People In Endemic Areas Research Articles

A Case Report of Crimean-Congo Hemorrhagic Fever in Iran

Introduction: Crimean Congo hemorrhagic fever (CCHF) is a tick-borne, zoonotic disease distributed globally. As the clinical features of CCHF and COVID-19 are similar, getting an early and reliable diagnosis may be difficult. Case Presentation: We report the first misdiagnosed case of CCHF in the setting of a COVID-19 pandemic from Ravansar County of Kermanshah province in Iran. Our patient was initially misdiagnosed with COVID-19, got hospitalized, but later tested positive for CCHF. However, the delay in diagnosis caused her death. Conclusions: Crimean Congo hemorrhagic fever should be considered among people in endemic areas who show COVID-19 symptoms for urgent medical attention.

Antileishmanial activity of tetra-cationic porphyrins with peripheral Pt(II) and Pd(II) complexes mediated by photodynamic therapy

Leishmaniasis is a neglected disease that impacts more than one billion people in endemic areas of the globe. Several drawbacks are associated with the currently existing drugs for treatment such as low effectiveness, toxicity, and the emergence of resistant strains that demonstrate the importance of looking for novel therapeutic alternatives. Photodynamic therapy (PDT) is a promising novel alternative for cutaneous leishmaniasis treatment because its topical application avoids potential side effects generally associated with oral/parenteral application. A light-sensitive compound known as photosensitizer (PS) interacts with light and molecular oxygen to generate reactive oxygen species (ROS), which promote cell death by oxidative stress through PDT approaches. Here, for the first time, we demonstrate the antileishmanial effect of tetra-cationic porphyrins with peripheral Pt(II)- and Pd(II)-polypyridyl complexes using PDT. The isomeric tetra-cationic porphyrins in the meta positions, 3-PtTPyP, and 3-PdTPyP, exhibited the highest antiparasitic activity against promastigote (IC50-pro = 41.8 nM and 46.1 nM, respectively) and intracellular amastigote forms (IC50-ama = 27.6 nM and 38.8 nM, respectively) of L. amazonensis under white light irradiation (72 J cm–2) with high selectivity (SI > 50) for both forms of parasites regarding mammalian cells. In addition, these PS induced the cell death of parasites principally by a necrotic process in the presence of white light by mitochondrial and acidic compartments accumulation. This study showed that porphyrins 3-PtTPyP and 3-PdTPyP displayed a promising antileishmanial-PDT activity with potential application for cutaneous leishmaniasis treatment.

Assessment of co-infection of typhoid and malaria in patients attending F.M.C Umuahia Abia state

Malaria and typhoid fever are major public health problems in tropical and subtropical countries. People in endemic areas are at risk of contracting both infections concurrently. This study was aimed at assessing malaria and co-infection of typhoid fever among patients. A cross-sectional study was conducted on 256 patients suspected for malaria and typhoid fever from March to August 2017 at Federal Medical Centre Umuahia Abia State. Blood samples were collected for blood film preparation and widal test. The prevalence of malaria was 78.90% (n = 202). Among these age groups, (11 – 15), (16 – 20), (21 – 25) and (26 – 30) years were mostly infected. The seroprevalence of typhoid fever was found high and poor hand washing habit were associated with typhoid fever infection. Further studies should be done on malaria and typhoid fever co-infection in different seasons and different study areas.

Oxidative Stress in Malaria: Potential Benefits of Antioxidant Therapy.

Malaria is an infectious disease and a serious public health problem in the world, with 3.3 billion people in endemic areas in 100 countries and about 200 million new cases each year, resulting in almost 1 million deaths in 2018. Although studies look for strategies to eradicate malaria, it is necessary to know more about its pathophysiology to understand the underlying mechanisms involved, particularly the redox balance, to guarantee success in combating this disease. In this review, we addressed the involvement of oxidative stress in malaria and the potential benefits of antioxidant supplementation as an adjuvant antimalarial therapy.

