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Objective: Hypertensive disorders of pregnancy (HDP) are responsible for several maternal and fetal complications. This study investigated the occurrence of HDP, associated factors, and neonatal complications in women living in the Western Brazilian Amazon. Methods: This is a population‐based cross‐sectional study with 1521 mother–child pairs enrolled in the Maternal and Child Health and Nutrition in Acre birth cohort (MINA‐Brazil study). All parturients with HDP (registered in the medical records) were identified. Crude and adjusted prevalence ratios were calculated in Poisson regression models with robust variance. Results: The prevalence of HDP was 11.0% (95% CI: 9.5–12.7). Factors associated with the prevalence of HDP were maternal age ≥ 35 years (PR: 1.9; 95% CI: 1.3–3.0), primigravida status (PR: 2.0; 95% CI: 1.5–2.7), pre‐pregnancy obesity (PR: 2.7; 95% CI: 1.9–4.0), higher gestational weight gain (highest quartile RP: 2.5; 95% CI: 1.6–3.8), chronic hypertension (RP: 3.6; 95% CI: 2.7–4.9), and diabetes in pregnancy (RP: 1.9; 95% CI: 1.1–3.2). HDP was associated with risk for caesarean delivery (PR: 1.8; 95% CI: 1.6–2.0) and prematurity (PR: 2.0; 95% CI: 1.3–3.2). Gestational malaria was not associated with HDP in Amazonian pregnant women. Conclusions: Evaluating risk factors before pregnancy and during the prenatal period is essential for reducing adverse maternal and neonatal outcomes. [ABSTRACT FROM AUTHOR]

Background Malarial infections are often missed by microscopy, and most parasite carriers are asymptomatic in low-endemicity settings. Whether parasite detectability and its ability to elicit symptoms change as transmission declines remains unclear. Methods We performed a prospective panel survey with repeated measurements on the same participants over 12 months to investigate whether Plasmodium vivax detectability by microscopy and risk of symptoms upon infection varied during a community-wide larviciding intervention in the Amazon basin of Brazil that markedly reduced vector density. We screened 1096 to 1400 residents in the intervention site for malaria by microscopy and quantitative TaqMan assays at baseline and twice during intervention. Results We found that more P vivax infections than expected from their parasite densities measured by TaqMan assays were missed by microscopy as transmission decreased. At lower transmission, study participants appeared to tolerate higher P vivax loads without developing symptoms. We hypothesize that changes in the ratio between circulating parasites and those that accumulate in the bone marrow and spleen, by avoiding peripheral blood microscopy detection, account for decreased parasite detectability and lower risk of symptoms under low transmission. Conclusions P vivax infections are more likely to be subpatent and remain asymptomatic as malaria transmission decreases. [ABSTRACT FROM AUTHOR]

Background: Imperfect adherence is a major barrier to effective primaquine radical cure of Plasmodium vivax. This study investigated the effect of reduced adherence on the risk of P. vivax recurrence. Methods: Efficacy studies of patients with uncomplicated P. vivax malaria, including a treatment arm with daily primaquine, published between January 1999 and March 2020 were identified. Individual patient data from eligible studies were pooled using standardized methodology. Adherence to primaquine was inferred from i) the percentage of supervised doses and ii) the total mg/kg dose received compared to the target total mg/kg dose per protocol. The effect of adherence to primaquine on the incidence of P. vivax recurrence between days 7 and 90 was investigated by Cox regression analysis. Results: Of 82 eligible studies, 32 were available including 6917 patients from 18 countries. For adherence assessed by percentage of supervised primaquine, 2790 patients (40.3%) had poor adherence (≤ 50%) and 4127 (59.7%) had complete adherence. The risk of recurrence by day 90 was 14.0% [95% confidence interval: 12.1–16.1] in patients with poor adherence compared to 5.8% [5.0–6.7] following full adherence; p = 0.014. After controlling for age, sex, baseline parasitaemia, and total primaquine dose per protocol, the rate of the first recurrence was higher following poor adherence compared to patients with full adherence (adjusted hazard ratio (AHR) = 2.3 [1.8–2.9]). When adherence was quantified by total mg/kg dose received among 3706 patients, 347 (9.4%) had poor adherence, 88 (2.4%) had moderate adherence, and 3271 (88.2%) had complete adherence to treatment. The risks of recurrence by day 90 were 8.2% [4.3–15.2] in patients with poor adherence and 4.9% [4.1–5.8] in patients with full adherence; p < 0.001. Conclusion: Reduced adherence, including less supervision, increases the risk of vivax recurrence. [ABSTRACT FROM AUTHOR]

