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1.
Nature ; 602(7895): 106-111, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34883497

RESUMEN

Host genetic factors can confer resistance against malaria1, raising the question of whether this has led to evolutionary adaptation of parasite populations. Here we searched for association between candidate host and parasite genetic variants in 3,346 Gambian and Kenyan children with severe malaria caused by Plasmodium falciparum. We identified a strong association between sickle haemoglobin (HbS) in the host and three regions of the parasite genome, which is not explained by population structure or other covariates, and which is replicated in additional samples. The HbS-associated alleles include nonsynonymous variants in the gene for the acyl-CoA synthetase family member2-4 PfACS8 on chromosome 2, in a second region of chromosome 2, and in a region containing structural variation on chromosome 11. The alleles are in strong linkage disequilibrium and have frequencies that covary with the frequency of HbS across populations, in particular being much more common in Africa than other parts of the world. The estimated protective effect of HbS against severe malaria, as determined by comparison of cases with population controls, varies greatly according to the parasite genotype at these three loci. These findings open up a new avenue of enquiry into the biological and epidemiological significance of the HbS-associated polymorphisms in the parasite genome and the evolutionary forces that have led to their high frequency and strong linkage disequilibrium in African P. falciparum populations.


Asunto(s)
Genotipo , Hemoglobina Falciforme/genética , Adaptación al Huésped/genética , Malaria Falciparum/sangre , Malaria Falciparum/parasitología , Parásitos/genética , Plasmodium falciparum/genética , Alelos , Animales , Niño , Femenino , Gambia/epidemiología , Genes Protozoarios/genética , Humanos , Kenia/epidemiología , Desequilibrio de Ligamiento , Malaria Falciparum/epidemiología , Masculino , Polimorfismo Genético
2.
PLoS Pathog ; 19(6): e1011442, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37307293

RESUMEN

A signature remains elusive of naturally-acquired immunity against Plasmodium falciparum. We identified P. falciparum in a 14-month cohort of 239 people in Kenya, genotyped at immunogenic parasite targets expressed in the pre-erythrocytic (circumsporozoite protein, CSP) and blood (apical membrane antigen 1, AMA-1) stages, and classified into epitope type based on variants in the DV10, Th2R, and Th3R epitopes in CSP and the c1L region of AMA-1. Compared to asymptomatic index infections, symptomatic malaria was associated with reduced reinfection by parasites bearing homologous CSP-Th2R (adjusted hazard ratio [aHR]:0.63; 95% CI:0.45-0.89; p = 0.008) CSP-Th3R (aHR:0.71; 95% CI:0.52-0.97; p = 0.033), and AMA-1 c1L (aHR:0.63; 95% CI:0.43-0.94; p = 0.022) epitope types. The association of symptomatic malaria with reduced hazard of homologous reinfection was strongest for rare epitope types. Symptomatic malaria provides more durable protection against reinfection with parasites bearing homologous epitope types. The phenotype represents a legible molecular epidemiologic signature of naturally-acquired immunity by which to identify new antigen targets.


Asunto(s)
Vacunas contra la Malaria , Malaria Falciparum , Malaria , Parásitos , Animales , Plasmodium falciparum/metabolismo , Reinfección , Proteínas Protozoarias/metabolismo , Malaria/parasitología , Malaria Falciparum/parasitología , Antígenos de Protozoos , Epítopos/genética , Anticuerpos Antiprotozoarios/metabolismo
3.
J Infect Dis ; 229(4): 969-978, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-37713614

RESUMEN

BACKGROUND: People with suspected malaria may harbor Plasmodium falciparum undetected by rapid diagnostic test (RDT). The impact of these subpatent infections on the risk of developing clinical malaria is not fully understood. METHODS: We analyzed subpatent P. falciparum infections using a longitudinal cohort in a high-transmission site in Kenya. Weighted Kaplan-Meier models estimated the risk difference (RD) for clinical malaria during the 60 days following a symptomatic subpatent infection. Stratum-specific estimates by age and transmission season assessed modification. RESULTS: Over 54 months, we observed 1128 symptomatic RDT-negative suspected malaria episodes, of which 400 (35.5%) harbored subpatent P. falciparum. Overall, the 60-day risk of developing clinical malaria was low following all episodes (8.6% [95% confidence interval, 6.7%-10.4%]). In the low-transmission season, the risk of clinical malaria was slightly higher in those with subpatent infection, whereas the opposite was true in the high-transmission season (low-transmission season RD, 2.3% [95% confidence interval, .4%-4.2%]; high-transmission season RD, -4.8% [-9.5% to -.05%]). CONCLUSIONS: The risk of developing clinical malaria among people with undetected subpatent infections is low. A slightly elevated risk in the low-transmission season may merit alternate management, but RDTs identify clinically relevant infections in the high-transmission season.