Faktor Risiko Perilaku dan Bitting Activity Anopheles Sp. Dengan Kejadian Malaria di Indonesia: Literature Review

Malaria is one of the vector-borne diseases that affect the morbidity and mortality of people in the world. Malaria cases recorded in 2017 were 219 million cases worldwide. In 2020, In the southeast Asian region, Indonesia was the highest contributor to confirmed malaria cases at 49.6%, followed by India at 36.4% and Myanmar at 11.5%. The purpose of this study was to determine the risk factors for people's behavior and the activity of biting Anopheles with the incidence of malaria in Indonesia. This research uses the literature review method by analyzing 22 scientific articles related to the research. The results of this study showed that the behavior of not using mosquito nets when sleeping at night, the habit of going out at night, not using mosquito repellent, and not using long clothes are risk factors for malaria events. The peak bites Anopheles at night at 20.00-05.00 WIB and is exofagic. People in endemic areas are expected to be able to use mosquito nets, reduce activities outside the home at night, use mosquito repellent, and use long clothes, especially at night.

EXPERT SYSTEM FOR DIAGNOSIS OF MALARIA AND TYPHOID

An expert system is a computer program designed to solve problems in a domain that has human expertise. The knowledge built into the system is usually obtained from experts in the field. Based on this knowledge, an expert system can replicate the thinking process of the human experts and make logical deductions accordingly. Malaria and Typhoid are major health challenge in our society today (Nigeria), its symptoms can lead to other illness which include prolonged fever, fatigue, headaches, nausea, abdominal pain and constipation or diarrhea. People in endemic areas are at risk of contracting both infections concurrently. According to the world malaria report 2011, there were about 216 million cases of malaria and typhoid and estimated 655,000 deaths in 2010. (WHO report, 2011). The main challenging issue confronting the healthcare is lack of quality of service at minimal cost implying from diagnosing to predicting patients correctly. This issue can sometimes lead to an unfortunate clinical decision that can result in devastating consequences that are unacceptable. Although many studies were carried out by different researchers in the medical domain using various data techniques. In this research work, an efficient expert system that diagnoses patients with malaria and typhoid was developed. A secondary data was collected from university of Maiduguri teaching hospital for the period of four years which ranges from 2017 to 2020. The work explored the potential benefits of proposing a new model for prediction and diagnosis of malaria and typhoid using symptoms. The model adopted the Naive bayes and was implemented using the python. The system diagnoses a patient in real time (within 30 minutes) without necessarily visiting the laboratory for a test. Three algorithms were used these are, Support vector machine, Artificial neural network and Naïve bayes. From our finding, it is observed that Naïve bayes and support vector machine give the best result which is 100% in terms of accuracy of diagnosis. Keywords: Diagnosis, Prediction, Expert System, Typhoid, Malaria

Assessment of knowledge, attitude and practices of people toward Japanese Encephalitis in endemic areas of Nepal

Japanese encephalitis is a serious vector borne viral zoonotic disease, particularly in Asia and Northern Australia. In Nepal, JE cases were reported in 63 out of 75 districts up until the year 2005. The aim of this study was to assess the level of knowledge, attitude and practices (KAP) toward JE and associated factors. A structured questionnaire was used to gather information on the KAP of people in endemic areas. Accordingly, 397 respondents demonstrated a desirable attitude, while half of the population exhibited desirable knowledge and practices. Age was found to be a significant factor for knowledge, wherein the senior population had better awareness of the vectors of JE. Moreover, education and occupation were found to be significant factors for KAP scores with an increase in level of education leading to an increase in desirable characteristics. This study determined that the characteristics of the surrounding environment were prominent factors. A significant number of people were not aware of the JE vaccine even though the government has made it available to most of the population of Nepal. Thus, more effective awareness programs should be implemented to increase the KAP of the population with regard to JE.

