疟疾 malaria - PubMed 文献(第 3 页)
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疟疾 的 PubMed 搜索结果(第 3 页)
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Malaria in prehistoric southeastern Asia. 史前东南亚的疟疾
This paper reviews the evolutionary and natural history of malarias; it is proposed that all human malarial parasites originated from zoonotic simian plasmodiids in tropical forests of southeastern Asia, during the terminal Pleistocene or early Holocene. The modes of malarial transmission among prehistoric natives of that geographic area is reconstructed, based primarily on ecological, archeological and ethnographic evidence. Early Holocene hunters and food gatherers of southeastern Asia shared the same forest habitats as several mosquito members of the Anopheles leucosphyrus group, known to be efficient malarial vectors. These forest dwellers could have maintained endemic malaria, however at low levels due to their low population density. With the abundance and interactive roles in transmitting human malaria of the An. dirus and An. minimus mosquitos in forest fringe areas, the middle Holocene settled farmers occupying such habitats would have been subject all year round to highly endemic malaria. Generally much lower and less uniform transmission of the disease could have been found among early coastal occupants, in the presence of the less efficient An. sundaicus vector. Malaria was practically absent on lowland floodplains, extensively occupied by human populations since the first millennium BC onwards, due to lack of major vectors.
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The emerging of the fifth malaria parasite (Plasmodium knowlesi): a public health concern? 第五种疟疾寄生虫（诺氏疟原虫）的出现：一个公共卫生问题？
After examining the most recent scientific evidences, which assessed the role of some malaria plasmodia that have monkeys as natural reservoirs, the authors focus their attention on Plasmodium knowlesi. The infective foci attributable to this last Plasmodium species have been identified during the last decade in Malaysia, in particular in the states of Sarawak and Sabah (Malaysian Borneo), and in the Pahang region (peninsular Malaysia). The significant relevance of molecular biology assays (polymerase chain reaction, or PCR, performed with specific primers for P. knowlesi), is underlined, since the traditional microscopic examination does not offer distinguishing features, especially when the differential diagnosis with Plasmodium malariae is of concern. Furthermore, Plasmodium knowlesi disease may be responsible of fatal cases, since its clinical presentation and course is more severe compared with those caused by P. malariae, paralleling a more elevated parasitemia. The most effective mosquito vector is represented by Anopheles latens; this mosquito is a parasite of both humans and monkeys. Among primates, the natural hosts are Macaca fascicularis, M. nemestina, M. inus, and Saimiri scirea. When remarking the possible severe evolution of P. knowlesi malaria, we underline the importance of an early recognition and a timely management, especially in patients who have their first onset in Western Hospitals, after journeys in Southeast Asian countries, and eventually participated in trekking excursions in the tropical forest. When malaria-like signs and symptoms are present, a timely diagnosis and treatment become crucial. In the light of its emerging epidemiological features, P. knowlesi may be added to the reknown human malaria parasites, whith includes P. vivax, P. ovale, P. malariae, and P. falciparum, as the fifth potential ethiologic agent of human malaria. Over the next few years, it will be mandatory to support an adequate surveillance and epidemiological network. In parallel with epidemiological and health care policy studies, also an accurate appraisal of the clinical features of P. knowlesi-affected patients will be strongly needed, since some preliminary experiences seem to show an increased disease severity, associated with increased parasitemia, in parallel with the progressive increase of inter-human infectious passages of this emerging Plasmodium.
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Immunological testing for malaria and blood donor deferral: the experience of the Ca' Granda Polyclinic Hospital in Milan. 疟疾免疫检测与献血者延期：米兰Ca' Granda综合医院的经验
Current European regulations require a deferral period of 6 months or 3 years, depending on the risk of exposure, for prospective blood donors at risk of malaria. This period may be reduced to 4 months if an immunological or molecular genomic test is negative at each donation, but Italian regulations have not adopted this provision. As cases of transfusion-transmitted malaria have been recorded in medical literature in blood donors deferred for 3 years and not tested, the Immunohematology and Transfusion Centre of the Ca' Grande Polyclinic Hospital in Milan decided to introduce immunological testing for all donors at risk of malaria. Four hundred and twelve blood donors at risk of malaria, who had lived in a malarial area during the first 5 years of life or for more than 6 consecutive months, were tested for malarial antibodies using an enzyme immunoassay kit. The kit (Malaria EIA, Newmarket, UK) uses four recombinant antigens specific for P. falciparum and P. vivax and with cross-reactivity for P. ovale and P. malariae. The kit detects total immunoglobulin antibodies against P. falciparum and P. vivax and shows 80% cross-reactivity with P. ovale and 67% with P. malariae. Antibody-positive samples were further checked by an immunochromatographic test for P. falciparum, P. vivax, P. ovale and P. malariae antigens and by haemoscopy (thin film and thick smear). Italian citizens accounted for 16.8% (69/412) of the whole group of donors examined. We found that 8.7% of the donors who were classified as being at risk of malaria were positive for total immunoglobulin antibodies. Only one Italian citizen resulted positive for the test. The positive candidates were deferred from blood donation. None of the antibody-positive donors was confirmed positive by the immunochromatographic test and by haemoscopy. The introduction of a malarial screening test in the assessment of blood donor eligibility may increase the safety of blood donations, but could further reduce blood availability. If immunological testing were to be accepted nationally as a valid method of assessing the risk of malaria, more than 90% of the donors who are currently deferred for 3 years could be accepted 4 months after their last visit to an endemic area, thus increasing the availability of blood.
