Natural Ehrlichia phagocytophila transmission coefficients from sheep ‘carriers’ to Ixodes ricinus ticks vary with the numbers of feeding ticks

Parasitology ◽  
2002 ◽  
Vol 124 (2) ◽  
pp. 127-136 ◽  
Author(s):  
N. H. OGDEN ◽  
A. N. J. CASEY ◽  
N. P. FRENCH ◽  
K. J. BOWN ◽  
J. D. W. ADAMS ◽  
...  
Keyword(s):  
Ixodes Ricinus ◽  
Tick Infestation ◽  
Infection Intensity ◽  
Adult Tick ◽  
Transmission Efficiency ◽  
Infection Prevalence ◽  
Direct Effects ◽  
Transmission Coefficients ◽  
Ehrlichia Phagocytophila ◽  
Ixodes Ricinus Ticks

In a longitudinal study in a UK upland site, 38% of adult sheep were detected as infected with the tick-borne bacterium Ehrlichia phagocytophila by PCR of blood samples. Infection prevalence declined significantly with sheep age but varied significantly and non-linearly with the number of adult Ixodes ricinus ticks feeding per sheep. These findings suggested that under conditions of natural repeated tick-borne challenge sheep remain partially susceptible to re-infections, but the likelihood of re-infection depended on the numbers of feeding ticks. Transmission efficiency from sheep to immature ticks also varied significantly and non-linearly with the number of adult ticks feeding per sheep: transmission efficiency was almost zero in sheep with low adult tick infestations rising to 30% at certain levels of adult tick infestation. Infection intensity in infected engorged immature ticks also varied with the number of adult ticks feeding per sheep, but neither prevalence nor intensity of infection in engorged ticks were related to sheep blood PCR result. These findings suggest that variation in the numbers of ticks feeding per sheep may influence E. phagocytophila transmission by direct effects on transmission at the tick–host interface.

Field evidence for density-dependent facilitation amongst Ixodes ricinus ticks feeding on sheep

Parasitology ◽  
2002 ◽  
Vol 124 (2) ◽  
pp. 117-125 ◽  
Author(s):  
N. H. OGDEN ◽  
A. N. J. CASEY ◽  
N. P. FRENCH ◽  
J. D. W. ADAMS ◽  
Z. WOLDEHIWET
Keyword(s):  
Ixodes Ricinus ◽  
Adult Female ◽  
Adult Tick ◽  
Field Site ◽  
Density Dependent ◽  
Ehrlichia Phagocytophila ◽  
Adult Females ◽  
Field Evidence ◽  
Ixodes Ricinus Ticks ◽  
Tick Resistance

Engorged Ixodes ricinus nymphs collected from sheep resident in an upland UK field site were significantly lighter than nymphs that engorged on previously tick-naïve sheep, indicating that site-resident sheep continually exposed to ticks acquired anti-tick resistance. The weights of engorged nymphs that fed on naturally tick-resistant sheep increased significantly, however, when increasingly high numbers of adult female ticks fed on the sheep during seasonal peaks of tick activity. This relationship was unaffected by variations in nymph weight amongst individual sheep, between seasons and years, and potential effects of sheep infection with Ehrlichia phagocytophila; this suggests that high adult tick infestations may directly inhibit the expression of acquired anti-tick resistance by sheep. The length, width and weight of adult ticks and the scutum length of adult females were linearly related to their weight as an engorged nymph. The mean scutum length of adult female ticks feeding on sheep in the field site was greater than that of adult females obtained from engorged nymphs collected from sheep of the same site. This suggests that larger ticks have a survival advantage and that I. ricinus ticks exhibit density-dependent intraspecific facilitation at high infestation levels with potential consequences for the transmission of tick-borne diseases.

scholarly journals Ecological Factors Characterizing the Prevalence of Bacterial Tick-Borne Pathogens in Ixodes ricinus Ticks in Pastures and Woodlands

2010 ◽  
Vol 76 (13) ◽  
pp. 4413-4420 ◽  
Author(s):  
Lénaïg Halos ◽  
Séverine Bord ◽  
Violaine Cotté ◽  
Patrick Gasqui ◽  
David Abrial ◽  
...  
Keyword(s):  
Forest Fragmentation ◽  
Ixodes Ricinus ◽  
Spotted Fever ◽  
Ecological Factors ◽  
Adult Tick ◽  
Reservoir Host ◽  
Host Community ◽  
Infection Prevalence ◽  
Spotted Fever Group ◽  
Reservoir Hosts

