RESUMEN
INTRODUCTION: According to the World Health Organization, Microscopy is the gold standard for diagnosing malaria. However, the performance of this examination depends on the experience of the microscopist and the level of parasitemia. Thus, molecular biology detection of malaria could be an alternative technique. AIM: evaluate the contribution of molecular biology in detecting imported malaria. METHODS: This was a descriptive, prospective study, including all students, from the Monastir region, and foreigners, from countries endemic to malaria. The study period was from September 2020 to April 2021. Each subject was screened for malaria by three methods: direct microscopic detection of Plasmodium, detection of plasmodial antigens, and detection of plasmodial DNA by nested PCR. RESULTS: Among the 127 subjects screened, only one had a positive microscopic examination for Plasmodium falciparum. Among the 126 subjects with a negative microscopic examination, twelve students had a positive nested PCR result, i.e. 9.5%. Molecular sequencing allowed the identification of ten isolates of Plasmodium falciparum, one Plasmodium malariae and one Plasmodium ovale. Our study showed that the results of nested PCR agreed with those of microscopy in 90.6% of cases. CONCLUSION: Nested PCR seems more sensitive for the detection of low parasitemias. Hence the importance of including molecular biology as a malaria screening tool to ensure better detection of imported cases.
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Malaria , Reacción en Cadena de la Polimerasa , Humanos , Reacción en Cadena de la Polimerasa/métodos , Malaria/diagnóstico , Estudios Prospectivos , Femenino , Masculino , Adulto Joven , Adulto , Tamizaje Masivo/métodos , Tamizaje Masivo/normas , Plasmodium falciparum/aislamiento & purificación , Plasmodium falciparum/genética , Microscopía/métodos , Biología Molecular/métodos , Adolescente , Parasitemia/diagnóstico , Enfermedades Transmisibles Importadas/diagnóstico , Enfermedades Transmisibles Importadas/epidemiología , Enfermedades Transmisibles Importadas/parasitología , Túnez/epidemiología , Sensibilidad y Especificidad , ADN Protozoario/análisis , Plasmodium/aislamiento & purificación , Plasmodium/genética , Plasmodium malariae/aislamiento & purificación , Plasmodium malariae/genéticaRESUMEN
BACKGROUND: The Gran Chaco ecoregion is a well-known hotspot of several neglected tropical diseases (NTDs) including Chagas disease, soil-transmitted helminthiasis and multiparasitic infections. Interspecific interactions between parasite species can modify host susceptibility, pathogenesis and transmissibility through immunomodulation. Our objective was to test the association between human co-infection with intestinal parasites and host parasitaemia, infectiousness to the vector and immunological profiles in Trypanosoma cruzi-seropositive individuals residing in an endemic region of the Argentine Chaco. METHODS: We conducted a cross-sectional serological survey for T. cruzi infection along with an intestinal parasite survey in two adjacent rural villages. Each participant was tested for T. cruzi and Strongyloides stercoralis infection by serodiagnosis, and by coprological tests for intestinal parasite detection. Trypanosoma cruzi bloodstream parasite load was determined by quantitative PCR (qPCR), host infectiousness by artificial xenodiagnosis and serum human cytokine levels by flow cytometry. RESULTS: The seroprevalence for T. cruzi was 16.1% and for S. stercoralis 11.5% (n = 87). We found 25.3% of patients with Enterobius vermicularis. The most frequent protozoan parasites were Blastocystis spp. (39.1%), Giardia lamblia (6.9%) and Cryptosporidium spp. (3.4%). Multiparasitism occurred in 36.8% of the examined patients. Co-infection ranged from 6.9% to 8.1% for T. cruzi-seropositive humans simultaneously infected with at least one protozoan or helminth species, respectively. The relative odds of being positive by qPCR or xenodiagnosis (i.e. infectious) of 28 T. cruzi-seropositive patients was eight times higher in people co-infected with at least one helminth species than in patients with no such co-infection. Trypanosoma cruzi parasite load and host infectiousness were positively associated with helminth co-infection in a multiple regression analysis. Interferon-gamma (IFN-γ) response, measured in relation to interleukin (IL)-4 among humans infected with T. cruzi only, was 1.5-fold higher than for T. cruzi-seropositive patients co-infected with helminths. The median concentration of IL-4 was significantly higher in T. cruzi-seropositive patients with a positive qPCR test than in qPCR-negative patients. CONCLUSIONS: Our results show a high level of multiparasitism and suggest that co-infection with intestinal helminths increased T. cruzi parasitaemia and upregulated the Th2-type response in the study patients.