Designing multi-epitope subunit vaccine for ocular trachoma infection using Chlamydia trachomatis polymorphic membrane proteins G

Chlamydia trachomatis serovars A, B, Ba and C are bacteria serovars responsible for the blinding disease trachoma, the infection affects the upper tarsal conjunctiva of the eye. Repeated infection occurs among people in endemic areas throughout childhood which may later lead to blindness at adulthood. Chlamydia trachomatis contains a highly conserved surface glycoprotein, the polymorphic membrane protein which are surface antigens and are target for neutralizing antibodies as they are strongly immunogenic hence elicit proinflammatory response. It is suggested that they may be virulence by modulating inflammation and adherence to host cell, therefore one can argue that PMPs may be important in host-cell invasion as a virulence factor; this fact makes it a good entrant for Chlamydia trachomatis vaccine design.In this study a combination of bioinformatics and immunoinformatics methods and tools were applied to design multi-epitope subunit vaccines using Chlamydia trachomatis polymorphic membrane protein G (PMPG). The vaccine candidate was constructed using suitable linkers to link the CTL epitopes, HTC epitopes and adjuvant together, this constructed vaccine candidate was appraised for its antigenic and allergenic properties, the physicochemical parameters which include the molecular formula, theoretical isoelectric point (pI), molecular weight, half-life, instability index, solubility score, GRAVY and aliphatic index were also predicted. The vaccine secondary structure was predicted to evaluate the properties of the secondary structure of the vaccine such as the helices, sheets and coils. The tertiary structure was also predicted, refined and validated using data like Ramachandran plot and Z-score. Disulfide engineering was executed in regions having high mobility in order to improve the protein stability of the candidate vaccine, from this, three pairs of amino acid residues GLY112-THR135, TYR137-ARG139 and THR144-ASN147 were finalized based on their chi3 and B-factor value. Codon adaptation carried out revealed that the vaccine candidate sequence has a GC-content of 53.75% and codon adaptation index of 1.0. In silico cloning was also carried out to determine the vector and cloning site suitable for overproduction of the vaccine protein for large scale production process. To determine the complex stability and binding free energy of the vaccine candidate, molecular docking was performed using the vaccine protein as ligand while TLR-2 and TLR-4 were the receptors. The lowest binding energy for the vaccine-TLR4 complex was −1626.7 and −1305.1 for the vaccine-TLR2 complex. Dynamic simulation provided predictions such as eigenvalue of 5.277774 × 10−06 for TLR-4 receptor and 7.403984 × 10−06 for TLR-2 receptor. From results obtained from the various predictions and validations, it can be concluded that the candidate vaccine will be capable of inducing anti-inflammatory immunity which may be able to prevent Chlamydia trachomatis invasion among human hosts.

Repurposing of N-Acetylcysteine for the Treatment of Dengue Virus-Induced Acute Liver Failure.

The prevalence of dengue infection-induced acute liver damage is increasing from time to time. Since it has no specific antiviral treatment in the world, people in endemic areas suffer more from dengue disorders. Thus, there is a need for searching options for the treatment of dengue-induced acute liver failure. N-acetylcysteine, which is used for the treatment of nasal congestion disorder and paracetamol overdose toxicity, could be used as a definitive therapy for dengue virus-induced acute liver disease. Therefore, this review discusses the therapeutic use of N-acetylcysteine for dengue-induced acute liver disease. Various case reports and case series showed that patients received NAC recovered from their clinical status. Additionally, a preclinical study showed that N-acetylcysteine has anti-dengue virus activity. Thus, N-acetylcysteine could be used as a definitive therapy in dengue virus-induced hepatitis. This might encourage researchers to further investigate the importance of N-acetylcysteine for dengue virus-induced hepatitis.

Expected rate of liver fluke-related cholangiocarcinoma in endemic area of liver fluke with antiparasitic drug distribution program for disease control in Thailand.

Parasitic-induced cancer is an important problem in tropical oncology. Liver fluke-related biliary tract cancer of cholangiocarcinoma is an important kind of endemic cancer in Southeast Asia. This cancer is related to the liver fluke infection. The local public health policies for disease control include antiparasitic drug, praziquantel, distributing aiming at getting rid of risk factor, and opisthorchiasis. In the present report, the authors reappraise on the local epidemiological data on liver fluke infection among the local people in endemic area Thailand under antiparasitic drug distribution program for further assessment for expected rate of cholangiocarcinoma. The present study is a clinical mathematical modeling study. First, the retrospective reappraisal on the available local data on liver fluke infection among the local people in endemic area of Thailand, a tropical country in Indochina, with a different history of previous exposure to antiparasitic drug is done. Then, a mathematical model based on predictive modeling and probability assignment technique is developed for the assessment of estimated rate of cholangiocarcinoma. According to the present study, the expected rate of liver fluke-related cholangiocarcinoma is equal to 0.0564%. There is a strong relationship between expected rate of liver fluke-related cholangiocarcinoma and number of previous exposure to praziquantel (r = 0.99, P = 0.02). According to the study, the high expected rare of cholangiocarcinoma is observed despite the use of general antiparasitic drug distribution policy. It implies finding for new adjusted public health manipulation for disease prevention and management.