Background: Larvicides are typically applied to fixed and findable mosquito breeding sites, such as fish farming ponds used in commercial aquaculture, to kill immature forms and thereby reduce the size of adult malaria vector populations. However, there is little evidence suggesting that larviciding may suppress community-wide malaria transmission outside Africa. Here, we tested whether the biological larvicide VectoMax FG applied at monthly intervals to fish farming ponds can reduce malaria incidence in Amazonian Brazil. Methods: This study was carried out in Vila Assis Brasil (VAB; population 1700), a peri-urban malaria hotspot in northwestern Brazil with a baseline annual parasite incidence of 553 malaria cases per 1000 inhabitants. The intervention consisted of monthly treatments with 20 kg/ha of VectoMax FG of all water-filled fish ponds in VAB (n ranging between 167 and 170) with a surface area between 20 and 8000 m2, using knapsack power mistblowers. We used single-group interrupted time-series analysis to compare monthly larval density measurements in fish ponds during a 14-month pre-intervention period (September 2017–October 2018), with measurements made during November 2018–October 2019 and shortly after the 12-month intervention (November 2019). We used interrupted time-series analysis with a comparison group to contrast the malaria incidence trends in VAB and nearby nonintervention localities before and during the intervention. Results: Average larval densities decreased tenfold in treated fish farming ponds, from 0.467 (95% confidence interval [CI], 0.444–0.490) anopheline larvae per dip pre-intervention (September 2017–October 2018) to 0.046 (95% CI, 0.041–0.051) larvae per dip during (November 2018–October 2019) and shortly after the intervention (November 2019). Average malaria incidence rates decreased by 0.08 (95% CI, 0.04–0.11) cases per 100 person-months (P < 0.0001) during the intervention in VAB and remained nearly unchanged in comparison localities. We estimate that the intervention averted 24.5 (95% CI, 6.2–42.8) malaria cases in VAB between January and December 2019. Conclusions: Regular larviciding is associated with a dramatic decrease in larval density and a modest but significant decrease in community-wide malaria incidence. Larviciding may provide a valuable complementary vector control strategy in commercial aquaculture settings across the Amazon. [ABSTRACT FROM AUTHOR]

Background: Plasmodium vivax is a neglected human malaria parasite that causes significant morbidity in the Americas, the Middle East, Asia, and the Western Pacific. Population genomic approaches remain little explored to map local and regional transmission pathways of P. vivax across the main endemic sites in the Americas, where great progress has been made towards malaria elimination over the past decades. Methodology/Principal findings: We analyze 38 patient-derived P. vivax genome sequences from Mâncio Lima (ML)–the Amazonian malaria hotspot next to the Brazil-Peru border—and 24 sequences from two other sites in Acre State, Brazil, a country that contributes 23% of malaria cases in the Americas. We show that the P. vivax population of ML is genetically diverse (π = 4.7 × 10−4), with a high polymorphism particularly in genes encoding proteins putatively involved in red blood cell invasion. Paradoxically, however, parasites display strong genome-wide linkage disequilibrium, being fragmented into discrete lineages that are remarkably stable across time and space, with only occasional recombination between them. Using identity-by-descent approaches, we identified a large cluster of closely related sequences that comprises 16 of 38 genomes sampled in ML over 26 months. Importantly, we found significant ancestry sharing between parasites at a large geographic distance, consistent with substantial gene flow between regional P. vivax populations. Conclusions/Significance: We have characterized the sustained expansion of highly inbred P. vivax lineages in a malaria hotspot that can seed regional transmission. Potential source populations in hotspots represent a priority target for malaria elimination in the Amazon. Authors' summary: Plasmodium vivax is the geographically most widespread human malaria parasite and causes 80% of the malaria burden in the Americas. Here we use whole-genome sequencing to explore levels of parasite relatedness and infer P. vivax transmission networks in the upper Juruá Valley, the main transmission hotspot in Amazonian Brazil. We characterize a genetically diverse population that displays significant linkage disequilibrium, consistent with the local circulation of highly inbred but genetically distant parasite lineages. Noteworthy, these discrete lineages remain stable over time and share recent ancestry with parasites at a large geographic distance. These results illustrate the power of genomic epidemiology approaches to map potential source parasite populations and prioritize areas for targeted control interventions to eliminate residual P. vivax transmission in the Amazon and similar endemic settings worldwide. [ABSTRACT FROM AUTHOR]

