共查询到20条相似文献,搜索用时 15 毫秒
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Maertyn G. Murray 《African Journal of Ecology》1993,31(2):172-177
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Impala (Aepyceros melampus) and wildebeest (Connochaetes taurinus) were infected with bovine strains of foot and mouth disease virus by intradermolingual inoculation. No clinical signs developed in the impala but mild atypical lesions developed in the tongues of the wildebeest with generalized spread to one foot in two of the eight animals exposed. All the impala but only some of the wildebeest developed viraemia. No virus could be isolated from any tissues in either species after the 7th day following virus inoculation. Immune response occurred in both species. A field survey revealed few animals of either species with significant antibody titers and no virus 'carriers' were found. 相似文献
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A serologic survey of blue wildebeest (Connochaetes taurinus Burchell) and African buffalo (Syncerus caffer Sparrman) in the Masai Mara area was conducted. Antibodies to Brucella spp. were found in 18% of the blue wildebeest and 30% of the African buffalo examined. There were titers in all age groups and in both sexes. Hygromata were seen in both species. The increase in numbers of blue wildebeest and African buffalo which share grazing and watering areas with cattle of the Masai people, makes the presence of infections by Brucella spp. in wildlife an important consideration in any program for control of brucellosis. 相似文献
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JESSEC. HILLMAN 《African Journal of Ecology》1988,26(2):135-148
Data were collected in Kenya on the movements of individually recognizable wild eland over a 30-month period. Further information on movement was obtained from monthly ground counts of Nairobi National Park, and two aerial censuses of the Park and Athi Kapiti plains. Results indicated that adult male eland had restricted home ranges, but that females and juveniles carried out extensive seasonal movements between open grassland and bushed habitats. The numbers of eland in the Park were found to be related to rainfall over the previous two months in the areas outside the Park. It was concluded that females and juveniles were taking advantage of seasonal food abundance in open grassland areas, where the formation of large groups gives protection to small-sized juveniles. 相似文献
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Sarah E. Reece Eltayeb Ali Petra Schneider Hamza A. Babiker 《Proceedings. Biological sciences / The Royal Society》2010,277(1697):3123-3129
Life-history theory predicts that sexually reproducing organisms have evolved to resolve resource-allocation trade-offs between growth/survival versus reproduction, and current versus future reproduction. Malaria parasites replicate asexually in their vertebrate hosts, but must reproduce sexually to infect vectors and be transmitted to new hosts. As different specialized stages are required for these functions, the division of resources between these life-history components is a fundamental evolutionary problem. Here, we test how drug-sensitive and drug-resistant isolates of the human malaria parasite Plasmodium falciparum resolve the trade-off between in-host replication and between-host transmission when exposed to treatment with anti-malarial drugs. Previous studies have shown that parasites increase their investment in sexual stages when exposed to stressful conditions, such as drugs. However, we demonstrate that sensitive parasites facultatively decrease their investment in sexual stages when exposed to drugs. In contrast to previous studies, we tested parasites from a region where treatment with anti-malarial drugs is common and transmission is seasonal. We hypothesize that when exposed to drugs, parasites invest in their survival and future transmission by diverting resources from reproduction to replication. Furthermore, as drug-resistant parasites did not adjust their investment when exposed to drugs, we suggest that parasites respond to changes in their proliferation (state) rather the presence of drugs. 相似文献
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Birds respond to capture, handling and restraint with increased secretion of corticosterone, a glucocorticoid hormone that helps birds adjust to stressful situations. Hoods are reported to calm birds, but possible effects of hoods on corticosterone responses have not been reported for any bird. Corticosterone responses to restraint in Adelie penguins held by their legs with their head covered by a hood were markedly lower than responses of penguins restrained in a mesh bag inside a cardboard box (corticosterone at 30 min 15.69+/-1.72 cf. 28.32+/-2.75 ng/ml). The birds restrained by the two methods were sampled at the same location but in different years, so the differences in corticosterone responses cannot unequivocally be ascribed to an effect of hoods to reduce corticosterone responses. Corticosterone responses have been measured in some penguins, but not in the largest, the emperor penguin (Aptenodytes forsteri). The relationship between body mass and corticosterone responses to capture and restraint in penguins was examined in emperor penguins captured on sea ice in McMurdo Sound and Adelie penguins (Pygoscelis adeliae) captured at Cape Bird, Ross Island, Antarctica. Total integrated corticosterone responses were higher in the emperor than the Adelie penguins, but corrected integrated corticosterone responses, which represent the increase in corticosterone from initial concentrations and hence the corticosterone response to restraint, were the same. The results for the emperor and Adelie penguins, together with data from other penguin species, suggest that there is no relationship between the size of corticosterone responses and body mass in penguins. 相似文献
