疟疾 malaria - PubMed 文献(第 5 页)
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疟疾 的 PubMed 搜索结果(第 5 页)
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Presence and potential distribution of malaria-infected New World primates of Costa Rica. 感染疟疾的新世界灵长类动物的存在和潜在分布…… (原文已截断)
In South and Central America, Plasmodium malariae/Plasmodium brasilianum, Plasmodium vivax, Plasmodium simium, and Plasmodium falciparum has been reported in New World primates (NWP). Specifically in Costa Rica, the presence of monkeys positive to P. malariae/P brasilianum has been identified in both captivity and in the wild. The aim of the present study was to determine the presence of P. brasilianum, P. falciparum, and P. vivax, and the potential distribution of these parasites-infecting NWP from Costa Rica. The locations with PCR (Polymerase Chain Reaction) positive results and bioclimatic predictors were used to construct ecological niche models based on a modelling environment that uses the Maxent algorithm, named kuenm, capable to manage diverse settings to better estimate the potential distributions and uncertainty indices of the potential distribution. PCR analysis for the Plasmodium presence was conducted in 384 samples of four primates (Howler monkey [n = 130], White-face monkey [n = 132], Squirrel monkey [n = 50], and red spider monkey [n = 72]), from across Costa Rica. Three Plasmodium species were detected in all primate species (P. falciparum, P. malariae/P. brasilianum, and P. vivax). Overall, the infection prevalence was 8.9%, but each Plasmodium species ranged 2.1-3.4%. The niche model approach showed that the Pacific and the Atlantic coastal regions of Costa Rica presented suitable climatic conditions for parasite infections. However, the central pacific coast has a more trustable prediction for malaria in primates. The results indicate that the regions with higher suitability for Plasmodium transmission in NWP coincide with regions where most human cases have been reported. These regions were also previously identified as areas with high suitability for vector species, suggesting that enzootic and epizootic cycles occur.
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Malaria surveillance--United States, 2006.
Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium (i.e., P. falciparum, P. vivax, P. ovale, and P. malariae). These parasites are transmitted by the bite of an infective female Anopheles species mosquito. The majority of malaria infections in the United States occur among persons who have traveled to areas with ongoing malaria transmission. In the United States, cases can occur through exposure to infected blood products, congenital transmission, or local mosquitoborne transmission. Malaria surveillance is conducted to identify episodes of local transmission and to guide prevention recommendations for travelers. This report summarizes cases in persons with onset of illness in 2006 and summarizes trends during previous years. Malaria cases confirmed by blood film or polymerase chain reaction (PCR) are mandated to be reported to local and state health departments by health-care providers or laboratory staff members. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS), National Notifiable Diseases Surveillance System (NNDSS), and direct CDC consultations. Data from these reporting systems serve as the basis for this report. CDC received reports of 1,564 cases of malaria among persons in the United States with onset of symptoms in 2006, six of which were fatal. This is an increase of 2.4% from the 1,528 cases reported for 2005. P. falciparum, P. vivax, P. malariae, and P. ovale were identified in 39.2%, 17.6%, 2.9%, and 3.0% of cases, respectively. Ten patients (0.6%) were infected by two or more species. The infecting species was unreported or undetermined in 36.6% of cases. Compared with 2005, the largest increases in cases were from Asia (16.0%). Based on estimated volume of travel, the highest estimated relative case rates of malaria among travelers occurred among those returning from West Africa. Of 602 U.S. civilians who acquired malaria abroad and for whom chemoprophylaxis information was known, 405 (67.3%) reported that they had not followed a chemoprophylactic drug regimen recommended by CDC for the area to which they had traveled. Seventeen cases were reported in pregnant women, among whom only one reported taking chemoprophylaxis precautions. Six deaths were reported; five of the persons were infected with P. falciparum and one with P. malariae. Despite the 2.4% increase in cases from 2005 to 2006, the numbers of malaria cases remained relatively stable during 2001--2006. No change was detected in the proportion of cases by species responsible for infection. U.S. civilians traveling to West Africa had the highest estimated relative case rates. In the majority of reported cases, U.S. civilians who acquired infection abroad had not adhered to a chemoprophylaxis regimen that was appropriate for the country in which they acquired malaria. Additional investigations were conducted of the six fatal cases that occurred in the United States. Persons traveling to a malarious area should take one of the recommended chemoprophylaxis regimens appropriate for the region of travel and use personal protection measures to prevent mosquito bites. Any person who has been to a malarious area and who subsequently has a fever or influenza-like symptoms should seek medical care immediately and report their travel history to the clinician; investigation should always include blood-film tests for malaria, with results made available immediately. Malaria infections can be fatal if not diagnosed and treated promptly. CDC recommendations concerning malaria prevention are available at http://wwwn. cdc.gov/travel/contentdiseases.aspx#malaria or by calling the CDC Malaria Branch on weekdays (telephone: 770-488-7788; Monday--Friday, 8:00 A.M.--4:30 P.M. EST); during evenings, weekends, and holidays, call the CDC Director's Emergency Operations Center (telephone: 770-488-7100), and ask to page the person on call for the Malaria Branch. Recommendations concerning malaria treatment are available at http://www.cdc.gov/malaria/diagnosis_treatment/treatment.htm or by calling the CDC Malaria Hotline.