ABSTRACT Ecological changes are recognized as an important driver behind the emergence of infectious diseases. The prevalence of infection in ticks depends upon ecological factors that are rarely taken into account simultaneously. Our objective was to investigate the influences of forest fragmentation, vegetation, adult tick hosts, and habitat on the infection prevalence of three tick-borne bacteria, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Rickettsia sp. of the spotted fever group, in questing Ixodes ricinus ticks, taking into account tick characteristics. Samples of questing nymphs and adults were taken from 61 pastures and neighboring woodlands in central France. The ticks were tested by PCR of pools of nymphs and individual adults. The individual infection prevalence was modeled using multivariate regression. The highest infection prevalences were found in adult females collected in woodland sites for B. burgdorferi sensu lato and A. phagocytophilum (16.1% and 10.7%, respectively) and in pasture sites for Rickettsia sp. (8.7%). The infection prevalence in nymphs was lower than 6%. B. burgdorferi sensu lato was more prevalent in woodlands than in pastures. Forest fragmentation favored B. burgdorferi sensu lato and A. phagocytophilum prevalence in woodlands, and in pastures, the B. burgdorferi sensu lato prevalence was favored by shrubby vegetation. Both results are probably because large amounts of edges or shrubs increase the abundance of small vertebrates as reservoir hosts. The Rickettsia sp. prevalence was maximal on pasture with medium forest fragmentation. Female ticks were more infected by B. burgdorferi sensu lato than males and nymphs in woodland sites, which suggests an interaction between the ticks and the bacteria. This study confirms the complexity of the tick-borne pathogen ecology. The findings support the importance of small vertebrates as reservoir hosts and make a case for further studies in Europe on the link between the composition of the reservoir host community and the infection prevalence in ticks.

scholarly journals Local Population Structure and Seasonal Variability of Borrelia garinii Genotypes in Ixodes ricinus Ticks, Slovakia

2020 ◽  
Vol 17 (10) ◽  
pp. 3607 ◽  
Author(s):  
Zuzana Mtierová ◽  
Markéta Derdáková ◽  
Michal Chvostáč ◽  
Yuliya M. Didyk ◽  
Barbara Mangová ◽  
...  
Keyword(s):  
Population Structure ◽  
Ixodes Ricinus ◽  
Local Population ◽  
Clinical Manifestations ◽  
Infection Intensity ◽  
Breeding Period ◽  
Borrelia Garinii ◽  
Wide Range ◽  
Questing Ticks ◽  
Ixodes Ricinus Ticks

Lyme disease (LD) is the most common tick-borne human disease in Europe, and Borrelia garinii, which is associated with avian reservoirs, is one of the most genetically diverse and widespread human pathogenic genospecies from the B. burgdorferi sensu lato (s.l.) complex. The clinical manifestations of LD are known to vary between regions and depend on the genetic strain even within Borrelia genospecies. It is thus of importance to explore the genetic diversity of such pathogenic borreliae for the wide range of host and ecological contexts. In this study, multilocus sequence typing (MLST) was employed to investigate the local population structure of B. garinii in Ixodes ricinus ticks. The study took place in a natural wetland in Slovakia, temporally encompassing spring and autumn bird migration periods as well as the breeding period of resident birds. In total, we examined 369 and 255 ticks collected from 78 birds and local vegetation, respectively. B. burgdorferi s.l. was detected in 43.4% (160/369) of ticks recovered from birds and in 26.3% (67/255) of questing ticks, respectively. Considering the ticks from bird hosts, the highest prevalence was found for single infections with B. garinii (22.5%). Infection intensity of B. garinii in bird-feeding ticks was significantly higher than that in questing ticks. We identified ten B. garinii sequence types (STs) occurring exclusively in bird-feeding ticks, two STs occurring exclusively in questing ticks, and one ST (ST 244) occurring in both ticks from birds and questing ticks. Four B. garinii STs were detected for the first time herein. With the exception of ST 93, we detected different STs in spring and summer for bird-feeding ticks. Our results are consistent with previous studies of the low geographic structuring of B. garinii genotypes. However, our study reveals some consistency in local ST occurrence and a geographic signal for one of the clonal complexes.

scholarly journals Factors influencing the level of infestation of Ixodes ricinus (Acari: Ixodidae) on Lacerta agilis and Zootoca vivipara (Squamata: Lacertidae)

Acarologia ◽  
2020 ◽  
Vol 60 (2) ◽  
pp. 390-397
Author(s):  
Dariusz J. Gwiazdowicz ◽  
Anna K. Gdula ◽  
Rafał Kurczewski ◽  
Bogna Zawieja
Keyword(s):  
Body Size ◽  
Ixodes Ricinus ◽  
Tick Infestation ◽  
Additional Information ◽  
Factors Influencing ◽  
Zootoca Vivipara ◽  
Ixodes Ricinus Ticks ◽  
Lower Infection ◽  
Lacerta Agilis ◽  
The Impact

