Long-term population dynamics of ixodid ticks and development of tick-borne encephalitis foci under conditions of the middle taiga subzone

2006 ◽  
Vol 37 (5) ◽  
pp. 325-329 ◽  
Author(s):  
L. A. Bespyatova ◽  
E. P. Ieshko ◽  
E. V. Ivanter ◽  
S. V. Bugmyrin
2021 ◽  
Vol 101 (2) ◽  
pp. 273-281
Author(s):  
L. A. Bespyatova ◽  
S. V. Bugmyrin ◽  
S. A. Kutenkov ◽  
I. A. Nikonorova

Author(s):  
Alena Borisovna Konkova-Reidman ◽  
D. N. Barsukova ◽  
E. I. Bondarenko ◽  
A. N. Shvalov ◽  
S. V. Lucinina

An analysis of the incidence in the dynamics of years (1998-2018) showed that the leading place among infections transmitted by ixodid ticks in the Chelyabinsk region is occupied by tick-borne tick-borne borreliosis (IKB), tick-borne encephalitis (TBE) is less common. Long-term monitoring of the natural foci of TBE and IKB showed their high epizootological potential. In 2018, febrile forms prevailed in the structure of clinical forms of TBE - 61.9%, meningeal and focal forms were found in 28.5% and 9.4%, respectively. Focal forms were represented by meningoencephalitic and polioencephalomyelitis forms with the same frequency of 4.7%. In the structure of the nosological diagnosis of ICD in the South Urals, erythema forms of the disease prevail (69.5%). The detection frequency of Borrelia DNA of the pathogenic complex B.burgdorferi s.l. in the blood serum and leukocyte fraction of patients was 13%. In 4 patients, for the first time in the Chelyabinsk region, DNA of a new Borrelia miyamotoi Borrelia genotype was detected in whole blood samples and in the samples of the leukocyte fraction using PCR-RV. Phylogenetic analysis of B. miyamotoi was carried out on all sequences of glpQ and 23SrRNA gene fragments, deposited at NCBI and homologous sequences of Chelyabinsk-2018 isolates. The disease proceeded in non-erythema form, intoxication syndrome, myalgia, chills were observed in the clinical picture.


Author(s):  
Ivan G. Horak ◽  
Gordon J. Gallivan ◽  
Arthur M. Spickett

Despite a large number of studies on tick biology, there is limited information on long- term changes in tick populations. This study thus aimed to assess the long-term population dynamics of questing ixodid ticks in two landscape zones of the Kruger National Park (KNP). Questing ixodid ticks were collected in the KNP from August 1988 to March 2002 by monthly dragging of the vegetation in three habitats (grassland, woodland and gully) at two sites (Nhlowa Road and Skukuza). Findings pertaining to total tick numbers and Amblyomma hebraeum and Rhipicephalus decoloratus specifically are presented here. Fourteen tick species were collected, as well as four others that could be identified only to generic level. More ticks (211 569 vs 125 810) were collected at Nhlowa Road than at Skukuza. Larvae were the most commonly collected stage of all the major tick species. A. hebraeum was the most commonly collected tick (63.6%) at Nhlowa Road, whereas R. decoloratus accounted for 15.3% of the ticks collected there. At Skukuza, 31.6% and 27.1% of the collected ticks were R. decoloratus and A. hebraeum respectively. Most A. hebraeum larvae were collected in summer and the fewest in winter and early spring, mostly in woodland and least often in grassland habitats. Most R. decoloratus larvae were collected in spring and the fewest in autumn and winter, and were more frequently collected in woodland and grassland than in gullies. The largest collections of most tick species were made during the early 1990s, while numbers were lowest in the mid-1990s after a drought during 1991 and 1992 and then increased towards the late 1990s, followed by a final decrease. The changes in tick numbers over time probably reflect differences in their host communities at the two sites and the effect of climatic conditions on both hosts and free-living ticks. The population dynamics of questing ticks reflect a complex interaction between ticks, their hosts and the environment.


2009 ◽  
Vol 90 (8) ◽  
pp. 1781-1794 ◽  
Author(s):  
K. L. Mansfield ◽  
N. Johnson ◽  
L. P. Phipps ◽  
J. R. Stephenson ◽  
A. R. Fooks ◽  
...  

