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Ixodes scapularis transmits a group of pathogens, including Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, the causative agents for Lyme disease, babesiosis, and anaplasmosis, respectively. I. scapularis ticks submitted by state residents to the Connecticut Agricultural Experiment Station-Tick Testing Laboratory between 2015 and 2018 were screened using standard PCR and pathogen-specific primers. Infection and coinfection prevalence in I. scapularis was estimated to assess differences in infection status by life stage (nymph or adult female), county, and year, as well as whether infection with B. burgdorferi changes the likelihood of infection with either B. microti or A. phagocytophilum. Of the 11,254 I. scapularis acquired in Connecticut, 40.7% tested positive for at least one pathogen and the remaining 59.3% were negative. Most I. scapularis ticks tested positive for a single pathogen (33.6%), and only 7.2% were infected with more than one pathogen, of which 93.2% were identified with dual infection and 6.8% tested positive for all three pathogens. Adults were more likely than nymphs to be infected or coinfected with these pathogens. Furthermore, we found that ticks were 74% more likely to be infected with B. microti and 98% more likely to be infected with A. phagocytophilum if infected with B. burgdorferi compared with those not infected. We did not find spatial differences in infection or coinfection prevalence, but between 2015 and 2018, the likelihood that a tick was coinfected increased with time. These results from Connecticut, an endemic state for Lyme disease with long-established populations of I. scapularis, suggest that the increased likelihood of coinfection prevalence over time may have significant implications for clinical diagnosis, course, severity, and treatment of human disease cases. [ABSTRACT FROM AUTHOR]

Ixodes scapularis is currently known to transmit 7 pathogens responsible for Lyme disease, anaplasmosis, babesiosis, tick-borne relapsing fever, ehrlichiosis, and Powassan encephalitis. Ixodes scapularis can also be colonized by endosymbiotic bacteria including those in the genus of Rickettsia. We screened 459 I. scapularis ticks submitted to the Connecticut Agricultural Experiment Station Tick Testing Laboratory with the objectives to (1) examine differences in infection prevalence of Borrelia burgdorferi, Anaplasma phagocytophilum, Babesia microti, and Borrelia miyamotoi, (2) evaluate whether prevalence of co-infections occur at the same frequency that would be expected based on single infection, and (3) determine the presence of rickettsial endosymbionts in I. scapularis. The prevalence of infection in I. scapularis was highest with Bo. burgdorferi sensu lato (nymph = 45.8%; female = 47.0%), followed by A. phagocytophilum (nymph =4.0%; female = 6.9%), Ba. microti (nymph = 5.7%; female = 4.7%), and Bo. miyamotoi (nymph = 0%; female = 7.3%). We also identified rickettsial endosymbionts in 93.3% of I. scapularis. Nymphs were significantly more likely to be infected with Bo. burgdorferi if they were infected with Ba. microti, whereas adult females were significantly more likely to be infected with Bo. burgdorferi if they were infected with A. phagocytophilum. Our study suggests that the infection prevalence of Bo. burgdorferi is not independent of other co-circulating pathogens and that there is a substantially higher infection of Bo. miyamotoi in I. scapularis females compared with nymphs in this study. High prevalence of infection and co-infection with multiple pathogens in I. scapularis highlights the public health consequences in Connecticut, a state endemic for Lyme and other tick-borne diseases. [ABSTRACT FROM AUTHOR]

Lyme disease is the most prevalent vector-borne disease in the United States. Ixodes scapularis , commonly referred to as the blacklegged tick, is the primary vector of Lyme disease spirochetes, Borrelia burgdorferi sensu lato (s.l.), in the eastern United States. Connecticut has pervasive populations of I. scapularis and remains a hotspot for Lyme disease. A primary aim of this study was to determine if passively collected data on human-biting I. scapularis ticks in Connecticut could serve as a useful proxy for Lyme disease incidence based on the cases reported by the Connecticut Department of Public Health (CDPH). Data for human-biting I. scapularis ticks submitted to the Tick Testing Laboratory at the Connecticut Agricultural Experiment Station (CAES-TTL), and tested for infection with B. burgdorferi s.l., were used to estimate the rate of submitted nymphs, nymphal infection prevalence, and the rate of submitted infected nymphs. We assessed spatiotemporal patterns in tick-based measures and Lyme disease incidence with generalized linear and spatial models. In conjunction with land cover and household income data, we used generalized linear mixed effects models to examine the association between tick-based risk estimates and Lyme disease incidence. Between 2007 and 2017, the CAES-TTL received 26,116 I. scapularis tick submissions and the CDPH reported 23,423 Lyme disease cases. The rate of submitted nymphs, nymphal infection prevalence, the rate of submitted infected nymphs, and Lyme disease incidence all decreased over time during this eleven-year period. The rate of submitted nymphs, the rate of submitted infected nymphs, and Lyme disease incidence were spatially correlated, but nymphal infection prevalence was not. Using a mixed modeling approach to predict Lyme disease incidence and account for spatiotemporal structuring of the data, we found the best fitting tested model included a strong, positive association with the rate of submitted infected nymphs and a negative association with the percent of developed land for each county. We show that within counties, submissions of B. burgdorferi s.l. infected nymphs were strongly and positively associated with inter-annual variation in reported Lyme disease cases. Tick-based passive surveillance programs may be useful in providing independent measures of entomological risk, particularly in settings where Lyme disease case reporting practices change substantially over time. [ABSTRACT FROM AUTHOR]

