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1.
The prevalence of intestinal protozoans and helminths in stool samples of individuals with allergic cutaneous symptoms was evaluated to study a possible link between parasites and allergy. Altogether, 218 patients who had chronic urticaria, atopic dermatitis, or pruritus of unknown origin were included in the study. Standard laboratory tests for the detection of allergic etiology were performed for all patients. The presence of intestinal parasites was investigated using microscopy, immunofluorescence, and immunoenzymatic assays. Overall, protozoans and helminths were recovered from the stools of 48 subjects (P = 0.004), 18 of whom were affected with intestinal symptoms (P = 0.023). The presence of Giardia lamblia in the stools was significantly associated with allergic cutaneous manifestations (P = 0.030). In addition, patients with allergy were significantly more likely to have > or = 5 Blastocystis hominis organisms per field (P = 0.046). There was a set of patients with allergic cutaneous diseases in whom the presence of intestinal parasites may not be incidental.  相似文献   

2.
The parasite fauna of stray cat populations, comprising mainly helminth parasites, is described for the first time from the arid environment of the Qatar peninsula. During the winter and summer months of 2005, 824 faecal samples were examined from six sites in Qatar. Up to seven species of parasites were identified, six of which were nematodes - Strongyloides stercoralis as the most prevalent (18.4%), followed by Aelurostrongylus abstrusus (7.5%), Toxocara cati (6.1%), Ancylostoma tubaeforme (5.9%) and Physaloptera sp. (4.8%) and Toxascaris leonina (0.7%) - and one sporozoan species, Isospora felis (0.5%). Unidentified cestode eggs were also recovered from 10.7% of samples examined. The parasite species were found to be highly overdispersed in faecal samples from all sites, whereas the prevalence and intensity of infections were influenced by site and season. Infection levels tended to be higher during the winter season, especially in the case of A. abstrusus and A. tubaeforme, when conditions of temperature and humidity were more favourable for the development of egg and/or larval stages of parasites compared with the extremely hot and dry summer months. The results are discussed in relation to the distribution of the cat population in the vicinity of Doha and its outskirts and the potential threat of parasite transmission to human communities in Qatar.  相似文献   

3.
Abstract. Australian alpine vegetation is confined to the southeast of the continent and the island of Tasmania. It exhibits strong geographic patterns of floristic variation. These patterns have been attributed to variation in edaphic conditions resulting from geographic variation in substrate, climate and glacial history. This edaphic hypothesis is tested using floristic and environmental data from 166 quadrats distributed throughout the floristic and geographic range of Australian alpine vegetation. Environmental vector fitting in three-dimensional ordination space, the number of significant environmental differences between all pairs of 17 floristic groups and overall statistical analyses of the environmental differences between communities suggest a primacy of climatic variables over edaphic variables in explaining the broad patterns of floristic variation. Continentality, summer warmth, summer rainfall and winter cold all provide a better statistical explanation of floristic variation than the most explanatory of the edaphic variables, extractable P. The environmental variables that best discriminate the groups at each dichotomy of the divisive classification of the floristic data are largely climatic at the upper two levels, with edaphic, topographic and biotic variables being generally more important than climatic variables at the lower levels. Many of the edaphic variables that were most important in discriminating dichotomous groups were relatively insignificant in the broader analyses, suggesting that it is important to partition large data sets for environment/floristic analyses. The results of such partitioning show that the environmental factors most important in influencing floristic variation in alpine vegetation in Australia vary by location and geographic scale.  相似文献   

