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Jonathan A. Polonsky Melissa Ivey Md. Khadimul Anam Mazhar Ziaur Rahman Olivier le Polain de Waroux Basel Karo Katri Jalava Sirenda Vong Amrish Baidjoe Janet Diaz Flavio Finger Zakir H. Habib Charls Erik Halder Christopher Haskew Laurent Kaiser Ali S. Khan Lucky Sangal Tahmina Shirin Quazi Ahmed Zaki Md. Abdus Salam Kate White 《PLoS medicine》2021,18(4)
BackgroundUnrest in Myanmar in August 2017 resulted in the movement of over 700,000 Rohingya refugees to overcrowded camps in Cox’s Bazar, Bangladesh. A large outbreak of diphtheria subsequently began in this population.Methods and findingsData were collected during mass vaccination campaigns (MVCs), contact tracing activities, and from 9 Diphtheria Treatment Centers (DTCs) operated by national and international organizations. These data were used to describe the epidemiological and clinical features and the control measures to prevent transmission, during the first 2 years of the outbreak. Between November 10, 2017 and November 9, 2019, 7,064 cases were reported: 285 (4.0%) laboratory-confirmed, 3,610 (51.1%) probable, and 3,169 (44.9%) suspected cases. The crude attack rate was 51.5 cases per 10,000 person-years, and epidemic doubling time was 4.4 days (95% confidence interval [CI] 4.2–4.7) during the exponential growth phase. The median age was 10 years (range 0–85), and 3,126 (44.3%) were male. The typical symptoms were sore throat (93.5%), fever (86.0%), pseudomembrane (34.7%), and gross cervical lymphadenopathy (GCL; 30.6%). Diphtheria antitoxin (DAT) was administered to 1,062 (89.0%) out of 1,193 eligible patients, with adverse reactions following among 229 (21.6%). There were 45 deaths (case fatality ratio [CFR] 0.6%). Household contacts for 5,702 (80.7%) of 7,064 cases were successfully traced. A total of 41,452 contacts were identified, of whom 40,364 (97.4%) consented to begin chemoprophylaxis; adherence was 55.0% (N = 22,218) at 3-day follow-up. Unvaccinated household contacts were vaccinated with 3 doses (with 4-week interval), while a booster dose was administered if the primary vaccination schedule had been completed. The proportion of contacts vaccinated was 64.7% overall. Three MVC rounds were conducted, with administrative coverage varying between 88.5% and 110.4%. Pentavalent vaccine was administered to those aged 6 weeks to 6 years, while tetanus and diphtheria (Td) vaccine was administered to those aged 7 years and older. Lack of adequate diagnostic capacity to confirm cases was the main limitation, with a majority of cases unconfirmed and the proportion of true diphtheria cases unknown.ConclusionsTo our knowledge, this is the largest reported diphtheria outbreak in refugee settings. We observed that high population density, poor living conditions, and fast growth rate were associated with explosive expansion of the outbreak during the initial exponential growth phase. Three rounds of mass vaccinations targeting those aged 6 weeks to 14 years were associated with only modestly reduced transmission, and additional public health measures were necessary to end the outbreak. This outbreak has a long-lasting tail, with Rt oscillating at around 1 for an extended period. An adequate global DAT stockpile needs to be maintained. All populations must have access to health services and routine vaccination, and this access must be maintained during humanitarian crises.Jonathan Polonsky and colleagues report on a diphtheria outbreak among Rohingya people in Cox’s Bazar, Bangladesh during 2017-19. 相似文献
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La Kondasso Taïga Serge Alexis Kamgang Eric Moïse Bakwo Fils Tsakem Christian Samuel Vera Rduch 《African Journal of Ecology》2021,59(1):142-151
Assessing the population status of wildlife is useful for enhancing biodiversity management strategies in protected areas. This study was carried out within the framework of the Faro National Park (FNP) management plan. The objective was to provide baseline data on the status and population dynamics of the Buffon's kob (Kobus kob kob). The surveys were conducted in the month of June at the beginning of the rainy season. Data were collected along 145 line transects of 2.5 km apart and analysed using Distance 7.2 and Quantum GIS 3.4 software. The Buffon's kob population was estimated to comprise around 4,094 ± 1,303 individuals, with an overall density of 1.24 individuals/km2. When compared to results from a study conducted in the year 2000, the concentration of Buffon's kob was higher in the northern part of the national park as opposed to the southern part, as was previously recorded. The population trend shows an extensive decline of approximately 80% compared to records of the year 2000. There was also a weak negative correlation between Buffon's kob density and human activities in the FNP. 相似文献
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Brian M. Myers Kevin J. Burns Christopher J. Clark Alan Brelsford 《Ecology and evolution》2021,11(4):1850
Allen''s Hummingbird comprises two subspecies, one migratory (Selasphorus sasin sasin) and one nonmigratory (S. s. sedentarius). The nonmigratory subspecies, previously endemic to the California Channel Islands, apparently colonized the California mainland on the Palos Verdes Peninsula some time before 1970 and now breeds throughout coastal southern California. We sequenced and compared populations of mainland nonmigratory Allen''s Hummingbird to Channel Island populations from Santa Catalina, San Clemente, and Santa Cruz Island. We found no evidence of founder effects on the mainland population. Values of nucleotide diversity on the mainland were higher than on the Channel Islands. There were low levels of divergence between the Channel Islands and the mainland, and Santa Cruz Island was the most genetically distinct. Ecological niche models showed that rainfall and temperature variables on the Channel Islands are similar in the Los Angeles basin and predicted continued expansion of nonmigratory Allen''s Hummingbird north along the coast and inland. We also reviewed previous genetic studies of vertebrate species found on the Channel Islands and mainland and showed that broad conclusions regarding island–mainland patterns remain elusive. Challenges include the idiosyncratic nature of colonization itself as well as the lack of a comprehensive approach that incorporates similar markers and sampling strategies across taxa, which, within the context of a comparative study of island–mainland relationships, may lead to inconsistent results. 相似文献