Most tickborne disease studies in the United States are conducted in low-intensity residential development and forested areas, leaving much unknown about urban infection risks. To understand Lyme disease risk in New York, New York, USA, we conducted tick surveys in 24 parks throughout all 5 boroughs and assessed how park connectivity and landscape composition contribute to Ixodes scapularis tick nymphal densities and Borrelia burgdorferi infection. We used circuit theory models to determine how parks differentially maintain landscape connectivity for white-tailed deer, the reproductive host for I. scapularis ticks. We found forested parks with vegetated buffers and increased connectivity had higher nymph densities, and the degree of park connectivity strongly determined B. burgdorferi nymphal infection prevalence. Our study challenges the perspective that tickborne disease risk is restricted to suburban and natural settings and emphasizes the need to understand how green space design affects vector and host communities in areas of emerging urban tickborne disease. [ABSTRACT FROM AUTHOR]

Tick-borne diseases continue to threaten human health across the United States. Both active and passive tick surveillance can complement human case surveillance, providing spatio-temporal information on when and where humans are at risk for encounters with ticks and tick-borne pathogens. However, little work has been done to assess the concordance of the acarological risk metrics from each surveillance method. We used data on Ixodes scapularis and its associated human pathogens from Connecticut (2019–2021) collected through active collections (drag sampling) or passive submissions from the public to compare county estimates of tick and pathogen presence, infection prevalence, and tick abundance by life stage. Between the surveillance strategies, we found complete agreement in estimates of tick and pathogen presence, high concordance in infection prevalence estimates for Anaplasma phagocytophilum, Borrelia burgdorferi sensu stricto , and Babesia microti , but no consistent relationships between actively and passively derived estimates of tick abundance or abundance of infected ticks by life stage. We also compared nymphal metrics (i.e., pathogen prevalence in nymphs, nymphal abundance, and abundance of infected nymphs) with reported incidence of Lyme disease, anaplasmosis, and babesiosis, but did not find any consistent relationships with any of these metrics. The small spatial and temporal scale for which we had consistently collected active and passive data limited our ability to find significant relationships. Findings are likely to differ if examined across a broader spatial or temporal coverage with greater variation in acarological and epidemiological outcomes. Our results indicate similar outcomes between some actively and passively derived tick surveillance metrics (tick and pathogen presence, pathogen prevalence), but comparisons were variable for abundance estimates. [ABSTRACT FROM AUTHOR]

Pathogens transmitted by ticks are the leading cause of arthropod-associated human diseases in the United States and managing the risk of exposure to potentially infected ticks is of vital public health importance. A 3-year integrated tick management program to control blacklegged ticks, Ixodes scapularis, the primary vector for the pathogenic agents of Lyme disease, human anaplasmosis, and babesiosis, was implemented in the town of Redding in southwestern Connecticut beginning in 2013. Combinations of white-tailed deer, Odocoileus virginianus, reduction, area application of the entomopathogenic fungus Metarhizium anisopliae, and fipronil-based rodent bait boxes were evaluated for their ability to reduce nymphal I. scapularis over 3 years. Interference from local hunters prevented sufficient, sustained deer removal previously reported to negatively impact I. scapularis abundances ( i.e., <5 deer/km2). The combination of fipronil-based bait boxes and broadcast application of M. anisopliae had the most impact of any treatment combination; questing nymphs were reduced 78-95% within each year and Borrelia burgdorferi-infected questing nymphal I. scapularis encounter potential was reduced by 66% as compared with no treatment in the third year of the study. A combination of the broadcast application of M. anisopliae and small rodent-targeted fipronil-based bait boxes is an effective low-toxicity integrated approach that significantly reduced encounters with B. burgdorferi-infected questing nymphal I. scapularis on individual properties. [ABSTRACT FROM AUTHOR]