4.
The present study investigated the peripheral plasma inhibin levels in relation to 1) the stage of estrous cycle and the effect of climatic variations. Blood samples were collected from cyclic buffalo (n=5) once daily for 32 consecutive days during the tropical hot humid (summer) and cold (winter) seasons. Estrus was recorded by parading a vasectomized bull as well as by plasma progesterone determination. In the winter season, peripheral inhibin concentrations which were lowest (0.35 +/- 0.02 ng/ml) during the mid-luteal phase of estrous cycle (Day 6 to Day 14, Day 0 = day of estrus) increased significantly (P < 0.02) to 0.47 +/- 0.04 ng/ml during the late luteal phase (Day -4 to Day -2) and then further to 0.52 +/- 0.03 ng/ml (P< 0.02) during the periestrus phase (Day -1 to Day 1). Inhibin concentrations then decreased significantly (P < 0.02) to 0.40 +/- 0.03 ng/ml during the early luteal phase (Day 2 to Day 5). In the summer season the differences in peripheral inhibin concentrations among different phases of estrous cycle were found to be nonsignificant. A comparison of the circulating inhibin concentrations between the two seasons indicated that inhibin concentrations were significantly higher in the late luteal phase (P < 0.01) and periestrus phase (P < 0.05) during the winter season compared with corresponding periods during the summer season. The present study suggests that peripheral inhibin concentrations change in the estrous cycle during cooler breeding season and that environmental heat stress can cause a reduction in peripheral inhibin concentrations.  相似文献   

5.
Exotic poeciliid fishes introduced into Hawaiian freshwaters are responsible for the introduction of several exotic parasites, of which the most important are Camallanus cotti and Bothriocephalus acheilognathi in terms of potential disease threat to native stream fishes. This roundworm and tapeworm are the most prevalent and abundant freshwater fish helminths in Hawaiian streams. This study examined the seasonal and yearly population structure of C. cotti and B. acheilognathi to determine if the tropical Hawaiian environment characterized by low climatic variability permits continuous opportunities for parasite transmission regardless of time of year. Camallanus cotti displayed seasonal differences in prevalence and mean abundance, whereas B. acheilognathi did not. Camallanus cotti prevalence and mean abundance were higher in the Hawaiian summer (47.7%, 0.79) than in winter (25.8%, 0.36). A seasonal relationship of C. cotti levels is likely explained by extensive rains associated with the Hawaiian winter season, which may act to decrease parasite transmission by flushing infected poeciliid hosts, intermediate copepod hosts, and possibly free-living infective worm stages downstream. Bothriocephalus acheilognathi displayed low prevalence and mean abundance in both summer (4.0%, 0.06) and winter (6.5%, 0.07), and it may be difficult to detect seasonal changes due to these low levels. Camallanus cotti prevalence and mean abundance remained relatively constant from the summer of 1995 to the summer of 1999, indicating that levels of this roundworm are stable in Waianu Stream. Whereas B. acheilognathi prevalence and mean abundance were low during the summer of 1995 and the summer of 1997, a dramatic peak in prevalence and mean abundance was observed in the summer of 1998 (41.2%, 1.06), with levels decreasing sharply in the summer of 1999 (4.4%, 0.07). It appears that B. acheilognathi also is present in stable populations at low levels, even though levels rose sharply during a single year.  相似文献   

6.
S. K. Seah  G. Hucal  C. Law 《CMAJ》1975,112(10):1191-1194
The stools of 239 stray dogs were examined for intestinal parasites. Of the helminths found, Toxocara canis (43.5%), tapeworms (25.5%), Ascaris species (21.3%) and hookworms (12.5%) were the commonest. Of the protozoans found, Isospora species and Entamoeba coli were the most prevalent. An unusual feature of the present study was the finding of Ascaris species. The importance of the high prevalence of intestinal parasites in dogs, the close contact of humans with dogs'' excreta and the possible role of this environmental pollution in the spread of human disease are discussed.  相似文献   

7.
Dynamics of communities of gastrointestinal helminths of cotton rats (Sigmodon hispidus) were monitored in response to five experimental brush management treatments using herbicide applications with and without prescribed burning on the Cross Timbers Experimental Range in Payne County, Oklahoma (USA). A total of 113 adult cotton rats (68 male and 45 female) was collected from experimental pastures in winter and summer 1986 resulting in the recovery of five species of helminths: Longistriata adunca, Syphacia sigmodontis, Strongyloides sp., Protospirura muris, and Raillietina sp. Prevalences of Raillietina sp. and S. sigmodontis were greater on control than herbicide-treated pastures. Prevalence and abundance of Raillietina sp. and prevalence of S. sigmodontis were significantly lower on annually burned, herbicide-treated pastures compared to unburned herbicide-treated pastures. Triclopyr-treated pastures had greater abundances of L. adunca and lower abundances of Raillietina sp. than those treated with tebuthiuron. Abundances of L. adunca also decreased from winter to summer on annually burned, herbicide-treated pastures while increasing on other pastures. Distribution of all helminths was overdispersed, but distribution of L. adunca showed a significant brush treatment by season interaction as a result of greater overdispersion in summer than winter for cotton rats inhabiting brush-treated pastures. Our results indicate that man-induced habitat modifications can alter host-parasite relationships in the community.  相似文献   

