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1.
J Med Entomol ; 57(5): 1532-1538, 2020 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-32277701

RESUMO

Tick-borne diseases are a growing threat to public health in the United States, especially among outdoor workers who experience high occupational exposure to ticks. Long-lasting permethrin-impregnated clothing has demonstrated high initial protection against bites from blacklegged ticks, Ixodes scapularis Say (Acari: Ixodidae), in laboratory settings, and sustained protection against bites from the lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), in field tests. However, long-lasting permethrin impregnation of clothing has not been field tested among outdoor workers who are frequently exposed to blacklegged ticks. We conducted a 2-yr randomized, placebo-controlled, double-blinded trial among 82 outdoor workers in Rhode Island and southern Massachusetts. Participants in the treatment arm wore factory-impregnated permethrin clothing, and the control group wore sham-treated clothing. Outdoor working hours, tick encounters, and bites were recorded weekly to assess protective effectiveness of long-lasting permethrin-impregnated garments. Factory-impregnated clothing significantly reduced tick bites by 65% in the first study year and by 50% in the second year for a 2-yr protective effect of 58%. No significant difference in other tick bite prevention method utilization occurred between treatment and control groups, and no treatment-related adverse outcomes were reported. Factory permethrin impregnation of clothing is safe and effective for the prevention of tick bites among outdoor workers whose primary exposure is to blacklegged ticks in the northeastern United States.

3.
Paediatr Perinat Epidemiol ; 33(4): 286-290, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31347726

RESUMO

BACKGROUND: Several health agencies define microcephaly for surveillance purposes using a single criterion, a percentile or Z-score cut-off for newborn head circumference. This definition, however, conflicts with the reported prevalence of microcephaly even in populations with endemic Zika virus. OBJECTIVE: We explored possible reasons for this conflict, hypothesising that the definition of microcephaly used in some studies may be incompletely described, lacking the additional clinical criteria that clinicians use to make a formal diagnosis. We also explored the potential for misclassification that can result from differences in these definitions, especially when applying a percentile cut-off definition in the presence of the much lower observed prevalence estimates that we believe to be valid. METHODS: We conducted simulations under a theoretical bimodal distribution of head circumference. For different definitions of microcephaly, we calculated the sensitivity and specificity using varying cut-offs of head circumference. We then calculated and plotted the positive predictive value for each of these definitions by prevalence of microcephaly. RESULTS: Simple simulations suggest that if the true prevalence of microcephaly is approximately what is reported in peer-reviewed literature, then relying on cut-off-based definitions may lead to very poor positive predictive value under realistic conditions. CONCLUSIONS: While a simple head circumference criterion may be used in practice as a screening or surveillance tool, the definition lacks clarification as to what constitutes true pathological microcephaly and may lead to confusion about the true prevalence of microcephaly in Zika-endemic areas, as well as bias in aetiologic studies.


Assuntos
Microcefalia/classificação , Complicações Infecciosas na Gravidez/diagnóstico , Infecção por Zika virus/diagnóstico , Cefalometria , Surtos de Doenças , Feminino , Humanos , Recém-Nascido , Gravidez , Complicações Infecciosas na Gravidez/virologia
4.
PLoS Negl Trop Dis ; 13(5): e0007383, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31059501