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Enfermedad de Chagas , Coinfección , Helmintiasis , Parasitosis Intestinales , Trypanosoma cruzi , Humanos , Trypanosoma cruzi/inmunología , Trypanosoma cruzi/genética , Trypanosoma cruzi/aislamiento & purificación , Coinfección/parasitología , Coinfección/epidemiología , Coinfección/inmunología , Enfermedad de Chagas/epidemiología , Enfermedad de Chagas/complicaciones , Enfermedad de Chagas/parasitología , Enfermedad de Chagas/sangre , Enfermedad de Chagas/inmunología , Animales , Adulto , Estudios Transversales , Masculino , Femenino , Parasitosis Intestinales/epidemiología , Parasitosis Intestinales/parasitología , Parasitosis Intestinales/complicaciones , Parasitosis Intestinales/inmunología , Persona de Mediana Edad , Helmintiasis/complicaciones , Helmintiasis/parasitología , Helmintiasis/epidemiología , Helmintiasis/inmunología , Adulto Joven , Adolescente , Argentina/epidemiología , Estudios Seroepidemiológicos , Strongyloides stercoralis/inmunología , Strongyloides stercoralis/aislamiento & purificación , Parasitemia/parasitología , Parasitemia/epidemiología , Células Th2/inmunología , Niño , Estrongiloidiasis/epidemiología , Estrongiloidiasis/parasitología , Estrongiloidiasis/complicaciones , Estrongiloidiasis/inmunología , Estrongiloidiasis/sangre , Anciano , Citocinas/sangre , Anticuerpos Antiprotozoarios/sangreRESUMEN
Water frogs of the genus Pelophylax host a variety of parasites, from protozoa to helminths. Among the blood parasites, representatives of Apicomplexa, Trypanosoma and Nematoda show the highest prevalence. In this study, we focused on blood parasites of water frogs living in the Danube Delta, Romania. In total, 74 individuals of P. ridibundus and eight individuals of P. esculentus from six localities were examined. Blood parasites were detected microscopically and using a molecular marker (18S rDNA). 89.77% of frogs from all investigated localities were found to be infected with at least one parasitic group, specifically with haemogregarines (84.09%), nematodes (1.14%), and trypanosomes (63.64%). The parasitemia of haemogregarines and trypanosomes differed significantly among the studied locations. There was no statistically significant difference in parasitemia between male and female hosts. However, adults were found to have a significantly higher parasitemia in comparison with subadults infected with haemogregarines. Correlation between parasitemia and the body length of frogs infected with haemogregarines was also significant (r = 0.226). By comparing the 18S rDNA sequences with the corresponding GenBank sequences, Hepatozoon species identified in water frogs showed a close similarity (98.1-99.8%) to Hepatozoon magna. Trypanosomes showed the highest sequence similarity to Trypanosoma sp. isolate R10 clone L2-3, Trypanosoma ranarum, and Trypanosoma cobitis.
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Parasitemia , ARN Ribosómico 18S , Ranidae , Animales , Rumanía/epidemiología , Ranidae/parasitología , Masculino , Femenino , Parasitemia/veterinaria , Parasitemia/parasitología , Parasitemia/epidemiología , ARN Ribosómico 18S/análisis , Trypanosoma/aislamiento & purificación , Trypanosoma/clasificación , Trypanosoma/genética , Filogenia , Nematodos/aislamiento & purificación , Nematodos/clasificaciónRESUMEN
BACKGROUND: The current definition of severe malaria in non-endemic areas follows WHO criteria, which mainly target children in malaria-endemic areas, potentially misclassifying cases in non-endemic regions. We assessed the performance of a modified severe malaria classification criteria within our patient cohort. METHODS: A cohort study of patients managed for malaria in a non-endemic setting (2005-2023) was analyzed. We classified patients into severe malaria (SM) using WHO 2013 criteria except for hyperparasitemia, where 2 % threshold was applied. Patients with SM were distinguished as very severe malaria (VSM) when presenting at least one of the following conditions: parasitemia >10 %, pulmonary edema, impaired consciousness, seizures, renal failure, metabolic acidosis or hyperlactatemia, shock or hypoglycemia. In patients with SM and no criteria for VSM, less severe malaria (LSM) was defined by: 2-10 % parasitemia, hyperbilirubinemia, prostration, anemia or minor bleeding. The primary composite outcome was death or the need for a life-saving intervention, as analyzed in the three comparative groups. Secondary outcome was the prevalence of co-infections. RESULTS: Among 506 patients with malaria, 176 (34.8 %) presented with SM. A total of 37 (7.3 %) patients developed a life-threatening condition, namely death (n = 4) and/or the need for life-saving interventions (n = 34). All fatalities and 33 out of the 34 life-saving interventions occurred in the VSM group. Patients in LSM group did not develop any life-threatening conditions. As to co-infections, 28 (5.5 %) patients had a community-acquired co-infection, with no differences between groups (p = 0.763). CONCLUSIONS: Severity criteria definitions would benefit from a review when assessing patients with malaria in non-endemic areas. Within the spectrum of SM, patients reclassified as LSM have a low risk of developing a life-threatening condition and present low co-infection incidence and could benefit from management out of intensive care units and a restrictive use of empirical antibiotics.
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Malaria , Índice de Severidad de la Enfermedad , Humanos , Masculino , Femenino , Malaria/epidemiología , Malaria/diagnóstico , Malaria/complicaciones , Adulto , Persona de Mediana Edad , Estudios de Cohortes , Adolescente , Preescolar , Niño , Parasitemia/epidemiología , Adulto Joven , Coinfección/epidemiología , Anciano , LactanteRESUMEN
BACKGROUND: Dihydroartemisinin-piperaquine (DHP) recently showed superior effectiveness over sulfadoxine-pyrimethamine for malaria intermittent preventive treatment in pregnancy (IPTp). We investigated day 7 piperaquine pharmacokinetics and its therapeutic efficacy in preventing malaria during pregnancy. METHODS: Malaria-free (mRDT) pregnant women (n = 400) who received monthly IPTp-DHP were enrolled and followed till delivery. Day 7 Plasma piperaquine concentrations were determined after each IPTp dose using UPLC/MS/MS. IPTp outcomes (symptomatic malaria and parasitemia during pregnancy, placental malaria, and maternal malaria at delivery) were monitored. Linear mixed model and Cox regression were used to assess predictors of day 7 piperaquine concentration and treatment outcome, respectively. RESULTS: The incidences of symptomatic malaria and parasitemia during pregnancy per 100 person-year at risk were 2 and 33, respectively. The prevalence of histopathologically confirmed placental malaria and maternal malaria at delivery were 3% and 9.8%, respectively. Repeated monthly IPTp-DHP resulted in significantly increased day 7 plasma piperaquine concentration (p < 0.001). Following the 1st, 2nd, and 3rd monthly IPTp-DHP doses, the proportions of women with day 7 piperaquine concentration below the therapeutic threshold (< 30 ng/mL) were 6.1%, 4.1% and 3.6%, respectively. Factors such as maternal age, body weight and trimester were not significant predictors of day 7 piperaquine concentration. However, having a low day 7 piperaquine plasma concentration (< 30 ng/mL) was significantly associated with a higher risk of parasitemia during pregnancy (p = 0.004). CONCLUSION: Lower day 7 piperaquine plasma concentration is a risk factor for parasitemia during pregnancy. Single plasma sampling at day 7 can be used to monitor piperaquine effectiveness during IPTp-DHP. TRIAL REGISTRATION: Registered 09/12/2016, PACTR201612001901313.