8.
Terminal stem joints from three opuntias were detached and maintained for 160 days under natural climatic conditions in the winter and summer. Neither Crassulacean acid metabolism (CAM) nor CAM-idling, as evidenced by a diurnal malate flux, was maintained throughout the two periods; ceasing earlier in the summer period. A 13 to 20% fresh weight loss occurred over the winter period, as opposed to a 30 to 40% loss over the summer period, although tissue water potentials remained above −1.5 megapascals. Chlorophyll and protein contents remained essentially constant in the winter but decreased in the summer. Starch content decreased slightly over the winter but more significantly over the summer. Mucilage content increased slightly in winter and declined slightly in summer. The initiation of rooting was found to be inversely related to spine density and dependent upon orientation and season. Comparison of these data suggest rooting coincided with the cessation of CAM-idling in both climatic periods and was uncoupled from the occurrence of precipitation. The physiological limit for survival of these propagules after detachment was lower than anticipated being of only a few months' duration.  相似文献   

9.
目的:季节气候的变化能够影响人体肠道的生理功能和病理变化,这在中医学的长期临床实践和现代流行病学调查中都有记载和证实,但是相关的机制并不清晰。因此本研究通过观察不同气候下大鼠空肠、回肠、结肠的IL-10水平变化,从而从免疫功能的角度探讨季节气候变化对肠道功能的影响机制。方法:根据北京地区气象资料,大致可将一年之中气候划分为五种季节气候,分别由春、夏、长夏、秋和冬来代表;实验分为正常组和松果腺摘除模型组;分别把两组大鼠饲养五种正常自然季节气候下一个月,然后用ELISA方法检测大鼠空肠、回肠和结肠的IL-10水平。结果:①正常组空肠IL-10水平在长夏季节明显升高(P〈0.001);②回肠的IL-10表达水平则是在长夏与冬季这两个季节含量最多(P〈0.01,P〈0.001);③结肠IL-10含量则在冬季呈现出高峰(P〈0.01)。结论:季节气候变化对肠道功能的影响的机制与肠道免疫功能的季节性变化有关。具体表现在:①肠道IL-10水平是有季节气候变化规律的,而且空肠、回肠和结肠表现出来的季节气候规律是不相同的。②松果腺参与了肠道免疫功能气候调节过程。  相似文献   

10.
Gastrointestinal parasitism is one of the major constraints for profitable livestock production. The present study was conducted to determine the prevalence and seasonal variation in gastrointestinal helminthic infections in cattle of New Alluvial zone of West Bengal. A total 2520 faecal samples of cattle were collected from five different places of NAZ of West Bengal during the study period i.e. March 2014 to February 2015. The faecal samples were examined by standard sedimentation and floatation technique. The overall prevalence of gastrointestinal parasites was recorded as 55.71% in cattle of NAZ and Paramphistome (40.64%) was recorded as the predominant parasite followed by Strongyle group of nematodes (8.25%) and Fasciola (3.33%). Moniezia was the only cestode parasite recorded with an overall prevalence of 1.97%. Statistically significant (p < 0.05) variation was observed in the prevalence of gastrointestinal helminths among the various seasons. Monsoon season has significantly (p < 0.05) higher prevalence of gastrointestinal helminthes (64.28%) followed by winter (57.14%) and lowest in summer (45.24%). Prevalence of Paramphistome (47.62%) and Strongyle (9.52) were also significantly (p < 0.05) higher monsoon compared to other seasons. The epidemiological knowledge/information gathered in the present study would be exploited for evolving strategic control method against gastrointestinal parasitic infections in cattle.  相似文献   

