Population Genetics of Plasmodium vivax in the Peruvian Amazon.

BACKGROUND: Characterizing the parasite dynamics and population structure provides useful information to understand the dynamic of transmission and to better target control interventions. Despite considerable efforts for its control, vivax malaria remains a major health problem in Peru. In this study, we have explored the population genetics of Plasmodium vivax isolates from Iquitos, the main city in the Peruvian Amazon, and 25 neighbouring peri-urban as well as rural villages along the Iquitos-Nauta Road. METHODOLOGY/ RESULTS: From April to December 2008, 292 P. vivax isolates were collected and successfully genotyped using 14 neutral microsatellites. Analysis of the molecular data revealed a similar proportion of monoclonal and polyclonal infections in urban areas, while in rural areas monoclonal infections were predominant (p = 0.002). Multiplicity of infection was higher in urban (MOI = 1.5-2) compared to rural areas (MOI = 1) (p = 0.003). The level of genetic diversity was similar in all areas (He = 0.66-0.76, p = 0.32) though genetic differentiation between areas was substantial (PHIPT = 0.17, p<0.0001). Principal coordinate analysis showed a marked differentiation between parasites from urban and rural areas. Linkage disequilibrium was detected in all the areas ([Formula: see text] = 0.08-0.49, for all p<0.0001). Gene flow among the areas was stablished through Bayesian analysis of migration models. Recent bottleneck events were detected in 4 areas and a recent parasite expansion in one of the isolated areas. In total, 87 unique haplotypes grouped in 2 or 3 genetic clusters described a sub-structured parasite population. CONCLUSION/SIGNIFICANCE: Our study shows a sub-structured parasite population with clonal propagation, with most of its components recently affected by bottleneck events. Iquitos city is the main source of parasite spreading for all the peripheral study areas. The routes of transmission and gene flow and the reduction of the parasite population described are important from the public health perspective as well for the formulation of future control policies

Anafilaxia en niños y adultos: prevención, diagnóstico y tratamiento

La anafilaxia es una condición que requiere asistencia inmediata para su resolución, se puede presentar en diferentes entornos: consultorio, hospital, escuela, hogar o en algún otro espacio público. La información aquí contenida forma parte de lineamientos conocidos sobre prevención, diagnóstico y tratamiento. Se abordan aspectos epidemiológicos, desencadenantes, factores de riesgo y cofactores; se explican de una manera didáctica los mecanismos fisiopatológicos que se traducen en fenotipos de presentación. Se enfatiza el diagnóstico clínico con base en criterios ya establecidos, se mencionan clasificaciones para evaluar la gravedad de la reacción, así como el rol de las pruebas clínicas o de laboratorio. Como aspectos de relevancia, se abordan el tratamiento de primera elección con adrenalina, instrucciones sobre autoinyectores y diferentes elementos para el tratamiento complementario y de segunda elección. También se refieren aspectos a considerar al dar de alta a un paciente y medidas de seguimiento, con un énfasis preventivo en la comunidad. Finalmente, se menciona el abordaje en el consultorio de alergia para decidir sobre opciones de inmunomodulación. ABSTRACT Anaphylaxis is a condition that requires immediate assistance for its resolution, it can occur in different settings: office, hospital, school, home or some other public space. The information contained herein forms part of known guidelines on prevention, diagnosis and treatment. Epidemiological aspects, triggers, risk factors and co-factors are addressed; physiopathological mechanisms that are translated into presentation phenotypes are explained in a didactic way. Clinical diagnosis is emphasized based on established criteria, classifications are mentioned to evaluate the severity of the reaction, as well as the role of clinical or laboratory tests. As relevant aspects, the first choice treatment with adrenaline, instructions on auto-injectors and different elements for the complementary and second choice treatment are dealt with. They also refer to aspects to consider when discharging a patient and followup measures, with a preventive emphasis on the community. Finally, the allergy clinic approach to deciding on immunomodulation options is mentione

Presence of anti-Toxoplasma antibodies in humans and their cats in the urban zone of Guadalajara

Cats are the definitive hosts of Toxoplasma gondii. Infected cats excrete oocysts in their feces, infecting humans and other animals. The objective of the present study was to determine the presence of anti-Toxoplasma antibodies in cat owners and their pets, and determine if there was a relationship between Toxoplasma infection and humans who live with infected cats. IgG anti-Toxoplasma antibodies in sera of 59 cat owners were determined by enzyme-linked immunosorbent assay (ELISA), in 24 sera from their cats, IgG, IgM, and IgA antibodies were found using Burney's ELISA. Thirty-eight (64%) of 59 cat owners were positive to IgG anti-Toxoplasma. Seropositivity for cats was 70.8% IgG, 8.3% IgM, and 62.5% IgA. Cohabitation with cats infected by T. gondii, feeding with leftovers or raw viscera, and lack of control over how their feces were handled are risk factors conducive for humans to become infected by T. gondii

<i>PHI</i>_PT values obtained from pairwise comparison between study areas (A1–A5) and between villages within each area.

<p><i>PHI</i>_PT values obtained from pairwise comparison between study areas (A1–A5) and between villages within each area.</p

PCoA of the parasite population at village and individual haplotype level.

<p>(A) Principal coordinate analysis of the study areas resulted from intercomparison of individual villages. Percentages in the parenthesis indicate the proportion of total variation explained by each principal coordinate. The term “others…” was used to group villages within specific areas that had less than 2 isolates with known haplotype. (B) PCoA among the individual haplotypes within the areas. Areas are defined in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004376#pntd.0004376.g001" target="_blank">Fig 1A</a> and village abbreviations are detailed in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004376#pntd.0004376.s001" target="_blank">S1 Table</a>.</p

Comparison of 13 parasite migration models and summary estimates of gene flow.

<p><b>(A)</b> The study areas were pooled as an unique population and in 3–5 populations. The arrows represent the direction of migration and the models are displayed by its rank order. The marginal log-likelihoods and LBF used to rank the models are tabulated in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004376#pntd.0004376.s004" target="_blank">S4 Table</a>. The model XIII (panmixia) has the highest model probability (>0.99) while all the rest have near zero probability. <b>(B)</b> The estimated number of immigrants per generation are described for the models XI and III. The thicknesses of the arrows are proportional to the number of immigrants. The Θ and <i>M</i> estimates for the models XIII, XI and III are tabulated in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004376#pntd.0004376.s005" target="_blank">S5 Table</a>.</p

Population Genetics of <i>Plasmodium vivax</i> in the Peruvian Amazon - Table 3

<p>Multilocus linkage disequilibrium assessed using the Index of association ().</p