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Miguel Prudêncio 《EMBO reports》2021,22(2)
Despite its limited resources, Portugal has gained a prominent position in research on malaria. Several historical and personal factors have contributed to this achievement. Subject Categories: S&S: Economics & Business, S&S: History & Philosophy of Science, Microbiology, Virology & Host Pathogen InteractionDespite a significant increase that started during the 1990s, Portugal’s scientific production remains rather modest compared with the overall research output in the European Union (EU). However, the country’s achievements in malaria research are truly remarkable and, in relative terms, far above its EU neighbors in most relevant accounts. The factors to explain this accomplishment include the fact that malaria was autochthonous in Portugal until 1973; the country’s colonial history and its close ties with its former colonies; and several outstanding scientists who each inspired generations of malariologists.For most of the 20th century, research in Portugal was underfunded, and the country’s overall contribution to science was modest at best. This started to change when Portugal joined the European Union (then the European Economic Community) in 1985 and gained further momentum in the 1990s with the creation of a dedicated Ministry of Science. As a consequence, the Portuguese scientific production increased significantly in terms of the number of scientific articles published. Nevertheless, public funding for research has remained well below that of many other EU countries, and far from the target of 3% of the country’s GDP, which limits Portugal’s overall scientific output. Yet, there is one field of research where Portugal has been making significant contributions, even long before 1985: malaria.
… there is one field of research where Portugal has been making significant contributions, even long before 1985: malaria.Among many other achievements, Portuguese laboratories have delivered important contributions to malaria research in areas as diverse as drug development, discovery and repurposing, genetic diversity of Plasmodium parasites, mechanisms of drug resistance, co‐infection between Plasmodium and other parasites, host–Plasmodium interactions, nutrient sensing and acquisition by malaria parasites, modulation of Plasmodium liver infection, immune and inflammatory responses to Plasmodium infection, diagnosis, vaccines, the role of microbiota on malaria transmission, pathogenesis of placental and cerebral malaria and acute lung injury, mechanisms of tolerance to malaria, malaria epidemiology, and vector genetics (see Further Reading for examples). Portugal’s percentage of scientific papers published in the field of malaria during the past decade relative to the total number of published articles is the highest in the EU (Fig 1A). Naturally, Portugal cannot compete with larger or more affluent countries in terms of the absolute numbers of articles published on malaria. Yet, the country ranks 5th in this regard, closely following the Netherlands, Belgium, Sweden, and Denmark, four countries that have been investing much more and much longer in scientific research (Fig 1B). In fact, if one takes into account the funding for R&D in the EU nations, Portugal ranks ahead of every other country in terms of the number of malaria papers published relative to the investment made in science at the national level (Fig 1C).Open in a separate windowFigure 1Malaria research in Portugal and in the EU(A) Percentage of papers on the subject of malaria relative to the total number of papers from each of the indicated countries from 2009 to present. (B) Number of malaria research articles per 1,000 researchers in each of the indicated countries. (C) Number of malaria research articles per 100,000 Euros of gross domestic expenditure on R&D in each of the indicated countries. Total R&D personnel and intramural R&D expenditure data are from 2017. Papers were quantified through searches of PubMed for articles with affiliation to each of the indicated countries, published from 2009 to present, by use of the terms “malaria” or “Plasmodium”. Data on R&D investments from Eurostat.This raises the question of why Portugal, a rather small country with only a few decades of research history and an overall moderate scientific performance, fares relatively so well when it comes to research on malaria. I argue that there are three independent, albeit interrelated factors to explain this feat.A lasting reality demanding an appropriate responseThe first factor was the presence of autochthonous malaria in Portugal until the second half of the 20th century and the establishment of research institutions largely dedicated to studying and fighting the disease. Until the end of the World War II, malaria was endemic throughout much of Southern Europe; Italy, Greece, and Portugal were particularly affected. From 1955 to 1969, the WHO conducted its Global Malaria Eradication Programme, which successfully eliminated malaria in several regions of the world, including Southern Europe. The specific history of malaria eradication in Portugal is described in great detail by Bruce‐Chwatt (Bruce‐Chwatt, 1977) and highlights the intense efforts by multiple state‐sponsored institutions dedicated to studying and combating the disease.Even before the war, in 1931, the Malaria Research Station (Estação Experimental de Combate ao Sezonismo, EECS) was created in Benavente, the goals of which included the collection and analysis of blood samples from infected individuals, treatment of malaria patients, identification of mosquito populations, and malaria prophylaxis. In 1938, the Malaria Institute (Instituto de Malariologia, iMal) was founded in Águas de Moura to investigate the epidemiology of the disease, promoting adequate treatment and implementing vector control measures (Saavedra, 2010). Nonetheless, it was not until 1973 that malaria was eventually eliminated in Portugal, three years after Italy, and only one year before Greece.