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Epidemiological and ecological aspects related to malaria in the area of influence of the lake at Porto Primavera dam, in western São Paulo State, Brazil.
A study was carried out in the area of influence of the Porto Primavera Hydroelectric Power Station, in western São Paulo State, to investigate ecological and epidemiological aspects of malaria in the area and monitor the profile of the anopheline populations following the environmental changes brought about by the construction of the lake. Mosquitoes captured were analyzed by standardized indicator species analysis (ISA) before and during different flooding phases (253 m and 257 m elevations). The local human population was studied by means of parasitological (thin/thick blood smears), molecular (PCR) and serological tests. Serological tests consisted of Enzyme Linked Immunosorbent Assay (ELISA) with synthetic peptides of the circumsporozoite protein (CSP) from classic Plasmodium vivax, P. vivax variants (VK247 and "vivax-like"), P. malariae and P. falciparum and Indirect Immunofluorescence Assay (IFA) with asexual forms of P. vivax, P. malariae and P. falciparum. The results of the entomological survey indicated that, although the Anopheles darlingi population increased after the flooding, the population density remained very low. No malaria, parasite infection or DNA was detected in the inhabitants of the study area. However, there was a low frequency of antibodies against asexual forms and a significant prevalence of antibodies against P. vivax, P. vivax variants, P. falciparum and P. malariae; the presence of these antibodies may result from recent or less recent contact with human or simian Plasmodium (a parallel study in the same area revealed the existence of a sylvatic cycle). Nevertheless, these results suggest that, as in other places where malaria is present and potential vectors circulate, the local epidemiological conditions observed could potentially support the transmission of malaria in Porto Primavera Lake if infected individuals are introduced in sufficient numbers. Further studies are required to elucidate the phenomena described in this paper.
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[The placenta and malaria. A morphologic, parasitologic and clinical study (author's transl)].
In 115 consecutive placentae from an unselected population living in a high malaria endemic region (Franceville, Haut-Ogooué, Gabon, 40 (35%) have the peculiar lesions of maternal plasmodium infection. The lesions show considerable histological variation but the following features are constant: a) deposits of variable amounts of malarial pigment and b) excess of perivillous fibrinoid. Accumulation of maternal erythrocytes with parasites, concentration of macrophages in intervillous spaces and villities are inconstant. In addition, splitting and segmental thickening of the trophoblast basal membrane with occasional aggregations of dense fibrillary structures are found at ultrastructural level. 56% of the mothers have Plasmodium falciparum (94%) or Plasmodium malariae in their peripheral blood. Placental lesions have been found only in 65% of the cases with peripheral parasitemia. Although Plasmodium are present in 35 (87%) placentae, no parasites have been found in the cord blood. The difference between the mean birth-weight of full-term neonates from mothers with placental lesions (n = 38) or with normal placenta (n = 54) is 220 g. This difference is statistically highly significant (p less than 0,001). It appears that the low mean birth-weight is not related to the high percentage (39%) of primipare in the infected group but, in all probability, to the placental lesions.
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Genome sequencing of Plasmodium malariae identifies continental segregation and mutations associated with reduced pyrimethamine susceptibility.
