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Plastics are dominant pollutants in freshwater ecosystems worldwide. Scientific studies that investigated the interaction between plastics and freshwater biodiversity are incipient, especially if compared to the marine realm. In this review, we provide a brief overview of plastic pollution in freshwater ecosystems around the world. We found evidence of plastic ingestion by 206 freshwater species, from invertebrates to mammals, in natural or seminatural ecosystems. In addition, we reported other consequences of synthetic polymers in freshwater ecosystems—including, for instance, the entanglement of animals of different groups (e.g., birds). The problem of plastic pollution is complex and will need coordinated actions, such as recycling programs, correct disposal, stringent legislation, regular inspection, replacement of synthetic polymers with other materials, and ecological restoration. Current information indicates that the situation in freshwater ecosystems may be as detrimental as the pollution found in the ocean, although highly underappreciated.

The construction of dams in Brazilian semiarid regions has been a common governmental practice since the early 1900s, initially with the aim of providing water to meet the needs of humans and animals, and, later, to improve fisheries. Along with dams, several nonnative fish species were introduced with the intention of supplying new fisheries. We used a dataset compiled since the 1950s for the following: (i) evaluate fisheries for native and nonnative species across space–time scales and (ii) quantify the spatial and temporal changes in taxonomic and functional similarity of freshwater fish assemblages in semiarid reservoirs. Overall, fisheries for native species decreased over time, while fisheries for nonnative species increased during the early periods, which then, for the most part, decreased after 2000. At the Inter-region scale, we recorded a transition from homogenization to differentiation over time, both in taxonomic and functional terms. At the Intra-region scale, we also found a transition phase from taxonomic homogenization to differentiation over time, while functional differentiation was recorded for most of the regions. This study highlights the variation in fisheries for native and nonnative species over a period of ~ 70 years, and the homogenization dynamics of Brazil’s semiarid freshwater fish resulting from the construction of dams, stocking programs, and aquaculture using nonnative species.

In 2021 the countries of the world will discuss a framework under the Convention on Biological Diversity (CBD) for a new environmental agenda for the next 10 years (“post-2020”). Parties should consider Brazil to be a central nation in these discussions. The country holds a large freshwater biodiversity that needs to be conserved, but current policies imperil species and ecosystems. Here we present topics to guide other CBD parties in discussing with Brazil a better agenda to conserve freshwater biodiversity post-2020. These initiatives include: (1) a national plan to reduce threats, (2) restoration of freshwater ecosystems, (3) protected areas, (4) more investment in research, and (5) science communication. Brazil’s participation in these CBD negotiations is fundamental for a new agreement, but the country is under a presidential administration with little concern for the environment. While our suggestions are intended for participants in the CBD negotiations, they will also be relevant to other international actors in the coming years. Nations, international investors, private companies and NGOs around the world must therefore use their influence to press the current administration to protect the country’s environment, including its enormous freshwater biodiversity.

Plasmodium vivax is the most widely distributed human malaria parasite. Previous studies have shown that circulating microparticles during P. vivax acute attacks are indirectly associated with severity. Extracellular vesicles (EVs) are therefore major components of circulating plasma holding insights into pathological processes. Here, we demonstrate that plasma-derived EVs from Plasmodium vivax patients ( Pv EVs) are preferentially uptaken by human spleen fibroblasts ( h SFs) as compared to the uptake of EVs from healthy individuals. Moreover, this uptake induces specific upregulation of ICAM-1 associated with the translocation of NF-kB to the nucleus. After this uptake, P. vivax -infected reticulocytes obtained from patients show specific adhesion properties to h SFs, reversed by inhibiting NF-kB translocation to the nucleus. Together, these data provide physiological EV-based insights into the mechanisms of human malaria pathology and support the existence of P. vivax -adherent parasite subpopulations in the microvasculature of the human spleen. Extracellular vesicles (EVs) in plasma can affect pathogenesis of parasites, but details remain unclear. Here, Toda et al. characterize plasma-derived EVs from Plasmodium vivax patients and show that Pv EVs are preferentially taken up by human spleen fibroblasts, facilitating parasite cytoadherence.

Background Population-based studies conducted in Latin America have shown a high proportion of asymptomatic and submicroscopic malarial infections. Considering efforts aiming at regional elimination, it is important to investigate the role of this asymptomatic reservoir in malaria transmission in peri-urban areas. This study aimed to estimate the prevalence of Plasmodium spp. and gametocyte burden on symptomatic and asymptomatic infections in the Brazilian Amazon. Results Two cross-sectional household surveys (CS) were conducted including all inhabitants in a peri-urban area of Manaus, western Amazonas State, Brazil. Malaria parasites were detected by light microscopy (LM) and qPCR. Sexual stages of Plasmodium spp. were detected by LM and RT-qPCR. A total of 4083 participants were enrolled during the two surveys. In CS1, the prevalence of Plasmodium vivax infections was 4.3% (86/2010) by qPCR and 1.6% (32/2010) by LM. Fifty percent (43/86) of P. vivax infected individuals (qPCR) carried P. vivax gametocytes. In CS2, 3.4% (70/2073) of participants had qPCR-detectable P. vivax infections, of which 42.9% (30/70) of infections were gametocyte positive. The P. vivax parasite density was associated with gametocyte carriage ( P  < 0.001). Sixty-seven percent of P. vivax infected individuals and 53.4% of P. vivax gametocyte carriers were asymptomatic. Conclusions This study confirms a substantial proportion of asymptomatic and submicroscopic P. vivax infections in the study area. Most asymptomatic individuals carried gametocytes and presented low asexual parasitemia. This reservoir actively contributes to malaria transmission in the Brazilian Amazon, underscoring a need to implement more efficient control and elimination strategies.

