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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rapid antigen assays provide an effective tool for the detection of malaria in symptomatic patients. However, the efficacy of these devices for detecting asymptomatic malaria, where parasite levels are normally significantly lower than in symptomatic patients, is less well established. We evaluated the efficacy of a new combined Plasmodium falciparum-Plasmodim vivax immunochromatographic test (ICT Malaria Pf/Pv) in a cross-sectional malaria survey of the village of Ban Kong Mong Tha, Kanchanaburi Provice, Thailand, from August to December 2000. A total of 1,976 bleeds were made from 559 individuals over the course of the study. Blinded microscopy of thick and thin blood films was used as the gold standard; all discordant and 10% of concordant results were cross-checked. Of 1,976 ICT Malaria Pf/Pv dipsticks tested, 98.3% (n = 1,943) performed as expected, as evidenced by the appearance of the control line. The ICT Malaria Pf/Pv test was both sensitive (100.0%) and specific (99.7 %) for the diagnosis of falciparum malaria with parasitemias of > or = 500 trophozoites/microL; however, only 15.9% (13/82) of infected individuals had parasitemia rates this high. When P. falciparum parasitemia rates were < 500/microL, the sensitivity of the diagnosis was only 23.3%, with a positive predictive value (PPV) and a negative predictive value (NPV) of 76.2 and 97.2%, respectively. The ICT Malaria Pf/Pv test was specific, but not sensitive, for the diagnosis of vivax malaria with parasite rates of > or = 500 trophozoites/microl, with sensitivity, specificity, PPV, and NPV of 66.7%, 99.9%, 66.7%, and 99.9%, respectively. At parasite rates of < 500/microL, corresponding values were 0.0%, 99.9%, 0%, and 95.1%. Because of the relatively high cost of these assays, low parasite rates found in the majority of asymptomatic individuals, and low sensitivity of this assay with rates of < 500/microl, use of this assay as a tool for active case detection is of limited value in western Thailand.
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PMID:Field evaluation of the ICT Malaria Pf/Pv immunochromatographic test for the detection of asymptomatic malaria in a Plasmodium falciparum/vivax endemic area in Thailand. 1216 91

Anopheline mosquito larvae and adults were sampled at Ban Pu Teuy, Tri-Yok District, Kanchanaburi Province, western Thailand, from January 2000 to December 2001. Over the period of 2 yr, Anopheles minimus sensu lato was the most commonly collected species, followed by Anopheles swadiwongporni and Anopheles dirus sensu lato; all three species are important vectors of malaria in Thailand. Attempted blood feeding by An. minimus occurred throughout the night, with two distinct feeding peaks: strong activity immediately after sunset (1800-2100 hours), followed by a second, less pronounced, rise before sunrise (0300-0600 hours). Anopheles minimus were more abundant during the wet season compared with the dry and hot seasons, although nocturnal adult feeding patterns were similar. Anopheles minimus fed readily on humans inside and outside of houses, showing a slight preference for exophagy. The human-biting peak of An. minimus in our study area differed from other localities sampled in Thailand, indicating the possible existence of site-specific populations of An. minimus exhibiting different host-seeking behavior. These results underscore the importance of conducting site-specific studies to accurately determine vector larval habitats and adult activity patterns and linking their importance in malaria transmission in a given area.
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PMID:Seasonal abundance and blood feeding activity of Anopheles minimus Theobald (Diptera: Culicidae) in Thailand. 1476 65

We sampled 291 bodies of water for Anopheles larvae around three malaria-endemic villages of Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau, Mae Sot district, Tak Province, Thailand during August 2001-December 2002 and collected 4,387 larvae from 12 categories of breeding habitat types. We modeled surface slope and wetness indices to identify the extent and spatial pattern of potential mosquito breeding habitats by digitizing base topographical maps of the study site and overlaying them with coordinates for each larval habitat. Topographical contours and streamlines were incorporated into the Geographical Information System (GIS). We used Global Positioning System (GPS) instruments to locate accurately each field observed breeding habitat, and produced a 30-m spatial resolution Digital Elevation Model (DEM). The slope (of less than 12 degrees) and wetness (more than 8 units) derived from spatial modeling were positively associated with the abundance of major malaria vectors An. dirus, An. maculatus, An. minimus, and An. sawadwongporni. These associations permit real-time monitoring and possibly forecasting of the distributions of these four species, enabling public health agencies to institute control measures before the mosquitos emerge as adults and transmit disease.
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PMID:Use of GIS-based spatial modeling approach to characterize the spatial patterns of malaria mosquito vector breeding habitats in northwestern Thailand. 1511 21