During the last 30 years, there has been a continued increase in human cases of tick-borne encephalitis (TBE) in Europe, a disease caused by tick-borne encephalitis virus (TBEV). TBEV is endemic in an area ranging from northern China and Japan, through far-eastern Russia to Europe, and is maintained in cycles involving Ixodid ticks (Ixodes ricinus and Ixodes persulcatus) and wild vertebrate hosts. The virus causes a potentially fatal neurological infection, with thousands of cases reported annually throughout Europe. TBE has a significant mortality rate depending upon the strain of virus or may cause long-term neurological/neuropsychiatric sequelae in people affected. In this review, we comprehensively reviewed TBEV, its epidemiology and pathogenesis, the clinical manifestations of TBE, along with vaccination and prevention. We also discuss the factors which may have influenced an apparent increase in the number of reported human cases each year, despite the availability of effective vaccines.


Author(s):  
Alena Borisovna Konkova-Reidman ◽  
D. N. Barsukova ◽  
E. I. Bondarenko ◽  
A. N. Shvalov ◽  
S. V. Lucinina

An analysis of the incidence in the dynamics of years (1998-2018) showed that the leading place among infections transmitted by ixodid ticks in the Chelyabinsk region is occupied by tick-borne tick-borne borreliosis (IKB), tick-borne encephalitis (TBE) is less common. Long-term monitoring of the natural foci of TBE and IKB showed their high epizootological potential. In 2018, febrile forms prevailed in the structure of clinical forms of TBE - 61.9%, meningeal and focal forms were found in 28.5% and 9.4%, respectively. Focal forms were represented by meningoencephalitic and polioencephalomyelitis forms with the same frequency of 4.7%. In the structure of the nosological diagnosis of ICD in the South Urals, erythema forms of the disease prevail (69.5%). The detection frequency of Borrelia DNA of the pathogenic complex B.burgdorferi s.l. in the blood serum and leukocyte fraction of patients was 13%. In 4 patients, for the first time in the Chelyabinsk region, DNA of a new Borrelia miyamotoi Borrelia genotype was detected in whole blood samples and in the samples of the leukocyte fraction using PCR-RV. Phylogenetic analysis of B. miyamotoi was carried out on all sequences of glpQ and 23SrRNA gene fragments, deposited at NCBI and homologous sequences of Chelyabinsk-2018 isolates. The disease proceeded in non-erythema form, intoxication syndrome, myalgia, chills were observed in the clinical picture.


2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>


Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 824
Author(s):  
Egor Dyukarev ◽  
Evgeny Zarov ◽  
Pavel Alekseychik ◽  
Jelmer Nijp ◽  
Nina Filippova ◽  
...  

The peatlands of the West Siberian Lowlands, comprising the largest pristine peatland area of the world, have not previously been covered by continuous measurement and monitoring programs. The response of peatlands to climate change occurs over several decades. This paper summarizes the results of peatland carbon balance studies collected over ten years at the Mukhrino field station (Mukhrino FS, MFS) operating in the Middle Taiga Zone of Western Siberia. A multiscale approach was applied for the investigations of peatland carbon cycling. Carbon dioxide fluxes at the local scale studied using the chamber method showed net accumulation with rates from 110, to 57.8 gC m−2 at the Sphagnum hollow site. Net CO2 fluxes at the pine-dwarf shrubs-Sphagnum ridge varied from negative (−32.1 gC m−2 in 2019) to positive (13.4 gC m−2 in 2017). The cumulative May-August net ecosystem exchange (NEE) from eddy-covariance (EC) measurements at the ecosystem scale was −202 gC m−2 in 2015, due to the impact of photosynthesis of pine trees which was not registered by the chamber method. The net annual accumulation of carbon in the live part of mosses was estimated at 24–190 gC m−2 depending on the Sphagnum moss species. Long-term carbon accumulation rates obtained by radiocarbon analysis ranged from 28.5 to 57.2 gC m−2 yr−1, with local extremes of up to 176.2 gC m−2 yr−1. The obtained estimates of various carbon fluxes using EC and chamber methods, the accounting for Sphagnum growth and decomposition, and long-term peat accumulation provided information about the functioning of the peatland ecosystems at different spatial and temporal scales. Multiscale carbon flux monitoring reveals useful new information for forecasting the response of northern peatland carbon cycles to climatic changes.


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