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A dose range was determined for anesthesia of recently boma-captured Lichtenstein's hartebeest (Sigmoceros lichtensteinii) (n = 13) with the synthetic opiate thiafentanil (THIA) (formerly called A3080) combined with medetomidine (MED) and ketamine (KET) in the Kasungu National Park, Malawi on 4 to 5 September 1999. The dose range of 11-29 micrograms/kg THIA (mean +/- SD = 21 +/- 4 micrograms/kg) combined with 5-10 mg/kg MED (8 +/- 1 micrograms/kg) plus 0.7-1.4 mg/kg KET (1.1 +/- 0.2 mg/kg) was found to be safe and effective for the field conditions associated with this study. The anesthesia produced by this drug combination was very predictable and characterized by a short induction time (3:34 +/- 1:20 min:sec), good muscle relaxation, and acceptable physiologic parameters for anesthesia periods ranging from 22:30-35:00 min:sec (31:14 +/- 2:50). Within the range of doses used in this study, times to onset of initial effects and recumbency were not dependent on THAI, MED, or KET doses. Anesthesia was rapidly and completely reversed by intravenous injections of naltrexone at 30 times the THAI dosage (0.69 +/- 0.19 mg/kg) and atipamezole at about four times the MED dosage (38 +/- 14 micrograms/kg). There was no residual effect from ketamine noted following reversal of THIA and MED and no mortality or morbidity was associated with this anesthetic regimen. 相似文献
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Home range, dispersal and the clan system of impala 总被引:1,自引:0,他引:1
M.G. MURRAY 《African Journal of Ecology》1982,20(4):253-269
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Deep litter has been shown to decrease stereotypic wire-gnawing in male golden hamsters, suggesting that increased litter depth may be associated with decreased chronic stress levels. To determine the relationship between litter depth and stress levels in hamsters, the authors measured serum levels of corticosterone, cortisol, and ACTH in male golden hamsters kept in cages with three different depths of litter. The duration of handling the hamsters significantly increased the concentrations of corticosterone, cortisol, and the ratio of cortisol/corticosterone. It took longer to catch hamsters housed in cages with deep litter and the ACTH levels were higher in these hamsters. The positive effect of the enrichment (deep litter) was diminished by methodological problems during handling/anesthesia. 相似文献
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HIV,Disease Plague,Demoralization and ``Burnout': Resident Experience of the Medical Profession in Nairobi,Kenya 总被引:2,自引:0,他引:2
This paper describes the experiencesof physicians-in-training at a public hospitalin Nairobi, Kenya, where medical professionalspractice in an environment characterized byboth significant lack of resources andpatients with HIV/AIDS in historicallyunprecedented numbers. The data reported hereare part of a larger study examining ethicaldilemmas in medical education and practiceamong physicians in East Africa. Aquestionnaire and semi-structured interviewwere completed by fifty residents in fourmedical specialties, examining social andemotional supports, personal and professionalsources of stress, emotional numbing anddisengagement from patients and peers, andsymptoms of post-traumatic stress anddepression. The factors affecting residentwell-being are found in this study to be morecomplex than previous interviews suggested. This study highlights the fact that as a resultof working in an environment characterized by poor communication among hospital staff aswell as a lack of resources and high numbersof patients with HIV/AIDS, residents'perceptions of themselves – their technicalproficiency, their ability to care and feel forothers and themselves, and for some theirentire sense of self – are significantlyaffected. Also affected are the patients theywork to treat. 相似文献
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MARY L. OWAGA 《African Journal of Ecology》1975,13(3-4):375-383
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R S Gainer 《Journal of wildlife diseases》1987,23(1):175-178
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Antimicrobial resistance in faecal samples from buffalo,wildebeest and zebra grazing together with and without cattle in Tanzania
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A.A.S. Katakweba K.S. Møller J. Muumba A.P. Muhairwa P. Damborg J.T. Rosenkrantz U.M. Minga M.M.A. Mtambo J.E. Olsen 《Journal of applied microbiology》2015,118(4):966-975
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The single species of Aepyceros, Aepyceros melampus (impala), is native to central and southern Africa, from Uganda to South Africa. It inhabits open woodlands, sandy bush country and acacia savannah. This study tested the morphological and geographical variation among specimens of impala and their possible relation with described subspecies. Nineteen skull and horn measurements were taken. A multivariate analysis was used and size and shape were explored. Facial coat patterns were also coded. The results supported four out of five traditionally described subspecies: Aepyceros melampus petersi from Angola/Namibia, Aepyceros melampus melampus from South Africa, Aepyceros melampus suara from East Africa and Aepyceros melampus johnstoni from Zambia and Malawi. We consider Aepyceros melampus rendilis to be a synonym of suara . A revised synopsis is suggested, with comments on the geographical ranges of the subspecies. Skull dimensions also allowed us to estimate the geographical origin and subspecies of some individuals of unknown provenance. Coat patterns showed no clear relation with subspecies or geographic location, with the exception of A. m. petersi . 相似文献