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According to the World Health Organization, Microscopy is the gold standard for diagnosing malaria. However, the performance of this examination depends on the experience of the microscopist and the level of parasitemia. Thus, molecular biology detection of malaria could be an alternative technique. evaluate the contribution of molecular biology in detecting imported malaria. This was a descriptive, prospective study, including all students, from the Monastir region, and foreigners, from countries endemic to malaria. The study period was from September 2020 to April 2021. Each subject was screened for malaria by three methods: direct microscopic detection of Plasmodium, detection of plasmodial antigens, and detection of plasmodial DNA by nested PCR. Among the 127 subjects screened, only one had a positive microscopic examination for Plasmodium falciparum. Among the 126 subjects with a negative microscopic examination, twelve students had a positive nested PCR result, i.e. 9.5%. Molecular sequencing allowed the identification of ten isolates of Plasmodium falciparum, one Plasmodium malariae and one Plasmodium ovale. Our study showed that the results of nested PCR agreed with those of microscopy in 90.6% of cases. Nested PCR seems more sensitive for the detection of low parasitemias. Hence the importance of including molecular biology as a malaria screening tool to ensure better detection of imported cases.
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Identification of Plasmodium malariae, a human malaria parasite, in imported chimpanzees. 在进口黑猩猩中鉴定人类疟疾寄生虫三日疟原虫
It is widely believed that human malaria parasites infect only man as a natural host. However, earlier morphological observations suggest that great apes are likely to be natural reservoirs as well. To identify malaria parasites in great apes, we screened 60 chimpanzees imported into Japan. Using the sequences of small subunit rRNA and the mitochondrial genome, we identified infection of Plasmodium malariae, a human malaria parasite, in two chimpanzees that were imported about thirty years ago. The chimpanzees have been asymptomatic to the present. In Japan, indigenous malaria disappeared more than fifty years ago; and thus, it is most likely inferred that the chimpanzees were infected in Africa, and P. malariae isolates were brought into Japan from Africa with their hosts, suggesting persistence of parasites at low level for thirty years. Such a long term latent infection is a unique feature of P. malariae infection in humans. To our knowledge, this is the first to report P. malariae infection in chimpanzees and a human malaria parasite from nonhuman primates imported to a nonendemic country.
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Plasmodium falciparum and P. malariae epidemiology in a West African village. 西非村庄恶性疟原虫和三日疟原虫的流行病学
Transmission of Plasmodium falciparum and P. malariae was studied in a village in Burkina Faso. Consecutive captures of mosquitos were organized twice a month over a year and the species of the mosquitos identified. Also, the prevalences and densities of Plasmodium spp. were determined every 2 months in a sample of children who lived in the village. Anopheles gambiae, A. funestus, and A. nili were the local vectors, but only the first two played a predominant role in both P. falciparum and P. malariae transmission. The parasitological sporozoite index (SI) was 4.48% for A. gambiae and 4.22% for A. funestus. The immunological SIs were higher: 5.82% of A. gambiae were infected with P. falciparum and only 0.16% with P. malariae; the corresponding proportions for A. funestus were 6.45% and 0.41%. Transmission of Plasmodium spp. by A. gambiae was important during the rainy season (July-October) and by A. funestus at the beginning of the dry season (September-November). Each child in the study village could receive about 396 P. falciparum-infected bites per year but only 22 of P. malariae. The P. falciparum parasite indices were maximum during the middle of the rainy season (August), while those for P. malariae reached a peak during the dry season (February).
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Prevalence and level of antibodies to the circumsporozoite proteins of human malaria parasites, including a variant of Plasmodium vivax, in the population of two epidemiologically distinct areas in the state of Acre, Brazil. 巴西亚克州两个流行病学不同地区人群中抗人类疟疾寄生虫环子孢子蛋白抗体（包括间日疟原虫变异型）的流行率和水平
A seroepidemiological study of the prevalence of antibodies against the repeating epitopes of circumsporozoite (CS) proteins of human malaria parasites was conducted in 2 different areas in the state of Acre, Brazil in 1987 and 1990. In 1987 antibodies against the CS protein of the VK 247 variant Plasmodium vivax as well as antibodies against the CS proteins of P. falciparum and the classic P. vivax were found at relatively high rates in the 2 areas, but significant microepidemiological differences were observed. In 1990, when large scale migration in Amazonia had ceased and control measures were applied in the study areas, the malaria endemicity decreased, as determined by the declining prevalence of anti-sporozoite antibodies against all Plasmodium species, and the small number of individuals with positive blood smears. Antibodies against sporozoites of the variant P. vivax did not cross-react with the CS proteins of the classic P. vivax, nor with antibodies against sporozoites of P. falciparum and P. malariae. Sera containing antibodies against the CS protein of P. malariae were found at a very low frequency, and only in 1987. The anti-CS protein antibody response to all Plasmodium species was age-related.