We mapped overall malaria cases and located each field observed major malaria vector breeding habitat using Global Positioning System (GPS) instruments from September 2000 to October 2003 around the three malaria-endemic villages of Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau, Mae Sod district, Tak Province, Thailand. The land-use/land-cover classifications of the three villages and surrounding areas were performed on IKONOS satellite images acquired on 12 November 2001 with a spatial resolution of 1 x 1 m. Stream network was delineated and displayed. Proximity analysis was performed on the locations of the houses with and without malaria cases within a 1.5 km buffer from An. minimus immature mosquito breeding habitats, mainly stream margins. The 1.5 km used in our proximity analysis was arbitrarily estimated based on the An. minimus flight range. A statistical t-test at 5% significance level was performed to evaluate whether houses with malaria cases have higher proximities to streams than houses without malaria cases. The result shows no significant difference between proximity to streams between houses with malaria cases and houses without malaria cases. We suspect that the actual flight range of An. minimus may be greater than 1.5 km. The An. minimus larval habitat deserves more detailed investigation. Further studies on human behavior contrary to that required for adequate malaria control among these three villages are also recommended.
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PMID:Ikonos-derived malaria transmission risk in northwestern Thailand. 1590 37

Malaria transmission is dependent upon many hydrology-driven ecological factors that directly affect the vectorial competence, including the presence of suitable habitats for the development of anopheline larvae. Larval habitats were identified and characterized at three malaria endemic villages (Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau) in Mae Sot district, Tak Province, in northwestern Thailand between July 2002 and June 2003. The Global Positioning System (GPS) was used to provide precise locational data for the spatial distribution of anopheline mosquito larvae and their habitats. Ten habitat categories were identified. Eighteen adult Anopheles species were identified from larvae in all the surveyed habitats. An. minimus was the most common species throughout the year. The relationship between eight abiotic variables (temperature, hardness, carbon dioxide, dissolved oxygen, nitrate, phosphate, silica and pH) and the abundance of four major species of malaria vectors (An. (Cel.) dirus, An. (Cel.) minimus, An. (Cel.) maculatus, and An. (Cel.) sawadwongporni), and six species of non-vectors (An. (Cel.) kochi, An. (Cel.) jamesii, An. (Ano.) peditaeniatus, An. (Ano.) barbirostris, An. (Ano.) campestris, and An (Cel.) vagus) larvae was investigated. The results from the multiple regression models suggest that hardness, water temperature and carbon dioxide are the best predictor variables associated with the abundance of An. minimus larvae (p < 0.001); water pH for An. dirus larvae (p < 0.001); temperature and pH for An. kochi larvae (p < 0.01); temperature and silica concentration for An. jamesii larvae (p < 0.001); dissolved oxygen and silica concentration for An. campestris larvae (p < 0.001); and pH and silica concentration for An. vagus larvae (p < 0.001). We could not identify key environmental variables for An. maculatus, An. sawadwongporni, An. peditaeniatus, and An. barbirostris.
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PMID:Water quality and breeding habitats of anopheline mosquito in northwestern Thailand. 1590 41

Anopheles minimus Theobald is one of the major vectors of malaria throughout the Oriental Region, and it's complex consists of at least 2 sibling species (A and C) in Thailand. This study aimed to determine the morphological variations of wings of An. minimus A and to clarify the specific status of An. minimus in Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau, Mae Sot district, Tak Province, Thailand. Anopheline larvae were collected from the fields between October 2002 and September 2003, allowed to emerge into adults in the laboratory and identified by morphological and molecular characterization. About 1,715 of female An. minimus A were separated into 8 groups based on their wing scale patterns. Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) assay (ribosomal DNA ITS2) confirmed the identification of An. minimus A in all 8 groups.
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PMID:Morphological variations of Anopheles minimus A in Tak Province, Thailand. 1612 26