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Antimaláricos , Malaria , Complicaciones Parasitarias del Embarazo , Quinolinas , Humanos , Femenino , Embarazo , Quinolinas/farmacocinética , Quinolinas/sangre , Quinolinas/uso terapéutico , Quinolinas/administración & dosificación , Antimaláricos/farmacocinética , Antimaláricos/uso terapéutico , Antimaláricos/sangre , Antimaláricos/administración & dosificación , Adulto , Complicaciones Parasitarias del Embarazo/prevención & control , Complicaciones Parasitarias del Embarazo/sangre , Adulto Joven , Malaria/prevención & control , Malaria/tratamiento farmacológico , Artemisininas/farmacocinética , Artemisininas/uso terapéutico , Artemisininas/administración & dosificación , Artemisininas/sangre , Parasitemia/sangre , Parasitemia/prevención & control , Resultado del Tratamiento , Combinación de Medicamentos , Adolescente , PiperazinasRESUMEN
P21 is a protein secreted by all forms of Trypanosoma cruzi (T. cruzi) with recognized biological activities determined in studies using the recombinant form of the protein. In our recent study, we found that the ablation of P21 gene decreased Y strain axenic epimastigotes multiplication and increased intracellular replication of amastigotes in HeLa cells infected with metacyclic trypomastigotes. In the present study, we investigated the effect of P21 in vitro using C2C12 cell lines infected with tissue culture-derived trypomastigotes (TCT) of wild-type and P21 knockout (TcP21-/-) Y strain, and in vivo using an experimental model of T. cruzi infection in BALB/c mice. Our in-vitro results showed a significant decrease in the host cell invasion rate by TcP21-/- parasites as measured by Giemsa staining and cell count in bright light microscope. Quantitative polymerase chain reaction (qPCR) analysis showed that TcP21-/- parasites multiplied intracellularly to a higher extent than the scrambled parasites at 72h post-infection. In addition, we observed a higher egress of TcP21-/- trypomastigotes from C2C12 cells at 144h and 168h post-infection. Mice infected with Y strain TcP21-/- trypomastigotes displayed higher systemic parasitemia, heart tissue parasite burden, and several histopathological alterations in heart tissues compared to control animals infected with scrambled parasites. Therewith, we propose that P21 is important in the host-pathogen interaction during invasion, cell multiplication, and egress, and may be part of the mechanism that controls parasitism and promotes chronic infection without patent systemic parasitemia.
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Enfermedad de Chagas , Proteínas Protozoarias , Trypanosoma cruzi , Animales , Humanos , Ratones , Línea Celular , Enfermedad de Chagas/parasitología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Modelos Animales de Enfermedad , Técnicas de Inactivación de Genes , Interacciones Huésped-Parásitos , Ratones Endogámicos BALB C , Parasitemia , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Trypanosoma cruzi/genética , Trypanosoma cruzi/patogenicidad , Trypanosoma cruzi/fisiología , Trypanosoma cruzi/metabolismo , VirulenciaRESUMEN
Oxidative stress is involved in the pathogenesis of malaria, causing anemia, respiratory complications, and cerebral malaria. To mitigate oxidative stress, we investigated the effect of nutritional supplementation whit lycopene (LYC) on the evolution of parasitemia and survival rate in mice infected with Plasmodium berghei ANKA (Pb), comparing to the effects promoted by N-acetylcysteine (NAC). Therefore, 175 mice were randomly distributed into 4 groups; Sham: untreated and uninfected animals; Pb: animals infected with Pb; LYC+Pb: animals treated with LYC and infected with Pb; NAC+Pb: animals treated with NAC and infected with Pb. The animals were followed for 12 days after infection, and survival and parasitemia rates were evaluated. There was a 40.1% increase in parasitemia in the animals of the Pb group on the 12th day, and a survival rate of 45%. LYC supplementation slowed the development of parasitemia to 19% and promoted a significative increase in the survival rate of 80% on the 12th day after infection, compared to the Pb group, effects superior to those promoted by NAC, providing strong evidence of the beneficial effect of LYC on in vivo malaria and stressing the importance of antioxidant supplementation in the treatment of this disease.
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Acetilcisteína , Antioxidantes , Suplementos Dietéticos , Licopeno , Malaria , Parasitemia , Plasmodium berghei , Animales , Licopeno/uso terapéutico , Licopeno/administración & dosificación , Licopeno/farmacología , Parasitemia/tratamiento farmacológico , Ratones , Malaria/tratamiento farmacológico , Acetilcisteína/administración & dosificación , Acetilcisteína/uso terapéutico , Acetilcisteína/farmacología , Plasmodium berghei/efectos de los fármacos , Antioxidantes/uso terapéutico , Antioxidantes/administración & dosificación , Estrés Oxidativo/efectos de los fármacos , Carotenoides/uso terapéutico , Carotenoides/administración & dosificación , Masculino , Modelos Animales de Enfermedad , Distribución AleatoriaRESUMEN
BACKGROUND: Application of numerous malaria control interventions has led to reduction in clinical malaria cases and deaths but also the realisation that asymptomatic parasite carriers play a key role in sustaining transmission. This study assessed the effectiveness of using the Ultra-sensitive NxTek eliminate RDT (uRDT) and conventional SD Bioline HRP2 RDT (cRDT) in diagnosing asymptomatic parasitaemia while measuring the impact of mass testing, treatment and tracking (MTTT) on the prevalence of asymptomatic malaria over a 1-year period in Ghana. METHODS: A total of 4000 targeted participants from two towns, Obom and Kofi Kwei, with their surrounding villages, were tested for asymptomatic malaria four times over the study period using uRDT (intervention) and the cRDT (control) respectively. Participants carrying malaria parasites were followed by home visit and phone calls for compliance to treatment, and filter paper blood blots collected from participants were used to determine true parasite carriage by PET-PCR. A mathematical model of the study site was developed and used to test the impact of test sensitivity and mass migration on the effect of MTTT. RESULTS: The start and end point sensitivities of the cRDT were 48.8% and 41.7% and those for the uRDT were 52.9% and 59.9% respectively. After a year of MTTTs, asymptomatic parasite prevalence, as determined by PCR, did not differ statistically in the control site (40.6% to 40.1%, P = 0.730) but decreased at the intervention site (55.9% to 46.4%, P < 0.0001). Parasite prevalence by RDT, however, indicated statistical reduction in the control site (25.3% to 22.3%, P = 0.017) and no change in the intervention site (35.1% to 36.0%, P = 0.614). The model predicted a mild effect of both diagnostic sensitivity and human movement in diminishing the impact of MTTT in the study sites. CONCLUSIONS: Asymptomatic parasite prevalence at the molecular level reduced significantly in the site where the uRDT was used but not where the cRDT was used. Overall, the uRDT exhibited higher sensitivity relative to the cRDT. Highly sensitive molecular techniques such as PET-PCR should be included in parasite prevalence estimation during MTTT exercises.
