Antibody response to Plasmodium vivax in the context of Epstein-Barr virus (EBV) co-infection: A 14-year follow-up study in the Amazon rainforest.

Background: To develop an effective vaccine against Plasmodium vivax, the most widely dispersed human malaria parasite, it is critical to understand how coinfections with other pathogens could impact malaria-specific immune response. A recent conceptual study proposed that Epstein-Barr virus (EBV), a highly prevalent human herpesvirus that establishes lifelong persistent infection, may influence P. vivax antibody responses.

Application of a targeted amplicon sequencing panel to screen for insecticide resistance mutations in Anopheles darlingi populations from Brazil.

Large-scale surveillance and informed vector control approaches are urgently needed to ensure that national malaria programs remain effective in reducing transmission and, ultimately, achieving malaria elimination targets. In South America, Anopheles darlingi is the primary malaria vector and is responsible for the majority of Plasmodium species transmission. However, little is known about the molecular markers associated with insecticide resistance in this species.

Exploring the naturally acquired response to Pvs47 gametocyte antigen.

Malaria represents a challenging global public health task, with being the predominant parasite in Brazil and the most widely distributed species throughout the world. Developing a vaccine against malaria demands innovative strategies, and targeting gametocyte antigens shows promise for blocking transmission prevention. Among these antigens, Pvs47, expressed in gametocytes, has shown remarkable efficacy in transmission blocking.

Perception and barriers to access Pre-exposure Prophylaxis for HIV/AIDS (PrEP) among the MSM (men who have sex with men) Brazilian Amazon: A qualitative study.

Pre-exposure prophylaxis (PrEP) is an effective HIV prevention strategy that consists in the use of antiretroviral drugs by seronegative people at risk of HIV. Negative perceptions, inadequate understanding, and access barriers have been associated with decreased medication adherence. Manaus is the largest city in the Brazilian Amazon, where the incidence of HIV/AIDS is high, and the rates of adherence to the antiretroviral treatment for HIV and PrEP are low.

Cell Death of Blood Stages Occurs in Absence of Classical Apoptotic Events and Induces Eryptosis of Parasitized Host Cells.

Elucidation of pathways regulating parasite cell death is believed to contribute to identification of novel therapeutic targets for protozoan diseases, and in this context, apoptosis-like cell death has been reported in different groups of protozoa, in which metacaspases seem to play a role. In the genus , apoptotic markers have been detected in and , and no study focusing on cell death has been reported so far. In the present study, we investigated the susceptibility of to undergo apoptotic cell death after incubating mature trophozoites with the classical apoptosis inducer staurosporine.

A two-dose viral-vectored multistage vaccine confers durable protection and transmission-blockade in a pre-clinical study.

Among spp. responsible for human malaria, ranks as the second most prevalent and has the widest geographical range; however, vaccine development has lagged behind that of , the deadliest species. Recently, we developed a multistage vaccine for based on a heterologous prime-boost immunization regimen utilizing the attenuated vaccinia virus strain LC16m8Δ (m8Δ)-prime and adeno-associated virus type 1 (AAV1)-boost, and demonstrated 100% protection and more than 95% transmission-blocking (TB) activity in the mouse model.

Profile of metacaspase gene expression in Plasmodium vivax field isolates from the Brazilian Amazon.

Background: Metacaspases comprise a family of cysteine proteases implicated in both cell death and cell differentiation of protists that has been considered a potential drug target for protozoan parasites. However, the biology of metacaspases in Plasmodium vivax - the second most prevalent and most widespread human malaria parasite worldwide, whose occurrence of chemoresistance has been reported in many endemic countries, remains largely unexplored. Therefore, the present study aimed to address, for the first time, the expression pattern of metacaspases in P.

Optimization of Plasmodium vivax infection of colonized Amazonian Anopheles darlingi.

Obtaining Plasmodium vivax sporozoites is essential for in vitro culture of liver stage parasites, not only to understand fundamental aspects of parasite biology, but also for drug and vaccine development. A major impediment to establish high-throughput in vitro P. vivax liver stage assays for drug development is obtaining sufficient numbers of sporozoites.

Evolution and assembly of 's immune genes: primary malaria vector of coastal Central and South America and the Caribbean Islands.

Anophelines are vectors of malaria, the deadliest disease worldwide transmitted by mosquitoes. The availability of genomic data from various species allowed evolutionary comparisons of the immune response genes in search of alternative vector control of the malarial parasites. Now, with the genome, it was possible to obtain more information about the evolution of the immune response genes.

Antigenicity and adhesiveness of a Plasmodium vivax VIR-E protein from Brazilian isolates.

Background: Plasmodium vivax, the major cause of malaria in Latin America, has a large subtelomeric multigene family called vir. In the P. vivax genome, about 20% of its sequences are vir genes.

Total parasite biomass but not peripheral parasitaemia is associated with endothelial and haematological perturbations in patients.

is the major cause of human malaria in the Americas. How infection can lead to poor clinical outcomes, despite low peripheral parasitaemia, remains a matter of intense debate. Estimation of total biomass based on circulating markers indicates existence of a predominant parasite population outside of circulation.

Gametocytes Adherence to Bone Marrow Endothelial Cells.