Asunto(s)
Malaria Falciparum , Malaria , Humanos , Plasmodium falciparum , Kenia/epidemiología , Riesgo , Pruebas Diagnósticas de Rutina/métodos , Prevalencia
4.
Regul Toxicol Pharmacol ; 150: 105629, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38657894

RESUMEN

The world's hunger for novel food ingredients drives the development of safe, sustainable, and nutritious novel food products. For foods containing novel proteins, potential allergenicity of the proteins is a key safety consideration. One such product is a fungal biomass obtained from the fermentation of Rhizomucor pusillus. The annotated whole genome sequence of this strain was subjected to sequence homology searches against the AllergenOnline database (sliding 80-amino acid windows and full sequence searches). In a stepwise manner, proteins were designated as potentially allergenic and were further compared to proteins from commonly consumed foods and from humans. From the sliding 80-mer searches, 356 proteins met the conservative >35% Codex Alimentarius threshold, 72 of which shared ≥50% identity over the full sequence. Although matches were identified between R. pusillus proteins and proteins from allergenic food sources, the matches were limited to minor allergens from these sources, and they shared a greater degree of sequence homology with those from commonly consumed foods and human proteins. Based on the in silico analysis and a literature review for the source organism, the risk of allergenic cross-reactivity of R. pusillus is low.


Asunto(s)
Alérgenos , Biomasa , Rhizomucor , Alérgenos/inmunología , Rhizomucor/inmunología , Humanos , Ingredientes Alimentarios , Simulación por Computador , Hipersensibilidad a los Alimentos/inmunología , Proteínas Fúngicas/inmunología
5.
Emerg Infect Dis ; 29(11): 2385-2387, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37779220

RESUMEN

In urban and rural areas of Turkana County, Kenya, we found that 2% of household members of patients with Plasmodium falciparum infections were infected with P. vivax. Enhanced surveillance of P. vivax and increased clinical resources are needed to inform control measures and identify and manage P. vivax infections.


Asunto(s)
Malaria Falciparum , Malaria Vivax , Humanos , Plasmodium vivax , Kenia/epidemiología , Plasmodium falciparum , Prevalencia , Malaria Vivax/epidemiología , Malaria Falciparum/epidemiología
6.
PLoS Pathog ; 17(6): e1009659, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34115805

RESUMEN

Sickle-trait hemoglobin protects against severe Plasmodium falciparum malaria. Severe malaria is governed in part by the expression of the Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) that are encoded by var genes, specifically those variants that bind Endothelial Protein C Receptor (EPCR). In this study, we investigate the effect of sickle-trait on parasite var gene expression and function in vitro and in field-collected parasites. We mapped var gene reads generated from RNA sequencing in parasite cultures in normal and sickle-cell trait blood throughout the asexual lifecycle. We investigated sickle-trait effect on PfEMP1 interactions with host receptors CD36 and EPCR using static adhesion assays and flow cytometry. Var expression in vivo was compared by assembling var domains sequenced from total RNA in parasites infecting Malian children with HbAA and HbAS. Sickle-trait did not alter the abundance or type of var gene transcripts in vitro, nor the abundance of overall transcripts or of var functional domains in vivo. In adhesion assays using recombinant host receptors, sickle-trait reduced adhesion by 73-86% to CD36 and 83% to EPCR. Similarly, sickle-trait reduced the surface expression of EPCR-binding PfEMP1. In conclusion, Sickle-cell trait does not directly affect var gene transcription but does reduce the surface expression and function of PfEMP1. This provides a direct mechanism for protection against severe malaria conferred by sickle-trait hemoglobin. Trial Registration: ClinicalTrials.gov Identifier: NCT02645604.


Asunto(s)
Hemoglobina Falciforme/metabolismo , Malaria Falciparum/genética , Plasmodium falciparum/genética , Proteínas Protozoarias/genética , Antígenos CD36/metabolismo , Receptor de Proteína C Endotelial/metabolismo , Eritrocitos/parasitología , Hemoglobina Falciforme/genética , Humanos , Malaria Falciparum/metabolismo , Rasgo Drepanocítico/genética , Rasgo Drepanocítico/metabolismo
7.
J Infect Dis ; 225(11): 2002-2010, 2022 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-34888658