An immunoinformatics approach for the design of a multi-epitope subunit vaccine for urogenital schistosomiasis.

Discovery of T and B memory cells capable of eliciting long-term immunity against schistosomiasisis is important for people in endemic areas. Changes in schistosomes environment due to developmental cycle, induces up-regulation of Heat Shock Proteins (HSPs) which assist the parasite in coping with the hostile conditions associated with its life cycle. This study therefore focused on exploring the role of HSPs in urogenital schistosomiasis to develop new multi-epitope subunit vaccine against the disease using immunoinformatic approaches. The designed subunit vaccine was subjected to in silico antigenicity, immunogenicity, allergenicity and physicochemical parameters analysis. A 3D structure of the vaccine construct was predicted, followed by disulphide engineering for stability, codon adaptation and in silico cloning for proper expression and molecular protein–protein docking of vaccine construct in the vector against toll-like receptor 4 receptor, respectively. Consequently, a 493 amino acid multi-epitope vaccine construct of antigenicity probability of 0.91 was designed. This was predicted to be stable, non-allergenic in nature and safe for human use.

Japanese encephalitis virus - exploring the dark proteome and disorder-function paradigm.

Japanese encephalitis virus (JEV) is one of the major causes of viral encephalitis all around the globe. Approximately 3billion people in endemic areas are at risk of Japanese encephalitis. To develop a wholistic understanding of the viral proteome, it is important to investigate both its ordered and disordered proteins. However, the functional and structural significance of disordered regions in the JEV proteome has not been systematically investigated as of yet. To fill this gap, we used here a set of bioinformatics tools to analyze the JEV proteome for the predisposition of its proteins for intrinsic disorder and for the presence of the disorder-based binding regions (also known as molecular recognition features, MoRFs). We also analyzed all JEV proteins for the presence of the probable nucleic acid-binding (DNA and RNA) sites. The results of these computational studies are experimentally validated using JEV capsid protein as an illustrative example. In agreement with bioinformatic analysis, we found that the N-terminal region of the JEV capsid (residues 1-30) is intrinsically disordered. We showed that this region is characterized by the temperature response typical for highly disordered proteins. Furthermore, we have experimentally shown that this disordered N-terminal domain of a capsid protein has a noticeable 'gain-of-structure' potential. In addition, using DOPS liposomes, we demonstrated the presence of pronounced membrane-mediated conformational changes in the N-terminal region of JEV capsid. In our view, this disorder-centric analysis would be helpful for a better understanding of the JEV pathogenesis.

The effect of memantine, an antagonist of the NMDA glutamate receptor, in in vitro and in vivo infections by Trypanosoma cruzi.

Chagas disease, caused by Trypanosoma cruzi, is a neglected tropical disease that affects 5–6 million people in endemic areas of the Americas. Presently, chemotherapy relies on two compounds that were proposed as trypanocidal drugs four decades ago: nifurtimox and benznidazole. Both drugs are able to eliminate parasitemia and to avoid seroconversion in infected people when used in the acute phase; however, their use in the chronic phase (the time when the majority of cases are diagnosed) is limited due to their serious side effects. Memantine is a glutamate receptor antagonist in the central nervous system of mammals that has been used for the treatment of Alzheimer’s disease. Our group previously reported memantine as a trypanocidal drug that is able to induce apoptosis-like death in T. cruzi. In the present work, we further investigated the effects of memantine on the infection of RAW 264.7 macrophages and in vivo (in BALB/c mice). Here, we showed that memantine is able to diminish NO and Ca2+ entry in both LPS-activated and non-activated cells. These results, together with the fact that memantine was also able to reduce the infection of macrophages, led us to propose that this drug is able to activate a pro-oxidant non-NO-dependent cell defense mechanism. Finally, infected mice that were treated with memantine had diminished parasitemia, cardiac parasitic load, and inflammatory infiltrates. In addition, the treated mice had an increased survival rate. Taken together, these results indicate memantine to be a candidate drug for the treatment of Chagas disease.