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Sensibilidad y Especificidad , Ghana/epidemiología , Humanos , Femenino , Masculino , Adulto , Adolescente , Preescolar , Adulto Joven , Niño , Pruebas Diagnósticas de Rutina/métodos , Parasitemia/epidemiología , Parasitemia/diagnóstico , Malaria Falciparum/diagnóstico , Malaria Falciparum/epidemiología , Persona de Mediana Edad , Malaria/diagnóstico , Malaria/epidemiología , Malaria/tratamiento farmacológico , Plasmodium falciparum/aislamiento & purificación , Plasmodium falciparum/genética , Prevalencia , Tamizaje Masivo/métodos , LactanteRESUMEN
BACKGROUND: It is unknown whether lymphopenia is a risk factor for the reactivation of Chagas disease in heart transplantation (HTx), as recently described in the reactivation of cytomegalovirus in transplant patients. OBJECTIVE: To evaluate whether lymphopenia in the perioperative period of heart transplantation is related to early Trypanosoma cruzi parasitemia. METHODS: This observational, retrospective study analyzed a sample from January 2014 to January 2023). Parasitemia was evaluated in the first 3 months after HTx using serum polymerase chain reaction (PCR) and compared with the total lymphocyte count in the perioperative period of HTx using receiver operating characteristic curves. Baseline characteristics were compared with PCR for Chagas using independent Cox proportional hazards models. A significance level of 5% was adopted. RESULTS: The sample (n = 35) had a mean age of 52.5 ± 8.1 years, and 22 patients (62.8%) had positive PCR for Chagas. The mean lowest lymphocyte values in the first 14 days after HTx were 398 ± 189 and 755 ± 303 cells/mm3 in patients with and without parasitemia, respectively, within 3 months after HTx (area under the curve = 0.857; 95% confidence interval: 0.996 to 0.718, sensitivity and specificity of 83.3% and 86.4%). A cutoff value of less than 550 lymphocytes/mm3 was determined as a risk factor for the presence of parasitemia. Patients with lymphocytes < 550 units/mm3 in the first 14 days after HTx presented positive PCR in 80% of cases. For every increase of 100 lymphocytes/mm3, the risk of PCR positivity was reduced by 26% (hazard rate ratio = 0.74; 95% confidence interval: 0.59 to 0.93, p = 0.009). CONCLUSION: There was an association between lymphopenia in the perioperative period of HTx and early T. cruzi parasitemia detected by PCR.
FUNDAMENTO: É desconhecido se a linfopenia é fator de risco para a reativação da doença de Chagas no transplante cardíaco (TxC), como recentemente descrito na reativação de citomegalovírus em pacientes transplantados. OBJETIVO: Avaliar se a linfopenia no perioperatório do TxC está relacionada à parasitemia precoce pelo Trypanosoma cruzi. MÉTODOS: Amostra analisada (janeiro de 2014 a janeiro de 2023) em estudo observacional e retrospectivo. A parasitemia foi avaliada nos primeiros 3 meses após o TxC por meio da reação em cadeia da polimerase sérica (PCR) e comparada com a contagem total de linfócitos no perioperatório do TxC por curvas ROC. Comparadas características de base com a PCR Chagas por modelos de risco proporcionais de Cox independentes. Nível de significância adotado de 5%. RESULTADOS: Amostra (n = 35) apresentou idade média de 52,5 ± 8,1 anos e PCR Chagas positiva em 22 pacientes (62,8%). As médias dos menores valores de linfócitos nos primeiros 14 dias do TxC foram 398 ± 189 e 755 ± 303 células/mm3 em pacientes com e sem parasitemia nos 3 meses após o TxC, respectivamente (área sob a curva = 0,857; intervalo de confiança de 95%: 0,996 a 0,718, sensibilidade e especificidade de 83,3% e 86,4%). Determinado valor de corte inferior a 550 linfócitos/mm3 como fator de risco para presença de parasitemia. Pacientes com linfócitos < 550 unidades/mm3 nos primeiros 14 dias do pós-TxC apresentaram PCR positiva em 80% dos casos. Para cada aumento de 100 linfócitos/mm3, o risco de positividade da PCR é reduzido em 26% (razão de riscos = 0,74; intervalo de confiança de 95%: 0,59 a 0,93, p = 0,009). CONCLUSÃO: Houve associação entre a linfopenia no perioperatório do TxC com a parasitemia precoce pelo T. cruzi detectada por PCR.