RESUMEN

BACKGROUND: Malaria can have deleterious effects early in pregnancy, during placentation. However, malaria testing and treatment are rarely initiated until the second trimester, leaving pregnancies unprotected in the first trimester. To inform potential early intervention approaches, we sought to identify clinical and demographic predictors of first-trimester malaria. METHODS: We prospectively recruited women from sites in the Democratic Republic of the Congo (DRC), Kenya, and Zambia who participated in the ASPIRIN (Aspirin Supplementation for Pregnancy Indicated risk Reduction In Nulliparas) trial. Nulliparous women were tested for first-trimester Plasmodium falciparum infection by quantitative polymerase chain reaction. We evaluated predictors using descriptive statistics. RESULTS: First-trimester malaria prevalence among 1513 nulliparous pregnant women was 6.3% (95% confidence interval [CI], 3.7%-8.8%] in the Zambian site, 37.8% (95% CI, 34.2%-41.5%) in the Kenyan site, and 62.9% (95% CI, 58.6%-67.2%) in the DRC site. First-trimester malaria was associated with shorter height and younger age in Kenyan women in site-stratified analyses, and with lower educational attainment in analyses combining all 3 sites. No other predictors were identified. CONCLUSIONS: First-trimester malaria prevalence varied by study site in sub-Saharan Africa. The absence of consistent predictors suggests that routine parasite screening in early pregnancy may be needed to mitigate first-trimester malaria in high-prevalence settings.


Asunto(s)
Malaria Falciparum , Malaria , Aspirina/uso terapéutico , República Democrática del Congo/epidemiología , Femenino , Humanos , Kenia/epidemiología , Malaria/epidemiología , Malaria Falciparum/parasitología , Plasmodium falciparum , Embarazo , Primer Trimestre del Embarazo , Prevalencia , Zambia/epidemiología
8.
PLoS Med ; 19(10): e1004104, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36215323

RESUMEN

BACKGROUND: Children with sickle cell anemia (SCA) in areas of Africa with endemic malaria transmission are commonly prescribed malaria chemoprevention. Chemoprevention regimens vary between countries, and the comparative efficacy of prevention regimens is largely unknown. METHODS AND FINDINGS: We enrolled Kenyan children aged 1 to 10 years with homozygous hemoglobin S (HbSS) in a randomized, open-label trial conducted between January 23, 2018, and December 15, 2020, in Homa Bay, Kenya. Children were assigned 1:1:1 to daily Proguanil (the standard of care), monthly sulfadoxine/pyrimethamine-amodiaquine (SP-AQ), or monthly dihydroartemisinin-piperaquine (DP) and followed monthly for 12 months. The primary outcome was the cumulative incidence of clinical malaria at 12 months, and the main secondary outcome was the cumulative incidence of painful events by self-report. Secondary outcomes included other parasitologic, hematologic, and general events. Negative binomial models were used to estimate incidence rate ratios (IRRs) per patient-year (PPY) at risk relative to Proguanil. The primary analytic population was the As-Treated population. A total of 246 children were randomized to daily Proguanil (n = 81), monthly SP-AQ (n = 83), or monthly DP (n = 82). Overall, 53.3% (n = 131) were boys and the mean age was 4.6 ± 2.5 years. The clinical malaria incidence was 0.04 episodes/PPY; relative to the daily Proguanil group, incidence rates were not significantly different in the monthly SP-AQ (IRR: 3.05, 95% confidence interval [CI]: 0.36 to 26.14; p = 0.39) and DP (IRR: 1.36, 95% CI: 0.21 to 8.85; p = 0.90) groups. Among secondary outcomes, relative to the daily Proguanil group, the incidence of painful events was not significantly different in the monthly SP-AQ and DP groups, while monthly DP was associated with a reduced rate of dactylitis (IRR: 0.47; 95% CI: 0.23 to 0.96; p = 0.038). The incidence of Plasmodium falciparum infection relative to daily Proguanil was similar in the monthly SP-AQ group (IRR 0.46; 95% CI: 0.17 to 1.20; p = 0.13) but reduced with monthly DP (IRR 0.21; 95% CI: 0.08 to 0.56; p = 0.002). Serious adverse events were common and distributed between groups, although compared to daily Proguanil (n = 2), more children died receiving monthly SP-AQ (n = 7; hazard ratio [HR] 5.44; 95% CI: 0.92 to 32.11; p = 0.064) but not DP (n = 1; HR 0.61; 95% CI 0.04 to 9.22; p = 0.89), although differences did not reach statistical significance for either SP-AQ or DP. Study limitations include the unexpectedly limited transmission of P. falciparum in the study setting, the high use of hydroxyurea, and the enhanced supportive care for trial participants, which may limit generalizability to higher-transmission settings where routine sickle cell care is more limited. CONCLUSIONS: In this study with limited malaria transmission, malaria chemoprevention in Kenyan children with SCA with monthly SP-AQ or DP did not reduce clinical malaria, but DP was associated with reduced dactylitis and P. falciparum parasitization. Pragmatic studies of chemoprevention in higher malaria transmission settings are warranted. TRIAL REGISTRATION: clinicaltrials.gov (NCT03178643). Pan-African Clinical Trials Registry: PACTR201707002371165.