… it was not until 1973 that malaria was eventually eliminated in Portugal, three years after Italy, and only one year before Greece.Yet, the threat of malaria reemergence meant ongoing vigilance, and iMal paved the way for the creation of the Centre for the Study of Malaria and Parasitology (Centro de Estudos de Malária e Parasitologia), in 1973, later to become the Centre for the Study of Zoonoses (Centro de Estudos de Zoonoses) in 1987, and the Centre for Vector and Infectious Disease Studies (Centro de Estudos de Vetores e Doenças Infeciosas) in 1993. In addition, the Portuguese School of Tropical Medicine (later called National School of Public Health and Tropical Medicine, ENSPMT, now the Institute of Tropical Medicine and Hygiene, IHMT), founded in 1902, was one of only four institution of its kind in the world (Amaral, 2008). Since its inception, its mission has been the teaching and research in tropical medicine, biomedical sciences, and international health and, to this day, a significant part of its research continues to focus on malaria.A close bond with AfricaAnother major factor for Portugal’s prominent position in malaria research is its colonial past and the country’s close ties with its former colonies. During its period of maritime expansion in the 15th and 16th centuries, Portugal colonized many territories from Asia to the Americas and Africa. Most, if not all, of these territories were, and for a large part still are, endemic for malaria. Former colonies, such as Brazil or the Portuguese territories in India, gained their independence during the 19th century, but maintained close ties with Portugal.However, several African countries, specifically Angola, Cape Verde, Guinea‐Bissau, Mozambique, and S. Tomé & Príncipe, remained under Portuguese rule until well into the second half of the 20th century (Miller, 1975). In fact, while most African nations gained their independence from European countries during the 1950s and 1960s, Portugal’s dictatorship held on to and suppressed its African overseas territories, which led to armed uprisings in Angola and Guinea‐Bissau in 1961, and in Mozambique in 1964 (Miller, 1975). During the ensuing colonial wars, thousands of Portuguese soldiers were sent to these countries, where they were exposed not only to the horrors of war, but also to malaria (Campos, 2017). The Portuguese military actions in Africa finally came to an end in 1974 after the peaceful Carnation Revolution, which established democracy in Portugal and ended the colonization of all Portuguese‐held African territories.Over the next few years, hundreds of thousands of military personnel and former residents of the ex‐colonies, known as “retornados”, moved back to Portugal, leading to an increase in the number of imported malaria cases (Bruce‐Chwatt, 1977). Since then, these numbers have subsided, but the close ties that Portugal maintains with its former colonies mean that travel to and from malaria‐endemic regions remains high, contributing to the prevalence of imported malaria cases (Piperaki, 2018). It also means that malaria is not such a distant threat for most Portuguese; even today, many younger people have direct contact with family members or friends who have experienced malaria, bringing the reality of this scourge closer to home than in many other EU countries.
… even today, many younger people have direct contact with family members or friends who have experienced malaria, bringing the reality of this scourge closer to home than in many other EU countries.Remarkable and inspiring figuresThe third and final factor is the enormous and lasting influence of various uniquely inspiring figures from several generations of malaria researchers. Indeed, the history of Portuguese malaria research is rich in prominent scientists who shaped the national research landscape. Attempting to highlight specific names among the many doctors, epidemiologists, and scientists from the past and present is a naturally risky exercise that runs the risk of overlooking important figures. Nevertheless, the crucial contribution of a few representatives of four generations of Portuguese scientists is beyond dispute.Ricardo Jorge (1858–1939) was a renowned epidemiologist responsible for the 1899–1901 National Sanitary Plan, which marked the introduction of modern sanitary concepts in Portugal and changed national public health. In 1903, Jorge was the first to collect reliable and extensive data on the incidence of malaria and its seasonal distribution (JORGE, 1903). He was Portugal’s Health Inspector‐General from 1899 to 1926, succeeded by José Alberto de Faria (1888–1958), another key figure who, with the support of the Rockefeller Foundation (Saavedra, 2014), created the EECS in Benavente, the first step for advancing knowledge about malaria in Portugal (Bruce‐Chwatt, 1977).Well within the 20th century, Francisco Cambournac (1903–1994) and Fausto Landeiro (1896–1949) were arguably the most important contributors to Portuguese malariology during that period. Following extensive training in some of the most reputed parasitology schools in Europe, Cambournac became Director of Benavente’s EECS in 1933, and Landeiro occupied that position from 1938 to 1949. Cambournac founded the iMal in Águas de Moura, serving as its Director from 1939 to 1954, and became Director of the WHO’s African region from 1954 to 1964 (Lobo, 2012).Cambournac and Landeiro published extensively on the epidemiology, entomology, and control of malaria during the 1930s and 1940s, and gave