Brucellosis of the common vole (Microtus arvalis)

A systemic disease occurred in a wild population of the common vole Microtus arvalis in South Moravia (Czech Republic) during the years 1999-2003. Acute infections were characterized by edema of extremities, occasionally with colliquating abscesses, arthritis, lymphadenitis, perforations of the skin resulting from colliquated abscesses, orchitis, and peritoneal granulomas. From the clinical samples, small Gram-negative coccobacilli were isolated and identified as Ochrobactrum intermedium by API 20NE and colistin sensitivity profiles. However, subsequent rrs (16S rRNA) and recA (recombinase A) gene sequencing analysis of two isolates (CCM 4915=CAPM 6434; CCM 4916=CAPM 6435) identified them as Brucella sp. with sequence identities of 100% to other Brucella spp. Analysis of the omp2a/b genes confirmed the two isolates as Brucella. In AMOS polymerase chain reaction (PCR), a 2000-bp fragment was generated that was not seen in other brucellae. Experimental infection of outbred ICR mice with these isolates resulted in a mortality rate of 50%. Based on the results of the molecular investigations and the mortality observed in experimentally infected mice we conclude that the epizootic was caused by Brucella sp. and not by Ochrobactrum intermedium. The study demonstrates the limitations of commercial biochemical test systems in accurately differentiating among Ochrobactrum and Brucella.     

生态保留带中普通田鼠种群活动格局的初步的研究

目的研究生态保留带地栖息环境质量对普通田鼠活动格局的影响和普通田鼠对周围农作物的扩散.方法用新型无线电自动跟踪器从2003年5～10月和2004年3～9月研究了生态保留带中的普通田鼠种群.结果普通田鼠的巢区大小分别在125 m2 (最小凸起多边形方法)和30 m2(Kernel法),巢区大小比较稳定,巢区日间重叠率达到90%左右,巢区基本在生态保留带之内,包括不同核心区;夏天普通田鼠的白日活动比较活跃,包括多阶段活动格局,阶段间隔时间为1.7 h.结论生态保留带对普通田鼠提供高质量的栖息环境,持续高种群密度,对周围农地不会产生危害.     

抗草原兔尾鼠抗体制备及特异性检测

目的研究生态保留带地栖息环境质量对普通田鼠活动格局的影响和普通田鼠对周围农作物的扩散。方法用新型无线电自动跟踪器从2003年5~10月和2004年3~9月研究了生态保留带中的普通田鼠种群。结果普通田鼠的巢区大小分别在125 m2(最小凸起多边形方法)和30 m2(Kernel法),巢区大小比较稳定,巢区日间重叠率达到90%左右,巢区基本在生态保留带之内,包括不同核心区;夏天普通田鼠的白日活动比较活跃,包括多阶段活动格局,阶段间隔时间为1.7 h。结论生态保留带对普通田鼠提供高质量的栖息环境,持续高种群密度,对周围农地不会产生危害。     

The root-vole Microtus oeconomus (Pallas, 1776): a new potential reservoir of Anaplasma phagocytophilum

Anaplasma phagocytophilum infection is a recently emerged tick-borne zoonosis. The bacterium's reservoirs likely comprise cervids, some ruminants, rodents, and perhaps other small and intermediate-size mammals; the main vector in Europe is the Ixodes ricinus tick. The Bia?owieza Primeval Forest is an ecosystem with a known prevalence of tick-borne pathogens. We studied the root-vole Microtus oeconomus to evaluate the natural infection of A. phagocytophilum. Intragranulocytic bacterial clusters (morulae) were not seen, but the A. phagocytophilum-specific nested polymerase chain reaction (PCR) product, targeting the rrs gene, was detected in two out of 30 rodent samples (GenBank accession nos. DQ361024 and DQ361025). Twenty-six root vole (86.6%) hosted ticks, mainly Dermacentor reticulatus larvae and nymphs. Only two rodents were parasitazed by I. ricinus single larvae. These data show the presence of natural infection of A. phagocytophilum among the root-vole M. oeconomus in the Bia?owieza Primeval Forest ecosystem.     

Impact of behavior on central and peripheral circadian clocks in the common vole Microtus arvalis, a mammal with ultradian rhythms

In most mammals, daily rhythms in physiology are driven by a circadian timing system composed of a master pacemaker in the suprachiasmatic nucleus (SCN) and peripheral oscillators in most body cells. The SCN clock, which is phase-entrained by light-dark cycles, is thought to synchronize subsidiary oscillators in peripheral tissues, mainly by driving cyclic feeding behavior. Here, we examined the expression of circadian clock genes in the SCN and the liver of the common vole Microtus arvalis, a rodent with ultradian activity and feeding rhythms. In these animals, clock-gene mRNAs accumulate with high circadian amplitudes in the SCN but are present at nearly constant levels in the liver. Interestingly, high-amplitude circadian liver gene expression can be elicited by subjecting voles to a circadian feeding regimen. Moreover, voles with access to a running wheel display a composite pattern of circadian and ultradian behavior, which correlates with low-amplitude circadian gene expression in the liver. Our data indicate that, in M. arvalis, the amplitude of circadian liver gene expression depends on the contribution of circadian and ultradian components in activity and feeding rhythms.     