Plasmodium malariae parasites are widely observed across the tropics and sub-tropics. This slow-growing species, known to maintain chronic asymptomatic infections, has been associated with reduced antimalarial susceptibility. We analyse 251 P. malariae genomes from 28 countries, and leveraging 131,601 high-quality SNPs, demonstrate segregation of African and Asian isolates. Signals of recent evolutionary selection were identified in genes encoding putative surface proteins (pmmsp1) and putative erythrocyte invasion proteins (pmdpap3, pmrbp2, pmnif4). Amino acid substitutions were identified in orthologs of genes associated with antimalarial susceptibility including 2 amino acid substitutions in pmdhfr aligning with pyrimethamine resistance mutations in P. falciparum. Additionally, we characterise pmdhfr mutation F57L and demonstrate its involvement in reduced susceptibility to pyrimethamine in an in vitro parasite assay. We validate CRISPR-Cas9 mediated ortholog replacement in P. knowlesi parasites to determine the function of pmdhfr mutations and demonstrate that circulating pmdhfr genotypes are less susceptible to pyrimethamine.
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Case Report: Cambodian National Malaria Surveillance Program Detection of Plasmodium knowlesi.
Despite recent success in reducing the regional incidence of Plasmodium falciparum malaria, cases of zoonotic malaria are on the rise in Southeast Asia. The Cambodian National Malaria Surveillance Program has previously relied on rapid diagnostic tests and blood smear microscopy with confirmatory polymerase chain reaction (PCR) testing in a subset of cases to further distinguish P. falciparum, P. malariae, P. ovale, and P. vivax species. Here, metagenomic next-generation sequencing identified P. knowlesi mono-infection in six Cambodian patients initially diagnosed with P. malariae by blood smear microscopy in February-May 2020. These findings of recent human infections with P. knowlesi in Cambodia led to the incorporation of P. knowlesi-specific PCR diagnostics to national malaria surveillance efforts.
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Novel Cross-Border Approaches to Optimise Identification of Asymptomatic and Artemisinin-Resistant Plasmodium Infection in Mobile Populations Crossing Cambodian Borders.
Human population movement across country borders presents a real challenge for malaria control and elimination efforts in Cambodia and its neighbouring countries. To quantify Plasmodium infection among the border-crossing population, including asymptomatic and artemisinin resistant (AR) parasites, three official border crossing points, one from each of Cambodia's borders with Thailand, Laos and Vietnam, were selected for sampling. A total of 3206 participants (of 4110 approached) were recruited as they crossed the border, tested for malaria and interviewed. By real-time polymerase chain reaction (RT-PCR), 5.4% of all screened individuals were found to harbour Plasmodium parasites. The proportion was highest at the Laos border (11.5%). Overall there were 97 P. vivax (55.7%), 55 P. falciparum (31.6%), two P. malariae (1.1%) and 20 mixed infections (11.5%). Of identified infections, only 20% were febrile at the time of screening. Of the 24 P. falciparum samples where a further PCR was possible to assess AR, 15 (62.5%) had mutations in the K13 propeller domain gene, all from participants at the Laos border point. Malaria rapid diagnostic test (RDT) pLDH/HRP-2 identified a positivity rate of 3.2% overall and sensitivity compared to RT-PCR was very low (43.1%). Main individual risk factors for infection included sex, fever, being a forest-goer, poor knowledge of malaria prevention methods and previous malaria infection. Occupation, day of the week and time of crossing (morning vs. afternoon) also appeared to play an important role in predicting positive cases. This study offers a novel approach to identify asymptomatic infections and monitor AR parasite flow among mobile and migrant populations crossing the borders. Similar screening activities are recommended to identify other hot borders and characterise potential hot spots of AR. Targeted "customised" interventions and surveillance activities should be implemented in these sites to accelerate elimination efforts in the region.