a comprehensive account of the status of the disease in Portugal during that period. Cambournac’s 237‐page long review (Cambournac, 1942) provided all the epidemiological and other data needed for future planning of control and eradication of malaria in the country, the success of which is widely acknowledged to his immense work (Bruce‐Chwatt, 1977).During the 1960s and early 1970s, the National School of Public Health and Tropical Medicine, ENSPMT, now the Institute of Tropical Medicine and Hygiene, IHMT, played an important role not only in Portuguese research on malaria and other tropical diseases, but also in the cooperation with Portugal’s overseas territories at the time. The 1974 revolution and the decolonization in Africa led to a reshaping of this cooperation, which became increasingly centered on reinforcing the newly independent countries’ health systems, on their capacity to carry out research on endemic diseases, and on training programs in tropical and preventive medicine (Havik, 2015). Virgílio do Rosário, professor at the IHMT and, later, head of the Institute’s Centre for Malaria and Other Tropical Diseases (CMDT), played a pivotal role in this process. Do Rosário was the founder of several national and international networks for studying malaria and neglected diseases in various regions around the world. He inspired a whole generation of future malaria researchers, making him an inescapable figure among Portuguese malariologists in the second half of the 20th century.At the dawn of the 21st century, many Portuguese scientists, who had benefitted from the country’s investment in science in the 1980s and 1990s to acquire international training, came back home to set up their own research groups. Among them was Maria Mota, who returned from New York University to Portugal in 2002 to become a group leader, initially at the Instituto Gulbenkian de Ciência (IGC), and subsequently at the Instituto de Medicina Molecular (iMM). Mota’s research on the liver stage of infection by Plasmodium parasites has had an enormous impact and yielded a plethora of outstanding publications. She became Director of iMM in 2014, and commonly features among the most influential women in Portugal. Mota is also a gifted and engaging communicator, who has helped to garner public attention to malaria research and to the fight against the disease. As a great scientist and public advocate for malaria research, Mota has inspired numerous scientists, several of whom have become independent malaria researchers themselves, both in Portugal and internationally.
As a great scientist and public advocate for malaria research, Mota has inspired numerous scientists, several of whom have become independent malaria researchers themselves…These historical, epidemiological, and humane factors have made Portugal an important player in malaria research, from the basic science of the parasite to the pathology of the disease, and from epidemiology to clinical research and drug development. However, these great achievements, and the role played by individual inspiring scientists, should not be taken for granted, but rather serve as an argument for nurturing and supporting research on malaria by future generations of scientists and political decision‐makers. A small country with fairly limited financial and human resources cannot reasonably aspire to excel in every area of research, but it can efficiently direct and focus its investment on those that are more likely to generate success. The history of Portuguese malaria research clearly demonstrates this and warrants its continued support as a top priority for national science policies.Further ReadingImportant contributions to malaria research by Portuguese laboratories during the past decade Drug development, discovery and repurposing Oliveira R, Guedes RC, Meireles P, Albuquerque IS, Goncalves LM, Pires E, Bronze MR, Gut J, Rosenthal PJ, Prudencio M, Moreira R, O''Neill PM, Lopes F (2014) Tetraoxane‐pyrimidine nitrile hybrids as dual stage antimalarials. J Med Chem 57: 4916–4923da Cruz FP, Martin C, Buchholz K, Lafuente‐Monasterio MJ, Rodrigues T, Sonnichsen B, Moreira R, Gamo FJ, Marti M, Mota MM, Hannus M, Prudencio M (2012) Drug screen targeted at Plasmodium liver stages identifies a potent multistage antimalarial drug. J Infect Dis 205: 1278–1286Hanson KK, Ressurreicao AS, Buchholz K, Prudencio M, Herman‐Ornelas JD, Rebelo M, Beatty WL, Wirth DF, Hanscheid T, Moreira R, Marti M, Mota MM (2013) Torins are potent antimalarials that block replenishment of Plasmodium liver stage parasitophorous vacuole membrane proteins. Proc Natl Acad Sci USA 110: E2838–E2847Machado M, Sanches‐Vaz M, Cruz JP, Mendes AM, Prudencio M (2017) Inhibition of Plasmodium Hepatic Infection by Antiretroviral Compounds. Front Cell Infect Microbiol 7: 329 Genetic diversity of Plasmodium parasites Guerra M, Neres R, Salgueiro P, Mendes C, Ndong‐Mabale N, Berzosa P, de Sousa B, Arez AP (2017) Plasmodium falciparum Genetic Diversity in Continental Equatorial Guinea before and after Introduction of Artemisinin‐Based Combination Therapy. Antimicrob Agents Chemother 61Mendes C, Salgueiro P, Gonzalez V, Berzosa P, Benito A, do Rosario VE, de Sousa B, Cano J, Arez AP (2013) Genetic diversity and signatures of selection of drug resistance in Plasmodium populations from both human and mosquito hosts in continental Equatorial Guinea. Malar J 12: 114 Mechanisms of drug resistance Escobar C, Pateira S, Lobo E, Lobo L, Teodosio R, Dias F, Fernandes N, Arez AP, Varandas L, Nogueira