RESUMO

Triatomine vectors transmit Trypanosoma cruzi, the etiological agent of Chagas disease in humans. Transmission to humans typically occurs when contaminated triatomine feces come in contact with the bite site or mucosal membranes. In the Southern Cone of South America, where the highest burden of disease exists, Triatoma infestans is the principal vector for T. cruzi. Recent studies of other vector-borne illnesses have shown that arthropod microbiota influences the ability of infectious agents to colonize the insect vector and transmit to the human host. This has garnered attention as a potential control strategy against T. cruzi, as vector control is the main tool of Chagas disease prevention. Here we characterized the microbiota in T. infestans feces of both wild-caught and laboratory-reared insects and examined the relationship between microbial composition and T. cruzi infection using highly sensitive high-throughput sequencing technology to sequence the V3-V4 region of the 16S ribosomal RNA gene on the MiSeq Illumina platform. We collected 59 wild (9 with T. cruzi infection) and 10 lab-reared T. infestans (4 with T. cruzi infection) from the endemic area of Arequipa, Perú. Wild T. infestans had greater hindgut bacterial diversity than laboratory-reared bugs. Microbiota of lab insects comprised a subset of those identified in their wild counterparts, with 96 of the total 124 genera also observed in laboratory-reared insects. Among wild insects, variation in bacterial composition was observed, but time and location of collection and development stage did not explain this variation. T. cruzi infection in lab insects did not affect α- or ß-diversity; however, we did find that the ß-diversity of wild insects differed if they were infected with T. cruzi and identified 10 specific taxa that had significantly different relative abundances in infected vs. uninfected wild T. infestans (Bosea, Mesorhizobium, Dietzia, and Cupriavidus were underrepresented in infected bugs; Sporosarcina, an unclassified genus of Porphyromonadaceae, Nestenrenkonia, Alkalibacterium, Peptoniphilus, Marinilactibacillus were overrepresented in infected bugs). Our findings suggest that T. cruzi infection is associated with the microbiota of T. infestans and that inferring the microbiota of wild T. infestans may not be possible through sampling of T. infestans reared in the insectary.


Assuntos
Bactérias/isolamento & purificação , Doença de Chagas/transmissão , Insetos Vetores/microbiologia , Microbiota , Triatoma/microbiologia , Animais , Bactérias/classificação , Bactérias/genética , Doença de Chagas/parasitologia , DNA Bacteriano/genética , Fezes/microbiologia , Trato Gastrointestinal/microbiologia , Humanos , Insetos Vetores/parasitologia , Insetos Vetores/fisiologia , Laboratórios , Filogenia , RNA Ribossômico 16S/genética , Triatoma/parasitologia , Triatoma/fisiologia , Trypanosoma cruzi/fisiologia
5.
JCI Insight ; 4(8)2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-30996133

RESUMO

The recent Zika virus (ZIKV) epidemic in the Americas has revealed rare but serious manifestations of infection. ZIKV has emerged in regions endemic for dengue virus (DENV), a closely related mosquito-borne flavivirus. Cross-reactive antibodies confound studies of ZIKV epidemiology and pathogenesis. The immune responses to ZIKV may be different in people, depending on their DENV immune status. Here, we focus on the human B cell and antibody response to ZIKV as a primary flavivirus infection to define the properties of neutralizing and protective antibodies generated in the absence of preexisting immunity to DENV. The plasma antibody and memory B cell response is highly ZIKV type-specific, and ZIKV-neutralizing antibodies mainly target quaternary structure epitopes on the viral envelope. To map viral epitopes targeted by protective antibodies, we isolated 2 type-specific monoclonal antibodies (mAbs) from a ZIKV case. Both mAbs were strongly neutralizing in vitro and protective in vivo. The mAbs recognize distinct epitopes centered on domains I and II of the envelope protein. We also demonstrate that the epitopes of these mAbs define antigenic regions commonly targeted by plasma antibodies in individuals from endemic and nonendemic regions who have recovered from ZIKV infections.

6.
Emerg Infect Dis ; 25(4): 808-810, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30882329

RESUMO

Zika virus, an arthropod-borne flavivirus pathogen in humans, is unusual because it can be sexually transmitted and can be shed for prolonged periods in semen. We report viral shedding in vaginal secretions for up to 6 months, indicating the potential for sexual and vertical transmission by infected women.