Characterization of Retinopathy Among Patients With Yellow Fever During 2 Outbreaks in Southeastern Brazil

Yellow fever still threatens people in endemic areas, and besides conjunctival icterus, little is known about the ocular changes that occur in these patients. To characterize retinal changes in patients with confirmed yellow fever during 2 recent outbreaks of the disease in Minas Gerais, Southeastern Brazil. This cross-sectional, observational study conducted at a single referral center for infectious diseases in Southeastern Brazil collected data between January 2017 and February 2018 from 94 consecutive patients with suspicion of yellow fever who were eligible for the study. Patients underwent ophthalmic examination. Clinical findings, laboratory results, and occurrence of retinopathy and death during hospitalization were reported, including age, sex, comorbidities, disease severity, serum aspartate aminotransferase level, total bilirubin level, serum creatinine level, arterial lactate level, international normalized ratio, and platelet count at hospital admission. In total, 64 patients were included who had received a confirmed diagnosis of yellow fever, with a median (interquartile range) age of 47 (38-56) years, and 12 patients (19%) were women. Twenty eyes (16%) of 13 patients (20%) had retinopathy at the same time as yellow fever. The most common fundus changes among the 20 eyes were retinal nerve fiber layer infarcts (11 [55%]), superficial hemorrhages (7 [35%]) and grayish deep lesions (6 [30%]), possibly at the level of the outer retina or choroid. Aspartate aminotransferase levels higher than 3000 U/L (odds ratio [OR], 14.2; 95% CI, 3.5-77.8; P < .001), total bilirubin levels higher than 2.3 mg/dL (OR, 20.0; 95% CI, 4.4-159.7; P < .001), serum creatinine levels higher than 2.0 mg/dL (OR, 8.2; 95% CI, 2.1-36.0; P = .003), arterial lactate levels higher than 17.1/mg/dL (OR, 4.6; 95% CI, 1.1-19.0; P = .03), platelet count lower than 94 × 103/μL (OR, 7.8; 95% CI, 1.8-59.9; P = .004), and classification of disease as severe (OR, 11.7; 95% CI, 2.0-301.0; P = .003) were associated with retinopathy. Arterial hypertension, diabetes, international normalized ratio, and death were not associated with retinopathy. Retinopathy was present in 20% of patients with yellow fever and appeared to be associated with more severe systemic disease. Retinal nerve fiber layer infarcts and superficial hemorrhages, but not the grayish deep lesions, resembled those associated with other flavivirus (eg, dengue virus) infections. The clinical relevance of these findings may warrant further investigation.

Diagnosis of spotted fever group Rickettsia infections: the Asian perspective.

Spotted fever group rickettsiae (SFG) are a neglected group of bacteria, belonging to the genus Rickettsia, that represent a large number of new and emerging infectious diseases with a worldwide distribution. The diseases are zoonotic and are transmitted by arthropod vectors, mainly ticks, fleas and mites, to hosts such as wild animals. Domesticated animals and humans are accidental hosts. In Asia, local people in endemic areas as well as travellers to these regions are at high risk of infection. In this review we compare SFG molecular and serological diagnostic methods and discuss their limitations. While there is a large range of molecular diagnostics and serological assays, both approaches have limitations and a positive result is dependent on the timing of sample collection. There is an increasing need for less expensive and easy-to-use diagnostic tests. However, despite many tests being available, their lack of suitability for use in resource-limited regions is of concern, as many require technical expertise, expensive equipment and reagents. In addition, many existing diagnostic tests still require rigorous validation in the regions and populations where these tests may be used, in particular to establish coherent and worthwhile cut-offs. It is likely that the best strategy is to use a real-time quantitative polymerase chain reaction (qPCR) and immunofluorescence assay in tandem. If the specimen is collected early enough in the infection there will be no antibodies but there will be a greater chance of a PCR positive result. Conversely, when there are detectable antibodies it is less likely that there will be a positive PCR result. It is therefore extremely important that a complete medical history is provided especially the number of days of fever prior to sample collection. More effort is required to develop and validate SFG diagnostics and those of other rickettsial infections.

