tick abundance
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Author(s):  
Bruce H Noden ◽  
Megan A Roselli ◽  
Scott R Loss

Abstract Urbanization alters components of natural ecosystems which can affect tick abundance and tick-borne disease prevalence. Likely due to these changes, tick-borne pathogen prevalence has increased in many U.S. urban areas. Despite the growing public health importance of tick-borne diseases, little is known about how they are influenced by urbanization in North America, especially in the central U.S. where several pathogens occur at or near their highest levels of incidence nationally. To determine whether urban development influences tick infection with bacteria and protozoa, we collected ticks at 16 parks across a gradient of urbanization intensity in Oklahoma City, Oklahoma, USA and tested them using a variety of PCR assays. Adult ticks tested positive for Rickettsia parkeri, R. amblyommatis, R. rhiphicephali, ‘Candidatus R. andeanae’, Ehrlichia chaffeensis, E. ewingii, Panola Mountain Ehrlichia, ‘Borrelia lonestari’, Theileria cervi, Babesia spp. Coco, and Cytauxzoon felis. These results indicate the presence of a high diversity of tick-borne bacteria and protozoa across an expanding urban area in the U.S. Great Plains. Although there appeared to be some risk of encountering tick-borne microorganisms across the entire urbanization gradient, E. chaffeensis, E. ewingii, and T. cervi-infected ticks and microbe diversity decreased with increasing urbanization intensity. We identified a low rate of coinfection between different microorganisms, with coinfected ticks mainly collected from sites in the least-urbanized areas. This study suggests the need for awareness of tick-borne disease risk throughout urban areas in the central U.S., and highlights a need for studies of tick host habitat use and movement in cities.


Author(s):  
E A Bacon ◽  
H Kopsco ◽  
P Gronemeyer ◽  
N Mateus-Pinilla ◽  
R L Smith

Abstract The range of ticks in North America has been steadily increasing likely, in part, due to climate change. Along with it, there has been a rise in cases of tick-borne disease. Among those medically important tick species of particular concern are Ixodes scapularis Say (Acari: Ixodidae), Dermacentor variabilis Say (Acari: Ixodidae), and Amblyomma americanum Linneaus (Acari: Ixodidae). The aim of this study was to determine if climate factors explain existing differences in abundance of the three aforementioned tick species between two climatically different regions of Illinois (Central and Southern), and if climate variables impact each species differently. We used both zero-inflated regression approaches and Bayesian network analyses to assess relationships among environmental variables and tick abundance. Results suggested that the maximum average temperature and total precipitation are associated with differential impact on species abundance and that this difference varied by region. Results also reinforced a differential level of resistance to desiccation among these tick species. Our findings help to further define risk periods of tick exposure for the general public, and reinforce the importance of responding to each tick species differently.


Author(s):  
NF Vasilenko ◽  
DA Prislegina ◽  
EA Manin ◽  
LI Shaposhnikova ◽  
UM Ashibokov ◽  
...  

Background: Tick-borne diseases are a serious threat to the epidemiological safety of the population of the Stavropol Region, making up more than 70 per cent of all natural focal infectious diseases registered in this territory annually. A wide range of hosts contributes to high tick abundance, diversity of tick-borne pathogens, and maintenance of the natural foci. Objective: To assess the activity of natural foci of tick-borne infections in the Stavropol Region in 2016–2020. Materials and methods: We used notifications submitted by the Center for Hygiene and Epidemiology in the Stavropol Region to the Scientific and Methodological Center for Monitoring the Pathogens of Infectious and Parasitic Diseases of Pathogenicity Groups II–IV for the subjects of the North Caucasian and Southern Federal Districts and the results of an epizootological survey of the Stavropol territory by specialists of the Stavropol Plague Control Research Institute. Markers of the causative agents of tick-borne diseases were detected by ELISA and PCR methods. Data processing was carried out using Microsoft Excel 2010. Results: Active natural foci of Crimean-Congo hemorrhagic fever, Q fever, a group of tick-borne spotted fevers, Lyme disease, human granulocytic anaplasmosis, and human monocytic ehrlichiosis were established in the region in 2016–2020. Human cases of the Crimean-Congo hemorrhagic fever, Lyme borreliosis and Q fever were also registered annually. The abundance of infected ticks in resort towns of the Caucasian Mineral Waters is of particular concern. Conclusion: We established up-to-date epizootic and epidemic manifestations of tick-borne infections in the Stavropol Region in the modern period, which are an important link in epidemiological surveillance and the basis for improving preventive measures


2021 ◽  
Vol 18 (184) ◽  
Author(s):  
Tam Tran ◽  
W. Tanner Porter ◽  
Daniel J. Salkeld ◽  
Melissa A. Prusinski ◽  
Shane T. Jensen ◽  
...  