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Screening for malaria antigen and anti-malarial IgG antibody in forcibly-displaced Myanmar nationals: Cox's Bazar district, Bangladesh, 2018. 强迫流离的缅甸国民中疟疾抗原和抗疟疾IgG抗体筛查：孟加拉国科克斯巴扎尔区，2018年
Several refugee settlements in Bangladesh have provided housing and medical care for the forcibly-displaced Myanmar nationals (FDMN, also known as Rohingya) population. The identification of malaria infection status in the refugee settlements is useful in treating infected persons and in developing malaria prevention recommendations. Assays for Plasmodium antigens and human IgG against Plasmodium parasites can be used as indicators to determine malaria infection status and exposure. Dried blood spot (DBS) samples (N = 1239) from a household survey performed April-May 2018 in three settlements in Cox's Bazar district, Bangladesh were utilized for a sample population of children from ages 1-14 years of age. The samples were tested using a bead-based multiplex antigen assay for presence of the pan-Plasmodium antigen aldolase as well as Plasmodium falciparum histidine rich protein 2 (HRP2). A bead-based multiplex assay was also used to measure human IgG antibody response to P. falciparum, Plasmodium malariae, and Plasmodium vivax merozoite surface protein 1 antigen (MSP1) isoforms, and P. falciparum antigens LSA1, CSP, and GLURP-R0. There were no detectable Plasmodium antigens in any samples, suggesting no active malaria parasite infections in the tested children. IgG seroprevalence was highest to P. vivax (3.1%), but this was not significantly different from the percentages of children antibody responses to P. falciparum (2.1%) and P. malariae (1.8%). The likelihood of an anti-Plasmodium IgG response increased with age for all three malaria species. Evidence of exposure to any malaria species was highest for children residing 8-10 months in the settlements, and was lower for children arriving before and after this period of time. Absence of Plasmodium antigen in this population provides evidence that children in these three Bangladeshi refugee settlements did not have malaria at time of sampling. Higher rates of anti-malarial IgG carriage from children who were leaving Myanmar during the malaria high-transmission season indicate these migrant populations were likely at increased risk of malaria exposure during their transit.
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Multiplex bead assays (MBA) that measure IgG antibodies to the carboxy-terminal 19-kDa sub-unit of the merozoite surface protein 1 (MSP1) are currently used to determine malaria seroprevalence in human populations living in areas with both stable and unstable transmission. However, the species specificities of the IgG antibody responses to the malaria MSP1 antigens have not been extensively characterized using MBA. Recombinant Plasmodium falciparum (3D7), Plasmodium malariae (China I), Plasmodium ovale (Nigeria I), and Plasmodium vivax (Belem) MSP1 proteins were covalently coupled to beads for MBA. Threshold cut-off values for the assays were estimated using sera from US citizens with no history of foreign travel and by receiver operator characteristic curve analysis using diagnostic samples. Banked sera from experimentally infected chimpanzees, sera from humans from low transmission regions of Haiti and Cambodia (N = 12), and elutions from blood spots from humans selected from a high transmission region of Mozambique (N = 20) were used to develop an antigen competition MBA for antibody cross-reactivity studies. A sub-set of samples was further characterized using antibody capture/elution MBA, IgG subclass determination, and antibody avidity measurement. Total IgG antibody responses in experimentally infected chimpanzees were species specific and could be completely suppressed by homologous competitor protein at a concentration of 10 μg/ml. Eleven of 12 samples from the low transmission regions and 12 of 20 samples from the high transmission area had antibody responses that were completely species specific. For 7 additional samples, the P. falciparum MSP1 responses were species specific, but various levels of incomplete heterologous competition were observed for the non-P. falciparum assays. A pan-malaria MSP1 cross-reactive antibody response was observed in elutions of blood spots from two 20-30 years old Mozambique donors. The antibody response from one of these two donors had low avidity and skewed almost entirely to the IgG subclass. Even when P. falciparum, P. malariae, P. ovale, and P. vivax are co-endemic in a high transmission setting, most antibody responses to MSP1 antigens are species-specific and are likely indicative of previous infection history. True pan-malaria cross-reactive responses were found to occur rarely.
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Malaria. 疟疾
Malaria continues to present staggering morbidity and mortality statistics. In this well-detailed article, the authors examine the increased incidence of malaria in many areas, describe the malarial parasites, discuss the clinical course, pathogenesis, diagnosis, and treatment, and address the issues of transfusion malaria, congenital malaria, immunity, chemoprophylaxis, and vaccine.