F (2015) Polymorphisms in Plasmodium falciparum K13‐propeller in Angola and Mozambique after the introduction of the ACTs. PLoS One 10: e0119215Ferreira A, Marguti I, Bechmann I, Jeney V, Chora A, Palha NR, Rebelo S, Henri A, Beuzard Y, Soares MP (2011) Sickle hemoglobin confers tolerance to Plasmodium infection. Cell 145: 398–409Veiga MI, Osorio NS, Ferreira PE, Franzen O, Dahlstrom S, Lum JK, Nosten F, Gil JP (2014) Complex polymorphisms in the Plasmodium falciparum multidrug resistance protein 2 gene and its contribution to antimalarial response. Antimicrob Agents Chemother 58: 7390–7397 Host‐Plasmodium interactions Portugal S, Carret C, Recker M, Armitage AE, Goncalves LA, Epiphanio S, Sullivan D, Roy C, Newbold CI, Drakesmith H, Mota MM (2011) Host‐mediated regulation of superinfection in malaria. Nat Med 17: 732–737Real E, Rodrigues L, Cabal GG, Enguita FJ, Mancio‐Silva L, Mello‐Vieira J, Beatty W, Vera IM, Zuzarte‐Luis V, Figueira TN, Mair GR, Mota MM (2018) Plasmodium UIS3 sequesters host LC3 to avoid elimination by autophagy in hepatocytes. Nat Microbiol 3: 17–25Sa ECC, Nyboer B, Heiss K, Sanches‐Vaz M, Fontinha D, Wiedtke E, Grimm D, Przyborski JM, Mota MM, Prudencio M, Mueller AK (2017) Plasmodium berghei EXP‐1 interacts with host Apolipoprotein H during Plasmodium liver‐stage development. Proc Natl Acad Sci USA 114: E1138–E1147 Nutrient sensing and acquisition Itoe MA, Sampaio JL, Cabal GG, Real E, Zuzarte‐Luis V, March S, Bhatia SN, Frischknecht F, Thiele C, Shevchenko A, Mota MM (2014) Host cell phosphatidylcholine is a key mediator of malaria parasite survival during liver stage infection. Cell Host Microbe 16: 778–786Mancio‐Silva L, Slavic K, Grilo Ruivo MT, Grosso AR, Modrzynska KK, Vera IM, Sales‐Dias J, Gomes AR, MacPherson CR, Crozet P, Adamo M, Baena‐Gonzalez E, Tewari R, Llinas M, Billker O, Mota MM (2017) Nutrient sensing modulates malaria parasite virulence. Nature 547: 213–216Meireles P, Mendes AM, Aroeira RI, Mounce BC, Vignuzzi M, Staines HM, Prudencio M (2017) Uptake and metabolism of arginine impact Plasmodium development in the liver. Sci Rep 7: 4072 Modulation of Plasmodium liver infection Ruivo MTG, Vera IM, Sales‐Dias J, Meireles P, Gural N, Bhatia SN, Mota MM, Mancio‐Silva L (2016) Host AMPK Is a Modulator of Plasmodium Liver Infection. Cell Rep 16: 2539–2545Zuzarte‐Luis V, Mello‐Vieira J, Marreiros IM, Liehl P, Chora AF, Carret CK, Carvalho T, Mota MM (2017) Dietary alterations modulate susceptibility to Plasmodium infection. Nat Microbiol 2: 1600–1607 Immune and inflammatory responses to Plasmodium infection Liehl P, Zuzarte‐Luis V, Chan J, Zillinger T, Baptista F, Carapau D, Konert M, Hanson KK, Carret C, Lassnig C, Muller M, Kalinke U, Saeed M, Chora AF, Golenbock DT, Strobl B, Prudencio M, Coelho LP, Kappe SH, Superti‐Furga G et al (2014) Host‐cell sensors for Plasmodium activate innate immunity against liver‐stage infection. Nat Med 20: 47–53Munoz‐Ruiz M, Ribot JC, Grosso AR, Goncalves‐Sousa N, Pamplona A, Pennington DJ, Regueiro JR, Fernandez‐Malave E, Silva‐Santos B (2016) TCR signal strength controls thymic differentiation of discrete proinflammatory gammadelta T cell subsets. Nat Immunol 17: 721–727Seixas E, Gozzelino R, Chora A, Ferreira A, Silva G, Larsen R, Rebelo S, Penido C, Smith NR, Coutinho A, Soares MP (2009) Heme oxygenase‐1 affords protection against noncerebral forms of severe malaria. Proc Natl Acad Sci USA 106: 15837–15842 Diagnosis Frita R, Rebelo M, Pamplona A, Vigario AM, Mota MM, Grobusch MP, Hanscheid T (2011) Simple flow cytometric detection of haemozoin containing leukocytes and erythrocytes for research on diagnosis, immunology and drug sensitivity testing. Malar J 10: 74 Vaccines Reuling IJ, Mendes AM, de Jong GM, Fabra‐Garcia A, Nunes‐Cabaco H, van Gemert GJ, Graumans W, Coffeng LE, de Vlas SJ, Yang ASP, Lee C, Wu Y, Birkett AJ, Ockenhouse CF, Koelewijn R, van Hellemond JJ, van Genderen PJJ, Sauerwein RW, Prudencio M (2020) An open‐label phase 1/2a trial of a genetically modified rodent malaria parasite for immunization against Plasmodium falciparum malaria. Sci Transl Med 12 Pathogenesis of placental and cerebral malaria de Moraes LV, Tadokoro CE, Gomez‐Conde I, Olivieri DN, Penha‐Goncalves C (2013) Intravital placenta imaging reveals microcirculatory dynamics impact on sequestration and phagocytosis of Plasmodium‐infected erythrocytes. PLoS Pathog 9: e1003154Ribot JC, Neres R, Zuzarte‐Luis V, Gomes AQ, Mancio‐Silva L, Mensurado S, Pinto‐Neves D, Santos MM, Carvalho T, Landry JJM, Rolo EA, Malik A, Silva DV, Mota MM, Silva‐Santos B, Pamplona A (2019) gammadelta‐T cells promote IFN‐gamma‐dependent Plasmodium pathogenesis upon liver‐stage infection. Proc Natl Acad Sci USA 116: 9979–9988 Mechanisms of tolerance to malaria Gozzelino R, Andrade BB, Larsen R, Luz NF, Vanoaica L, Seixas E, Coutinho A, Cardoso S, Rebelo S, Poli M, Barral‐Netto M, Darshan D, Kuhn LC, Soares MP (2012) Metabolic adaptation to tissue iron overload confers tolerance to malaria. Cell Host Microbe 12: 693–704Jeney V, Ramos S, Bergman ML, Bechmann I, Tischer J, Ferreira A, Oliveira‐Marques V, Janse CJ, Rebelo S, Cardoso S, Soares MP (2014) Control of disease tolerance to malaria by nitric oxide and carbon monoxide. Cell Rep 8: 126–136 Epidemiology Corder RM, Ferreira MU, Gomes MGM (2020) Modelling the epidemiology of residual Plasmodium vivax malaria in a heterogeneous host population: A case study in the Amazon Basin. PLoS Comput Biol 16: e1007377 Vector genetics Salgueiro P, Moreno M, Simard F, O''Brochta D, Pinto J (2013) New insights into the population structure of Anopheles gambiae s.s. in the Gulf of Guinea Islands revealed by Herves transposable elements. PLoS One 8: e62964Vicente JL, Sousa CA, Alten B, Caglar SS, Falcuta E, Latorre JM, Toty C, Barre H, Demirci B, Di Luca M, Toma L, Alves R, Salgueiro P, Silva TL, Bargues MD, Mas‐Coma S, Boccolini D, Romi R, Nicolescu G, do Rosario VE et al (2011) Genetic and phenotypic variation of the malaria vector Anopheles atroparvus in southern Europe. Malar J 10: 5Early Portuguese institutions dedicated to malaria investigation and researchLandeiro F (1932) Relatório do primeiro ano de luta antisezonática na estação de BenaventeLandeiro F (1934) Organização do Serviço Antisezonático em Portugal 相似文献