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Enfermedad de Chagas , Trasplante de Corazón , Linfopenia , Parasitemia , Reacción en Cadena de la Polimerasa , Trypanosoma cruzi , Humanos , Trasplante de Corazón/efectos adversos , Masculino , Persona de Mediana Edad , Femenino , Trypanosoma cruzi/genética , Trypanosoma cruzi/aislamiento & purificación , Estudios Retrospectivos , Recuento de Linfocitos , Enfermedad de Chagas/complicaciones , Reacción en Cadena de la Polimerasa/métodos , Adulto , Factores de Riesgo , Factores de Tiempo , Valor Predictivo de las Pruebas , Cardiomiopatía Chagásica/cirugía , Cardiomiopatía Chagásica/sangre , Curva ROCRESUMEN
Malaria is a global disease affecting a large portion of the world's population. Although vaccines have recently become available, their efficacies are suboptimal. We generated virus-like particles (VLPs) that expressed either apical membrane antigen 1 (AMA1) or microneme-associated antigen (MIC) of Plasmodium berghei and compared their efficacy in BALB/c mice. We found that immune sera acquired from AMA1 VLP- or MIC VLP-immunized mice specifically interacted with the antigen of choice and the whole P. berghei lysate antigen, indicating that the antibodies were highly parasite-specific. Both VLP vaccines significantly enhanced germinal center B cell frequencies in the inguinal lymph nodes of mice compared with the control, but only the mice that received MIC VLPs showed significantly enhanced CD4+ T cell responses in the blood following P. berghei challenge infection. AMA1 and MIC VLPs significantly suppressed TNF-α and interleukin-10 production but had a negligible effect on interferon-γ. Both VLPs prevented excessive parasitemia buildup in immunized mice, although parasite burden reduction induced by MIC VLPs was slightly more effective than that induced by AMA1. Both VLPs were equally effective at preventing body weight loss. Our findings demonstrated that the MIC VLP was an effective inducer of protection against murine experimental malaria and should be the focus of further development.
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Antígenos de Protozoos , Vacunas contra la Malaria , Proteínas de la Membrana , Plasmodium berghei , Proteínas Protozoarias , Vacunas de Partículas Similares a Virus , Animales , Femenino , Ratones , Anticuerpos Antiprotozoarios/inmunología , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/inmunología , Linfocitos B/inmunología , Linfocitos B/metabolismo , Linfocitos T CD4-Positivos/inmunología , Malaria/prevención & control , Malaria/inmunología , Vacunas contra la Malaria/inmunología , Vacunas contra la Malaria/administración & dosificación , Proteínas de la Membrana/inmunología , Ratones Endogámicos BALB C , Parasitemia/inmunología , Parasitemia/prevención & control , Plasmodium berghei/inmunología , Proteínas Protozoarias/inmunología , Proteínas Protozoarias/genética , Vacunas de Partículas Similares a Virus/inmunología , Vacunas de Partículas Similares a Virus/administración & dosificaciónRESUMEN
BACKGROUND: The interaction between iron status and malaria is incompletely understood. We evaluated longitudinal changes in iron homeostasis in volunteers enrolled in malaria volunteer infection studies (VIS) and in Malaysian patients with falciparum and vivax malaria. METHODS: We retrieved data and samples from 55 participants (19 female) enrolled in malaria VIS, and 171 patients (45 female) with malaria and 30 healthy controls (13 female) enrolled in clinical studies in Malaysia. Ferritin, hepcidin, erythropoietin, and soluble transferrin receptor (sTfR) were measured by ELISA. FINDINGS: In the VIS, participants' parasitaemia was correlated with baseline mean corpuscular volume (MCV), but not iron status (ferritin, hepcidin or sTfR). Ferritin, hepcidin and sTfR all increased during the VIS. Ferritin and hepcidin normalised by day 28, while sTfR remained elevated. In VIS participants, baseline ferritin was associated with post-treatment increases in liver transaminase levels. In Malaysian patients with malaria, hepcidin and ferritin were elevated on admission compared to healthy controls, while sTfR increased following admission. By day 28, hepcidin had normalised; however, ferritin and sTfR both remained elevated. INTERPRETATION: Our findings demonstrate that parasitaemia is associated with an individual's MCV rather than iron status. The persistent elevation in sTfR 4 weeks post-infection in both malaria VIS and clinical malaria may reflect a causal link between malaria and iron deficiency. FUNDING: National Health and Medical Research Council (Program Grant 1037304, Project Grants 1045156 and 1156809; Investigator Grants 2016792 to BEB, 2016396 to JCM, 2017436 to MJG); US National Institute of Health (R01-AI116472-03); Malaysian Ministry of Health (BP00500420).
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Ferritinas , Hepcidinas , Homeostasis , Hierro , Malaria , Humanos , Femenino , Hierro/metabolismo , Hierro/sangre , Masculino , Adulto , Hepcidinas/sangre , Hepcidinas/metabolismo , Malaria/sangre , Malaria/parasitología , Malaria/metabolismo , Ferritinas/sangre , Receptores de Transferrina/metabolismo , Receptores de Transferrina/sangre , Persona de Mediana Edad , Malasia/epidemiología , Adulto Joven , Estudios Longitudinales , Malaria Falciparum/parasitología , Malaria Falciparum/sangre , Malaria Falciparum/metabolismo , Eritropoyetina/metabolismo , Eritropoyetina/sangre , Biomarcadores , Parasitemia/sangreRESUMEN
BACKGROUND: Well-built housing limits mosquito entry and can reduce malaria transmission. The association between community-level housing and malaria burden in Uganda was assessed using data from randomly selected households near 64 health facilities in 32 districts. METHODS: Houses were classified as 'improved' (synthetic walls and roofs, eaves closed or absent) or 'less-improved' (all other construction). Associations between housing and parasitaemia were made using mixed effects logistic regression (individual-level) and multivariable fractional response logistic regression (community-level), and between housing and malaria incidence using multivariable Poisson regression. RESULTS: Between November 2021 and March 2022, 4.893 children aged 2-10 years were enrolled from 3.518 houses; of these, 1.389 (39.5%) were classified as improved. Children living in improved houses had 58% lower odds (adjusted odds ratio = 0.42, 95% CI 0.33-0.53, p < 0.0001) of parasitaemia than children living in less-improved houses. Communities with > 67% of houses improved had a 63% lower parasite prevalence (adjusted prevalence ratio 0.37, 95% CI 0.19-0.70, p < 0.0021) and 60% lower malaria incidence (adjusted incidence rate ratio 0.40, 95% CI 0.36-0.44, p < 0.0001) compared to communities with < 39% of houses improved. CONCLUSIONS: Improved housing was strongly associated with lower malaria burden across a range of settings in Uganda and should be utilized for malaria control.