Asunto(s)
Anemia de Células Falciformes , Antimaláricos , Artemisininas , Malaria Falciparum , Malaria , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Amodiaquina/uso terapéutico , Anemia de Células Falciformes/tratamiento farmacológico , Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , Quimioprevención , Combinación de Medicamentos , Hidroxiurea , Kenia/epidemiología , Malaria/epidemiología , Malaria/prevención & control , Malaria Falciparum/epidemiología , Malaria Falciparum/prevención & control , Proguanil/uso terapéutico , Pirimetamina/uso terapéutico , Sulfadoxina/uso terapéutico
9.
Malar J ; 21(1): 39, 2022 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-35135546

RESUMEN

BACKGROUND: In 2012, seasonal malaria chemoprevention (SMC) was recommended as policy for malaria control by the World Health Organization (WHO) in areas of highly seasonal malaria transmission across the Sahel sub-region in Africa along with monitoring of drug resistance. We assessed the long-term impact of SMC on Plasmodium falciparum resistance to sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) over a 3-year period of SMC implementation in the health district of Ouelessebougou, Mali. METHODS: In 8 randomly selected sub-districts of Ouelessebougou, Mali, children aged 0-5 years were randomly selected during cross-sectional surveys at baseline (August 2014) and 1, 2 and 3 years post-SMC, at the beginning and end of the malaria transmission season. Blood smears and blood spots on filter paper were obtained and frequencies of mutation in P. falciparum genes related to resistance to SP and AQ (Pfdhfr, Pfdhps, Pfmdr1, and Pfcrt) were assessed by PCR amplification on individual samples and PCR amplification followed by deep sequencing on pooled (by site and year) samples. RESULTS: At each survey, approximately 50-100 individual samples were analysed by PCR amplification and a total of 1,164 samples were analysed by deep sequencing with an average read depth of 18,018-36,918 after pooling by site and year. Most molecular markers of resistance did not increase in frequency over the period of study (2014-2016). After 3 years of SMC, the frequencies of Pfdhps 540E, Pfdhps 437G and Pfcrt K76T remained similar compared to baseline (4.0 vs 1.4%, p = 0.41; 74.5 vs 64.6%, p = 0.22; 71.3 vs 67.4%, p = 0.69). Nearly all samples tested carried Pfdhfr 59R, and this proportion remained similar 3 years after SMC implementation (98.8 vs 100%, p = 1). The frequency of Pfmdr1 N86Y increased significantly over time from 5.6% at baseline to 18.6% after 3 years of SMC (p = 0.016). Results of pooled analysis using deep sequencing were consistent with those by individual analysis with standard PCR, but also indicated for the first time the presence of mutations at the Pfdhps A581G allele at a frequency of 11.7% after 2 years of SMC, as well as the Pfdhps I431V allele at frequencies of 1.6-9.3% following 1 and 2 years of SMC, respectively. CONCLUSION: Two and 3 years of SMC implementation were associated with increased frequency of the Pfmdr1 N86Y mutation but not Pfdhps 540E, Pfdhps 437G and Pfcrt K76T. The first-time detection of the Pfdhps haplotype bearing the I431V and A581G mutations in Mali, even at low frequency, warrants further long-term surveillance.


Asunto(s)
Antimaláricos , Malaria Falciparum , Malaria , Amodiaquina/farmacología , Antimaláricos/farmacología , Antimaláricos/uso terapéutico , Quimioprevención , Niño , Preescolar , Estudios Transversales , Combinación de Medicamentos , Resistencia a Medicamentos/genética , Humanos , Lactante , Recién Nacido , Malaria/tratamiento farmacológico , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/prevención & control , Malí , Plasmodium falciparum/genética , Pirimetamina/farmacología , Estaciones del Año , Sulfadoxina/farmacología
10.
BMC Public Health ; 22(1): 1689, 2022 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-36068516