Assuntos
RNA Viral/isolamento & purificação , Eliminação de Partículas Virais , Infecção por Zika virus/transmissão , Zika virus/isolamento & purificação , Feminino , Humanos , Transmissão Vertical de Doença Infecciosa , Nicarágua , Vagina/virologia , Infecção por Zika virus/virologia
7.
Am J Trop Med Hyg ; 100(1): 83-89, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30457102

RESUMO

Quantitative polymerase chain reaction (qPCR) for Toxoplasma gondii multicopy genes has emerged as a promising strategy for sensitive detection of parasite DNA. qPCR can be performed from blood samples, which are minimally invasive to collect. However, there is no consensus about what type of blood specimen yields the best sensitivity. The development of a novel protocol for qPCR detection of T. gondii using blood clot, involving an appropriate DNA extraction method and the use of an internal amplification control to monitor the reaction is presented in the current study. Assays directed to the B1 and REP529 genes were performed in spiked specimens of whole blood, guanidine-ethylenediaminetetraacetic acid blood, and clot. The clot-based qPCR was shown to be more sensitive when compared with other types of specimens, detecting five and 0.05 T. gondii genomes, using B1 and REP529 targets, respectively. Finally, a comparative analysis with samples from HIV patients with clinical suspicion of toxoplasmosis was performed, demonstrating the detection of four positive suspected cases with clots compared with only one using guanidine-ethylenediaminetetraacetic acid blood. The high analytical sensitivity and the cost-effective advantages offered by clot supports this methodology as a good laboratory tool to monitor parasite burden.


Assuntos
Carga Parasitária/métodos , Reação em Cadeia da Polimerase/métodos , Trombose/parasitologia , Toxoplasma/isolamento & purificação , Toxoplasmose/diagnóstico , Adulto , DNA de Protozoário/genética , Genoma de Protozoário , Infecções por HIV/sangue , Infecções por HIV/parasitologia , Humanos , Técnicas de Diagnóstico Molecular/métodos , Sensibilidade e Especificidade , Toxoplasma/genética , Toxoplasmose/sangue , Adulto Jovem
8.
Clin Infect Dis ; 69(8): 1345-1352, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-30561541

RESUMO

BACKGROUND: Human immunodeficiency virus type 1 (HIV-1) populations are detected in cerebrospinal fluid (CSF) of some people on suppressive antiretroviral therapy (ART). Detailed analysis of these populations may reveal whether they are produced by central nervous system (CNS) reservoirs. METHODS: We performed a study of 101 asymptomatic participants on stable ART. HIV-1 RNA concentrations were cross-sectionally measured in CSF and plasma. In participants with CSF HIV-1 RNA concentrations sufficient for analysis, viral populations were genetically and phenotypically characterized over multiple time points. RESULTS: For 6% of participants (6 of 101), the concentration of HIV-1 RNA in their CSF was ≥0.5 log copies/mL above that of plasma (ie, CSF escape). We generated viral envelope sequences from CSF of 3 participants. One had a persistent CSF escape population that was macrophage-tropic, partially drug resistant, genetically diverse, and closely related to a minor macrophage-tropic lineage present in the blood prior to viral suppression and enriched for after ART. Two participants (1 suppressed and 1 not) had transient CSF escape populations that were R5 T cell-tropic with little genetic diversity. CONCLUSIONS: Extensive analysis of viral populations in 1 participant revealed that CSF escape was from a persistently replicating population, likely in macrophages/microglia, present in the CNS over 3 years of ART. CSF escape in 2 other participants was likely produced by trafficking and transient expansion of infected T cells in the CNS. Our results show that CNS reservoirs can persist during ART and that CSF escape is not exclusively produced by replicating CNS reservoirs.

