IMPORTANCEThere is no specific antiviral therapy recommended for coronavirus disease 2019 . In vitro studies indicate that the antiviral effect of chloroquine diphosphate (CQ) requires a high concentration of the drug. OBJECTIVE To evaluate the safety and efficacy of 2 CQ dosages in patients with severe COVID-19. DESIGN, SETTING, AND PARTICIPANTSThis parallel, double-masked, randomized, phase IIb clinical trial with 81 adult patients who were hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was conducted from March 23 to April 5, 2020, at a tertiary care facility in Manaus, Brazilian Amazon. INTERVENTIONS Patients were allocated to receive high-dosage CQ (ie, 600 mg CQ twice daily for 10 days) or low-dosage CQ (ie, 450 mg twice daily on day 1 and once daily for 4 days). MAIN OUTCOMES AND MEASURES Primary outcome was reduction in lethality by at least 50% in the high-dosage group compared with the low-dosage group. Data presented here refer primarily to safety and lethality outcomes during treatment on day 13. Secondary end points included participant clinical status, laboratory examinations, and electrocardiogram results. Outcomes will be presented to day 28. Viral respiratory secretion RNA detection was performed on days 0 and 4. RESULTS Out of a predefined sample size of 440 patients, 81 were enrolled (41 [50.6%] to highdosage group and 40 [49.4%] to low-dosage group). Enrolled patients had a mean (SD) age of 51.1 (13.9) years, and most (60 [75.3%]) were men. Older age (mean [SD] age, 54.7 [13.7] years vs 47.4 [13.3] years) and more heart disease (5 of 28 [17.9%] vs 0) were seen in the high-dose group. Viral RNA was detected in 31 of 40 (77.5%) and 31 of 41 (75.6%) patients in the low-dosage and highdosage groups, respectively. Lethality until day 13 was 39.0% in the high-dosage group (16 of 41) and 15.0% in the low-dosage group (6 of 40). The high-dosage group presented more instance of QTc interval greater than 500 milliseconds (7 of 37 [18.9%]) compared with the low-dosage group (4 of 36 [11.1%]). Respiratory secretion at day 4 was negative in only 6 of 27 patients (22.2%). CONCLUSIONS AND RELEVANCEThe preliminary findings of this study suggest that the higher CQ dosage should not be recommended for critically ill patients with COVID-19 because of its potential (continued) Key Points Question How safe and effective are 2 different regimens of chloroquine diphosphate in the treatment of severe coronavirus disease 2019 (COVID-19)? Findings In this phase IIb randomized clinical trial of 81 patients with COVID-19, an unplanned interim analysis recommended by an independent data safety and monitoring board found that a higher dosage of chloroquine diphosphate for 10 days was associated with more toxic effects and lethality, particularly affecting QTc interval prolongation. The limited sample size did not allow the study to show any benefit overall regarding treatment efficacy. Meaning The preliminary findings from the CloroCovid-19 trial suggest that higher dosage of chloro...

BackgroundIn the last few years, the study of microparticles (MPs) - submicron vesicles released from cells upon activation or apoptosis - has gained growing interest in the field of inflammation and in infectious diseases. Their role in the human malaria parasite Plasmodium vivax remains unexplored. Because acute vivax malaria has been related to pro-inflammatory responses, the main hypothesis investigated in this study was that Plasmodium vivax infection is associated with elevated levels of circulating MPs, which may play a role during acute disease in non-immune patients.MethodsPlasma MPs were analysed among thirty-seven uncomplicated P. vivax infections from an area of unstable malaria transmission in the Brazilian Amazon. The MP phenotype was analysed by flow cytometry using the classical MP marker, annexin, and fluorochrome-labeled monoclonal antibodies against specific cell surface markers. The frequencies of plasma MPs in P. vivax patients (n = 37) were further compared to malaria-unexposed controls (n = 15) and ovarian carcinoma patients (n = 12), a known MPs-inducing disease non-related to malaria.ResultsThe frequencies of plasma circulating MPs were markedly increased in P. vivax patients, as compared to healthy age-matched malaria-unexposed controls. Although platelets, erythrocytes and leukocytes were the main cellular sources of MPs during vivax malaria, platelet derived-MPs (PMPs) increased in a linear fashion with the presence of fever at the time of blood collection (β = 0.06, p < 0.0001) and length of acute symptoms (β = 0.36, p < 0.0001). Finally, the results suggest that plasma levels of PMPs diminish as patient experience more episodes of clinical malaria (β = 0.07, p < 0.003).ConclusionsAbundant circulating MPs are present during acute P. vivax infection, and platelet derived-MPs may play a role on the acute inflammatory symptoms of malaria vivax.

robust clinical studies on the safety and/or efficacy of chloroquine (CQ) and/or hydroxychloroquine (HCQ) for the treatment of COVID-19 during the recent 2020 pandemic.We searched PubMed and also MedRxiv.org (pre-print server for health sciences, without peer review), without any language restrictions and including Chinese publications, for studies published between Dec 2019 and April 5, 2020, using the search terms 'COVID-19, coronavirus, SARS-Cov-2'. We found three non-randomized studies with limited sample sizes in which (1) HCQ use led to a decrease in SARS-Cov-2 detected in respiratory secretions five days after treatment, together with azithromycin (France, 36 patients); (2) HCQ use shortened time to clinical recovery (China, 62 patients); and (3) CQ was superior to control treatment in inhibiting the exacerbation of pneumonia, improving lung imaging findings, and promoting virus-negative conversion and shortening the disease course (China, 100 patients). We found no published studies comparing different dosages of CQ/HCQ and their thorough safety assessment. Added value of this studyIn a larger patient population, we found that a higher dosage of CQ for 10 days presented toxicity red flags, particularly affecting QTc prolongation. The limited sample size recruited so far does not allow to show any benefit regarding treatment efficacy, however the higher fatality associated with the higher dosage by day 13 of follow-up resulted in a premature halting of this arm. This is the first double-blinded, randomized clinical trial addressing different dosages of CQ for the treatment of severe patients with COVID-19 in the absence of a control group using placebo. Due to the impossibility of not using the drug recommended at the national level, we used historical data from the literature to infer comparisons for lethality endpoints. Follow-up until day 28 is ongoing with a larger sample size, in which long-term lethality will be better estimated.