RESUMEN

BACKGROUND: Low adoption of effective health technologies increases illness morbidity and mortality worldwide. In the case of malaria, effective tools such as malaria rapid diagnostic tests (RDTs) and artemisinin-combination therapies (ACTs) are both under-used and used inappropriately. Individuals' confidence in RDTs and ACTs likely affects the uptake of these tools. METHODS: In a cohort of 36 households (280 individuals) in Western Kenya observed for 30 months starting in June 2017, we examined if experience with RDTs and ACTs changes people's beliefs about these technologies and how those beliefs affect treatment behavior. Household members requested a free RDT from the study team any time they suspected a malaria illness, and positive RDT results were treated with a free ACT. We conducted annual, monthly, and sick visit surveys to elicit beliefs about the accuracy of malaria RDT results and the effectiveness of ACTs. Beliefs were elicited on a 5-point Likert scale from "very unlikely" to "very likely." RESULTS: Over the study period, the percentage of survey respondents that said a hypothetical negative RDT result was "very likely" to be correct increased from approximately 55% to 75%. Controlling for initial beliefs, people who had been tested at least once with an RDT in the past year had 3.6 times higher odds (95% CI [1 1.718 7.679], P = 0.001) of saying a negative RDT was "very likely" to be correct. Confidence in testing was associated with treatment behavior: those who believed a negative RDT was "very likely" to be correct had 1.78 times higher odds (95% CI [1.079 2.934], P = 0.024) of adhering to a negative RDT result (by not taking ACTs) than those who were less certain about the accuracy of negative RDTs. Adherence to a negative test also affected subsequent beliefs: controlling for prior beliefs, those who had adhered to their previous test result had approximately twice the odds (OR = 2.19, 95% CI [1.661 2.904], P < 0.001) of saying that a hypothetical negative RDT was "very likely" to be correct compared to those who had not adhered. CONCLUSIONS: Our results suggest that greater experience with RDTs can not only increase people's confidence in their accuracy but also improve adherence to the test result.


Asunto(s)
Malaria , Tecnología Biomédica , Pruebas Diagnósticas de Rutina/métodos , Composición Familiar , Humanos , Kenia , Malaria/diagnóstico , Malaria/tratamiento farmacológico , Encuestas y Cuestionarios
11.
Rev Relig Res ; 64(4): 1001-1003, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-38625369

RESUMEN

[This corrects the article DOI: 10.1007/s13644-021-00480-z.].

12.
Rev Relig Res ; 64(4): 883-905, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36589525

RESUMEN

Background: The COVID-19 pandemic introduced disruption that crossed sectors, borders, and disciplinary boundaries. Among faith communities and religious leaders, numerous commentators have observed technological innovations in response to physical gathering disruptions. We outline a form of pandemic spiritual leadership that supports faith communities beyond digital innovation by combining original empirical research and a novel conceptual framework. Purpose: Our project examined innovation through a comparative study of how faith leaders adapt religious practices during a time of disruption. While existing research on congregational responses to COVID-19 has documented sustained technological innovation, our research argues that technological innovation is only one feature of a broader catalog of innovative practices. Methods: To generate a trans-national sample, we used purposive sampling in two distinct locations, Pacific Northwest United States and Aotearoa New Zealand. Although separated by culture and geography, a purposeful sample across these two contexts illustrated how spiritual leaders in post-Christian contexts similarly responded to the pandemic crisis. The research involved semi-structured interviewing of nineteen faith leaders from seventeen communities we observed undertaking creative adaption. A trans-national selection deepened understandings of the dynamism of the unfolding pandemic and how limits, experienced differently in diverse contexts, can be generative. Results: Our study identified six organizing practices: blessing, walking, slowing, place-making, connecting, and localizing care. We demonstrate how the presence of God is cultivated amid local letterboxes and neighborhood crossroads and argue for an intensification of the local as markers of pandemic spiritual leadership. These interrelated spiritual practices express features of Michel de Certeau's "pedestrian utterings," Joseph Schumpeter's "creative recombination" and Pierre Bourdieu's social theory. Working with Certeau, we describe pedestrian utterings as historic church practices reframed as everyday local practices. Working with Schumpeter, we describe how the six practices and the language of innovation used by participants express creative recombinations. Working with Bourdieu, we consider how disruption realigns social fields, including between individuals, congregations, and broader communities. Finally, amid social distancing, congregations proved to be an anchor in resourcing this pandemic spiritual leadership. Conclusions and Implications: These four theoretical foci and six localizing practices provide a conceptual framework for future research into spiritual practices and religious leadership in the wake of a crisis. Confinements in space and movement can be generative of spiritual practice. For religious leaders and organizations, the research informs the cultivation of concrete practices that can encourage communities of care as part of crisis preparation. For scholars and religious practitioners alike, while pandemics enforce social separation, pandemic spiritual leadership combines attention to the local and the particular, as new forms of in-place practice emerge to sustain faith communities.