9.
Pediatr Neurol ; 85: 16-20, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30343688

RESUMO

Limited information is available on health outcomes related to Zika virus infection acquired during childhood. Zika virus can cause severe central nervous system malformations in congenitally exposed fetuses and neonates. In vitro studies show the capacity of Zika virus to infect neural progenitor cells, induce central and peripheral neuronal cell deaths, and target different brain cells over the course of brain development. Studies of postnatally infected mice and nonhuman primates have detected degradation of neural cells and morphologic brain cell changes consistent with a broad neuroinflammatory response. In addition, case reports of central nervous system disease in adults and in adolescents secondary to Zika virus infection suggest that Zika virus may have a broader impact on neurological health beyond that observed in congenitally exposed newborns. Long-term neurological complications have been observed with other acquired flaviviral infections, with clinical symptoms manifesting for years after primary infection. The extent to which postnatal Zika virus infection in humans negatively affects the central and peripheral nervous systems and causes long-term neurological damage or cognitive effects is currently unknown. To better understand the potential for neurological sequelae associated with acquired Zika virus infection in children, we reviewed the biological, clinical, and epidemiologic literature and summarized the evidence for this link. First, we review biological mechanisms for neurological manifestations of Zika virus infection in experimental studies. Second, we review observational studies of congenital Zika virus infection and case studies and surveillance reports of neurological sequelae of Zika virus infection in adults and in children. Lastly, we discuss the challenges of conducting Zika virus-neurological sequela studies and future directions for pediatric Zika virus research.


Assuntos
Doenças do Sistema Nervoso/etiologia , Infecção por Zika virus/complicações , Animais , Criança , Humanos , Doenças do Sistema Nervoso/epidemiologia , Doenças do Sistema Nervoso/fisiopatologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/fisiopatologia
10.
PLoS One ; 13(5): e0196410, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29763445

RESUMO

Pyrethroid-treated clothing is commonly worn for protection against mosquitoes; pyrethroids are both insecticides and repellents. Pyrethroid resistance has become increasingly common in Aedes aegypti, the vector of dengue, Zika, and other arboviruses, but it is not clear whether resistance is associated with reductions in repellency. In order to determine whether long-lasting permethrin impregnated (LLPI) clothing is protective, we used Aedes aegypti from New Orleans, LA (pyrethroid-sensitive) and San Juan, PR (resistant) to measure both lethality and repellency. PCR and Sanger sequencing were used to confirm resistance status by detecting mutations in the kdr gene at positions 1016 and 1534. Arm-in-cage trials of 100 Aedes aegypti females from both populations were performed for 10 minutes to bare arm or an arm clothed in untreated military camouflage or military camouflage impregnated with deltamethrin, permethrin, or etofenprox. Trials were repeated 4-5 times on different days. Number of landings, number of blood meals, and immediate and 24-hour mortality were recorded. Mortality was extremely low in all trials. Compared to untreated cloth, mosquitoes demonstrated a trend towards a 2%-63% reduction in landings and a statistically significant 78-100% reduction in blood feeding on pyrethroid-treated cloth for most insecticides. Effects were observed in both pyrethroid-sensitive and pyrethroid-resistant mosquito populations. Our data show that kdr mutations are associated with pyrethroid resistance but are likely not the only contributors. Pyrethroids appear to maintain repellent effect against resistant mosquitoes. This finding suggests that even in places where pyrethroid resistance is widespread, permethrin still has a role for use as a repellent on clothing to protect against mosquito bites.


Assuntos
Aedes , Repelentes de Insetos , Inseticidas , Piretrinas , Aedes/genética , Animais , Resistência a Medicamentos/genética , Feminino , Genes de Insetos , Humanos , Proteínas de Insetos/genética , Mosquiteiros Tratados com Inseticida , Controle de Mosquitos , Mosquitos Vetores/genética , Mutação , Nitrilos , Permetrina , Canais de Sódio Disparados por Voltagem/genética
11.
Infect Genet Evol ; 55: 305-312, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28982545