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Vivienda , Mosquiteros Tratados con Insecticida , Malaria , Control de Mosquitos , Uganda/epidemiología , Preescolar , Vivienda/estadística & datos numéricos , Niño , Humanos , Malaria/epidemiología , Malaria/prevención & control , Mosquiteros Tratados con Insecticida/estadística & datos numéricos , Femenino , Control de Mosquitos/estadística & datos numéricos , Masculino , Incidencia , Prevalencia , Parasitemia/epidemiología , Parasitemia/parasitologíaRESUMEN
Malaria is a deadly disease that is transmitted through mosquito bites. Microscopists use a microscope to examine thin blood smears at high magnification (1000x) to identify parasites in red blood cells (RBCs). Estimating parasitemia is essential in determining the severity of the Plasmodium falciparum infection and guiding treatment. However, this process is time-consuming, labor-intensive, and subject to variation, which can directly affect patient outcomes. In this retrospective study, we compared three methods for measuring parasitemia from a collection of anonymized thin blood smears of patients with Plasmodium falciparum obtained from the Clinical Department of Parasitology-Mycology, National Reference Center (NRC) for Malaria in Paris, France. We first analyzed the impact of the number of field images on parasitemia count using our framework, MALARIS, which features a top-classifier convolutional neural network (CNN). Additionally, we studied the variation between different microscopists using two manual techniques to demonstrate the need for a reliable and reproducible automated system. Finally, we included thin blood smear images from an additional 102 patients to compare the performance and correlation of our system with manual microscopy and flow cytometry. Our results showed strong correlations between the three methods, with a coefficient of determination between 0.87 and 0.92.
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Malaria Falciparum , Microscopía , Parasitemia , Plasmodium falciparum , Humanos , Plasmodium falciparum/aislamiento & purificación , Parasitemia/diagnóstico , Parasitemia/sangre , Parasitemia/parasitología , Malaria Falciparum/diagnóstico , Malaria Falciparum/sangre , Malaria Falciparum/parasitología , Estudios Retrospectivos , Microscopía/métodos , Eritrocitos/parasitología , Procesamiento de Imagen Asistido por Computador/métodos , Redes Neurales de la Computación , Citometría de Flujo/métodosRESUMEN
Herein, we report a case of uncomplicated falciparum malaria with late parasitological failure in a 45-year-old businessman returning from Ghana. The patient visited the emergency department with high fever, headache, and dizziness. He traveled without antimalarial chemoprophylaxis. Laboratory tests led to the diagnosis of uncomplicated falciparum malaria with an initial density of 37,669 parasites per µL of blood (p/µL). The patient was treated with intravenous artesunate followed by atovaquone/proguanil. He was discharged with improved condition and decreased parasite density of 887 p/µL. However, at follow-up, parasite density increased to 7,630 p/µL despite the absence of any symptoms. Suspecting treatment failure, the patient was administered intravenous artesunate and doxycycline for seven days and then artemether/lumefantrine for three days. Blood smear was negative for asexual parasitemia after re-treatment but positive for gametocytemia until day 101 from the initial diagnosis. Overall, this case highlights the risk of late parasitological failure in patients with imported uncomplicated falciparum malaria.
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Antimaláricos , Atovacuona , Malaria Falciparum , Plasmodium falciparum , Proguanil , Humanos , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/diagnóstico , Ghana , Antimaláricos/uso terapéutico , Persona de Mediana Edad , Masculino , Plasmodium falciparum/aislamiento & purificación , Proguanil/uso terapéutico , Atovacuona/uso terapéutico , Viaje , Artemisininas/uso terapéutico , Artesunato/uso terapéutico , Parasitemia/tratamiento farmacológico , Parasitemia/diagnóstico , Doxiciclina/uso terapéutico , Combinación de Medicamentos , Insuficiencia del Tratamiento , Combinación Arteméter y Lumefantrina/uso terapéuticoRESUMEN
Host immune responses are tightly controlled by various immune factors during infection, and protozoan parasites also manipulate the immune system to evade surveillance, leading to an evolutionary arms race in hostâpathogen interactions; however, the underlying mechanisms are not fully understood. We observed that the level of superoxide dismutase 3 (SOD3) was significantly elevated in both Plasmodium falciparum malaria patients and mice infected with four parasite species. SOD3-deficient mice had a substantially longer survival time and lower parasitemia than control mice after infection, whereas SOD3-overexpressing mice were much more vulnerable to parasite infection. We revealed that SOD3, secreted from activated neutrophils, bound to T cells, suppressed the interleukin-2 expression and concomitant interferon-gamma responses crucial for parasite clearance. Overall, our findings expose active fronts in the arms race between the parasites and host immune system and provide insights into the roles of SOD3 in shaping host innate immune responses to parasite infection.