13.
Clin Infect Dis ; 73(7): 1176-1184, 2021 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-33904907

RESUMEN

BACKGROUND: Repeated exposure to malaria infections could protect against symptomatic progression as people develop adaptive immunity to infections acquired over time. METHODS: We investigated how new, recurrent, and persistent Plasmodium falciparum infections were associated with the odds of developing symptomatic compared with asymptomatic malaria. Using a 14-month longitudinal cohort in Western Kenya, we used amplicon deep sequencing of 2 polymorphic genes (pfama1 and pfcsp) to assess overlap of parasite genotypes (represented by haplotypes) acquired within an individual's successive infections. We hypothesized infections with novel haplotypes would increase the odds of symptomatic malaria. RESULTS: After excluding initial infections, we observed 534 asymptomatic and 88 symptomatic infections across 186 people. We detected 109 pfcsp haplotypes, and each infection was classified as harboring novel, recurrent, or persistent haplotypes. Incident infections with only new haplotypes had higher odds of symptomatic malaria when compared with infections with only recurrent haplotypes [odds ratio (OR): 3.24; 95% confidence interval (CI), 1.20-8.78], but infections with both new and recurrent haplotypes (OR: 0.64; 95% CI: 0.15-2.65) did not. Assessing persistent infections, those with mixed (persistent with new or recurrent) haplotypes (OR: 0.77; 95% CI: 0.21-2.75) had no association with symptomatic malaria compared with infections with only persistent haplotypes. Results were similar for pfama1. CONCLUSIONS: These results confirm that incident infections with only novel haplotypes were associated with increased odds of symptomatic malaria compared with infections with only recurrent haplotypes but this relationship was not seen when haplotypes persisted over time in consecutive infections.


Asunto(s)
Malaria Falciparum , Plasmodium falciparum , Infecciones Asintomáticas , Genotipo , Humanos , Kenia/epidemiología , Estudios Longitudinales , Malaria Falciparum/epidemiología , Plasmodium falciparum/genética
14.
PLoS Med ; 18(9): e1003701, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34582452

RESUMEN

BACKGROUND: Annually 125 million pregnancies are at risk of malaria infection. However, the impact of exposure to malaria in pregnancy on neurodevelopment in children is not well understood. We hypothesized that malaria in pregnancy and associated maternal immune activation result in neurodevelopmental delay in exposed offspring. METHODS AND FINDINGS: Between April 2014 and April 2015, we followed 421 Malawian mother-baby dyads (median [IQR] maternal age: 21 [19, 28] years) who were previously enrolled (median [IQR] gestational age at enrollment: 19.7 [17.9, 22.1] weeks) in a randomized controlled malaria prevention trial with 5 or 6 scheduled assessments of antenatal malaria infection by PCR. Children were evaluated at 12, 18, and/or 24 months of age with cognitive tests previously validated in Malawi: the Malawi Developmental Assessment Tool (MDAT) and the MacArthur-Bates Communicative Development Inventories (MCAB-CDI). We assessed the impact of antenatal malaria (n [%] positive: 240 [57.3]), placental malaria (n [%] positive: 112 [29.6]), and maternal immune activation on neurocognitive development in children. Linear mixed-effects analysis showed that children exposed to antenatal malaria between 33 and 37 weeks gestation had delayed language development across the 2-year follow-up, as measured by MCAB-CDI (adjusted beta estimate [95% CI], -7.53 [-13.04, -2.02], p = 0.008). Maternal immune activation, characterized by increased maternal sTNFRII concentration, between 33 and 37 weeks was associated with lower MCAB-CDI language score (adjusted beta estimate [95% CI], -8.57 [-13.09, -4.06], p < 0.001). Main limitations of this study include a relatively short length of follow-up and a potential for residual confounding that is characteristic of observational studies. CONCLUSIONS: This mother-baby cohort presents evidence of a relationship between malaria in pregnancy and neurodevelopmental delay in offspring. Malaria in pregnancy may be a modifiable risk factor for neurodevelopmental injury independent of birth weight or prematurity. Successful interventions to prevent malaria during pregnancy may reduce the risk of neurocognitive delay in children.


Asunto(s)
Trastornos del Desarrollo del Lenguaje/etiología , Malaria/fisiopatología , Trastornos Neurocognitivos/etiología , Complicaciones Infecciosas del Embarazo , Estudios de Cohortes , Femenino , Humanos , Lactante , Transmisión Vertical de Enfermedad Infecciosa , Malaria/embriología , Malaria/inmunología , Malaui , Masculino , Trastornos Neurocognitivos/prevención & control , Pruebas Neuropsicológicas , Embarazo , Complicaciones Infecciosas del Embarazo/inmunología
15.
Pediatr Dev Pathol ; 24(6): 513-522, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34176359

