Chapter 3: Transmission/Natural cycle

Chapter 3: Transmission/ Natural Cycle

Tick-borne encephalitis - The Book ◽

10.33442/26613980_3-3 ◽

2020 ◽

Keyword(s):

Coniferous Forests ◽

Natural Cycle ◽

Central European ◽

European Forests ◽

Transmission Cycle ◽

Tbe Virus ◽

Transmission Cycles ◽

Varying Environments ◽

Reservoir Hosts

The natural cycle of the TBE virus is dependent on vector ticks and reservoir hosts. There are differing transmission cycles in varying environments, from cold northern coniferous forests to temperate central European forests. Within a natural transmission cycle, there are different ways of transmission: tick-to-tick (transovarial, sexual), host-to-tick (viremic), and also tick-to-tick and host-to-host. The complexity of natural transmission cycles is inadequately explored and poorly understood.

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Chapter 3: Transmission / Natural cycle

Tick-borne encephalitis - The Book ◽

10.33442/978-981-14-0914-1_3 ◽

2019 ◽

Author(s):

Lidia Chitimia-Dobler ◽

Ute Mackenstedt ◽

Olaf Kahl ◽

Trevor N. Petney

Keyword(s):

Host Species ◽

Coniferous Forests ◽

Natural Cycle ◽

Central European ◽

European Forests ◽

Transmission Cycle ◽

Tick Vector ◽

Tbe Virus ◽

Transmission Cycles ◽

Varying Environments

• The natural cycle of the TBE virus is dependent on vector ticks and their hosts. • Enzootic cycles vary between different habitats and involve sympatric tick vector and host species. • There are differing transmission cycles in varying environments, from cold northern coniferous forests to temperate central European forests. • Within a natural transmission cycle there are complex differing transmission possibilities – tick to tick (transovarial, sexual), host to tick (viremic), host to host and transstadial persistence. • The complexity of natural transmission cycles is inadequately explored and poorly understood.

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TBE in Croatia

Tick-borne encephalitis - The Book ◽

10.33442/26613980_12b7-3 ◽

2020 ◽

Keyword(s):

Tick Species ◽

Limited Data ◽

Notifiable Disease ◽

Genetic Characteristics ◽

Central European ◽

Tick Borne Encephalitis ◽

Tbe Virus ◽

Endemic Areas ◽

European Subtype

Even though tick-borne encephalitis (TBE) has been a notifiable disease in Croatia since 2007, there are no or only limited data available on the occurring tick species in the endemic areas, on the prevalence of TBE virus (TBEV) in ticks, its distribution in Croatia, and its genetic characteristics. Reporting of human cases also is very scarce. The Central European subtype of virus (TBEV-EU) appears to be present in Croatia

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Ecological, coenotic and floristic analysis of groups of associations of broadleaved-coniferous forests from central European Russia

Vegetation of Russia ◽

10.31111/vegrus/2001.02.38 ◽

2001 ◽

pp. 38-48 ◽

Cited By ~ 4

Author(s):

L. B. Zaugolnova ◽

I. I. Istomina ◽

E. V. Tikhonova

Keyword(s):

Wide Distribution ◽

European Russia ◽

Coniferous Forests ◽

Computer Data ◽

East Europe ◽

Central European ◽

Reference Base ◽

Floristic Analysis ◽

Regional Factors

Two computer data bases were formed: reference base «Prodromus» including the nomenclature forest syntaxa and experienced geobotanic releves «Forests of European Russia». Ecological, coenotic and floristic analysis of broadleaved-coniferous forests mostly corresponding to association Rhodobryo rosei – Piceetum abietis Korotkov 1986 was conducted with these bases. Releves (305) from South taiga and broadleaved-coniferous subzone were used. The analysis revealed complex syntaxonomy, boreal-nemoral character and wide distribution ass. Rhodobryo-Piceetum from central European Russia. Ecological comparison of this association with some nomenclature types of broadleaved-coniferous communities in East Europe was carried out. Preliminary prodromus for European Russian mixed forests is suggested. Role of ecological, succession and regional factors was shown for differentiation of syntaxa.

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Triatomine Feeding Profiles and Trypanosoma cruzi Infection, Implications in Domestic and Sylvatic Transmission Cycles in Ecuador

Pathogens ◽

10.3390/pathogens10010042 ◽

2021 ◽

Vol 10 (1) ◽

pp. 42

Author(s):

Sofía Ocaña-Mayorga ◽

Juan José Bustillos ◽

Anita G. Villacís ◽

C. Miguel Pinto ◽

Simone Frédérique Brenière ◽

...