We investigated linear growth and weight attained among 772 children at 10–15 months of age in the first population-based birth cohort in the Brazilian Amazon. Sociodemographic, maternal and birth characteristics were collected in interviews soon after birth at baseline. Anthropometric evaluation was conducted at 10–15 months. Multiple linear regression models were fitted for length-for-age (LAZ) and body mass index (BMI)-for-age Z scores (BAZ), considering a hierarchical conceptual framework with determinants at distal, intermediate and proximal levels, with adjustment for the child’s sex and age. Mean LAZ and BAZ were 0.31 (SD: 1.13) and 0.35 (SD: 1.06), respectively. Overall, 2.2% of children were stunted and 6.6% overweight. Among socioeconomic factors, household wealth index was positively associated with LAZ (p for trend = 0.01), while children whose families received assistance from the Bolsa Família conditional cash transfer program were 0.16 Z score thinner (95% CI: -0.31, -0.00). Maternal height and BMI were positively associated with both LAZ and BAZ at 10–15 months of age (p for trend <0.001). Child’s size at birth was positively related with LAZ (p<0.001 for both birth weight and length). BAZ was 0.34 (95% CI: 0.24, 0.44) higher, but 0.11 lower (95% CI: -0.21, -0.02), for each increase in 1 Z score of birth weight and length, respectively. Children with at least one reported malaria episode within the first year of life were 0.58 (95% CI: -1.05, -0.11) Z score shorter. Socioeconomic and intergenerational factors were consistently associated with LAZ and BAZ at 10–15 months of age. The occurrence of malaria was detrimental to linear growth. In a malaria endemic region, reduction of inequalities and disease burden over the first 1,000 days of life is essential for taking advantage of a critical window of opportunity that can redirect child growth trajectories toward better health and nutrition conditions in the long term. [ABSTRACT FROM AUTHOR]

The human brain experiences intensive connectivity and size transformations after birth.1 Head circumference (HC) shows important increments in size, specifically in the first year; then, this growth rate decelerates over time.2 Identifying the different elements required for proper physical growth in children during critical periods is relevant for primary health care. The regression coefficients ( ) and their 95% confidence intervals (95% CIs) were calculated by multiple linear regression, to assess the independent associations with HC z-score values at the follow-up visit. After multiple adjustments, there were number of variables that were positive predictors of the HC z-score in the first year of life, in addition to the child's age, primiparity, type of delivery and birthweight. [Extracted from the article]

Background: A new species of phlebotomine sand flies belonging to Trichophoromyia Barretto, 1962 genus is described, based on males collected in Jaú National Park, Amazonas state, Brazil. Methods: The Sand flies were mounted in Canada balsam. They were measured with a binocular Olympus CH-2 microscope with the aid of a micrometer objective and the drawings were done with the help of a camera lucida. Results: This new species named Trichophoromyia uniniensis sp. nov. is closely related to Trichophoromyia omagua (Martins, Llanos & Silva, 1976). The former can be distinguished from the latter by the shape of its paramere that has the lower apical region turned up in the new species. Conclusion: With the new species here described a total of 39 species belonging to the Trichophoromyia genus are now known, most of them present in the Amazon rainforest. [ABSTRACT FROM AUTHOR]