The purpose of this study was to analyse selected factors determining the level of infestation of Ixodes ricinus ticks on Lacerta agilis and Zootoca vivipara lizards found in Central Europe. Both environmental factors (habitats within protected areas and areas transformed as a result of human activity) as well as morphological factors (age, sex and size of lizards, location of ticks on the lizard’s body) were assessed. We found that the age and size of a lizard played a significant role in the level of infestation, but this depended on the species and habitat. Females of both species differed significantly in their level of tick infestation; females of L. agilis had lower infection than Z. vivipara. In contrast, there was no difference in levels of infection between juveniles and males of the different species. We also found that the impact of body size changed in the different habitats: the number of ticks increased with body size in natural areas only. In addition, more frequently ticks were found in the front groin area (336 individuals) and forelimbs (202), less often on the neck (12) and never in the hind groin area. These differences might be because it is easier to infest a larger individual than a smaller one, and areas of the front of the lizard might be more accessible whilst foraging. This study provides additional information about tick infestation that may be relevant to the conservation of the species of lizards.

scholarly journals Evidence of the Human Granulocytic Ehrlichiosis Agent in Ixodes ricinus Ticks in Switzerland

1999 ◽  
Vol 37 (5) ◽  
pp. 1332-1334 ◽  
Author(s):  
Nicola Pusterla ◽  
Christian M. Leutenegger ◽  
Jon B. Huder ◽  
Rainer Weber ◽  
Ueli Braun ◽  
...  
Keyword(s):  
Ixodes Ricinus ◽  
Nucleotide Sequencing ◽  
Rrna Gene ◽  
Adult Males ◽  
Granulocytic Ehrlichiosis ◽  
Ehrlichia Phagocytophila ◽  
Stage Of Development ◽  
Human Granulocytic Ehrlichiosis ◽  
Pcr Products ◽  
Ixodes Ricinus Ticks

A total of 1,667 Ixodes ricinus ticks were collected from five regions in Switzerland where there have been sporadic occurrences of granulocytic ehrlichiosis in dogs and horses. The ticks were examined for rickettsiae of the Ehrlichia phagocytophila group via nested PCR. Twenty-one ticks (1.3%) were positive; 3 (0.5%) were nymphs, 6 (1.3%) were adult males, and 12 (1.9%) were adult females. The number of positive ticks varied with the stage of development and with the geographical origin. Nucleotide sequencing of the isolated PCR products identified these products as part of the 16S rRNA gene of Ehrlichia. In addition, these products had 100% homology with the agent of human granulocytic ehrlichiosis. The occurrence of this agent in I. ricinus in Switzerland presents a potential danger of transmission of granulocytic ehrlichiosis to dogs, horses, and humans.

scholarly journals Detection of Tick-Borne Pathogens of the Genera Rickettsia, Anaplasma and Francisella in Ixodes ricinus Ticks in Pomerania (Poland)

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 901
Author(s):  
Lucyna Kirczuk ◽  
Mariusz Piotrowski ◽  
Anna Rymaszewska
Keyword(s):  
Ixodes Ricinus ◽  
Large Scale ◽  
Tick Infestation ◽  
Livestock Grazing ◽  
Nucleotide Sequence Analysis ◽  
Tick Population ◽  
Life Stages ◽  
Scale Analysis ◽  
Large Scale Analysis ◽  
Ixodes Ricinus Ticks

Tick-borne pathogens are an important medical and veterinary issue worldwide. Environmental monitoring in relation to not only climate change but also globalization is currently essential. The present study aimed to detect tick-borne pathogens of the genera Anaplasma, Rickettsia and Francisella in Ixodes ricinus ticks collected from the natural environment, i.e., recreational areas and pastures used for livestock grazing. A total of 1619 specimens of I. ricinus were collected, including ticks of all life stages (adults, nymphs and larvae). The study was performed using the PCR technique. Diagnostic gene fragments msp2 for Anaplasma, gltA for Rickettsia and tul4 for Francisella were amplified. No Francisella spp. DNA was detected in I. ricinus. DNA of A. phagocytophilum was detected in 0.54% of ticks and Rickettsia spp. in 3.69%. Nucleotide sequence analysis revealed that only one species of Rickettsia, R. helvetica, was present in the studied tick population. The present results are a part of a large-scale analysis aimed at monitoring the level of tick infestation in Northwest Poland.