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Turtle leeches have not been recorded in Korea, although they occur in geographically adjacent countries including China and Japan. This study describes a turtle leech, Ozobranchus jantseanus (Clitellata: Ozobranchidae), found from Reeve’s turtle (Mauremys reevesii) in Korea. Of the 143 Reeve’s turtles collected from the freshwater reservoir in Jinju City, Gyeongsangnam-do, Korea, 95 unidentified leeches were found in 8 (5.6%) individuals. The leeches had 22 somites with 11 pairs of externally exposed branchiae, body-sized posterior suckers, and spines on the dorsal surface. We identified these leeches as Ozobranchus jantseanus Oka, 1912 (Clitellata: Ozobranchidae). This species of turtle leeches found in Korea may fill the gap in the biodiversity of East Asian annulus. 相似文献
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Abstract: A new genus and species of basal non‐Viverravidae Carnivoramorpha, Dawsonicyon isami, is named and described. This new taxon is based upon DMNH 19585, an almost complete skeleton, which was collected from the Black’s Fork Member (informal ‘Bridger B’ subunit) of the Bridger Formation in southwestern Wyoming, USA. The specimen is incorporated into an existing craniodental data matrix, and the associated phylogenetic analyses support the identification of this species as a new basal carnivoramorphan. This new taxon is dentally compared to all known genera of non‐viverravid basal carnivoramorphans, as well as with all known species of the problematic genus Miacis. Postcrania are compared in detail with other described specimens of non‐viverravid basal carnivoramorphans and more generally with known postcrania of viverravids. Preliminary functional interpretations of a scansorial locomotor mode are offered for this new taxon. Its implications for the diversity of middle Eocene basal carnivoramorphans is briefly discussed, including expansion of the already high diversity in the Black’s Fork Member of the Bridger Formation (at least 11 species in 8 genera). 相似文献
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Two new earwigs (Dermaptera) recently discovered in mid-Cretaceous (latest Albian) amber from Myanmar are described and figured. Astreptolabis ethirosomatiagen. et sp. n. is represented by a peculiar pygidicranoid female, assigned to a new subfamily, Astreptolabidinaesubfam. n., and differs from other protodermapterans in the structure of the head, pronotum, tegmina, and cercal forceps. Tytthodiplatys mecynocercusgen. et sp. n. is a distinctive form of first-instar nymph of the Diplatyidae, the earliest record for this basal earwig family. The taxon can be distinguished from other Early Cretaceous nymphs by the structure of the head, antennae, legs, and most notably its filamentous and annulate cerci. The character affinities of these taxa among Neodermaptera are generally discussed as is the identity of an enigmatic 'earwig-like' species from the Jurassic of China. 相似文献
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A new genus and species of tapiromorph, Skopaiolophus burmese nov. gen., nov. sp., is described from the middle Eocene Pondaung Formation in central Myanmar. This small form displays a striking selenolophodont morphology associated with a mixture of primitive “condylarthran” dental characters and derived tapiromorph features. Skopaiolophus is here tentatively referred to a group of Asian tapiromorphs unknown so far. The occurrence of such a form in Pondaung suggests that primitive tapiromorphs might have persisted in southeast Asia until the late middle Eocene while they became extinct elsewhere in both Eurasia and North America. 相似文献
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The vast majority of interspecific interactions are competitive or exploitative. Yet, some positive interspecies interactions exist, where one (commensalism) or both (mutualism) species benefit. One such interaction is cleaning mutualisms, whereby a cleaner removes parasites from a client. In this note, we document the novel observation of a black‐cheeked waxbill (Brunhilda charmosyna) appearing to clean a Kirk''s dik‐dik (Madoqua kirkii), at the Mpala Research Centre in Laikipia County, Kenya. The purported cleaning took place for over one minute and is notable firstly for the dik‐dik remaining still for the duration of cleaning and secondly for involving two species that are much smaller than those traditionally involved in bird–mammal cleaning interactions. Unfortunately, no further cleaning events were subsequently observed, raising questions about whether this record was opportunistic or a regular occurrence. Future observations may reveal whether this behavior is widespread and whether it involves other small passerines. 相似文献
12.
