Interacting effects of wildlife loss and climate on ticks and tick-borne disease

Both large-wildlife loss and climatic changes can independently influence the prevalence and distribution of zoonotic disease. Given growing evidence that wildlife loss often has stronger community-level effects in low-productivity areas, we hypothesized that these perturbations would have interactive effects on disease risk. We experimentally tested this hypothesis by measuring tick abundance and the prevalence of tick-borne pathogens ( Coxiella burnetii and Rickettsia spp . ) within long-term, size-selective, large-herbivore exclosures replicated across a precipitation gradient in East Africa. Total wildlife exclusion increased total tick abundance by 130% (mesic sites) to 225% (dry, low-productivity sites), demonstrating a significant interaction of defaunation and aridity on tick abundance. When differing degrees of exclusion were tested for a subset of months, total tick abundance increased from 170% (only mega-herbivores excluded) to 360% (all large wildlife excluded). Wildlife exclusion differentially affected the abundance of the three dominant tick species, and this effect varied strongly over time, likely due to differences among species in their host associations, seasonality, and other ecological characteristics. Pathogen prevalence did not differ across wildlife exclusion treatments, rainfall levels, or tick species, suggesting that exposure risk will respond to defaunation and climate change in proportion to total tick abundance. These findings demonstrate interacting effects of defaunation and aridity that increase disease risk, and they highlight the need to incorporate ecological context when predicting effects of wildlife loss on zoonotic disease dynamics.

Download Full-text

A 117 year retrospective analysis of Pennsylvania tick community dynamics

10.1101/433664 ◽

2018 ◽

Cited By ~ 1

Author(s):

Damie Pak ◽

Steven B. Jacobs ◽

Joyce M. Sakamoto

Keyword(s):

Retrospective Analysis ◽

Community Composition ◽

Tick Species ◽

Temporal Dynamics ◽

Disease Risk ◽

Dermacentor Variabilis ◽

Disease Spread ◽

Disease Case ◽

Tick Borne Disease

AbstractBackgroundTick-borne diseases have been increasing at the local, national, and global levels. Researchers studying ticks and tick-borne disease need a thorough knowledge of the pathogens, vectors, and epidemiology of disease spread. Three surveillance approaches are commonly used to provide insight into tick-borne disease risk: human disease case surveillance, active tick surveillance, and passive tick surveillance. Long-term passive surveillance can provide up-to-date data on the spatial variability and temporal dynamics of ectoparasite communities and shed light into the ecology of rarer tick species. We present a retrospective analysis on compiled data of ticks from Pennsylvania over the last 117 years.MethodsWe compiled data from ticks collected during tick surveillance research, and from citizen-based submissions to the Penn State University Department of Entomology (PSUEnt). Specimens were deposited at the PSUEnt arthropod collections that eventually became The Frost Entomological Museum. While most of the specimens were submitted by the public, a subset of the data were collected through active methods (flagging or dragging, or removal of ticks from wildlife). We analyzed all data from 1900-2017 for tick community composition, host associations, and spatio-temporal dynamics.ResultsIn total there were 4,491 submission lots consisting of 7,132 tick specimens. Twenty-four different species were identified, with the large proportion of submissions represented by five tick species. We observed a shift in tick community composition in which the dominant species of tick (Ixodes cookei) was overtaken in abundance byDermacentor variabilisin the early 1990s, and then replaced in abundance byI. scapularis. We analyzed host data and identified overlaps in host range amongst tick species, suggesting potential hubs of pathogen transfer between different tick vectors and their reservoir hosts.ConclusionsWe highlight the importance of long-term passive tick surveillance in investigating the ecology of both common and rare tick species. Information on the geographic distribution, host-association, and seasonality of the tick community can help researchers and health-officials to identify high-risk areas.

Download Full-text

Effect of Urbanization on Presence, Abundance, and Coinfection of Bacteria and Protozoa in Ticks in the US Great Plains

Journal of Medical Entomology ◽

10.1093/jme/tjab228 ◽

2022 ◽

Author(s):

Bruce H Noden ◽

Megan A Roselli ◽

Scott R Loss

Keyword(s):

Great Plains ◽

Urban Areas ◽

Disease Risk ◽

Natural Ecosystems ◽

Public Health Importance ◽

Rickettsia Parkeri ◽

Tick Abundance ◽

Tick Infection ◽

Tick Borne Disease ◽

Microbe Diversity

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.