RESUMO Uma epidemia de leishmaniose visceral teve início em 1998 na Região Metropolitana de Cuiabá, capital de Mato Grosso, atingindo hoje 34 (24,1%)

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Abstractobjective To investigate risk factors associated with the acquisition of antibodies against Plasmodium vivax Duffy binding protein (PvDBP) -a leading malaria vaccine candidate -in a well-consolidated agricultural settlement of the Brazilian Amazon Region and to determine the sequence diversity of the PvDBP ligand domain (DBP II ) within the local malaria parasite population.methods Demographic, epidemiological and clinical data were collected from 541 volunteers using a structured questionnaire. Malaria parasites were detected by conventional microscopy and PCR, and blood collection was used for antibody assays and molecular characterisation of DBP II .results The frequency of malaria infection was 7% (6% for P. vivax and 1% for P. falciparum), with malaria cases clustered near mosquito breeding sites. Nearly 50% of settlers had anti-PvDBP IgG antibodies, as detected by enzyme-linked immunosorbent assay (ELISA) with subject's age being the only strong predictor of seropositivity to PvDBP. Unexpectedly, low levels of DBP II diversity were found within the local malaria parasites, suggesting the existence of low gene flow between P. vivax populations, probably due to the relative isolation of the studied settlement.conclusion The recognition of PvDBP by a significant proportion of the community, associated with low levels of DBP II diversity among local P. vivax, reinforces the variety of malaria transmission patterns in communities from frontier settlements. Such studies should provide baseline information for antimalarial vaccines now in development.

Abstract. The antibody response to the C-terminal 19-kD fragment of Plasmodium falciparum merozoite surface protein-1 (PfMSP1-19) was investigated in groups of subjects living in areas of Brazil with different levels of malaria transmission. The prevalence and the levels of IgG to PfMSP1-19 increased with the time of exposure and were positively correlated with the absence of clinical symptoms in parasitemic patients. The frequency of positive response and the mean level of IgG were higher in areas where malaria prevalence was more intense, especially among asymptomatic patients. The serum absorbance values of the IgG1 isotype were significantly higher among subjects with long-term exposure and in asymptomatic infections. These data suggest a protective role of IgG1 in naturally acquired immunity in spite of the unstable transmission levels in the Brazilian Amazon.

In this study, exoantigens produced from two Paracoccidioides brasiliensis strains isolated in two different geographical areas were compared in terms of sensitivity and specificity in relation to paracoccidioidomycosis (PCM) diagnosis. Exoantigens from P. brasiliensis 550B (Ag 550B) isolated in the central-west region of Brazil (Mato Grosso State) and exoantigen produced from P. brasiliensis B-339 (Ag B-339) used in reference laboratories were compared by immunodiffusion (ID) tests. When Ag 550B was used in ID test against sera of patients from Mato Grosso and São Paulo, positivity was 92.3% and 41.3%, respectively. On the other hand, when Ag B-339 was tested with the same sera, positivity was 26.2% and 100%, respectively. These results suggest that differences in the antigenic composition probably related to phylogenetic peculiarities in P. brasiliensis isolates from the central-western region of Brazil should be considered in the diagnosis of PCM.Paracoccidioidomycosis (PCM) has long been recognised as a public health problem in many areas of Latin America, especially Brazil, Colombia, Venezuela and Argentina (Brummer E et al., Clin Microbiol Rev 1993; 6: 89-117). The only causal agent of the disease is the thermodimorphic fungus Paracoccidioides brasiliensis. Brazil has sustained the largest epidemiological indicators since 1908 when the first case of PCM was described by Adolpho Lutz (Lutz A. Brasil -Medico 1908; 22: 121). As PCM is not a compulsory notification disease, the real incidence of the disease in Brazil is unknown. Mato Grosso State contributes significantly to these statistics (Hahn RC et al., XXII Congresso Brasileiro de Microbiologia, 2003, Florianópolis. Resumos do Congresso Brasileiro de Microbiologia, DOC & Knowledge Management, São Paulo, 2003.As the control of PCM remains limited to the treatment of patients, precise clinical and laboratorial diagnoses are considered of prime importance to enable adequate therapeutic measures as early as possible. The Ôgold standardsÕ for PCM diagnosis are isolation of the fungus by culture and positive identification of multi-budding and birefringent yeast cells by direct examination of biological fluids or biopsy specimens (Brummer E et al., Clin Microbiol Rev 1993; 6: 89-117). Serological diagnosis relies on the detection of specific antibodies, mainly by immunodiffusion (ID) (Camargo ZP et al., Rev Iberoam Micol 2000; 17: 41-48; Del Negro GMB et al., J Med Microbiol 2000; 49: 37-46; Restrepo A et al., Appl Microbiol 1974; 28: 138-44); methods for detecting circulating antigens (Marques da Silva SH et al., J Clin Microbiol 2003; 41: 3675-80; Marques da Silva SH et al., J Clin Microbiol 2004; 42: 4480-6; Marques da Silva SH et al., J Clin Microbiol 2005; 43: 4680-3; Marques da Silva SH