Usefulness of environmental DNA for detecting Schistosoma mansoni occurrence sites in Madagascar

ObjectivesSchistosomiasis is an important disease in Madagascar, and several studies on the disease have focused on the occurrence of the parasite in humans. However, the range of the pathogen in the environment and its impact on human infection is difficult to predict. An environmental DNA (eDNA) detection system for Schistosoma mansoni was developed to improve schistosomiasis eco-epidemiology studies. MethodsPrimers and probes were designed and tested in experimental biotopes. The field study was conducted in Maevatanana District of Madagascar. Seven water sources with human use were sampled, with a total of 21 water samples collected. Snails were collected, and patients were examined by ultrasound to determine the occurrence of schistosomiasis in the study area. ResultsOne water source with active transmission was identified through the detection of S. mansoni eDNA in the water and the intermediate host Biomphalaria pfeifferi collected from the same water source. People with clinical schistosomiasis were found in the area, reinforcing the findings. ConclusionsThe application of eDNA in eco-epidemiology enables the determination of hot spots and safe spots in endemic areas, constituting an alternative ecological tool for follow-up and monitoring of control programs for schistosomiasis, and contributing information on water safety for improving the standard of living of the people in endemic areas.

From human antibody structure and function towards the design of a novel Plasmodium falciparum circumsporozoite protein malaria vaccine.

Malaria is a life-threatening vector-borne disease caused by Plasmodium parasites that infect millions of people in endemic areas every year. The most advanced malaria vaccine candidate RTS,S targets the immune response against circumsporozoite protein of Plasmodium falciparum (PfCSP), the most deadly Plasmodium species in humans. PfCSP plays a fundamental role in parasite development as well as the establishment of the infection and is a molecular target of protective antibodies. However, RTS,S shows overall low efficacy and insufficient long-term protection. Therefore, a major goal in the development of an improved PfCSP-based vaccine remains the reliable and stable induction of protective and ideally sterilizing antibody titers. The molecular and functional characterization of human anti-PfCSP antibody responses paves the way for the rational design of novel immunogens for the development of an improved next-generation PfCSP malaria vaccine.

A neglected risk for sparganosis: eating live tadpoles in central China

A 29-year-old farmer from central China was sent into the Emergency Department of the Affiliated Hospital of Zhengzhou University. He had a 15-day history of persistent high fever, abdominal distention and pain. The patient was clinically diagnosed as appendicitis and peritonitis, and treated with antibiotics in a local hospital, did not improve. On exploratory laparotomy, the appendicular perforation and peritonitis were seen; appendicectomy were performed, and antibiotics were given. However, high fever and abdominal pain still persisted; intestinal adhesion and obstruction, ascites appeared. He was given the “critically ill notice”. He had eosinophilia (12.95%) and the history of eating live frog tadpoles for treating his cutaneous pruritus 3 days before onset of the disease. Serum anti-sparganum antibodies assayed by ELISA were positive. This patient has hospitalized for one and half months and spend more than US$ 12 000. This patient was primarily diagnosed as visceral sparganosis, and cured with praziquantel.Sparganosis is one neglected but important parasitic zoonosis of poverty. Human infections were mainly acquired by eating raw or uncooked meat of frogs and snakes infected with plerocercoids, using frog or snake flesh as poultices, or drinking raw water contaminated with infected copepods. However, sparganosis caused by ingestion of live tadpoles are emerging in central China. Our surveys showed that 11.93% of tadpoles in Henan province are infected with plerocercoids. Eating live tadpoles is a high risk for sparganum infection. The comprehensive public health education should be carried out for people in endemic areas and the bad habit of eating live tadpoles must be discouraged.