The increasing prevalence of Lyme disease and the emergence of other tick-associated human diseases in the United States have become a major public health concern. A wide variety of personal protection measures and tick control strategies have been used or investigated to reduce contact between ticks and humans, reduce tick abundance, or lower the prevalence of tick-borne agents in the ticks. These methods have generally been applied or evaluated as single interventions and other than some early computer model simulations, studies applying integrated tick management approaches are few. In this paper, we review surveyed human behaviors and risks for exposure to ticks, concepts pertinent to integrated pest management for ticks, simulation models, various tick control strategies, integrated tick management studies, and highlight what is needed going forward. Increased education and communication between physicians and veterinarians is essential to address tick-associated diseases in a ‘one health’ approach and unify the animal and human branches of medicine to identify, treat, and implement preventive measures. Novel simulation models using more recent empirical data on tick population dynamics, hosts, efficacy of various combinations of interventions, human exposure elements, and utilization of personal and environmental measures will help us better understand the interactions of integrated strategies for tick population management. Many questions remain related to the ecology of ticks and tick-borne pathogens, observed and modeled efficacy of various integrated interventions, human behavior and exposure to tick bite and disease risk, comparative cost of interventions, and the acceptance and use of prevention and tick control tools. [ABSTRACT FROM AUTHOR]

Morphological anomalies have been reported in the blacklegged tick, Ixodes scapularis (Acari: Ixodidae), from the northeastern and upper Midwestern United States, complicating identification of this important vector of human pathogens. Here, we report a case of a local morphological anomaly in I. scapularis , parasitizing a human living in Connecticut. We used a dichotomous morphological key, high-resolution and scanning electron microscopy images, as well as DNA sequencing for identification. The specimen was identified as an adult female I. scapularis with the left leg II split at the trochanter, resulting in two complete legs from the femur to pretarsus giving the appearance of five legs on the left side versus four on the right side. Here we discuss recent reports of morphological anomalies in I. scapularis , and highlight the need for further studies of teratology in this important tick species and its potential implications. [ABSTRACT FROM AUTHOR]

Cases of anomalous morphologies in the blacklegged tick, Ixodes scapularis , have been reported in both field-collected and human-biting specimen in the Northeastern and Midwestern United States, complicating the identification of this medically important tick species. We herein describe four cases of morphological anomalies in I. scapularis females exhibiting nanism and abnormally small genital apertures. We also report a female I. scapularis displaying slight asymmetry in the lower abdomen oriented toward the right side and an abnormal anal groove completely enclosing the anus. The identity of each specimen was confirmed using taxonomic keys, high resolution light and scanning electron microscopy imaging, and DNA sequencing of the 18S rRNA gene. All specimens described in this study were found parasitizing human hosts and were submitted to the Connecticut Agricultural Experiment Station-Tick Testing Laboratory in 2021 for species identification and pathogen screening. Here, we also discuss recent reports of teratological abnormalities in I. scapularis as well as likely causes for such deformities and potential implications. [ABSTRACT FROM AUTHOR]

Cases of morphological anomalies in the blacklegged tick, Ixodes scapularis (Acari: Ixodidae), have recently been reported from the Northeastern and upper Midwestern United States, potentially complicating identification of this important vector of human disease-causing pathogens. We hereby report a case of a morphological anomaly in I. scapularis , biting a human host residing in Norwich, Connecticut. Using a dichotomous morphological key, high-resolution and scanning electron microscopy images, as well as DNA sequencing, the tick was identified as an adult female I. scapularis with three legs on the left side of the abdomen versus four on the right side, which we believe is the first case of ectromely in an adult I. scapularis. Using diagnostic genes in polymerase chain reaction, the specimen tested positive for Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum , the causative agents for Lyme disease and anaplasmosis, respectively, and also showed evidence of a rickettsial endosymbiont. Here we discuss recent reports of morphological anomalies in I. scapularis , and emphasize the significance of additional studies of teratology in this important tick species and its potential implications. [ABSTRACT FROM AUTHOR]