RESUMO

OBJECTIVES: Investigate clinical and epidemiological factors of pediatric GII.4 norovirus infections in children with acute gastroenteritis (AGE) in Nicaragua between 1999 and 2015. METHODS: We retrospectively analyzed laboratory and epidemiologic data from 1,790 children≤7years with AGE from 6 hospitals in Nicaragua (n=538), and 3 community clinics (n=919) and households (n=333) in León, between 1999 and 2015. Moreover, asymptomatic children from community clinics (n=162) and households (n=105) were enrolled. Norovirus was detected by real-time PCR and genotyped by sequencing the N-terminal and shell region of the capsid gene. RESULTS: Norovirus was found in 19% (n=338) and 12% (n=32) of children with and without AGE, respectively. In total, 20 genotypes including a tentatively new genotype were detected. Among children with AGE, the most common genotypes were GII.4 (53%), GII.14 (7%), GII.3 (6%) and GI.3 (6%). In contrast, only one (1.4%) GII.4 was found in asymptomatic children. The prevalence of GII.4 infections was significantly higher in children between 7 and 12months of age. The prevalence of GII.4 was lowest in households (38%), followed by community clinics (50%) and hospitals (75%). Several different GII.4 variants were detected and their emergence followed the global temporal trend. CONCLUSIONS: Overall our study found the predominance of pediatric GII.4 norovirus infections in Nicaragua mostly occurring in children between 7 and 12months of age, implicating GII.4 as the main norovirus vaccine target.


Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus , Adolescente , Infecções por Caliciviridae/história , Criança , Pré-Escolar , Gastroenterite/história , Genótipo , História do Século XXI , Humanos , Incidência , Lactente , Recém-Nascido , Nicarágua/epidemiologia , Norovirus/genética , Razão de Chances , Vigilância em Saúde Pública , Estudos Retrospectivos , Estações do Ano
12.
Am J Trop Med Hyg ; 97(3): 937-943, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28722577

RESUMO

Norovirus is a leading cause of pediatric gastroenteritis. Understanding norovirus epidemiology is essential for reducing disease burden. We conducted a case-control study to describe the distribution, clinical features, and risk factors of norovirus gastroenteritis among children < 5 years of age in León, Nicaragua. Cases were children testing positive for norovirus and controls were children living in the cases' communities. Study staff interviewed mothers of enrolled cases and controls to obtain detailed exposure information including food, water, and sanitation sources; recent exposures; household characteristics; and handwashing practices. In addition, study staff requested stool samples to be tested for norovirus from select household members. We used descriptive statistics to understand the epidemiologic and clinical features of gastroenteritis episodes. To analyze potential risk factors, we used Firth's penalized logistic regression to estimate crude and adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs). There were 102 children with gastroenteritis, 18 cases of norovirus and 31 controls. Norovirus cases occurred later in the year, corresponding to a delay in the rainy season. Cases were more likely to have a household member with norovirus in their stool as compared with controls [crude OR: 13.3 (95% CI: 2.5, 136.2) and adjusted OR: 11.5 (95% CI: 1.6, 223.2)]. In addition, alcohol-based hand sanitizer use among household members was reported for 10 (32%) of controls and but never for cases. Further research is needed to understand household transmission of norovirus in low- and middle-income countries and the potential impact of hand sanitizer use.


Assuntos
Infecções por Caliciviridae/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus , Infecções por Caliciviridae/epidemiologia , Estudos de Casos e Controles , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Nicarágua/epidemiologia , Fatores de Risco
13.
Am J Trop Med Hyg ; 95(3): 580-7, 2016 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-27481054

RESUMO

Naturally acquired immunity to Plasmodium falciparum presents a changing landscape as malaria control programs and vaccine initiatives are implemented. Determining which immunologic indicators remain surrogates of past infection, as opposed to mediators of protection, led us to compare stability of immune responses across regions with divergent malaria transmission intensities. A repeat cross-sectional study of Kenyan children from a malaria-holoendemic area and an epidemic-prone area was used to examine longitudinal antibody and interferon-gamma (IFN-γ) responses to the 3D7 and FVO variants of merozoite surface protein 1 (MSP1). Antibodies to MSP1 were common in both study populations and did not significantly wane over a 21-month time period. IFN-γ responses were less frequent and rapidly disappeared in children after a prolonged period of no malaria transmission. Antibody and IFN-γ responses rarely correlated with each other; however, MSP1-specific IFN-γ response correlated with lack of concurrent P. falciparum parasitemia of the same genotype, though only statistically significantly in the malaria-holoendemic region (odds ratio = 0.31, 95% confidence interval = 0.12-0.84). This study affirms that antimalarial antibodies are informative for evaluation of history of malaria exposure within individuals, whereas cell-mediated immunity, though short lived under natural exposure conditions, might provide an assessment of recent infection and protection from parasitemia.


