drug efficacy trial in Gabon. A finger-prick blood sample was taken from each child before treatment, and a post-treatment sample taken of the recrudescent parasites. Sample deoxyribonucleic acid was amplified by the polymerase chain reaction using primers specific to the P. falciparum antigen genes MSP-1, MSP-2 and GLURP. Seventy-seven children had identical parasites in their pre- and post-treatment samples, indicating genuine recrudescences of resistant parasites. Fourteen children had completely different parasites in their pre- and post-treatment samples, indicating either a fresh infection from a mosquito or growth of a population of parasites not detected in the pre-treatment sample, perhaps due to sequestration. The remaining 17 children had a mixture of pre-treatment and new parasites in their post-treatment samples. This study demonstrated the use of polymorphic markers to confirm whether parasites in patients with clinical recrudescences after drug treatment are genuinely resistant.