Keyword(s):

Blood Meal ◽

Mitochondrial Gene ◽

Intestinal Content ◽

Human Infection ◽

Dispersal Capacity ◽

Transmission Cycle ◽

Rhodnius Ecuadoriensis ◽

Transmission Cycles ◽

Endemic Areas ◽

Southern Highland

Understanding the blood meal patterns of insects that are vectors of diseases is fundamental in unveiling transmission dynamics and developing strategies to impede or decrease human–vector contact. Chagas disease has a complex transmission cycle that implies interactions between vectors, parasites and vertebrate hosts. In Ecuador, limited data on human infection are available; however, the presence of active transmission in endemic areas has been demonstrated. The aim of this study was to determine the diversity of hosts that serve as sources of blood for triatomines in domestic, peridomestic and sylvatic transmission cycles, in two endemic areas of Ecuador (central coastal and southern highland regions). Using conserved primers and DNA extracted from 507 intestinal content samples from five species of triatomines (60 Panstrongylus chinai, 17 Panstrongylus howardi, 1 Panstrongylus rufotuberculatus, 427 Rhodnius ecuadoriensis and 2 Triatoma carrioni) collected from 2006 to 2013, we amplified fragments of the cytb mitochondrial gene. After sequencing, blood meal sources were identified in 416 individuals (146 from central coastal and 270 from southern highland regions), achieving ≥ 95% identity with GenBank sequences (NCBI-BLAST tool). The results showed that humans are the main source of food for triatomines, indicating that human–vector contact is more frequent than previously thought. Although other groups of mammals, such as rodents, are also an available source of blood, birds (particularly chickens) might have a predominant role in the maintenance of triatomines in these areas. However, the diversity of sources of blood found might indicate a preference driven by triatomine species. Moreover, the presence of more than one source of blood in triatomines collected in the same place indicated that dispersal of vectors occurs regardless the availability of food. Dispersal capacity of triatomines needs to be evaluated to propose an effective strategy that limits human–vector contact and, in consequence, to decrease the risk of T. cruzi transmission.

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Macrofungal diversity patterns in central European forests affirm the key importance of old-growth forests

Fungal Ecology ◽

10.1016/j.funeco.2016.12.003 ◽

2017 ◽

Vol 27 ◽

pp. 145-154 ◽

Cited By ~ 16

Author(s):

Daniel Dvořák ◽

Martina Vašutová ◽

Jeňýk Hofmeister ◽

Miroslav Beran ◽

Jan Hošek ◽

...

Keyword(s):

Old Growth ◽

Central European ◽

Diversity Patterns ◽

European Forests ◽

Old Growth Forests

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Longer Growing Seasons Cause Hydrological Regime Shifts in Central European Forests

Forests ◽

10.3390/f12121656 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1656

Author(s):

Petr Kupec ◽

Jan Deutscher ◽

Martyn Futter

Keyword(s):

Regime Shift ◽

Hydrological Regime ◽

Annual Runoff ◽

Order Effects ◽

Runoff Generation ◽

Central European ◽

European Forests ◽

Water Limitation ◽

Growing Seasons

In this study, we present evidence for a hydrological regime shift in upland central European forests. Using a combination of long-term data, detailed field measurements and modelling, we show that there is a prolonged and persistent decline in annual runoff: precipitation ratios that is most likely linked to longer growing seasons. We performed a long term (1950–2018) water balance simulation for a Czech upland forest headwater catchment calibrated against measured streamflow and transpiration from deciduous and coniferous stands. Simulations were corroborated by long-term (1965–2018) borehole measurements and historical drought reports. A regime shift from positive to negative catchment water balances likely occurred in the early part of this century. Since 2007, annual runoff: precipitation ratios have been below the long-term average. Annual average temperatures have increased, but there have been no notable long term trends in precipitation. Since 1980, there has been a pronounced April warming, likely leading to earlier leaf out and higher annual transpiration, making water unavailable for runoff generation and/or soil moisture recharge. Our results suggest a regime shift due to second order effects of climate change where increased transpiration associated with a longer growing season leads to a shift from light to water limitation in central European forests. This will require new approaches to managing forests where water limitation has previously not been a problem.

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Operational TBE incidence forecasts for Austria, Germany, and Switzerland 2019-2021

10.1101/2020.07.09.20149492 ◽

2020 ◽

Author(s):

Franz Rubel ◽

Katharina Brugger

Keyword(s):

Negative Binomial ◽

High Reliability ◽

Virus Transmission ◽

Negative Binomial Regression ◽

European Beech ◽

Transmission Cycle ◽

Tick Borne Encephalitis ◽

Tbe Virus ◽

Binomial Regression ◽

First Time

In spring 2019, forecasts of the incidence of tick-borne encephalitis (TBE) for the next two years, i.e. 2019 and 2020, were made for the first time. For this purpose, negative binomial regression models with 4-5 predictors were fitted to the time series of annual human TBE incidences from Austria, Germany and Switzerland. The most important predictor for TBE incidences is the fructification index of the European beech (Fagus sylvatica) 2 years prior as a proxi for the intensity of the TBE virus transmission cycle. These forecasts were repeated in spring 2020 after the updated predictors and the confirmed TBE cases for 2019 became available. Forecasting TBE incidences for 2020 and 2021 results in 156±19 and 131±23 TBE cases for Austria, 663±95 and 543±112 TBE cases for Germany as well as 472±56 and 350±62 TBE cases for Switzerland. The newly implemented operational TBE forecasts will be verified every year with confirmed TBE cases. An initial verification for 2019 demonstrates the high reliability of the forecasts.

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