Assuntos
Imunidade Humoral/imunologia , Malária Falciparum/imunologia , Proteína 1 de Superfície de Merozoito/imunologia , Plasmodium falciparum/imunologia , Criança , Feminino , Genótipo , Humanos , Quênia , Malária Falciparum/transmissão , Masculino , Proteína 1 de Superfície de Merozoito/genética , Plasmodium falciparum/genética , Fatores de Tempo
14.
Am J Trop Med Hyg ; 94(6): 1290-8, 2016 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27044564

RESUMO

Autonomic dysfunction is common in Chagas disease and diabetes. Patients with either condition complicated by cardiac autonomic dysfunction face increased mortality, but no clinical predictors of autonomic dysfunction exist. Pupillary light reflexes (PLRs) may identify such patients early, allowing for intensified treatment. To evaluate the significance of PLRs, adults were recruited from the outpatient endocrine, cardiology, and surgical clinics at a Bolivian teaching hospital. After testing for Chagas disease and diabetes, participants completed conventional autonomic testing (CAT) evaluating their cardiovascular responses to Valsalva, deep breathing, and orthostatic changes. PLRs were measured using specially designed goggles, then CAT and PLRs were compared as measures of autonomic dysfunction. This study analyzed 163 adults, including 96 with Chagas disease, 35 patients with diabetes, and 32 controls. PLRs were not significantly different between Chagas disease patients and controls. Patients with diabetes had longer latency to onset of pupil constriction, slower maximum constriction velocities, and smaller orthostatic ratios than nonpatients with diabetes. PLRs correlated poorly with CAT results. A PLR-based clinical risk score demonstrated a 2.27-fold increased likelihood of diabetes complicated by autonomic dysfunction compared with the combination of blood tests, CAT, and PLRs (sensitivity 87.9%, specificity 61.3%). PLRs represent a promising tool for evaluating subclinical neuropathy in patients with diabetes without symptomatic autonomic dysfunction. Pupillometry does not have a role in the evaluation of Chagas disease patients.


Assuntos
Doenças do Sistema Nervoso Autônomo/diagnóstico , Doença de Chagas/complicações , Diabetes Mellitus/fisiopatologia , Retinopatia Diabética/diagnóstico , Reflexo Pupilar , Adulto , Doenças do Sistema Nervoso Autônomo/patologia , Doenças do Sistema Nervoso Autônomo/fisiopatologia , Bolívia/epidemiologia , Doença de Chagas/epidemiologia , Doença de Chagas/fisiopatologia , Retinopatia Diabética/epidemiologia , Retinopatia Diabética/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
16.
PLoS Negl Trop Dis ; 10(2): e0004407, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26919324

RESUMO

BACKGROUND: Early diagnosis of reactivated Chagas disease in HIV patients could be lifesaving. In Latin America, the diagnosis is made by microscopical detection of the T. cruzi parasite in the blood; a diagnostic test that lacks sensitivity. This study evaluates if levels of T. cruzi antigens in urine, determined by Chunap (Chagas urine nanoparticle test), are correlated with parasitemia levels in T. cruzi/HIV co-infected patients. METHODOLOGY/PRINCIPAL FINDINGS: T. cruzi antigens in urine of HIV patients (N = 55: 31 T. cruzi infected and 24 T. cruzi serology negative) were concentrated using hydrogel particles and quantified by Western Blot and a calibration curve. Reactivation of Chagas disease was defined by the observation of parasites in blood by microscopy. Parasitemia levels in patients with serology positive for Chagas disease were classified as follows: High parasitemia or reactivation of Chagas disease (detectable parasitemia by microscopy), moderate parasitemia (undetectable by microscopy but detectable by qPCR), and negative parasitemia (undetectable by microscopy and qPCR). The percentage of positive results detected by Chunap was: 100% (7/7) in cases of reactivation, 91.7% (11/12) in cases of moderate parasitemia, and 41.7% (5/12) in cases of negative parasitemia. Chunap specificity was found to be 91.7%. Linear regression analysis demonstrated a direct relationship between parasitemia levels and urine T. cruzi antigen concentrations (p<0.001). A cut-off of > 105 pg was chosen to determine patients with reactivation of Chagas disease (7/7). Antigenuria levels were 36.08 times (95% CI: 7.28 to 64.88) higher in patients with CD4+ lymphocyte counts below 200/mL (p = 0.016). No significant differences were found in HIV loads and CD8+ lymphocyte counts. CONCLUSION: Chunap shows potential for early detection of Chagas reactivation. With appropriate adaptation, this diagnostic test can be used to monitor Chagas disease status in T. cruzi/HIV co-infected patients.