RESUMEN

BACKGROUND: Diagnosis of non-esophageal eosinophilic gastrointestinal disorders requires quantification of tissue eosinophils. Our objective was to evaluate eosinophil peroxidase (EPX) immunohistochemistry (IHC) as a method for histologic diagnosis of eosinophilic gastritis (EG) and eosinophilic duodenitis (EoD). METHODS: We performed a retrospective analysis of biopsies from pediatric EG/EoD cases and controls. Subjects with EG or EoD had ≥30 eosinophils per high power field (eos/hpf) in ≥5 hpf in the stomach and/or ≥3 hpf in the duodenum, respectively. Controls had no histopathologic diagnosis recorded. Tissue eosinophil counts were assessed by hematoxylin & eosin stains. EPX stains were assessed using a unique histopathologic scoring system. Slides were digitized and EPX+ staining area/mm2 was quantified by image analysis. RESULTS: Twenty-six EG/EoD cases and 40 controls were analyzed. EPX scores and EPX/mm2 levels were markedly elevated in EG/EoD (p ≤ 0.0001). Eosinophil density (eos/mm2) correlated strongly with EPX scores and EPX/mm2 levels in the stomach (r ≥ 0.77) and moderately with EPX scores and EPX/mm2 levels in the duodenum (r ≥ 0.52); (p < 0.0001). EPX quantification identified EG/EoD subjects with high diagnostic accuracy (EPX score: AUC = 1 for EG and EoD; EPX/mm2: AUC = 0.98 (95%CI 0.96-1) for EG, AUC = 0.91 (95%CI 0.81-1) for EoD). CONCLUSION: EPX-based assessment of eosinophilic inflammation may facilitate automated histologic diagnosis.


Asunto(s)
Enteritis , Esofagitis Eosinofílica , Biopsia , Niño , Peroxidasa del Eosinófilo , Eosinofilia , Eosinófilos , Gastritis , Humanos , Inmunohistoquímica , Estudios Retrospectivos
16.
Am J Dermatopathol ; 43(12): e259-e262, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-33795555

RESUMEN

ABSTRACT: A 15-year-old boy presented to the pediatric dermatology department with long-standing patch stage CD8+ mycosis fungoides and subsequent development of recurrent pityriasis lichenoides et varioliformis acuta eruptions. There have been rare reports of patients with chronic, recalcitrant pityriasis lichenoides developing mycosis fungoides, but we believe this to be the second case of mycosis fungoides preceding a diagnosis of pityriasis lichenoides, and the first case reported in the pediatric population.


Asunto(s)
Micosis Fungoide/complicaciones , Pitiriasis Liquenoide/complicaciones , Neoplasias Cutáneas/complicaciones , Adolescente , Humanos , Masculino
17.
Molecules ; 26(9)2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-34068706

RESUMEN

Enzymes have been exploited by humans for thousands of years in brewing and baking, but it is only recently that biocatalysis has become a mainstream technology for synthesis. Today, enzymes are used extensively in the manufacturing of pharmaceuticals, food, fine chemicals, flavors, fragrances and other products. Enzyme immobilization technology has also developed in parallel as a means of increasing enzyme performance and reducing process costs. The aim of this review is to present and discuss some of the more recent promising technical developments in enzyme immobilization, including the supports used, methods of fabrication, and their application in synthesis. The review highlights new support technologies such as the use of well-established polysaccharides in novel ways, the use of magnetic particles, DNA, renewable materials and hybrid organic-inorganic supports. The review also addresses how immobilization is being integrated into developing biocatalytic technology, for example in flow biocatalysis, the use of 3D printing and multi-enzymatic cascade reactions.


Asunto(s)
Biocatálisis , Enzimas Inmovilizadas/metabolismo , Nanopartículas de Magnetita/química , Estructuras Metalorgánicas/química , Impresión Tridimensional , Ingeniería de Proteínas
18.
J Infect Dis ; 221(7): 1176-1184, 2020 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-31665350

RESUMEN

BACKGROUND: Malaria morbidity is highly overdispersed in the population. Fine-scale differences in mosquito exposure may partially explain this heterogeneity in individual malaria outcomes. METHODS: In 38 households we explored the effect of household-level mosquito exposure and individual insecticide-treated net (ITN) use on relative risk (RR) of confirmed malaria. We conducted monthly active surveillance (n = 254; 2624 person-months) and weekly mosquito collection (2092 household-days of collection), and used molecular techniques to confirm human blood feeding and exposure to infectious mosquitoes. RESULTS: Of 1494 female Anopheles (89.8% Anopheles gambiae sensu lato), 88.3% were fed, 51.9% had a human blood meal, and 9.2% were sporozoite infected. In total, 168 laboratory-confirmed malaria episodes were reported (incidence rate 0.064 episodes per person-month at risk; 95% confidence interval [CI], .055-.074). Malaria risk was directly associated with exposure to sporozoite-infected mosquitoes (RR, 1.24; 95% CI, 1.11-1.38). No direct effect was measured between ITN use and malaria morbidity; however, ITN use did moderate the effect of mosquito exposure on morbidity. CONCLUSIONS: Malaria risk increases linearly with vector density and feeding success for persons with low ITN use. In contrast, malaria risk among high ITN users is consistently low and insensitive to variation in mosquito exposure.