Parasitic infections of the European brown hare (<Emphasis Type="Italic">Lepus europaeus</Emphasis> Pallas, 1778) in south -western Slovakia

A total of 74 European brown hares (Lepus europaeus Pallas, 1778), hunted during the winter seasons of 2006 and 2007, were examined by dissection for the presence of helminths and coprologically for protozoa. The animals came from five districts with a high population density of this species. Our results revealed 54.5 % of specimens being infected with one or more helminth species and a high prevalence of eimeriid coccidia (91.89 %). The most prevalent helminth species was Trichuris leporis (55.41 %). Lower prevalence was found for Passalurus ambiguus (12.16 %) and Trichostrongylus retortaeformis (6.76 %). The intensity of infection was low for all parasite species. As for coccidia, Eimeria semisculpta (74.35 %) and E. leporis (61.54%) were recorded in all districts. Other coccidia showed lower prevalence rates: E. robertsoni (15.38 %), E. europaea (12.82 %), E. babatica (12.82 %), E. hungarica (5.13 %) and E. towsendi (2.56 %), occurring only in some districts. The highest infection rate was observed in E. semisculpta, 7657.8 oocysts per gram of faeces (OPG). The potential effect of protozoan infection on hare mortality is discussed.     

Unifying the spatial population dynamics and molecular evolution of epidemic rabies virus

Infectious disease emergence is under the simultaneous influence of both genetic and ecological factors. Yet, we lack a general framework for linking ecological dynamics of infectious disease with underlying molecular and evolutionary change. As a model, we illustrate the linkage between ecological and evolutionary dynamics in rabies virus during its epidemic expansion into eastern and southern Ontario. We characterized the phylogeographic relationships among 83 isolates of fox rabies virus variant using nucleotide sequences from the glycoprotein-encoding glycoprotein gene. The fox rabies virus variant descended as an irregular wave with two arms invading from northern Ontario into southern Ontario over the 1980s and 1990s. Correlations between genetic and geographic distance suggest an isolation by distance population structure for the virus. The divergence among viral lineages since the most recent common ancestor correlates with position along the advancing wave front with more divergent lineages near the origin of the epidemic. Based on divergence from the most recent common ancestor, the regional population can be partitioned into two subpopulations, each corresponding to an arm of the advancing wave. Subpopulation A (southern Ontario) showed reduced isolation by distance relative to subpopulation B (eastern Ontario). The temporal dynamics of subpopulation A suggests that the subregional viral population may have undergone several smaller waves that reduced isolation by distance. The use of integrated approaches, such as the geographical analysis of sequence variants, coupled with information on spatial dynamics will become indispensable aids in understanding patterns of disease emergence.     

Blood pressure and electrolyte excretion in the Yanomamo Indians, an isolated population

As part of the INTERSALT study, blood pressure, urinary electrolytes, age, and body mass index were assessed in a sample of 195 Yanomamo Indians from the Brazilian Amazon. Mean sodium excretion was 0.9 mmol/24 hr. Urinary sodium was lower than 1 mmol/24 hr in 84% of participants. Mean blood pressure was 96.0/60.6 mmHg (range 78/37 to 128/86). Systolic and diastolic blood pressure were not higher at older than at younger ages in men. In women, systolic pressure was lower at older ages. Mean body mass index was low (20.8 in women and 21.5 in men), and there was no alcohol intake reported. Mean 24 hour urinary potassium was 60 mmol in women and 67 in men. In the presence of the low sodium intake among the Yanomamo, body mass index and potassium, found to be related to blood pressure in the overall INTERSALT study, were not consistently related to pressure in this population. Results demonstrated that there was low average population blood pressure, no hypertension and no positive slope of blood pressure with age in a population with very low salt intake.     

仓储面粉中腐食酪螨自然种群消长动态及空间分布型研究

目的探讨腐食酪螨自然种群季节性消长动态及其在芜湖市仓储面粉中的空间分布型,为腐食酪螨的防制提供理论依据。方法自2013-1-2013-12,选择芜湖市区5个采样点,每月进行定点采样,鉴定及计数其中的腐食酪螨。运用扩散型指标、Iwao m*--x回归方程及Taylor lg S2-lg-x回归分析研究腐食酪螨种群在仓库面粉中的空间分布特征。结果芜湖市区仓储面粉中的腐食酪螨高峰期在7月和9月。扩散型指标I0,CA0,m*/-x1;Iwao的线性回归方程为m*=3.740 3+1.017 5-x(r=0.995 8),Taylor线性回归方程为lg S2=0.500 4+1.134 9 lg-x(r=0.832 8),表明腐食酪螨在仓储面粉中为聚集分布。结论腐食酪螨在芜湖市仓储面粉中的自然种群季节性消长呈双峰型,空间格局为聚集分布。     

Studies on the control and dynamics of thyrotropin secretion from isolated adenohypophyseal cells.

Thyrotropin (TSH) secretion from isolated anterior pituitary cells has been studied using the technique of cell column perifusion. The consistency in secretory rate and temporal profiles of TSH output in response to stimulation illustrated that the system is suitable for studying the kinetics of stimulation and inhibition of secretion. During perfusion TSH release was stimulated in response to a variety of secretogogues, namely TRH, raised potassium concentrations and phosphodiesterase inhibitors. The onset and termination of the secretory responses were rapid and displayed a temporally biphasic pattern of secretion. Dose-related increases in TSH output in response to TRH and consistent responses to repetitive pulses of TRH (5.5 X 10-10 M) during a 4 h period were demonstrated. Studies on the dynamics of thyroid hormone feedback on TRH-stimulated TSH secretion indicated that inhibition was manifest within 1 h and reached a maximum after 2 1/2 h during continual exposure to thyroid hormones. Isobutylmethylxanthine (IBMX) potentiated the effect of raised K+ as well as that of TRH on TSH secretion, suggesting an as yet unidentified relationship between Ca2+ and cyclic AMP.