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Malaria Falciparum , Ratones Endogámicos C57BL , Ratones Noqueados , Neutrófilos , Superóxido Dismutasa , Animales , Superóxido Dismutasa/metabolismo , Superóxido Dismutasa/genética , Humanos , Ratones , Neutrófilos/inmunología , Malaria Falciparum/inmunología , Malaria Falciparum/parasitología , Inmunidad Celular , Linfocitos T/inmunología , Plasmodium falciparum/inmunología , Femenino , Interacciones Huésped-Parásitos/inmunología , Interacciones Huésped-Parásitos/genética , Interferón gamma/metabolismo , Interferón gamma/inmunología , Masculino , Inmunidad Innata , Interleucina-2/metabolismo , Interleucina-2/inmunología , Interleucina-2/genética , Parasitemia/inmunologíaRESUMEN
Artemisinin resistance threatens malaria control and elimination efforts globally. Recent studies have reported the emergence of Plasmodium falciparum parasites tolerant to artemisinin agents in sub-Saharan Africa, including Uganda. The current study assessed the day 3 parasite clearance and its correlation with P. falciparum K13 propeller gene (pfkelch13) mutations in P. falciparum parasites isolated from patients with uncomplicated malaria under artemether-lumefantrine (AL) treatment. This study enrolled 100 P. falciparum-positive patients to whom AL was prescribed between 09/September/2022 and 06/November/2022. Blood samples were collected in EDTA tubes before treatment initiation (day 0) and on day 3. Parasitemia was assessed by microscopy from blood smears and quantitative polymerase chain reaction (qPCR) from the DNA extracted. The day 0 parasite K13 gene was sequenced using Sanger sequencing. Sequence data were analysed using MEGA version 11 software. The data were analysed using STATA version 15, and the MannâWhitney U test was used to compare PCR parasite clearance on day 3 using the comparative CT value method and pfkelch13 mutations. The prevalence of day 3 parasitaemia was 24% (24/100) by microscopy and 63% (63/100) by qPCR from the AL-treated patients. P. falciparum K13-propeller gene polymorphism was detected in 18.8% (15/80) of the day 0 DNA samples. The K13 mutations found were C469Y, 12.5% (10/80); A675V, 2.5% (2/80); A569S, 1.25%, (1/80), A578S, 1.25%, (1/80) and; F491S, 1.25%, (1/80) a new allele not reported anywhere. The C469Y mutation, compared to the wild-type, was associated with delayed parasite clearance p = 0.0278, Hodges-Lehmann estimation 3.2108 on the log scale, (95%CI 1.7076, 4.4730). There was a high prevalence of day 3 P. falciparum among malaria patients treated using artemether-lumefantrine. We conclude the presence of the K13 mutation associated with artemisinin resistance by P. falciparum in Adjumani district, Uganda, necessitates regular surveillance of the effectiveness and efficacy of artemether-lumefantrine in the country.
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Antimaláricos , Combinación Arteméter y Lumefantrina , Malaria Falciparum , Mutación , Parasitemia , Plasmodium falciparum , Humanos , Plasmodium falciparum/genética , Plasmodium falciparum/efectos de los fármacos , Combinación Arteméter y Lumefantrina/uso terapéutico , Uganda/epidemiología , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/parasitología , Malaria Falciparum/epidemiología , Antimaláricos/uso terapéutico , Masculino , Femenino , Parasitemia/tratamiento farmacológico , Parasitemia/parasitología , Parasitemia/epidemiología , Proteínas Protozoarias/genética , Adulto , Niño , Adolescente , Preescolar , Adulto Joven , Resistencia a Medicamentos/genética , Artemisininas/uso terapéutico , Persona de Mediana EdadRESUMEN
BACKGROUND: Effective testing for malaria, including the detection of infections at very low densities, is vital for the successful elimination of the disease. Unfortunately, existing methods are either inexpensive but poorly sensitive or sensitive but costly. Recent studies have shown that mid-infrared spectroscopy coupled with machine learning (MIRs-ML) has potential for rapidly detecting malaria infections but requires further evaluation on diverse samples representative of natural infections in endemic areas. The aim of this study was, therefore, to demonstrate a simple AI-powered, reagent-free, and user-friendly approach that uses mid-infrared spectra from dried blood spots to accurately detect malaria infections across varying parasite densities and anaemic conditions. METHODS: Plasmodium falciparum strains NF54 and FCR3 were cultured and mixed with blood from 70 malaria-free individuals to create various malaria parasitaemia and anaemic conditions. Blood dilutions produced three haematocrit ratios (50%, 25%, 12.5%) and five parasitaemia levels (6%, 0.1%, 0.002%, 0.00003%, 0%). Dried blood spots were prepared on Whatman™ filter papers and scanned using attenuated total reflection-Fourier Transform Infrared (ATR-FTIR) for machine-learning analysis. Three classifiers were trained on an 80%/20% split of 4655 spectra: (I) high contrast (6% parasitaemia vs. negative), (II) low contrast (0.00003% vs. negative) and (III) all concentrations (all positive levels vs. negative). The classifiers were validated with unseen datasets to detect malaria at various parasitaemia levels and anaemic conditions. Additionally, these classifiers were tested on samples from a population survey in malaria-endemic villages of southeastern Tanzania. RESULTS: The AI classifiers attained over 90% accuracy in detecting malaria infections as low as one parasite per microlitre of blood, a sensitivity unattainable by conventional RDTs and microscopy. These laboratory-developed classifiers seamlessly transitioned to field applicability, achieving over 80% accuracy in predicting natural P. falciparum infections in blood samples collected during the field survey. Crucially, the performance remained unaffected by various levels of anaemia, a common complication in malaria patients. CONCLUSION: These findings suggest that the AI-driven mid-infrared spectroscopy approach holds promise as a simplified, sensitive and cost-effective method for malaria screening, consistently performing well despite variations in parasite densities and anaemic conditions. The technique simply involves scanning dried blood spots with a desktop mid-infrared scanner and analysing the spectra using pre-trained AI classifiers, making it readily adaptable to field conditions in low-resource settings. In this study, the approach was successfully adapted to field use, effectively predicting natural malaria infections in blood samples from a population-level survey in Tanzania. With additional field trials and validation, this technique could significantly enhance malaria surveillance and contribute to accelerating malaria elimination efforts.