scholarly journals Detection of four Borrelia burgdorferi genospecies and first report of human granulocytic ehrlichiosis agent in Ixodes ricinus ticks collected in central Italy

2002 ◽  
Vol 129 (1) ◽  
pp. 93-97 ◽  
Author(s):  
I. SANTINO ◽  
M. DEL PIANO ◽  
R. SESSA ◽  
G. FAVIA ◽  
A. IORI
Keyword(s):  
Borrelia Burgdorferi ◽  
Ixodes Ricinus ◽  
Protected Area ◽  
Central Italy ◽  
First Report ◽  
Granulocytic Ehrlichiosis ◽  
Ehrlichia Phagocytophila ◽  
Human Granulocytic Ehrlichiosis ◽  
Ixodes Ricinus Ticks ◽  
Male Tick

The presence of Borrelia burgdorferi s.l. and of Ehrlichia phagocytophila group was sought by PCR in Ixodes ricinus collected in a protected area of central Italy. Nymphs (n = 1475, gathered in 295 pools of 5 nymphs each) and adult ticks (n = 28) were examined. B. burgdorferi s.l. was detected in 13.8% of the nymph pools; of these, 63.4% were infected by B. valaisiana, 26.8% by B. afzelii, 7.3% by B. garinii, and 2.5% by B. burgdorferi s.s. Only a single adult male tick proved to host B. afzelii. The agent of human granulocytic ehrlichiosis (HGE) was detected in 2.7% of the nymph pools. Two HGE agent-positive nymph pools were also found to be positive for B. garinii and for B. afzelii, respectively. This is the first report from central Italy of the finding of the HGE agent in ticks.

scholarly journals Detection of Ehrlichia phagocytophilaDNA in Ixodes ricinus Ticks from Areas in Switzerland Where Tick-Borne Fever Is Endemic

1998 ◽  
Vol 36 (9) ◽  
pp. 2735-2736 ◽  
Author(s):  
Nicola Pusterla ◽  
Jon B. Huder ◽  
Hans Lutz ◽  
Ueli Braun
Keyword(s):  
Ixodes Ricinus ◽  
Free Living ◽  
Ehrlichia Phagocytophila ◽  
Healthy Cattle ◽  
Ixodes Ricinus Ticks

A total of 1,523 adult Ixodes ricinus ticks were collected from regions where bovine ehrlichiosis is endemic and were examined for Ehrlichia phagocytophila via PCR. Of the ticks from cattle with ehrlichiosis, the ticks from healthy cattle, and the free-living ticks, 26.5% (18 of 68), 4.4% (35 of 802), and 0.8% (5 of 653), respectively, were positive.

scholarly journals Predicting the spatial abundance of Ixodes ricinus ticks in southern Scandinavia using environmental and climatic data

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Lene Jung Kjær ◽  
Arnulf Soleng ◽  
Kristin Skarsfjord Edgar ◽  
Heidi Elisabeth H. Lindstedt ◽  
Katrine Mørk Paulsen ◽  
...  
Keyword(s):  
Ixodes Ricinus ◽  
Adult Tick ◽  
Machine Learning Algorithms ◽  
Climatic Data ◽  
Tick Abundance ◽  
Incidence Data ◽  
Southern Scandinavia ◽  
Ixodes Ricinus Ticks ◽  
Risk Areas ◽  
Abundance And Distribution

AbstractRecently, focus on tick-borne diseases has increased as ticks and their pathogens have become widespread and represent a health problem in Europe. Understanding the epidemiology of tick-borne infections requires the ability to predict and map tick abundance. We measured Ixodes ricinus abundance at 159 sites in southern Scandinavia from August-September, 2016. We used field data and environmental variables to develop predictive abundance models using machine learning algorithms, and also tested these models on 2017 data. Larva and nymph abundance models had relatively high predictive power (normalized RMSE from 0.65–0.69, R2 from 0.52–0.58) whereas adult tick models performed poorly (normalized RMSE from 0.94–0.96, R2 from 0.04–0.10). Testing the models on 2017 data produced good results with normalized RMSE values from 0.59–1.13 and R2 from 0.18–0.69. The resulting 2016 maps corresponded well with known tick abundance and distribution in Scandinavia. The models were highly influenced by temperature and vegetation, indicating that climate may be an important driver of I. ricinus distribution and abundance in Scandinavia. Despite varying results, the models predicted abundance in 2017 with high accuracy. The models are a first step towards environmentally driven tick abundance models that can assist in determining risk areas and interpreting human incidence data.

Sign in / Sign up

Export Citation Format

Share Document