11.
Variations in biomass yield, essential oil yield and terpenoid composition in rose-scented geranium (Pelargonium species) in response to seasonal climatic changes were investigated under semiarid tropical climatic conditions. A large number of essential oil samples were collected during different seasonal months (once a month) and daily during the peak summer season months of May and June. They were analysed for terpenoid composition by GC and GC-MS. The crop yielded the lowest values for biomass yield, essential oil yield and essential oil concentration in the summer months of April to June. Evaluation of terpenoid compositions showed minimum concentrations (% of essential oil) of linalool, geraniol and its esters and maximum concentrations of citronellol and its esters during summer months. The percentages of geraniol and its esters were highest during cool winter season months of December and January followed by rainy and autumn season months. Isomenthone, 10-epi-gamma-eudesmol and other minor terpenoid compounds (present in <1% amounts in the essential oil) did not exhibit any definite seasonal trends. Rainy/monsoon (August and September) and autumn (October and November) season months were characterised by high rainfall, cloudy days and short photoperiods. These favourable environmental conditions encouraged crop growth and produced highest biomass yields, essential oil yields and maximum concentration of essential oil in rose-scented geranium plants.  相似文献   

12.
Modern pollen assemblages as climate indicators in southern Europe   总被引:1,自引:0,他引:1  
Aim and Location Our aim is to develop pollen–climate inference models for southern Europe and to test their performance and inference power by cross‐validation with modern climate data. Surface sediments collected from lakes along a climate gradient from the winter‐cold/summer‐wet Alps to winter‐wet/summer‐dry Sicily were analysed for modern pollen assemblages. Methods For each lake, mean monthly temperatures, seasonal precipitation and site‐specific climate uncertainties have been estimated. Pollen–climate relationships were studied using numerical analyses, and inference models were derived by partial least squares (PLS) and weighted‐averaging PLS (WA‐PLS) regressions for January and July temperatures (T), and for winter, spring and summer precipitation (P). In order to assess whether these variables are also of ecological importance for vegetation in the subregions, we split the data set into an Alpine and a Mediterranean subset. Results Low bootstrap cross‐validated root mean square errors of prediction (RMSEP) for January T (1.7 °C), July T (2.1 °C) and summer P (38 mm), as well as low RMSEPs expressed as a percentage of the gradient length (8–9%), indicate a good inference power. Models revealed excellent to good performance statistics for January T, July T and summer P (r2= 0.8), and for winter and spring P (r2=c. 0.5). We show that the variables with the highest explanatory power differ between the two subregions. These are summer T and P for the Alpine set, and January T, winter P and July T for the Mediterranean set. Main conclusions The study reveals the influence of climatic conditions during the growing season on modern pollen assemblages and indicates the potential of pollen data for long‐term climate reconstructions of parameters such as winter precipitation and temperature, which seem to be the main factors having an influence on the variability of Mediterranean climate. These models may therefore provide important information on past regional climate variability in southern Europe.  相似文献   

13.
Multihost parasites have been implicated in the emergence of new diseases in humans and wildlife, yet little is known about factors that influence the host range of parasites in natural populations. We used a comprehensive data set of 415 micro- and macroparasites reported from 119 wild primate hosts to investigate broad patterns of host specificity. The majority (68%) of primate parasites were reported to infect multiple host species, including animals from multiple families or orders. This pattern corresponds to previous studies of parasites found in humans and domesticated animals. Within three parasite groups (viruses, protozoans and helminths), we examined parasite taxonomy and transmission strategy in relation to measures of host specificity. Relative to other parasite groups, helminths were associated with the greatest levels of host specificity, whereas most viruses were reported to infect hosts from multiple families or orders. Highly significant associations between the degree of host specificity and transmission strategy arose within each parasite group, but not always in the same direction, suggesting that unique constraints influence the host range of parasites within each taxonomic group. Finally characteristics of over 100 parasite species shared between wild primates and humans, including those recognised as emerging in humans, revealed that most of these shared parasites were reported from multiple host orders. Furthermore, nearly all viruses that were reported to infect both humans and non-human primates were classified as emerging in humans.  相似文献   