Benson Okita‐Ouma Rajan Amin Frank Van Langevelde Nigel Leader‐Williams 《African Journal of Ecology》2010,48(3):791-799
Density‐dependent feedback mechanisms provide insights into the population dynamics and interactions of large herbivores with their ecosystem. Sex ratio also has particularly important implications for growth rates of many large mammal populations through its influence on reproductive potential. Therefore, the interrelationships between density‐dependent factors, comprising density, sex ratio and underlying growth rates (r) were examined for the Eastern black rhino (Diceros bicornis michaeli) living in three rhino sanctuaries in Kenya using four population models. The exponential and logistic models gave similar results and the former were accepted because they better portrayed the actual situation on the ground. Sex ratios in all sanctuary populations were positively correlated with r but interpreted with realization of other factors also affecting r. We caution that the results of population models should be interpreted alongside ground‐truthed observations. We recommend that future translocation strategies should take into account sex and age structures of the donor population, while future studies of density dependence should take into account both biotic and abiotic factors. 相似文献
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Abdul Quddus Nurhusien Yimer Faez Firdaus Abdullah Jesse Muhammad Abdul Basit Maria Amir Mohammed Sirajul Islam 《Saudi Journal of Biological Sciences》2021,28(12):7068
Cadmium (Cd) is often associated with reproductive disorders of mammals. Edible bird’s nest (EBN) is a natural food product made of swiftlet''s salivary secretion used to make their nests and it has been consumed as a tonic food for decades. This research aimed to study the protective effects of EBN against Cd-induced uterine toxicity in Sprague Dawley rats. Thirty (30) female Sprague Dawley rats were assigned into five groups as follows: group 1- negative control (NC) received distilled water; group 2 - positive control (PC) administered with CdCl2, 5 mg/kg BW; while groups EBN-1, EBN-2, and EBN-3 received CdCl2 (5 mg/kg BW) plus graded concentrations of 60, 90 and 120 mg/kg BW of EBN, respectively. After four weeks of daily oral treatment, rats were euthanized to collect the uterus for evluations of histopathological changes, Cd concentrations and Metallothionein (MT) expressions using H&E stain, inductive coupled plasma mass spectrometry (ICP-MS) and immunohistochemistry, respectively. Blood samples were collected for superoxide dismutase (SOD) analysis using SOD assay kit. Results revealed that the CdCl2 without EBN supplement (PC) group had elevated levels of Cd in the uterus along with increased MT expressions and decreased SOD enzyme activity as compared to the NC group. Moreover, uterine histopathological changes, including glandular cysts and loss of normal structure of luminal epithelium (LE) and glandular epithelium (GE) were found in the PC group. Interestingly, groups treated with CdCl2 along with EBN (EBN1, EBN2, EBN3) showed lower levels of uterine tissue Cd deposition and MT expression, lower degenerative changes with normal histomorphology of glands, and increased SOD activity as compared to the PC group. Overall, the findings revealed that oral exposure to Cd at a dose of 5 mg/kg BW resulted in significant alterations in the rat''s uterus. However, the toxicity effect was averted by EBN treatment in a dose dependant manner; highest protection achieved with EBN 120 mg/kg BW, through a possible detoxification mechanism and prevention of Cd deposition. 相似文献
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The study on the population status and human impacts on the endemic and endangered Swayne’s hartebeest (Alcelaphus buselaphus swaynei) was carried out in Nechisar Plains, Nechisar National Park, between 2009 and 2010. Direct and total count methods were applied in the population census. Data collected since 1967 were also examined to indicate trends of Swayne’s hartebeest populations and their translocation status. In eight illegal Guji Oromo settlements, a total of 134 household samples were identified for group discussion and interview. A trend on livestock population was carried out. The total count of Swayne’s hartebeest was 12, 11 and 12 during the 1st, 2nd and 3rd counts, respectively. The population has been decreasing and nowadays only 12 individuals remain. Most respondents had a negative attitude towards conservation areas. The increase in livestock population from 1985 to 1996 was 47.8%. It also increased by 49.9% and 56.5% during 2006 and 2010, respectively. There were 12,531 heads of livestock that depended on the grass plains illegally. Overstocking rate of livestock, illegal resource exploitation and loss of wildlife habitat were the major problems encountered. Active measures have to be implemented to control the human impact and safeguard the future of Swayne’s hartebeest. 相似文献
17.