Citizen science projects have the potential to address hypotheses requiring extremely large datasets that cannot be collected with the financial and labour constraints of most scientific projects. Data collection by the general public could expand the scope of scientific enquiry if these data accurately capture the system under study. However, data collection inconsistencies by the untrained public may result in biased datasets that do not accurately represent the natural world. In this paper, we harness the availability of scientific and public datasets of the Lyme disease tick vector to identify and account for biases in citizen science tick collections. Estimates of tick abundance from the citizen science dataset correspond moderately with estimates from direct surveillance but exhibit consistent biases. These biases can be mitigated by including factors that may impact collector participation or effort in statistical models, which, in turn, result in more accurate estimates of tick population sizes. Accounting for collection biases within large-scale, public participation datasets could update species abundance maps and facilitate using the wealth of citizen science data to answer scientific questions at scales that are not feasible with traditional datasets.


2021 ◽  
Vol 8 ◽  
Author(s):  
Nlingisisi D. Babayani ◽  
Anastacia Makati

Tick distribution and abundance is influenced by several factors that include micro-climate and environmental and host factors. Contextual understanding of the role played by these factors is critical to guide control measures. The aim of this study was to determine the predictive value of these factors for changes in tick distribution and abundance at the livestock–wildlife interface of the lower Okavango Delta. A two-stage quota sampling design was adopted to select 30 clusters of seven cattle each for tick investigation. Tick investigation was done by lifting the tail to count the total number of ticks at the anno-vulva region during the four meteorological seasons of the year. Additional data were collected on ear tag number, location of origin, sex, age, body condition score (BCS), season of the year, stocking density, and Normalized Difference Vegetation Index values of source terrain. A random effects model was used to evaluate predictive value of the above for tick abundance. Additional mapping of tick distribution pattern in the abattoir catchment area was conducted using spatial autocorrelation and hot-spot analysis. Tick intensity of infection increased linearly from males to females (Z = 3.84, p < 0.001), decreased linearly from lower to higher BCS (Z = −4.11, p < 0.001), and increased linearly from cold-dry through dry to wet seasons (Z = 10.19, p < 0.001). Significant clustering of neighboring crushes on account of tick count was noted in the late-hot-dry season, with high tick count in crushes located along the seasonal flood plains and low tick counts in those located in the dry grasslands. It was concluded from this study that cattle tick abundance is influenced largely by season of the year and that the micro-climatic conditions brought about by the seasonal flooding of the delta have a decided effect on tick distribution during the driest of the seasons. Our study has, for the first time, profiled drivers of tick distribution and population growth in this unique ecosystem. This has the potential to benefit human and veterinary public health in the area through implementation of sustainable tick control strategies that are not heavily reliant on acaricides.


Author(s):  
Madiou Thierno Bah ◽  
Vladimir Grobois ◽  
Frédéric Stachurski ◽  
facundo munoz ◽  
Maxime Duhayon ◽  
...  

For the first time we built a correlative model for predicting the distribution of H. marginatum, one of the main vector of Crimean-Congo Haemorrhagic fever virus (CCHFV), at high resolution in a recently colonized area, namely south of France. Field tick collections were conducted on horses from 2016 to 2021 in 14 French southern departments, which resulted in a first map of H. marginatum on the national territory. Such updated presence/absence data, as well as the mean number of H. marginatum per examined animal (mean parasitic load) as a proxy of the tick abundance, were correlated to multiple parameters that described the climate and habitats characterizing each collection site, as well as movements of horses as a possible source of tick diffusion and new establishment. Our model highlighted the importance of warm temperatures all along the year, as well as dry conditions during summer and moderate annual humidity for the establishment of H. marginatum. A predominance of open natural habitats in the environment was also identified as a supporting factor, in opposition to artificial and humid habitats that were determined as unsuitable. Based on this model, we predicted the current suitable areas for the establishment of the tick H. marginatum in South of France, with a relatively good accuracy using internal and external validation methods. Concerning tick abundance, some correlative relationships were similar than in the occurrence model but the type of horse movements were also pointed out as an important factor explaining the mean parasitic load, leading to differential exposure to ticks. The limitations of estimating and modelling H. marginatum abundance in a correlative model are discussed.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Attila D. Sándor ◽  
Boyan Milchev ◽  
Nóra Takács ◽  
Jenő Kontschán ◽  
Sándor Szekeres ◽  
...  