14.
Seasonal variation in most of the metazoan parasites of a Wood mouse population was investigated by a statistical analysis of their frequencies in 11 samples of about 30 mice trapped regularly over one year. Numbers of the flea Ctenophthalmus nobilis , most mesostigmatid mites and the beetle Leptinus testaceus were correlated with breeding in the mouse population and may have been directly linked with it as all ofthese arthropods are common in Wood mouse nests. The tick Ixodes ricinus was abundant over the summer but scarce in winter. Its preponderance on male hosts is doubtless because they cover more ground than females. Flukes were commonest in summer, probably as a result ofthe period of intensive feeding on invertebrates by the mice which usually occurs in early summer. Female mice were more heavily infected, perhaps because of their increased food requirements in the breeding season. Abundance of flukes declined with the turnover in the mouse population in autumn. The infestation pattern of the nematode Capillaria muris sylvatici is similar and the possibility of an invertebrate vector is discussed. While older mice were generally more heavily infected with helminths than were young, this was least marked in the tapeworm Cataenotaenia lobata (which most likely has a mite as an intermediate host and may be picked up as soon as juveniles start grooming) and the roundworm Syphacia stroma (eggs of which are almost certainly transferred by body contact between hosts)  相似文献   

15.
Little is known about the epidemiology of Campylobacter spp. in wild animal populations. However, zoological collections can provide valuable insights. Using records from the Zoological Society of London Whipsnade Zoo compiled between 1990 and 2003, the roles of a range of biotic and abiotic factors associated with the occurrence of campylobacteriosis were investigated. The occurrence of campylobacteriosis varied widely across host taxonomic orders. Furthermore, in mammals, a combination of changes in both rainfall and temperature in the week preceding the onset of gastroenteritis were associated with isolation of Campylobacter from feces. In birds, there was a weak negative correlation between mean weekly rainfall and isolation of Campylobacter from feces. Importantly, in birds we found that the mean weekly rainfall 3 to 4 weeks before symptoms of gastroenteritis appeared was the best predictor of Campylobacter infection. Campylobacter-related gastroenteritis cases with mixed concurrent infections were positively associated with the presence of parasites (helminths and protozoans) in mammals, while in birds Campylobacter was associated with other concurrent bacterial infections rather than with the presence of helminths and protozoans. This study suggests that climatic elements are important factors associated with Campylobacter-related gastroenteritis. Further investigations are required to improve our understanding of Campylobacter epidemiology in captive wild animal populations.  相似文献   

16.
Proto-fix (Alpha-Tec Systems, Inc., Vancouver, WA) is a new single vial, environmentally safe, parasitology (pathogenic and nonpathogenic protozoans and helminths) fixative and transport solution. It is used in conjunction with a new concentration/sedimentation reagent, CONSED, (Alpha-Tec Systems, Inc. Vancouver, WA) as a replacement to the formalin-ethyl acetate (FEA) concentration procedure using Lugol's iodine. The newly adopted procedure was tested against the FEA concentration samples using split proficiency testing samples supplied by the American Association of Bioanalysts (AAB). Routinely, patient samples collected, fixed, and transported in Proto-Fix were processed and tested at Diagnostic Labs, Inc. (DLI), Phoenix, AZ. Detected parasites were documented using a video camera-printer system attached to the optical equipment. The quality of the fixative and stain were found to be superior to that of the FEA-Lugol's method and the yield of detected parasites was considerably higher. Eighty-five percent of 39 unknown parasite species tested were correctly detected using the Proto-fix-CONSED system compared to 46% using the FEA-Lugol's method. Of all the other methods and stains used at DLI, the trichrome stain (a popular modification of Gomori's trichrome stain for tissue sections) was found to be least reliable.  相似文献   