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Malaria Falciparum , Plasmodium falciparum , Humanos , Malaria Falciparum/diagnóstico , Malaria Falciparum/sangre , Malaria Falciparum/parasitología , Plasmodium falciparum/aislamiento & purificación , Parasitemia/diagnóstico , Parasitemia/parasitología , Anemia/diagnóstico , Anemia/sangre , Anemia/parasitología , Espectrofotometría Infrarroja/métodos , Aprendizaje Automático , Carga de Parásitos , Adulto , Inteligencia Artificial , Sensibilidad y Especificidad , Femenino , Adulto Joven , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Adolescente , Masculino , Persona de Mediana Edad , Tamizaje Masivo/métodosRESUMEN
BACKGROUND: Plasmodium vivax malaria is a leading cause of morbidity in Ethiopia. The first-line treatment for P. vivax is chloroquine (CQ) and primaquine (PQ), but there have been local reports of CQ resistance. A clinical study was conducted to determine the efficacy of CQ for the treatment of P. vivax malaria in southern Ethiopia. METHODS: In 2021, patients with P. vivax mono-infection and uncomplicated malaria were enrolled and treated with 25 mg/kg CQ for 3 consecutive days. Patients were followed for 28 days according to WHO guidelines. The data were analysed using per-protocol (PP) and KaplanâMeier (KâM) analyses to estimate the risk of recurrent P. vivax parasitaemia on day 28. RESULTS: A total of 88 patients were enrolled, 78 (88.6%) of whom completed the 28 days of follow-up. Overall, 76 (97.4%) patients had adequate clinical and parasitological responses, and two patients had late parasitological failures. The initial therapeutic response was rapid, with 100% clearance of asexual parasitaemia within 48 h. CONCLUSION: Despite previous reports of declining chloroquine efficacy against P. vivax, CQ retains high therapeutic efficacy in southern Ethiopia, supporting the current national treatment guidelines. Ongoing clinical monitoring of CQ efficacy supported by advanced molecular methods is warranted to inform national surveillance and ensure optimal treatment guidelines.
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Antimaláricos , Cloroquina , Malaria Vivax , Malaria Vivax/tratamiento farmacológico , Cloroquina/uso terapéutico , Etiopía , Humanos , Antimaláricos/uso terapéutico , Masculino , Adulto , Femenino , Adolescente , Adulto Joven , Niño , Persona de Mediana Edad , Preescolar , Plasmodium vivax/efectos de los fármacos , Resultado del Tratamiento , Anciano , Parasitemia/tratamiento farmacológicoRESUMEN
Vaccination of malaria-naive volunteers with a high dose of Plasmodium falciparum sporozoites chemoattenuated by chloroquine (CQ) (PfSPZ-CVac [CQ]) has previously demonstrated full protection against controlled human malaria infection (CHMI). However, lower doses of PfSPZ-CVac [CQ] resulted in incomplete protection. This provides the opportunity to understand the immune mechanisms needed for better vaccine-induced protection by comparing individuals who were protected with those not protected. Using mass cytometry, we characterized immune cell composition and responses of malaria-naive European volunteers who received either lower doses of PfSPZ-CVac [CQ], resulting in 50% protection irrespective of the dose, or a placebo vaccination, with everyone becoming infected following CHMI. Clusters of CD4+ and γδ T cells associated with protection were identified, consistent with their known role in malaria immunity. Additionally, EMRA CD8+ T cells and CD56+CD8+ T cell clusters were associated with protection. In a cohort from a malaria-endemic area in Gabon, these CD8+ T cell clusters were also associated with parasitemia control in individuals with lifelong exposure to malaria. Upon stimulation with P. falciparum-infected erythrocytes, CD4+, γδ, and EMRA CD8+ T cells produced IFN-γ and/or TNF, indicating their ability to mediate responses that eliminate malaria parasites.
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Linfocitos T CD4-Positivos , Linfocitos T CD8-positivos , Vacunas contra la Malaria , Malaria Falciparum , Plasmodium falciparum , Esporozoítos , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto Joven , Antimaláricos/uso terapéutico , Antimaláricos/administración & dosificación , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Cloroquina/uso terapéutico , Cloroquina/farmacología , Europa (Continente) , Pueblo Europeo , Gabón , Vacunas contra la Malaria/inmunología , Vacunas contra la Malaria/administración & dosificación , Malaria Falciparum/inmunología , Malaria Falciparum/prevención & control , Parasitemia/inmunología , Plasmodium falciparum/inmunología , Esporozoítos/inmunología , Vacunación/métodos , Vacunas Atenuadas/inmunología , Vacunas Atenuadas/administración & dosificación , Pueblo CentroafricanoRESUMEN
In Indonesia, malaria remains a problem, with 94,610 active cases in 2021 and its current therapy includes chloroquine and artemisinin; however, resistance has been commonly reported. To overcome this problem, studies about potential medicinal plants that can be used as antimalaria, such as moringa (Moringa oleifera) started to receive more attention. The aim of this study was to investigate the effects of moringa in parasitemia, monocyte activation, and organomegaly on animal model malaria. This experimental study used male Mus musculus, infected by Plasmodium berghei ANKA, as an animal malaria model. The extract was made by maceration of dry moringa leaves, which were then divided into three concentrations: 25%, 50%, and 75%. Dihydroartemisinin-piperazine was used as a positive control treatment, and distilled water as a negative control treatment. The animals were observed for six days to assess the parasitemia count and the number of monocyte activation. On day 7, the animals were terminated, and the liver, spleen, and kidney were weighed. The results showed that the effective concentrations in reducing parasitemia and inducing monocyte activation were 50% and 25% of moringa leaf extract, respectively. The smallest liver and spleen enlargement was observed among animals within the group treated with a 50% concentration of M. oleifera extract. In contrast, the smallest kidney enlargement was observed in the group treated with 25% of M. oleifera extract. Further analysis is recommended to isolate compounds with antimalarial properties in moringa leaves.