Background To eliminate malaria by 2035, Brazil must address Plasmodium vivax . Previously, first-line treatment was chloroquine plus 7-day primaquine (PQ) without glucose-6-phosphate dehydrogenase (G6PD) deficiency testing. In 2021, point-of-care quantitative G6PD testing and single-dose tafenoquine (TQ) were piloted in two municipalities. This study evaluated healthcare professional (HCP) and patient perceptions of TQ implementation. Methods This qualitative observational study in Manaus and Porto Velho municipalities evaluated the pilot implementation of the new P. vivax malaria treatment algorithm in high/medium-complexity healthcare units (phase one), then low-complexity units (phase two). Qualitative data collection began 30 days after the first TQ treatment in each phase, i.e., October 2021 and March 2022. Perceptions of TQ were assessed using semi-structured in-depth interviews and field notes until saturation. Data were analysed through debriefing sessions, and systematic organization in Excel and MAXQDA, with themes derived by inductive and deductive analysis. Results The study included 55 patients who received TQ and 94 HCPs. HCPs viewed the TQ single-dose regimen as a significant advancement over 7-day PQ, enhancing adherence. Patients appreciated the shorter duration of treatment and perceived a rapid clinical recovery and fewer side effects. HCPs also noted that TQ resulted in fewer recurrences of P. vivax . The single-dose administration of TQ facilitated complete supervision of the treatment, reduced HCP workload and ensured that patients received the necessary care and did not share the medication with family members. TQ packaging instilled patient trust, though HCPs working in the community found the packaging too bulky. Prescription insecurities among HCPs after initial training prompted requests for additional training. While some patients initially doubted single-dose efficacy, confidence grew with experience. TQ implementation increased awareness of pharmacovigilance and enhanced patient communication, with HCPs adhering to protocols for monitoring haemolysis symptoms. Conclusion Single-dose TQ for P. vivax malaria in Brazil's Amazon region was positively received by HCPs and patients. Positive perceptions of the medication may aid in improving patient adherence to malaria treatment, thereby reducing malaria recurrences. The findings underscore the importance of adaptive training to optimize P. vivax radical cure implementation.

Clearing of the dormant liver stage (the hypnozoite) of P. vivax malaria is important to prevent the relapse of infection. In this randomized clinical trial, a single dose of tafenoquine is shown to have significant activity against the hypnozoite form of P. vivax .

Malaria remains a global health burden. Elimination of the hypnozoite is required in patients infected with P. vivax to prevent relapse. In this report, the safety of a single dose of tafenoquine was similar to that of a 14-day course of primaquine in patients with normal G6PD activity.

In the state of São Paulo in southeastern Brazil, a dangerous decree allows the culture of hybrids and non-native extralimital fish species in the Paraná and East Atlantic River basins. We recorded the illegal importation and sale of the non-native striped catfish Pangasianodon hypophthalmus in northeastern, central-western, southeastern, and southern areas of the country. This species is already consumed across Brazil and is cultivated for ornamental purposes. Besides escapes from fish farms and ‘fish and pays’, P. hypophthalmus can reach natural environments through aquarium dumping and ornamental ponds, motivated by its large size that reach after being sold at small size. The species has been introduced in many countries, and if established in Brazil, could put native Brazilian biodiversity and ecosystems at risk. Although importing specimens of P. hypophthalmus is prohibited by law, Decree 62.243/2016 in the state of São Paulo creates a new opportunity for invasion. In fact, once a novel fish species is moved to a new continent, it is irrational to supposed that it will stay static just in the area for which it was intended. In general, the fish disperse in the novel area on their own, by escapes from captivity or deliberate and illicit releases by persons or associations. The unwise attitude of Brazilian decision-makers and lay people in their attempt to develop aquaculture with non-native species goes against the objectives of responsible aquaculture based in native species.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency greatly hinders Plasmodium vivax malaria radical cure and further elimination due to 8-aminoquinolines-associated hemolysis. Although the deleterious health effects of primaquine in G6PD deficient individuals have been known for over 50 years, G6PD testing is not routinely performed before primaquine treatment in most P. vivax endemic areas. The qualitative CareStart G6PD screening test was implemented in 12 malaria treatment units (MTUs) in the municipality of Rio Preto da Eva, Western Brazilian Amazon, a malaria endemic area, between February 2019 and early January 2020. Training materials were developed and validated; evaluations were conducted on the effectiveness of training health care professionals (HCPs) to perform the test, the interpretation and reliability of routine testing performed by HCPs, and perceptions of HCPs and patients. Most HCPs were unaware of G6PD deficiency and primaquine-related adverse effects. Most of 110 HCPs trained (86/110, 78%) were able to correctly perform the G6PD test after a single 4-hour training session. The test performed by HCPs during implementation showed 100.0% (4/4) sensitivity and 68.1% (62/91) specificity in identifying G6PD deficient patients as compared to a point-of-care quantitative test (Standard G6PD). G6PD screening using the qualitative CareStart G6PD test performed by HCPs in MTUs of an endemic area showed high sensitivity and concerning low specificity. The amount of false G6PD deficiency detected led to substantial loss of opportunities for radical cure.