Download Full-text

Migraine and subsequent chronic kidney disease risk: a nationwide population-based cohort study

BMJ Open ◽

10.1136/bmjopen-2017-018483 ◽

2017 ◽

Vol 7 (12) ◽

pp. e018483 ◽

Cited By ~ 10

Author(s):

Shuo-Chun Weng ◽

Chia-Lin Wu ◽

Chew-Teng Kor ◽

Ping-Fang Chiu ◽

Ming-Ju Wu ◽

...

Keyword(s):

Chronic Kidney Disease ◽

Cohort Study ◽

Kidney Disease ◽

Disease Risk ◽

Population Based ◽

Interactive Effects ◽

Control Group ◽

Research Database ◽

Control Subjects

ObjectiveWe compared the incidence and risk of chronic kidney disease (CKD) between subjects with new-onset migraine and matched controls without migraine in this large-scale retrospective cohort study.DesignPopulation-based cohort study.Setting8880 subjects with migraine and 503 070 subjects without migraine were enrolled between January 1, 2000 and December 31, 2013, all diagnosed to be without kidney disease. All the participants were registered in the National Health Insurance Research Database.ParticipantsFinally, data from 7156 subjects with migraine and 7156 propensity-score-matched control subjects were analysed.Primary outcome measureWe used Cox proportional hazards regression to estimate adjusted HRs for incident CKD; subgroup analyses were performed to assess the interactive effects of migraine with demographics, comorbidities and long-term medications.ResultsThe incidence of CKD was higher in the migraine group than in the control group. The risk of developing CKD was significantly higher in subjects with migraine than without migraine (P=0.031). Subjects with migraine aged <65 years (age 40–64 (adjusted HR (aHR) 1.35; 95% CI 1.05 to 1.73); age <40 (aHR 1.55; 95% CI 1.02 to 2.36)), with ≥1 comorbid diseases (1–2 diseases (aHR 1.30; 95% CI 1.01 to 1.68); ≥3 diseases (aHR 1.45; 95% CI 1.01 to 2.07)), and not receiving anti-migraine agents (aHR 1.26; 95% CI 1.04 to 1.54) were at a higher risk of developing CKD compared with the control subjects. The interaction between migraine and comorbidities was not significant; age, male gender and long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) were independent risk factors for CKD in subjects with migraine.ConclusionMigraine may be an independent risk factor for CKD. Young subjects with migraine, and those with comorbid conditions or without medical control, are likely to be at higher risk for CKD. Ageing, male sex and NSAIDs tend to have an association with CKD in subjects with migraine.

Download Full-text

Effects of Climate on the Variation in Abundance of Three Tick Species in Illinois

Journal of Medical Entomology ◽

10.1093/jme/tjab189 ◽

2021 ◽

Author(s):

E A Bacon ◽

H Kopsco ◽

P Gronemeyer ◽

N Mateus-Pinilla ◽

R L Smith

Keyword(s):

Tick Species ◽

Ixodes Scapularis ◽

Species Abundance ◽

Dermacentor Variabilis ◽

Amblyomma Americanum ◽

Differential Impact ◽

Tick Abundance ◽

Network Analyses ◽

Average Temperature ◽

Tick Borne Disease

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.

Download Full-text

Long-Term Study of Borrelia and Babesia Species Distribution in Ixodes Ricinus and Dermacentor Recticulatus Ticks Removed From Humans in Poland, 2016-2019

10.21203/rs.3.rs-150028/v1 ◽

2021 ◽

Author(s):

Renata Welc-Falęciak ◽

Małgorzata Bednarska ◽

Adrianna Hamera ◽

Emilia Religa ◽

Milena Poryszewka ◽

...

Keyword(s):

Disease Risk ◽

Babesia Species ◽

Term Study ◽

Important Indicator ◽

Long Term Study ◽

Questing Ticks ◽

Tick Borne Disease ◽

Larger Sample ◽

Better Than

Abstract Monitoring changes in the prevalence of different Borrelia genospecies/ species in ticks might be an important indicator of risk assessment and of differences in pathogenicity in humans. Furthermore, the evaluation of pathogens in feeding ticks represents the risk of human exposure better than studies on questing ticks. The objective of our study was to assess the prevalence and distribution of Borrelia and Babesia species in ticks removed from humans, in a larger sample collected for several months during four years of studies. We confirmed high Borrelia prevalence, including B. miyamotoi, in ticks removed from humans as well as the shift in Borrelia genospecies/ species frequency of occurrence during the four-year study. Despite the fact that Babesia prevalence was relatively low, the majority of tested isolates are considered to be pathogenic for humans. The results of our study have also shown that Borrelia and Babesia coinfections in ticks are more common in Borrelia-infected ticks. Even if the overall risk of developing Lyme borreliosis after a tick bite in Europe is rather low, the knowledge of prevalence and distribution of Borrelia and Babesia species in ticks might be an important indicator of both tick-borne disease risk and pathogenicity assessment.