Asunto(s)
Anopheles/parasitología , Exposición a Riesgos Ambientales/estadística & datos numéricos , Mosquiteros Tratados con Insecticida/estadística & datos numéricos , Malaria , Mosquitos Vectores/parasitología , Adolescente , Adulto , Animales , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Kenia , Estudios Longitudinales , Malaria/epidemiología , Malaria/prevención & control , Malaria/transmisión , Adulto Joven
19.
J Infect Dis ; 222(4): 661-669, 2020 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-32221555

RESUMEN

BACKGROUND: Sulfadoxine-pyrimethamine (SP) is used as intermittent preventive therapy in pregnancy (IPTp) for malaria in sub-Saharan Africa. The resistance marker dhps A581G has been associated with reduced IPTp-SP efficacy and enhanced morbidity in SP recipients. METHODS: We measured SP-resistance allele frequencies in Malawian women participating in a trial comparing IPTp with SP against intermittent screening by rapid diagnostic tests (ISTp). We genotyped polymerase chain reaction-detected parasites using deep sequencing of SP-resistance alleles. RESULTS: Among 125 placental infections, A581G-bearing parasites were associated with reduced birth weight (mean difference [MD], 252 g; 95% confidence interval [CI], 46-457; P = .017). Relative to ISTp, IPTp-SP was associated with higher birth weights in women with wild-type parasites (MD, 116 g; 95% CI, -40 to 272; P = .142) and lower birth weights in women with A581G-bearing parasites (MD, 192 g; 95% CI, -264 to 648; P = .385) (Pinteraction = .033). Similar associations were noted on gestational age (Pinteraction = .075). Amongst only IPTp-SP recipients, relative to women who last received SP > 4 weeks before delivery, recent SP receipt was associated with lower birth weight in women with wild-type parasites (MD, 118 g; 95% CI, -376 to 139; P = .361) and higher birth weight in women with A581G-bearing parasites (MD, 783 g; 95% CI, -20 to 1586; P = .054) (Pinteraction = .005). CONCLUSIONS: The effectiveness in birth weight of IPTp-SP is compromised by A581G-bearing parasites, but there was no evidence that the adverse effects of these parasites are exacerbated by antenatal SP. ISRCTN REGISTRY: www.isrctn.com/ISRCTN69800930.


Asunto(s)
Resistencia a Medicamentos , Malaria Falciparum/prevención & control , Plasmodium falciparum/genética , Complicaciones Parasitarias del Embarazo/prevención & control , Pirimetamina/uso terapéutico , Sulfadoxina/uso terapéutico , Adolescente , Adulto , Animales , Peso al Nacer/efectos de los fármacos , Combinación de Medicamentos , Femenino , Genotipo , Humanos , Recién Nacido , Modelos Lineales , Malaria Falciparum/parasitología , Malaui , Mutación Missense , Plasmodium falciparum/aislamiento & purificación , Embarazo , Adulto Joven
20.
J Pediatr Psychol ; 45(5): 561-572, 2020 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-32374404

RESUMEN

OBJECTIVES: To characterize the types and magnitude of psychosocial burden present in caregivers who have a child with sickle cell disease (SCD) in Kenya and to identify predictors of caregiver psychosocial burden, including disease severity and financial hardship. METHODS: Primary caregivers (N = 103) of children aged 1-10 years diagnosed with SCD completed surveys assessing multiple domains of caregiver quality of life (QOL), adjustment to child illness, mental health, and financial hardship. Descriptive statistics characterize psychosocial burden, and linear models assess associations. RESULTS: On indicators of QOL, caregivers report multiple difficulties across most domains, including daily activities and physical, social, cognitive, and emotional well-being. Daily activities emerged as most burdensome. On indicators of parental adjustment to chronic illness, guilt and worry emerged as the greatest concern, followed by long-term uncertainty and unresolved sorrow and anger; relative to these, they reported higher levels of emotional resources. Financial hardship was high, as caregivers reported moderate to major financial losses due to the time spent caring for their child. General linear model analyses revealed that level of financial hardship was a significant predictor of all negative psychosocial outcomes. CONCLUSIONS: Results document that Kenyan caregivers of children with SCD experience difficulties across multiple domains of functioning and that financial difficulties are likely associated with psychosocial burden. Results can guide intervention development for caregivers of children with SCD in low-resource, global contexts.


Asunto(s)
Anemia de Células Falciformes , Cuidadores , Calidad de Vida , Cuidadores/psicología , Niño , Preescolar , Costo de Enfermedad , Familia , Femenino , Humanos , Lactante , Kenia , Encuestas y Cuestionarios
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