Zoe Muller 《African Journal of Ecology》2019,57(1):20-30
Giraffe populations have suffered a 40% decline in the past thirty years, making them a new priority for conservation and there are considerable uncertainty and disagreement over the taxonomic classification of giraffes. Consequently, there has never been a more critical time to fully understand the global population size and distribution of all giraffe subspecies. The Rothschild's giraffe Giraffa camelopardalis rothschildi (Linnaeus, 1758) is arguably one of the most imperilled giraffe subspecies. Once widespread across southern Sudan, Uganda and Kenya, the Rothschild's giraffe is now confined to a few, isolated and enclosed populations throughout Kenya and Uganda, with only one natural population remaining. Information about Rothschild's giraffe population size, distribution, and conservation history is patchy, and confined to recondite or inaccessible resources. Here, I present a review of taxonomy, distribution, conservation status and population size of the Rothschild's giraffe and present the most recent estimate of population sizes based on direct census data. Although the Latin name affixed to Rothschild's giraffe is subject to discussion, continued reference to this subspecies as G. c. rothschildi is strongly recommended. 相似文献
18.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1993,104(1):109-114
- 1.1. Blood, liver, heart, testis, skin, eye, muscle and kidney samples were obtained from elephants (Loxodonta africana) in the Kruger National Park during a culling programme in April 1992.
- 2.2. Gene products of 25 protein coding loci in L. africana were examined by horizontal starch-gel electrophoresis.
- 3.3. Eighteen protein coding loci (72%) displayed monomorphic gel banding patterns whereas only seven (28%) displayed polymorphic gel banding patterns.
- 4.4. Average heterozygosity values for adults, youngsters and the total population are respectively 0.058, 0.024 and 0.047.
- 5.5. Relative gene diversities within and between populations are 84% and 16% respectively.
- 6.6. Two population simulation programmes were utilized to predict the duration of the current variability present in this species, based on current genetic variation and gene transfer from one generation to the next.
19.
为分析古田山自然保护区内小麂种群资源的现状,制定合理的保护和管理措施,本研究结合传统的样带调查法和非损伤性标志重捕法进行小麂种群资源的调查与评估。2014年4月、7月、10月和2015年1月在古田山自然保护区内进行了4次调查,结果显示:样带法得到全区的种群密度为(5.8±0.4)只/km2,种群数量为(473.5±29.2)只,其中核心区种群密度最高,为(7.5±0.7)只/km2,种群数量为(160.8±14.0)只;缓冲区为(5.7±0.6)只/km2,种群数量为(98.2±10.4)只;实验区密度最低,为(3.3±0.5)只/km2,种群数量为(140.5±20.7)只。非损伤性标志重捕法得到全区种群密度为(4.9±0.3)只/km2,种群数量为(397±26)只。样带法调查显示,不同功能区之间的种群密度随季节发生变化,核心区、缓冲区和实验区均是春季种群密度最高,保护区内小麂主要栖息在海拔400-800 m之间,夏季向高海拔区域迁移,冬季则向低海拔迁移。SRY性别鉴定结果表明,古田山小麂种群季节间平均雌雄性比1.17∶1,周年雌雄性比为1.11∶1(9只雌性,84只雄性)(x=0.458,P=0.499),雌性个体的数量优势并不是很明显,若要进一步提高种群数量,则需要加强保护。 相似文献
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Lisa M. Lumley Esther Pouliot Jrme Laroche Brian Boyle Bryan M. T. Brunet Roger C. Levesque Felix A. H. Sperling Michel Cusson 《Ecology and evolution》2020,10(2):914-927
The spruce budworm, Choristoneura fumiferana, is presumed to be panmictic across vast regions of North America. We examined the extent of panmixia by genotyping 3,650 single nucleotide polymorphism (SNP) loci in 1975 individuals from 128 collections across the continent. We found three spatially structured subpopulations: Western (Alaska, Yukon), Central (southeastern Yukon to the Manitoba–Ontario border), and Eastern (Manitoba–Ontario border to the Atlantic). Additionally, the most diagnostic genetic differentiation between the Central and Eastern subpopulations was chromosomally restricted to a single block of SNPs that may constitute an island of differentiation within the species. Geographic differentiation in the spruce budworm parallels that of its principal larval host, white spruce (Picea glauca), providing evidence that spruce budworm and spruce trees survived in the Beringian refugium through the Last Glacial Maximum and that at least two isolated spruce budworm populations diverged with spruce/fir south of the ice sheets. Gene flow in the spruce budworm may also be affected by mountains in western North America, habitat isolation in West Virginia, regional adaptations, factors related to dispersal, and proximity of other species in the spruce budworm species complex. The central and eastern geographic regions contain individuals that assign to Eastern and Central subpopulations, respectively, indicating that these barriers are not complete. Our discovery of previously undetected geographic and genomic structure in the spruce budworm suggests that further population modelling of this ecologically important insect should consider regional differentiation, potentially co‐adapted blocks of genes, and gene flow between subpopulations. 相似文献