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The relationship between climate change and malaria in South-East Asia: A systematic review of the evidence. 东南亚气候变化与疟疾之间的关系：对证据的系统审查
: Climatic change is an inescapable fact that implies alterations in seasons where weather occurrences have their schedules shift from the regular and magnitudes intensify to more extreme variations over a multi-year period. Southeast Asia is one of the many regions experiencing changes in climate and concurrently still has endemicities of malaria. Given that previous studies have suggested the influence of climate on malaria's vector the mosquitoes and parasite the Plasmodium group, this study was conducted to review the evidence of associations made between malaria cases and climatic variables in Southeast Asia throughout a multi-year period. : Our systematic literature review was informed by the PRISMA guidelines and registered in PROSPERO: CRD42022301826 on 5 February 2022. We searched for original articles in English and Indonesian that focused on the associations between climatic variables and malaria cases. : The initial identification stage resulted in 535 records of possible relevance and after abstract screening and eligibility assessment we included 19 research articles for the systematic review. Based on the reviewed articles, changing temperatures, precipitation, humidity and windspeed were considered for statistical association across a multi-year period and are correlated with malaria cases in various regions throughout Southeast Asia. : According to the review of evidence, climatic variables that exhibited a statistically significant correlation with malaria cases include temperatures, precipitation, and humidity. The strength of each climatic variable varies across studies. Our systematic review of the limited evidence indicates that further research for the Southeast Asia region remains to be explored.
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US Malaria Casualties and Chemoprophylaxis during the Vietnam War. 越南战争期间美军疟疾伤亡与化学预防
Malaria caused mass casualties among US military personnel during the Vietnam War, resulting in as many hospitalizations as combat wounds in 1965. Its military impact was magnified because nearly all the disease-related casualties came from front-line units, particularly the infantry, with rates exceeding 10 per 1,000 man-days of exposure. The imperfect chemoprophylaxis using chloroquine-primaquine tablets developed during the Korean War proved inadequate. Adding daily dapsone was more effective but resulted in rare cases of agranulocytosis and at least eight deaths. After Vietnam, malaria in US military members, especially relapsing malaria due to Plasmodium vivax, caused thousands of infections in the United States, although indigenous transmission was rarely observed. Although severe malaria resulted in 78 known deaths in the US Army (and 46 in the US Marines), the real military issue was lost days due to illness, averaging more than 1 month per malaria case and at least 200,000 lost man-days per year. Malaria's potential to produce mass casualties in soldiers remains, especially during deployments to New Guinea or sub-Saharan Africa.
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{"_":"Regional and Age-Related Variations in Blood Calcium Levels among Patients with and malaria: A Systematic Review and Meta-Analysis.","i":["Plasmodium falciparum","P. vivax"]} {"_":"疟疾患者血钙水平的区域和年龄相关差异：系统综述与荟萃分析。","i":["恶性疟原虫","间日疟原虫"]}
Despite several studies examining the relationship between calcium levels and malaria, inconsistencies and varied results remain in the literature. This study aimed to synthesize the evidence on the association between blood calcium levels and malaria severity. A systematic literature search was conducted in the Embase, Scopus, PubMed, Ovid, and Google Scholar databases. The studies that investigated calcium levels in participants with malaria were reviewed and included for synthesis. The quality of included studies was assessed based on a standardized checklist by the Joanna Briggs Institute (JBI) critical appraisal checklists. The thematic synthesis had been used for qualitative synthesis. For the quantitative synthesis, the meta-analysis was performed to estimate the pooled effect sizes for differences in calcium levels between groups of participants using a random effect model using Hedge's g as a measure of effect size. Out of the 4574 identified records, 14 studies were reviewed. The thematic synthesis across these studies noted a consistent theme: reduced calcium levels in malaria patients compared to uninfected controls. However, the meta-analysis encompassing three specific analyses-comparing calcium levels between malaria patients and controls, severe and non-severe malaria cases, and fatal cases versus survivors-showed no significant difference in calcium levels. The statistics were as follows: (1) = 0.15, Hedge's g: -1.00, 95% CI: -2.37-0.38, : 98.97, 9 studies; (2) = 0.35, Hedge's g: -0.33, 95% CI: -1.02-0.36, : 81.61, 3 studies; and (3) = 0.71, Hedge's g: -0.14, 95% CI: -0.91-0.62, : 87.05, 3 studies. Subgroup analyses indicated that regional disparities, especially between Africa and Asia, and participant age groups may influence these outcomes. While a trend of decreased calcium levels in malaria patients was observed, the meta-analytical results suggest regional and age-related variations. Further investigations should emphasize these differences to better guide clinical management, prognostic applications, and the crafting of policies concerning malaria's metabolic effects.