Knowledge and the Late Theory of Forms in the Greatest Difficulty and Socrates' Dream

BACKGROUND: P. falciparum gametocytes may persist after treatment with sulphadoxine-pyrimethamine (SP) plus artesunate (AS) and contribute considerably to malaria transmission. We determined the efficacy of SP+AS plus a single dose of primaquine (PQ, 0.75 mg/kg) on clearing gametocytaemia measured by molecular methods. METHODOLOGY: The study was conducted in Mnyuzi, an area of hyperendemic malaria in north-eastern Tanzania. Children aged 3–15 years with uncomplicated P. falciparum malaria with an asexual parasite density between 500–100,000 parasites/µL were randomized to receive treatment with either SP+AS or SP+AS+PQ. P. falciparum gametocyte prevalence and density during the 42-day follow-up period were determined by real-time nucleic acid sequence-based amplification (QT-NASBA). Haemoglobin levels (Hb) were determined to address concerns about haemolysis in G6PD-deficient individuals. RESULTS: 108 individuals were randomized. Pfs25 QT-NASBA gametocyte prevalence was 88–91% at enrolment and decreased afterwards for both treatment arms. Gametocyte prevalence and density were significantly lower in children treated with SP+AS+PQ. On day 14 after treatment 3.9% (2/51) of the SP+AS+PQ treated children harboured gametocytes compared to 62.7% (32/51) of those treated with SP+AS (p<0.001). Hb levels were reduced in the week following treatment with SP+AS+PQ and this reduction was related to G6PD deficiency. The Hb levels of all patients recovered to pre-treatment levels or greater within one month after treatment. CONCLUSIONS: PQ clears submicroscopic gametocytes after treatment with SP+AS and the persisting gametocytes circulated at densities that are unlikely to contribute to malaria transmission. For individuals without severe anaemia, addition of a single dose of PQ to an efficacious antimalarial drug combination is a safe approach to reduce malaria transmission following treatment. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN6153496

Toxoplasma gondii seroprevalence among pregnant women attending antenatal clinic in Northern Tanzania

Abstract Background Acute Toxoplasma gondii infection during pregnancy represents a risk for congenital disease, especially among women without previous exposure to infection. There is, however, a paucity of information about the epidemiology of T. gondii infection in pregnant women in Tanzania. This study aimed to determine the seroprevalence of T. gondii infection and associated demographic, clinical, and behavioral risk factors in pregnant women attending ante-natal clinic (ANC) at Kilimanjaro Christian Medical Center (KCMC), a referral medical center in Northern Tanzania. Methods A hospital-based cross-sectional study was carried out from 1 February to 30 April 2017. Data on maternal demographic characteristics, obstetric history, knowledge, and practices related to T. gondii infection were collected from 254 pregnant women attending antenatal care at KCMC. A sample of 4 mL of blood was collected from each participant and sera prepared from each sample. Serum samples were tested for the presence of specific T. gondii IgG and IgM antibodies by indirect Enzyme-Linked Immunosorbent Assay (ELISA). DNA was extracted from whole blood for polymerase chain reaction (PCR) testing, targeting the DNA sequence coding for the Internal Transcribed Spacer 1 (ITS1). Results The overall T. gondii seroprevalence, including both IgM- and IgG-positive individuals, was 44.5%. Of the 254 tested women, 102 and 23 were seropositive for T. gondii-specific IgG and IgM antibodies respectively and 113 individuals had antibodies of either or both classes. All IgM-positive samples were also tested by PCR, and all were negative. The majority (90%) of the women surveyed had never heard about toxoplasmosis. Consumption of raw vegetables [aOR = 0. 344; 95% CI 0.151–0.784; p = 0.011] and having regular contact with soil [aOR = 0.482; 95% CI 0.268–0.8681; p = 0.015] were both associated with T. gondii antibody status. Inverse relationships with probability of T. gondii exposure were observed, such that these practices were associated with reduced probability of antibody detection. Conclusion Based on serology results, we report widespread exposure to T. gondii infection among pregnant women attending ANC in KCMC. The complex interaction of risk factors for T. gondii infection needs to be studied in larger longitudinal studies

Composição e variabilidade espaço-temporal da meiofauna de uma praia arenosa na região amazônica (Ajuruteua, Pará) Composition and spatio-temporal variability of meiofauna community on a sandy beach in the Amazon region (Ajuruteua, Pará, Brazil)

Este trabalho avalia a variabilidade espaço-temporal da meiofauna do médiolitoral na praia de Ajuruteua, Estado do Pará. As coletas foram realizadas a cada dois meses, entre abril de 2003 a fevereiro de 2004 durante as marés de sizígia, em diferentes zonas da praia. As amostras foram retiradas com um amostrador cilíndrico de 3,14 cm² e fixadas em formalina salina a 5%. Em laboratório, as amostras foram passadas em malha de 0,063 mm de abertura e os organismos retidos identificados em nível de grandes grupos taxonômicos, contados e fixados em álcool etílico a 70%. A meiofauna esteve representada por oito grupos: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, adultos de Copepoda Harpacticoida e juvenis de Copepoda Harpacticoida. Nematoda foi o grupo dominante, representando 74% do total de indivíduos, seguido de Copepoda (19%). Pôde-se observar clara zonação horizontal da fauna, que se distribuiu em três faixas paralelas à linha de praia, com características significativamente distintas quanto à abundância, riqueza e densidade dos principais grupos taxonômicos. No médiolitoral médio foram observados valores significativamente mais elevados de riqueza e abundância, enquanto os valores mais baixos foram registrados no médiolitoral superior e inferior. A comunidade de meiofauna, ainda que não tenha variado significativamente entre períodos climáticos, foi mais rica e abundante nos meses secos. Os principais fatores responsáveis pelas variações espaço-temporais da meiofauna foram a ação das ondas e das marés e as variações na salinidade da água.<br>The present study investigates the spatio-temporal changes in the meiofauna community along the intertidal zone of Ajuruteua Beach, State of Pará, Brazil. Samples were collected during spring tides at different levels of the beach face every two months from April 2003 to February 2004. The material was sampled using a cylindrical corer (3.14 cm²) and fixed with 5% saline formalin. In the laboratory, samples were sieved through a 0.063 mm mesh screen and the retained organisms were identified at higher taxonomic levels, counted and preserved in ethanol 70%. Meiofauna was composed of eight groups: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, Copepoda and nauplius (Copepoda). Nematoda was the dominant group, representing 74% of total organisms, followed by Copepoda (19%). A clear faunal zonation was observed on three lines parallel to the shoreline, which showed significant differences in abundance, richness and density of the main taxonomic groups. The mean density was lowest in April and highest in December. The highest densities and richness were recorded in the mid intertidal zone, while the lowest values were recorded in the upper and lower intertidal zones. Meiofauna community was most rich and abundant during the dry months, although differences were not significant between climatic periods. The main factors involved in the spatio-temporal variations of meiofauna were wave and tidal action and salinity fluctuations