Assuntos
Antígenos de Protozoários/urina , Doença de Chagas/diagnóstico , Coinfecção/diagnóstico , Testes Diagnósticos de Rotina/métodos , Infecções por HIV/complicações , Parasitemia/diagnóstico , Trypanosoma cruzi/isolamento & purificação , Adulto , Linfócitos T CD8-Positivos , Estudos de Casos e Controles , Doença de Chagas/complicações , Doença de Chagas/parasitologia , Doença de Chagas/urina , Coinfecção/imunologia , Coinfecção/parasitologia , Coinfecção/urina , Testes Diagnósticos de Rotina/instrumentação , Diagnóstico Precoce , Feminino , Infecções por HIV/urina , Humanos , Masculino , Pessoa de Meia-Idade , Nanopartículas/química , Parasitemia/imunologia , Parasitemia/parasitologia , Parasitemia/urina , Trypanosoma cruzi/genética , Trypanosoma cruzi/imunologia , Adulto Jovem
17.
Sci Rep ; 3: 1990, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23771124

RESUMO

Humoral immunity to Plasmodium falciparum circumsporozoite protein is partly mediated by a polymorphic NANP tetra-amino acid repeat. Antibody response to these repeats is the best correlate of protective immunity to the RTS,S malaria vaccine, but few descriptions of the natural variation of these repeats exist. Using capillary electrophoresis to determine the distribution of NANP repeat size polymorphisms among 98 isolates from Lilongwe, Malawi, we characterised the diversity of P. falciparum infection by several ecological indices. Infection by multiple distinct variants was common, and 20 distinct repeat sizes were identified. Diversity of P. falciparum appeared greater in children (18 variants) than adults (12 variants). There was evidence of genetic distance between different geographic regions by Nei's Standard Genetic Distance, suggesting parasite populations vary locally. We show that P. falciparum is very diverse with respect to NANP repeat length even on a local level and that diversity appears higher in children.


Assuntos
Plasmodium falciparum/metabolismo , Proteínas de Protozoários/metabolismo , Adulto , Animais , Criança , Pré-Escolar , Eletroforese Capilar , Feminino , Humanos , Malaui , Masculino , Proteínas de Protozoários/química
18.
Reprod Biomed Online ; 27(2): 140-6, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23683847

RESUMO

Time-lapse imaging of human preimplantation IVF embryos has enabled objective algorithms based on novel observations of development (morphokinetics) to be used for clinical selection of embryos. Embryo aneuploidy, a major cause of IVF failure, has been correlated with specific morphokinetic variables used previously to develop an aneuploidy risk classification model. The purpose of this study was to evaluate the effectiveness and potential impact of this model for unselected IVF patients without biopsy and preimplantation genetic screening (PGS). Embryo outcomes - no implantation, fetal heart beat (FHB) and live birth (LB) - of 88 transferred blastocysts were compared according to calculated aneuploidy risk classes (low, medium, high). A significant difference was seen for FHB (P<0.0001) and LB (P<0.01) rates between embryos classified as low and medium risk. Within the low-risk class, relative increases of 74% and 56%, compared with rates for all blastocysts, were observed for FHB and LB respectively. The area under the receiver operating characteristic curve was 0.75 for FHB and 0.74 for LB. This study demonstrates the clinical relevance of the aneuploidy risk classification model and introduces a novel, non-invasive method of embryo selection to yield higher implantation and live birth rates without PGS.