Download Full-text

Disaster displacement and zoonotic disease dynamics: The impact of structural and chronic drivers in Sindh, Pakistan

PLOS Global Public Health ◽

10.1371/journal.pgph.0000068 ◽

2021 ◽

Vol 1 (12) ◽

pp. e0000068

Author(s):

Dorien H. Braam ◽

Rafiq Chandio ◽

Freya L. Jephcott ◽

Alex Tasker ◽

James L. N. Wood

Keyword(s):

Rural Communities ◽

Disease Transmission ◽

Disease Risk ◽

Animal Health ◽

Forced Migration ◽

Zoonotic Disease ◽

Transmission Risk ◽

Disease Dynamics ◽

Displaced Populations ◽

The Impact

Projected increases in human and animal displacement driven by climate change, disasters and related environmental degradation will have significant implications to global health. Pathways for infectious disease transmission including zoonoses, diseases transmitted between animals and humans, are complex and non-linear. While forced migration is considered an important driver for the spread of zoonoses, actual disease dynamics remain under researched. This paper presents the findings of a case study investigating how disaster displacement affected zoonotic disease transmission risk following the 2010 ‘superfloods’ in Sindh province, Pakistan. We interviewed 30 key informants and 17 household members across 6 rural communities between March and November 2019, supported by observational studies and a review of secondary data. Results were analysed using the ecosocial theoretical framework. Buffalo, cattle and goats were often the only moveable asset, therefore livestock was an important consideration in determining displacement modality and destination location, and crowded locations were avoided to protect human and animal health. Meanwhile however, livestock was rarely included in the humanitarian response, resulting in communities and households fragmenting according to the availability of livestock provisions. We found that rather than a driver for disease, displacement acted as a process affecting community, household and individual zoonotic disease risk dynamics, based on available resources and social networks before, during and after displacement, rooted in the historical, political and socio-economic context. We conclude that in rural Sindh, disaster displaced populations’ risk of zoonoses is the result of changes in dynamics rooted in pre-existing structural and chronic inequalities, making people more or less vulnerable to disease through multiple interlinked pathways. Our findings have implications for policy makers and humanitarian responders assisting displaced populations dependent on livestock, with a call to integrate livestock support in humanitarian policies and responses for health, survival and recovery.

Download Full-text

Ticks and tick-borne pathogens in popular recreational areas in Tallinn, Estonia: an underestimated risk of tick-borne diseases

10.21203/rs.3.rs-543083/v1 ◽

2021 ◽

Author(s):

Maria Vikentjeva ◽

Olga Bragina ◽

Julia Geller

Keyword(s):

Lyme Borreliosis ◽

Tick Species ◽

Well Being ◽

Natural Environments ◽

Tick Abundance ◽

Outdoor Sports ◽

Tick Borne Encephalitis ◽

Morphological Criteria ◽

Green Areas ◽

Tick Borne Disease

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.

Download Full-text

Experimental Evidence for Opposing Effects of High Deer Density on Tick-Borne Disease Prevalence and Hazard

10.21203/rs.3.rs-190503/v1 ◽

2021 ◽

Author(s):

Sara Louise Gandy ◽

Elizabeth Kilbride ◽

Roman Biek ◽

Caroline Millins ◽

Lucy Gilbert

Keyword(s):