Molecular identification and genotyping of Trypanosoma cruzi DNA in autochthonous Chagas disease patients from Texas, USA

The parasitic protozoan Trypanosoma cruzi, the causative agent of Chagas disease, is widely distributed throughout the Americas, from the southern United States (US) to northern Argentina, and infects at least 6 million people in endemic areas. Much remains unknown about the dynamics of T. cruzi transmission among mammals and triatomine vectors in sylvatic and peridomestic eco-epidemiological cycles, as well as of the risk of transmission to humans in the US. Identification of T. cruzi DTUs among locally-acquired cases is necessary for enhancing our diagnostic and clinical prognostic capacities, as well as to understand parasite transmission cycles. Blood samples from a cohort of 15 confirmed locally-acquired Chagas disease patients from Texas were used for genotyping T. cruzi. Conventional PCR using primers specific for the minicircle variable region of the kinetoplastid DNA (kDNA) and the highly repetitive genomic satellite DNA (satDNA) confirmed the presence of T. cruzi in 12/15 patients. Genotyping was based on the amplification of the intergenic region of the miniexon gene of T. cruzi and sequencing. Sequences were analyzed by BLAST and phylogenetic analysis by Maximum Likelihood method allowed the identification of non-TcI DTUs infection in six patients, which corresponded to DTUs TcII, TcV or TcVI, but not to TcIII or TcIV. Two of these six patients were also infected with a TcI DTU, indicating mixed infections in those individuals. Electrocardiographic abnormalities were seen among patients with single non-TcI and mixed infections of non-TcI and TcI DTUs. Our results indicate a greater diversity of T. cruzi DTUs circulating among autochthonous human Chagas disease cases in the southern US, including for the first time DTUs from the TcII-TcV-TcVI group. Furthermore, the DTUs infecting human patients in the US are capable of causing Chagasic cardiac disease, highlighting the importance of parasite detection in the population.

Low-grade sulfadoxine-pyrimethamine resistance in Plasmodium falciparum parasites from Lubango, Angola.

BackgroundMalaria is a major parasitic disease, affecting millions of people in endemic areas. Plasmodium falciparum parasites are responsible for the most severe cases and its resistance to anti-malarial drugs is notorious. This is a possible obstacle to the effectiveness of intermittent preventive treatment (IPT) based on sulfadoxine–pyrimethamine (SP) cures administrated to pregnant women (IPTp) during their pregnancy. As this intervention is recommended in Angola since 2006, it has assessed, in this country, the molecular profiles in P. falciparumdhfr and dhps, two polymorphic genes associated to pyrimethamine and sulfadoxine resistance, respectively.MethodsBlood samples from 52 falciparum patients were collected in Lubango, Angola and pfdhfr and pfdhps polymorphisms were analysed using nested-PCR and DNA sequencing.ResultsIn the pfdhfr gene, the 108N mutation was almost fixed (98 %), followed by 59R (63 %), 51I (46 %), 50R and 164L (2 %, respectively). No 16V/S mutations were found. The most common double mutant genotype was CNRN (59 + 108; 46 %), followed by CICN (51 + 108; 29 %) whereas IRN (51 + 59 + 108; 15 %), CNRNVL (59 + 108 + 164; 2 %) and RICN (50 + 51 + 108; 2 %) triple mutant genotypes were detected. Investigations of the pfdhps gene showed that the 437G mutation was the most prevalent (97 %). Only two and one samples disclosed the 540E (7 %) and the 436A (3 %), respectively. Single mutant SGKAA (437; 86 %) was higher than SGEAA (437 + 540; 7 %) or AGKAA (436 + 437; 3 %) double mutants genotypes. No polymorphism was detected at codons 581G and 613T/S. Combining pfdhfr and pfdhps alleles two triple mutant haplotypes (double mutant in dhfr and single mutant in dhps) were observed: the ACICNVI/SGKAA in 14 (56 %) samples and the ACNRNVI/SGKAA in five (20 %) samples. One quadruple mutant haplotype was detected (ACIRNVI/SGKAA) in six (24 %) P. falciparum samples. No quintuple pfdhfr–pfdhps mutant was noted.Conclusionpfdhfr and pfdhps gene mutations in isolates from Lubango are suggestive of a low-grade SP resistance and IPT for pregnant women and infant based on SP treatment could be effective. Routine molecular studies targeting polymorphism in these two genes need to be routinely conducted at country level.