Assuntos
Aneuploidia , Ectogênese , Fertilização In Vitro , Modelos Biológicos , Adulto , Estudos de Coortes , Transferência Embrionária , Inglaterra/epidemiologia , Características da Família , Feminino , Humanos , Infertilidade Feminina/terapia , Infertilidade Masculina , Nascimento Vivo , Masculino , Pessoa de Meia-Idade , Gravidez , Taxa de Gravidez , Estudos Retrospectivos , Risco , Imagem com Lapso de Tempo
19.
Reprod Biomed Online ; 26(5): 477-85, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23518033

RESUMO

This study determined whether morphokinetic variables between aneuploid and euploid embryos differ as a potential aid to select euploid embryos for transfer. Following insemination, EmbryoScope time-lapse images from 98 blastocysts were collected and analysed blinded to ploidy. The morphokinetic variables were retrospectively compared with ploidy, which was determined following trophectoderm biopsy and analysis by array comparative genomic hybridization or single-nucleotide polymorphic array. Multiple aneuploid embryos were delayed at the initiation of compaction (tSC; median 85.1 hours post insemination (hpi); P=0.02) and the time to reach full blastocyst stage (tB; median 110.9hpi, P=0.01) compared with euploid embryos (tSC median 79.7 hpi, tB median 105.9 hpi). Embryos having single or multiple aneuploidy (median 103.4 hpi, P=0.004 and 101.9 hpi, P=0.006, respectively) had delayed initiation of blastulation compared with euploid embryos (median 95.1hpi). No significant differences were observed in first or second cell-cycle length, synchrony of the second or third cell cycles, duration of blastulation, multinucleation at the 2-cell stage and irregular division patterns between euploid and aneuploid embryos. This non-invasive model for ploidy classification may be used to avoid selecting embryos with high risk of aneuploidy while selecting those with reduced risk.


Assuntos
Algoritmos , Aneuploidia , Blastocisto/fisiologia , Transferência Embrionária/métodos , Desenvolvimento Embrionário/fisiologia , Modelos Estatísticos , Biópsia , Blastocisto/citologia , Estudos de Coortes , Desenvolvimento Embrionário/genética , Feminino , Humanos , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único/genética , Polimorfismo de Nucleotídeo Único/fisiologia , Estudos Retrospectivos , Fatores de Risco , Trofoblastos/patologia
20.
Am J Trop Med Hyg ; 87(6): 1022-7, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23045249

RESUMO

Human immunodeficiency virus (HIV) is common in pregnant women in many malaria-endemic regions and may increase risk of placental parasitemia. Placental malaria is more common in primigravidae than multigravidae, but the relationship between HIV and malaria across gravidities is not well characterized. We recruited pregnant Malawian women during the second trimester and followed them until delivery. Parasitemia was assessed at enrollment, follow-up visits, and delivery, when placental blood was sampled. There was no difference in risk of parasitemia between HIV-positive and HIV-negative primigravidae. Among multigravidae, HIV-infected women had greater than twice the risk of parasitemia as HIV-uninfected women throughout follow-up. Human immunodeficiency virus was also associated with more frequent peripheral parasitemia in multigravidae but not primigravidae. Both HIV and primigravid status were independently associated with higher peripheral and placental parasite densities. Although risk of parasitemia is lower in multigravidae than primigravidae, the HIV effect on risk of malaria is more pronounced in multigravidae.


Assuntos
Infecções por HIV/complicações , Malária Falciparum/complicações , Paridade , Complicações Infecciosas na Gravidez/parasitologia , Complicações Infecciosas na Gravidez/virologia , Estudos de Coortes , Feminino , Infecções por HIV/epidemiologia , Humanos , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Malaui/epidemiologia , Análise Multivariada , Parasitemia , Plasmodium falciparum , Gravidez , Fatores de Risco
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