Lyme Disease ◽

Disease Risk ◽

Dilution Effect ◽

Exclosure Experiment ◽

Deer Density ◽

Pathogen Prevalence ◽

Tick Reproduction ◽

Tick Borne Disease ◽

Vector Borne ◽

Opposing Effects

Abstract Identifying the mechanisms driving disease risk is challenging for multi-host pathogens, such as Borrelia. burgdorferi s.l., the tick-borne bacteria causing Lyme disease. Deer are tick reproduction hosts but do not transmit B. burgdorferi s.l., resulting in potentially opposing effects on transmission. Here, we use a deer exclosure experiment to test three hypotheses for how high deer density shapes B. burgdorferi s.l. prevalence in ticks: (H1) high transmission on rodents due to higher tick densities; alternatively, (H2) low B. burgdorferi s.l. prevalence because more ticks feed on deer rather than transmission-competent rodents (dilution effect); (H3) ecological cascades, whereby lower vegetation decreases rodent abundance thus reducing transmission. Although we found support for all three mechanisms, prevalence was reduced almost 3-fold in high deer density plots compared to exclosures, suggesting that the dilution (H2) and cascade (H3) mechanisms outweighed the increased opportunities for transmission (H1). High deer density led to lower vegetation and fewer rodents, providing evidence for an ecological cascade. However, Lyme disease hazard (density of infected ticks) was increased 5-fold at high deer densities due to an 18-fold rise in tick density. This demonstrates that reproduction hosts like deer can drive up vector-borne disease hazard at high densities, despite simultaneously reducing pathogen prevalence.

Download Full-text

Evaluation of NEON Data to Model Spatio-Temporal Tick Dynamics in Florida

Insects ◽

10.3390/insects10100321 ◽

2019 ◽

Vol 10 (10) ◽

pp. 321 ◽

Cited By ~ 1

Author(s):

Geraldine Klarenberg ◽

Samantha M. Wisely

Keyword(s):

Detection Probability ◽

Disease Risk ◽

Spatial And Temporal Variation ◽

Spatial And Temporal Variability ◽

Ecological Data ◽

Public Health Perspective ◽

Spatial And Temporal Scales ◽

Tick Abundance ◽

The Us

In 2013, the National Ecological Observatory Network (NEON) started collecting 30-year multi-faceted ecological data at various spatial and temporal scales across the US including ticks. Understanding the abundance and dynamics of disease vectors under changing environmental conditions in the long-term is important to societies, but sustained long-term collection efforts are sparse. Using hard-bodied tick data collected by NEON, the vegetation and atmospheric data and a statistical state-space model, which included a detection probability component, this study estimated the abundance of tick nymphs and adult ticks across a Florida NEON location. It took into account the spatial and temporal variation, and factors affecting detection. Its purpose was to test the applicability of data collected thus far and evaluate tick abundance. The study found an increase in tick abundance at this Florida location, and was able to explain spatial and temporal variability in abundance and detection. This approach shows the potential of NEON data. The NEON data collection is unique in scale, and promises to be of great value to understand tick and disease dynamics across the US. From a public health perspective, the detection probability of vectors can be interpreted as the probability of encountering that vector, making these types of analyses useful for estimating disease risk.

Download Full-text

Simulation of leaf curl disease dynamics in chili for strategic management options

Scientific Reports ◽

10.1038/s41598-020-79937-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Buddhadeb Roy ◽

Shailja Dubey ◽

Amalendu Ghosh ◽

Shalu Misra Shukla ◽

Bikash Mandal ◽

...

Keyword(s):

Disease Risk ◽

Virus Transmission ◽

Host Population ◽

High Rate ◽

Disease Dynamics ◽

Model Framework ◽

Management Options ◽

Transmission Parameters ◽

Vector Population ◽

Leaf Curl

AbstractLeaf curl, a whitefly-borne begomovirus disease, is the cause of frequent epidemic in chili. In the present study, transmission parameters involved in tripartite interaction are estimated to simulate disease dynamics in a population dynamics model framework. Epidemic is characterized by a rapid conversion rate of healthy host population into infectious type. Infection rate as basic reproduction number, R0 = 13.54, has indicated a high rate of virus transmission. Equilibrium population of infectious host and viruliferous vector are observed to be sensitive to the immigration parameter. A small increase in immigration rate of viruliferous vector increased the population of both infectious host and viruliferous vector. Migrant viruliferous vectors, acquisition, and transmission rates as major parameters in the model indicate leaf curl epidemic is predominantly a vector -mediated process. Based on underlying principles of temperature influence on vector population abundance and transmission parameters, spatio-temporal pattern of disease risk predicted is noted to correspond with leaf curl distribution pattern in India. Temperature in the range of 15–35 °C plays an important role in epidemic as both vector population and virus transmission are influenced by temperature. Assessment of leaf curl dynamics would be a useful guide to crop planning and evolution of efficient management strategies.

Download Full-text