The epidemiology of malaria is largely dependent on its vector habitat. Each species of Anopheles larvae has a specific habitat requirement for its development. Anopheline mosquitoes are common throughout Thailand and utilize a wide variety of habitats. The dominant malaria vectors in Thailand are An. dirus, An. maculatus, and An. minimus. The relationship between soil chemical components and the particular species of anopheline in their specific aquatic habitats was studied from September 2002 to July 2003 at Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau in the Mae Sot district, Tak Province, Thailand. Mapping of each habitat was performed using a Global Positioning System unit. A total count of 2,130 laboratory reared adult Anopheles were collected from 138 habitats categorized into 11 different types identified into 18 species from larval sampling in three villages. An. dirus, An. maculatus, and An. minimus were found 5.26%, 10.70%, and 55.31%, respectively, along with other minor species. Drainage and/or season seemed to be associated with the presence of An. dirus, An. maculatus, An. minimus, An. jamesii, An. sawadwongporni, and An. peditaeniatus. Chemical tests: pH, aluminum, magnesium, calcium, and ferric iron showed some associations with the presence of Anopheles. Only drainage was found to be a parameter associated with the presence of An. minimus.
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PMID:Soil analysis around anopheline breeding habitats in north-western Thailand. 1643 40

Artemisinin is an anti-malarial drug with poor water solubility and oral absorption; so a variety of derivatives based on the parent nucleus have been developed. Compared with artemisinin, dihydroartemisinin (DHA) has a stronger anti-malaria activity, and has the advantages of high metabolic rate and better water solubility. Recent studies have discovered that DHA has a good inhibitory effect on tumor cells, which is closely related to the peroxide bridge in its molecular structure. Since tumor cells need more Fe3+ than normal cells, there are a large number of transferrin receptors on the tumor cell membrane. DHA can break the peroxide bridge in the presence of Fe2+, and the free radicals generated can play its lethal effect on tumor cells. In addition, DHA can promote endocytosis of transferrin receptor, and thus prevent cancer cells from taking Fe3+ from microenvironment. This article reviews the anti-tumor molecular mechanism of DHA, including accelerating oxidative damage, inducing apoptosis, inhibiting the growth, proliferation and invasion of tumor cells, reversing tumor multidrug resistance.
Zhejiang Da Xue Xue Bao Yi Xue Ban 2016 May 25
PMID:[Progress on anti-tumor molecular mechanisms of dihydroartemisinin]. 2808 10

The oral environment provides suitable conditions for the colonization of various microorganisms. However, the oral microbials could be the initial factors of some kinds of oral infectious diseases, therefore the treatment against oral microbial pathogens has become an effective strategy. Artemisinin, a kind of sesquiterpene lactone extracted from Traditional Chinese Medicine Artemisia annua L., is the first-line therapy to treat tertian malaria, subtertian malaria and anti-chloroquine malaria for its high efficiency and low toxicity. In recent years, artemisinin and its derivatives have also been proven to be effective against bacteria, fungi, viruses, parasites, and tumors, some of which are closely related to oral diseases. In this review, we summarize the potential effects of artemisinin and its derivatives on oral microorganism by analyzing previous research and latest progress to provide the evidence for further improvement, and look forward to the new research directions. Further studies are needed to improve existing technologies and standards to clarify the effects of artemisinin and its derivatives on microorganisms with controversial effects, to expand the detection of microorganisms associated with oral infectious diseases, and to clarify the interaction with existing antifungal agents in the field of antifungal diseases. In addition, in the study of anti-oral infectious diseases, artemisinin and its derivatives' administration scheme, potential drug interactions, toxic and side effects and other aspects are necessary conditions for further research, which is also a new direction of research. With the maturity of the production process, the improvement of relevant research and the potential demand for the treatment of oral infectious diseases, artemisinin and its derivatives have a broad prospect in the field of oral microorganisms, and provide a new opportunity for the research and development of oral drugs.
Sichuan Da Xue Xue Bao Yi Xue Ban 2020 Nov
PMID:[Effects of Artemisinin and Its Derivatives on Oral Microbes]. 3323 97