Abstract Background Birds are major hosts for many tick species (Acari: Ixodidae, Argasidae), and their role is especially important in transporting ticks over large distances along their seasonal migratory routes. Accordingly, most studies across Europe focus on the importance of avian hosts in tick dispersal, and less emphasis is laid on resident birds and their role in supporting tick life cycles. Eurasian eagle owls (Bubo bubo) exemplify the latter, but all the few studies on their tick infestation were carried out in Western Europe and even those did not involve a large sample size and did not assess infestation prevalence in natural habitats. Methods In this study, 320 ixodid ticks were collected from nestlings of Eurasian eagle owls during the period 2018–2020 in Bulgaria in south-eastern Europe. These ticks were analysed morphologically, and selected specimens molecularly based on cytochrome c oxidase subunit I (cox1) gene. The effects of environmental and habitat-related conditions and of the species of prey eaten by eagle owls on tick infestation were also evaluated. Results The majority of ticks were identified as adults of Rhipicephalus turanicus (n = 296). In addition, 15 Hyalomma marginatum (three males, 11 nymphs and a larva), one female of Haemaphysalis erinacei and of Ha. punctata, and a nymph of Ixodes ricinus were found. Among R. turanicus, two distinct morphotypes were observed, but they do not form a monophyletic clade in the phylogenetic tree based on the mitochondrial gene cox1. We found a positive correlation between the total number of ticks on nestlings from a particular nest and the number of medium-sized to large prey mammals brought to the nestling owls. Also, the most important predictor for tick abundance was the effect of the extent of arable land (negative), while forests and grasslands contributed less, with no effect observed in case of urbanized areas and watercourses. Conclusions The intensity of tick infestation can be high on nestling Eurasian eagle owls (mean intensity 16.59 ticks/nestling). In this study, five different tick species were recorded, among which R. turanicus dominated. Two male morphotypes of this tick species were found, but their morphological differences were not reflected by genetic diversity or phylogenetic clustering. The most important factor determining tick abundance was the land-use structure. Graphic Abstract


Author(s):  
Daniel C Mathisson ◽  
Sara M Kross ◽  
Matthew I Palmer ◽  
Maria A Diuk-Wasser

Abstract Tick-borne illnesses have been on the rise in the United States, with reported cases up sharply in the past two decades. In this literature review, we synthesize the available research on the relationship between vegetation and tick abundance for four tick species in the northeastern United States that are of potential medical importance to humans. The blacklegged tick (Ixodes scapularis) (Say; Acari: Ixodidae) is found to be positively associated with closed canopy forests and dense vegetation thickets, and negatively associated with open canopy environments, such as grasslands or old agricultural fields. The American dog tick (Dermacentor variabilis) (Say; Acari: Ixodidae) has little habitat overlap with I. scapularis, with abundance highest in grasses and open-canopy fields. The lone star tick (Amblyomma americanum) (Linnaeus; Acari: Ixodidae) is a habitat generalist without consistent associations with particular types of vegetation. The habitat associations of the recently introduced Asian longhorned tick (Haemaphysalis longicornis) (Neumann; Acari: Ixodidae) in the northeastern United States, and in other regions where it has invaded, are still unknown, although based on studies in its native range, it is likely to be found in grasslands and open-canopy habitats.


2021 ◽  
Author(s):  
Maria Vikentjeva ◽  
Olga Bragina ◽  
Julia Geller

Abstract BACKGROUND For over several decades ticks are noticed to be widely present in the green spaces of urban environments. Rodents that provide essential blood-meals for subadult ticks and serve as natural reservoirs for many known tick-borne diseases, such as Lyme borreliosis and tick-borne encephalitis, might be quite abundant in green areas within urban settlements. In that way, the improvement of green infrastructures within cities possess not only to better human well-being but might also increase the risk of being bitten by a tick and having a tick-borne disease. This study aimed to provide a first insight into ticks and tick-borne pathogen presence and prevalence in popular recreational green areas in Tallinn, Estonia. METHODS Ticks were collected by flagging in May-June, 2018. Tick species identification was performed on morphological criteria. Tick-borne pathogens detection was performed by pathogen-specific PCR and qPCR reactions. RESULTS 855 Ixodes ticks were collected from a total area of 12 000 m2. An estimated tick abundance were up to 18.5 ticks per 100 m2. 34.3% of all ticks were revealed positive for at least one tick-borne pathogen. Borrelia burgdorferi s.l. was found in 17.5%, Rickettsia sp in 13.8%, Neoehrlichia mikurensis on 5.4%, B. miyamotoi in 2.5%, Anaplasma phagocytophilum in 0.6% and tick-borne encephalitis virus in 0.5% of ticks. CONCLUSION This study reports the occurrence of Ixodes tick species in popular recreational, outdoor sports and leisure areas in the largest city of Estonia, with abundance and prevalence rates compatible or even exceeding those detected previously in the most endemic foci in the natural environments. Taking into account increasing Lyme borreliosis incidence, the risk of acquiring a tick bite and being infected with a tick-borne disease in urban recreational sites should not be ignored and proper information about the precautions might be considered.


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