17.
The present study was conducted to examine differential expression pattern of HSP genes and adaptability in Indian goat breeds of semi-arid region. The study was conducted in five animals from each breed viz. Barbari, Sirohi, and Jhakrana during winter, thermo-neutral and summer seasons. The respiratory rate (RR) and rectal temperature (RT) of the goats were recorded at 09:00 h during the study period. The blood samples were collected for RNA isolation, cDNA synthesis, and quantitative analysis of HSP genes expression by quantitative RT-PCR. The RR increased significantly (p < 0.01) during summer as compared to winter and thermo-neutral season however, RT did not change (p > 0.05) during different seasons. The expression of HSP genes was significantly (p < 0.01) increased during summer (high THI) as compared to thermo-neutral season in all the goat breeds. Among HSPs, only HSP90 was upregulated (p < 0.01) in Jhakrana goats during winter as compared to thermo-neutral season. The deviation in expression of HSP genes during summer and winter with respect to thermo-neutral season was minimum in Barbari goats. Therefore, it can be concluded that Barbari goats possessed better adaptability during summer and winter as compared to Sirohi and Jhakrana goats in semi-arid climatic conditions of India.  相似文献   

18.
近50年山东省农业气候资源变化特征   总被引:9,自引:0,他引:9  
利用山东省90个气象站1961-2010年逐日气象观测数据,比较分析了该区域冬小麦和夏玉米生长季光、热、水等农业气候资源的时空变化特征.结果表明: 研究期间,山东省冬小麦和夏玉米生长季各项气温指标均呈显著升高趋势,冬小麦生长季升高趋势更明显;日照时数显著减少;降水量和干燥度无显著变化;夏玉米生长季蒸散量显著减少.冬小麦和夏玉米生长季各农业气候资源呈大致的经向或纬向递增或递减的空间分布.不同区域各农业气候资源历年变化特征差异明显,鲁西地区各气温指标升高趋势较弱,鲁中和鲁西南地区日照时数减少趋势最显著,鲁西地区蒸散量和干燥度减少趋势最显著,鲁中和鲁东南地区冬小麦生长季降水量增加趋势较明显,鲁中和鲁南地区夏玉米生长季降水量增加趋势较明显.山东省热量资源的增加有利于冬小麦生长季各阶段的发育,但植物病虫害的防治难度及农作物遭受高温热害的风险加大,日照时数减少不利于农作物生长期的光合作用,蒸散量减少则有利于土壤水分的保存.
  相似文献   

19.
Climate change treatments – winter warming, summer drought and increased summer precipitation – have been imposed on an upland grassland continuously for 7 years. The vegetation was surveyed yearly. In the seventh year, soil samples were collected on four occasions through the growing season in order to assess mycorrhizal fungal abundance. Mycorrhizal fungal colonisation of roots and extraradical mycorrhizal hyphal (EMH) density in the soil were both affected by the climatic manipulations, especially by summer drought. Both winter warming and summer drought increased the proportion of root length colonised (RLC) and decreased the density of external mycorrhizal hyphal. Much of the response of mycorrhizal fungi to climate change could be attributed to climate‐induced changes in the vegetation, especially plant species relative abundance. However, it is possible that some of the mycorrhizal response to the climatic manipulations was direct – for example, the response of the EMH density to the drought treatment. Future work should address the likely change in mycorrhizal functioning under warmer and drier conditions.  相似文献   

20.
Owing to Saudi Arabia's high-income economy many Saudi families hire foreign housemaids. However, since the housemaids are potential carriers of intestinal parasites, hiring them increases the risk of transmission to the Saudi community. In this context, this study aimed to evaluate the prevalence of intestinal parasitic infections in foreign housemaids in northwestern Saudi Arabia. Using direct wet mount and concentration by flotation, the stool samples of 169 housemaids were examined, and eleven parasite species, six helminths and five protozoans, were detected. The overall prevalence of intestinal parasitic infection was 20.11% (34/169). Twelve cases were infected with one intestinal helminth, 12 were infected with one intestinal protozoan, and 10 had polyparasitism. The most common intestinal parasites were Cryptosporidium spp. (n = 10), hookworms (n = 7), and T. Trichiura (n = 7). The findings highlight that intestinal parasites present an important public health concern for foreign housemaids in Saudi Arabia. More vigilance is thus required, and periodic follow-up should be exercised throughout foreign housemaids' stay in the country.  相似文献   

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