In a infection, it was shown a proportionally increased on gametocyte distribution within the bone marrow aspirant, suggesting a role of this organ as a reservoir for this parasite stage. Here, we evaluated the cytoadhesive capacity of gametocytes to bone marrow endothelial cells (HBMEC) and investigated the involvement of some receptors in the cytoadhesion process by using transfected CHO cells (CHO-ICAM1, CHO-CD36 and CHO-VCAM), wild type (CHO-K1) or deficient in heparan and chondroitin sulfate (CHO-745). cytoadhesion assays were performed using a total of 44  isolates enriched in gametocyte stages by Percoll gradient in the different cell lines.

Viability and Infectivity of Gametocytes in Short-Term Culture.

The control and elimination of malaria caused by both represent a great challenge due to the biological aspects of the species. Gametocytes are the forms responsible for the transmission of the parasite to the vector and the search for new strategies for blocking transmission are essential in a scenario of control and elimination The challenges in this search in regard to mainly stem from the lack of a long-term culture and the limitation of studies of gametocytes. This study evaluated the viability and infectivity of gametocytes in short-term culture.

A suitable RNA preparation methodology for whole transcriptome shotgun sequencing harvested from Plasmodium vivax-infected patients.

Plasmodium vivax is a world-threatening human malaria parasite, whose biology remains elusive. The unavailability of in vitro culture, and the difficulties in getting a high number of pure parasites makes RNA isolation in quantity and quality a challenge. Here, a methodological outline for RNA-seq from P.

Transmission-blocking compound candidates against Plasmodium vivax using P. berghei as an initial screening.

Background: Different strategies for improvement of malaria control and elimination are based on the blockage of malaria parasite transmission to the mosquito vector. These strategies include the drugs that target the plasmodial sexual stages in humans and the early developmental stages inside mosquitoes.

Objectives: Here we tested Malaria Box compounds in order to evaluate their activity against male and female gametocytes in Plasmodium berghei, mosquito infection in P.

Rosettes integrity protects Plasmodium vivax of being phagocytized.

Plasmodium vivax is the most prevalent cause of malaria outside of Africa. P. vivax biology and pathogenesis are still poorly understood.

Platelet disturbances correlate with endothelial cell activation in uncomplicated Plasmodium vivax malaria.

Platelets drive endothelial cell activation in many diseases. However, if this occurs in Plasmodium vivax malaria is unclear. As platelets have been reported to be activated and to play a role in inflammatory response during malaria, we hypothesized that this would correlate with endothelial alterations during acute illness.

Keras R-CNN: library for cell detection in biological images using deep neural networks.

Background: A common yet still manual task in basic biology research, high-throughput drug screening and digital pathology is identifying the number, location, and type of individual cells in images. Object detection methods can be useful for identifying individual cells as well as their phenotype in one step. State-of-the-art deep learning for object detection is poised to improve the accuracy and efficiency of biological image analysis.

Plasmodium vivax AMA1: Implications of distinct haplotypes for immune response.

In Brazil, Plasmodium vivax infection accounts for around 80% of malaria cases. This infection has a substantial impact on the productivity of the local population as the course of the disease is usually prolonged and the development of acquired immunity in endemic areas takes several years. The recent emergence of drug-resistant strains has intensified research on alternative control methods such as vaccines.

A First Natural Infection Induces Increased Activity of the Interferon Gamma-Driven Tryptophan Catabolism Pathway.

The human immune response that controls infection in the liver and blood stages of the parasite life cycle is composed by both pro- and anti-inflammatory programs. Pro-inflammatory responses primarily mediated by IFN-γ controls the infection, but also induce tolerogenic mechanisms to limit host damage, including the tryptophan (TRP) catabolism pathway mediated by the enzyme Indoleamine 2,3-Dioxygenase (IDO1), an enzyme that catalyzes the degradation of TRP to kynurenines (KYN). Here we assessed total serum kynurenines and cytokine dynamics in a cohort of natural human infection and compared them to those of endemic healthy controls and other febrile diseases.

A simple, ex vivo phagocytosis assay of Plasmodium vivax merozoites by flow cytometry.

As phagocytosis is the first line of defense against malaria, we developed a phagocytosis assay with Plasmodium vivax (P. vivax) merozoites that can be applied to evaluate vaccine candidates. Briefly, after leukocyte removal with loosely packed cellulose powder in a syringe, P.

A new heparan sulfate from the mollusk Nodipecten nodosus inhibits merozoite invasion and disrupts rosetting and cytoadherence of Plasmodium falciparum.

Background: Despite treatment with effective antimalarial drugs, the mortality rate is still high in severe cases of the disease, highlighting the need to find adjunct therapies that can inhibit the adhesion of Plasmodium falciparum-infected erythrocytes (Pf-iEs).

Objectives: In this context, we evaluated a new heparan sulfate (HS) from Nodipecten nodosus for antimalarial activity and inhibition of P. falciparum cytoadhesion and rosetting.

Use of anthropophilic culicid-based xenosurveillance as a proxy for Plasmodium vivax malaria burden and transmission hotspots identification.

Vector-borne diseases account for more than 17% of all infectious diseases, causing more than one million deaths annually. Malaria remains one of the most important public health problems worldwide. These vectors are bloodsucking insects, which can transmit disease-producing microorganisms during a blood meal.